Today we will study Definition, Construction or Main Parts, Working Principle, Advantages, Disadvantages, and Application [Notes and PDF] of Locomotive Boiler.
Download PDF at the end of the article.
As the name suggests it is mainly employed in the locomotives though it may be used as a stationary boiler. It is compact in construction and its stream production rate is very high.
Now coming to our main topic and which is Definition,
Table of Contents
Locomotive boiler Definition:
A locomotive boiler is a multi-tubular boiler and it has a horizontal drum axis. The circulation in the locomotive boiler is natural, also it is a medium pressure boiler, the draft is artificial, forced circulation, mobile, solid fuel fired fire tube boiler.
It is an external fire boiler and it has a large fire space. The locomotive boiler consists of a horizontal shell and this shell consists of a number of fire tubes.
The fuel is burned here and the flue gases which pass through the shell and on the other side there is a stake locomotive boiler. It does not have the chimney and they have stacks on the other side and flue gases are removed through the stake.
Locomotive Boiler Main Parts or Construction:
Locomotive Boiler Consists of following Main Parts:
Water Level Indicator
Flues or Tubes:
A large part of the locomotive boiler is composed of flues or tubes. The flues give to the boiler the largest part of its heating surface.tubes are made up of carbon molybdenum steel, 18-8 Cr Ni steel.
It is the flues that largely affect the life of the boiler and that why it is the life of the locomotive, for this reason, it is quite necessary to properly install and maintain them.
The grate is made up of a set of parallel bars at the bottom of the fire-box, which hold the fuel. it is made of cast iron and constructed in sections of 3-4 bars each.
They are supported at their ends by resting upon a frame and are connected by rods to a lever which can be moved back and forth to rack the bars and shake ashes and cinders out of the fire.
Ash pans are suspended beneath the fire-box for the purpose of catching and carrying the ashes. Coal that may drop between the grate bars is also corrected by ash pan. They are made of sheet steel.
A longitudinal section of an ash pan commonly used in fire-boxes placed between the axles of the engine. It is provided at each end with a damper a hinged at the top and which may be opened and set in any desired position in order to regulate the flow of air to the fire.
It is quite important that the dampers should be in good condition in order that the admission of air to the file may be regulated. The total unobstructed air openings in the ash pan need not exceed the total tube area.
It receives power for doing this work from the exhaust steam from the cylinders. The work which it performs consists of drawing air through the ash pan, grates, fire, fire door, and other openings, then continues its work by drawing the gases of combustion through the flues of the boiler into the front end.
Pressure must be maintained less than the atmosphere in the smoke-box. The difference in pressure between the atmosphere and the smoke-box is called a draft.
The diaphragm or deflector plate is an iron plate placed obliquely over a portion of the front end of the flues which deflects the flue gases downward before entering the stack, thus equalizing to a great extent the draft in the different flues.
This deflector plate may be adjusted to deflect the gases more or less as desired.
The stack is one of the most important features of the front end. Many different forms and proportions of stacks have been employed but at the present time, only two general types are found in use to any great extent, namely, the straight and tapered stacks.
The draft pipe employed to increase the draft and may be used singly or in multiple and raised or lowered as desired.
Smoke-Box and Front End Arrangement:
By the term front end is meant all that portion of the boiler beyond the front tube sheet and includes the cylindrical shell of the boiler and all the parts contained therein such as the steam or branch pipes, exhaust nozzle, netting, diaphragm, and draft
The universal practice at present is to use at least two safety valves of the pop type upon every locomotive boiler. On small locomotives where clearances will permit, the safety valves are placed in the dome cap.
On large locomotives where the available height of the dome is limited, the safety valves are usually placed on a separate turret. When limiting heights will not permit the use of turrets, the safety valves may be screwed directly into the roof of the boiler.
A brick arch is an arrangement placed in the fire-box to effect better combustion and to secure a more even distribution of the hot gases in their passage through the tubes.
A longitudinal section of the fire-box fitted with a brick arch and the method of action is very simple. It acts as a mixer of the products of combustion with the air and as a reflector of the radiant heat of the fire and the escaping gases.
It is maintained at a very high temperature and in this condition meets the air and gases as they come in contact with it and turns them back to the narrow opening. By this action, it maintains a sufficiently high temperature to burn with the smallest possible quantity of air.
Water level indicator:
The water level indicator is used to indicate the water level in the boiler and to maintain the water at a constant level because the production of steam majorly depends on the quantity of water.
In case the water level is below the normal level then water will be pumped from the reservoir by the operator.
Locomotive Boiler Working Principle:
The locomotive boiler consists of a cylindrical barrel with a rectangular box at one end and a smokebox at the other end. The coal is introduced through the fire hole in the great which is placed at the bottom of the firebox.
The hot gases which are generated due to burning of the coal are deflected by an arch of fire bricks, so that walls of the firebox may be heated properly.
The firebox is entirely surrounded by water except for the fire hole and the ash pit which is situated below the firebox which is fitted with dampers at its front and back ends.
The dampers control the flow of air to the great. Hot gases move from the firebox to smokebox through a series of fire tubes and through the chimney they are discharged into the atmosphere.
The fire tubes are placed inside the barrel. Some of these tubes are of larger diameter and the others of smaller diameter. Tubes of superheater are placed inside the fire tubes of larger diameter.
The heating value of the hot gases is transmitted into the water by heating the surface of the fire tubes. The steam generated is collected over the water surface. Dome-shaped chamber known as the steam dome is fitted on the upper part of the barrel, from where the stream flows through a steam pipe into the chamber.
It passes through the superheater tubes and returns to the superheated steam chamber from which it is led to the cylinder through the pipes, one to each cylinder.
The boiler itself is moving with a very high velocity with 60 kilometres per hour to 70 kilometres per hour.
So there is always a movement of air over this stake and if you use Bernoulli’s theorem you can find a temperature drop and there is a substantial pressure drop between this grate. The movement of the fluid pressure drop takes place so the chimney is not required in such boilers.
Advantages of Locomotive Boiler:
The following advantages of Locomotive Boiler are:
High steam capacity
Low cost of construction
Portability is easy.
Low installation cost
Compact in design.
Disadvantages of Locomotive Boiler:
The following disadvantages of Locomotive Boiler are:
Chances of corrosion and scale formation
Difficult to clean some parts
Need bracing for large parts
It cannot carry overloads that create overheating and damage.
Application of Locomotive Boiler:
The locomotive boiler is used at various place some of their application are:
Stationery power services.
Here we studied Locomotive Boiler in detail. If you want to read other different types of boiler just search it. Till than if this article help you please share to your friends and family. Thank you for reading.
In this article, we will study in detail Definition, Types, Application [Notes with PDF] of Screwdriver.
Note: At the end you can download PDF of this articles.
Lets start with the definition first,
The screwdriver is a tooling agent that can be manual or power and it is used for screwing and unscrewing screws. Its shaft is made up of tough steel to resist twisting and bending.
A simple screwdriver consists of a handle and a shaft, that ends with a tip and for the user, it puts into the screw head before turning the handle. A simple form of the screwdriver has been replaced in many workplaces and homes with a more modern and versatile tool, a Power Drill because they are quicker easier and can drill holes too.
Now we are going to study different types of screwdriver in very detail,
Flat Head (or Slotted Head) Screwdriver
Hex Screwdriver or Hexagon Screwdriver
Robertson or Square Screwdriver
Clutch Head or Bow Tie Screwdriver
Frearson or Reed and Prince Screwdriver
Hex Socket or hex screw drive
JIS (Japanese Industrial Standard)
Right Angle Screwdriver
Flat Head or Slotted Head Screwdriver:
A flat-head screwdriver has a wedge-shaped flat tip that is used to tighten or loosen screws that have a straight and linear notch on their heads. This is arguably the most common tool on the mechanical field and the ubiquitous flat-head screwdriver.
This comes in every shape with a handle attached to a steel shaft that is flattened into a wedge shape at the tip. While flat head screws aren’t used extensively in residential construction anymore, it can still find them in furniture construction, small cabinetmaking projects, and on some electrical applications.
It is installed with plate covers on outlets and switches and also where it’s not to over-tighten a screw.
These screwdriver bits are used for ratcheting screwdrivers and drills, it is labeled by both the size of the tip and the length of the steel shank. Tip sizes vary, from fractions of millimeters (which are tiny enough to tighten eyeglass screws) up to an inch or larger (fit for industrial size screws).
Phillips screws, identifiable by a plus on their heads, are widely used for construction and woodworking purposes. It is also the crosshead screwdriver when the X-shape blade fits into the head cavity snugly so it provides better traction when tightening or loosening the screw. It is used with power tools originally, electronics standards are also set.
A screwdriver manually works fine when it has just one or two screws to install, but construction projects use a number of screws notoriously. Option for a power drill with interchangeable Phillips bits for the most efficient build.
Best For Multipurpose building and remodeling, especially drywall installation. This screwdriver with power corded is designed to install Phillips drywall screws specifically.
In Philips screwdriver pre-set the screw depth takes place and eliminates chances of under- or over-inserting a drywall screw. We can fit the screwdriver deeper into the screw head and there is no blade sliding out sideways. These drivers are intentionally designed to slip out of the head when a certain torque limit is exceeded, which depends upon strength and weakness.
Torx screw is the favorite of builders and serious DIYers and it is sometimes called the star screw. It has a 6-point recessed star tip in sizes that range from 0.031” to 0.81” and are designated by T numbers (from T1 to T100).
Most common sizes are T15 and T25, and it is fitted on every size available. Power drill users like Torx screws for the same reason they like Robertson screws because they resist slippage with power application.
Torx screws are commonly used for structural framing, finish work, and even as wood-to-concrete fasteners. It features magnetic bits that assist in keeping the screws in place on the drill tip.
Hex Screwdriver or Hexagon Screwdriver:
Screwdrivers and bits come in size to fit the hex-head screw recesses from around 0.03” to 3/8”. Hex-head screws are small in size and commonly found in doorknobs, towel bars, and in some mechanical installations. The designs consist of a tapered square-tipped screwdriver that fits into a matching square recess in the screw head.
It requires a hex key screwdriver also known as an Allen screwdriver to tighten or loosen. Allen-type screwdrivers are L- or T-shaped screwdrivers, also Allen bits are come for ratcheting screwdrivers and drills.
For example, Installing small fixtures such as towel bars. It pays to have a variety of tip sizes available in the market. Allen Hex Screwdriver Xcelite’s 11-piece set has interchangeable Allen bits in sizes ranging from 0.050”- 3/16” also it has an optional extension bar for restricted spots. It is the fastening system that would provide a firmer hold and less slippage than conventional slotted screws and screwdrivers.
Robertson or Square Screwdriver:
This is the least common of the common screwdrivers and has perhaps the highest torque tolerance of all drive types. Squarehead screws are commonly found in the automotive and furniture industries because of their durability.
Cushion grip is provided for better handling and skips the slippage and quick driver size identification. It has a precision machine tip for exact fit. It has an integral flange inside handle provides a better solid twist-resistant blade anchor.
Pozidriv also is known as “Pozidrive”. It is an improved variation of Phillips drive design. The company GKN Screws and Fasteners created the Pozidriv design after the patent for the Phillips’s head expired. The Pozidriv drive style was originally formed to solve the issue come in Phillips screwdrivers that are prone to cam-out. The slipping out of a drive recess that occurs when torque exceeds a certain limit is called cam-out.
The Pozidriv drive has the same design as a Phillips drive style of self-centering. Increased torque without cam-out and Greater surface contact engagement between the drive and the recess in the fastener head making it harder to slip are the main features.
Pozidriv screws can be used like Phillips screws but easily available. This drive is still extremely popular in manufacturing due to its self-centering design. It provides a balance of strength and efficiency also its handle designed for faster rotation in low-torque applications, for a comfortable grip and higher performance. The screwdrivers are packaged that can easily be stored in a tool chest for storage.
Clutch Head or Bow Tie Screwdriver:
Clutch head screws have got design changes from the last few years. The slots resemble a bow-tie, with the older version having a circular recess in the middle. They have the application in the automotive industry as they are popular in recreational vehicles.
A clutch head screwdriver will have better torque with these heads and are designed with slotted drives a security version of a clutch screwdriver that can be screwed one way with a slotted screwdriver. It cannot be easily removed.
These are found mostly in places where maintenance is infrequent, such as bus stations or prisons. Helical-cut steel, heat-treated steel gears for long life.
Frearson or Reed and Prince Screwdriver:
At first glance, this variation of the screwdriver is the same as Phillips but has some important differences. The tip of a Frearson comes to a sharp point, as compared to the Phillips has a rounded point. the angle of the tip is closer to a 45-degree angle than on a Phillips.
The Frearson screwdriver due to its shape allows for higher torque than a Phillips and the ability to carry just one drive. Its main applications are in nautical equipment where precision and a smaller set of tools are required. Frearson (Reed and Prince) screwdriver bits from Cooper Tools.
It avoids typical problems such as shattering and premature bit wear. In the power tool, applications insert bits are commonly used with a bit holder. This combination is economical, provides flexibility, and allows a fastener to be magnetically held by the bit. It is placed directly into the power tool chuck.
Acetate handle is impact and chemical resistant. Serrated tip for maximum grip and reduced slippage. Blades are forged from high strength alloy steel Ergonomic acetate handle is impervious to most solvents and chemicals. Size identification stamped in the base of the handle Color-coded handle for easy tip identification. It Meets ANSI specifications.
Hex Socket or Hex screw drive:
Socket drivers can be very useful in mechanical industries. Socket drivers have a socket instead of a blade and tip, thus it acts as a socket wrench. The advantage of using a hex socket is when the moment we try to reach the recessed bolt.
Socket wrenches have a handle that runs parallel to the surface in which the bolt is embedded, requiring additional space to turn. The straight shank and handle of a hex socket mean that you can turn such bolts with very little clearance. It is applicable for low torque applications but used with normal ratchet plus socket combo for maximum applications.
The hex socket screw drive has a hexagonal recess and driven by an Allen key, hex key, or hex screwdriver. A hex screwdriver features a hexagonal tip for driving certain nuts, bolts, and screws. Hex screwdrivers are available in an extensive range of both standard and metric sizes. These screwdrivers can make the process of loosening and tightening hex nuts, bolts, and screws much easier. Hex nuts, bolts, and screws can be made out of many metals, such as aluminum, brass, copper, and any grade of steel.
JIS (Japanese Industrial Standard):
JIS (Japanese Industrial Standard)is one of the most recognized types and probably the most commonly used driver in your toolbox for fastening cross-point screws. It has no “cam-outs” and damage screws on Japanese brand products.
Its main advantage over the Phillips screwdrivers was that the self-centering design allowed operators to engage the tip of the driver into the screw head very quickly and easily. The Japanese industrial Standard has the self-centering and quick tool and screw engagement. It allowed torque and over-tightening to be controlled by the operator and not at the head of the screw.
Hitachi is renowned all over the world for the quality of its electronic and electro-mechanical products. Therefore, it did not come across as a surprise when their DB3DL2 cordless screwdriver kit surpassed my expectations.
Powered by a 1.5Ah battery, the tool easily completed all jobs I threw at it. The manufacturers have included two battery packs, ensuring that the user could keep on doing his job with one battery while charging the other. The dual position handle was one of the primary factors that led me to purchase this device. Let us dive in and see how this beauty performs. This tool is ideal for hobbyists, DIY enthusiasts, computer repair specialists, electricians, appliance repair personnel, as well as professionals.
Its lightweight along with its powerful LED light ensures that one can use it for tasks that are beyond the reach of other similar devices. For example, you can use it to remove and fix screws in computers without disassembling it.
It is the perfect tool when you need to lie beneath an object and there is hardly enough space between the floor and the working area. While this tool is not ideal for major driving or drilling, it is perfect for general light screw driving tasks. The torque is great even at the lowest setting and works fine up to the last few seconds of battery life, a feature that other similar devices cannot boast of.
Magnetic-tipped screwdrivers have a large application that is handy and make the screwing application very easier as magnetic bits attract and hold small screws and come comes with 2 double-ended bits Sizes 5/32 in., 1/8 in., 0PT, 1PT.
It is applicable in small electronics industries when trying to place screws in hard-to-reach locations. Its use is easy because they stick to your screwdriver. You can magnetize your existing screwdriver using a rare earth magnet instead of buying new sets of magnetic tipped screwdrivers.
Ratcheting screwdrivers reduce the lift as well as save time. It repositions the screwdriver tip after every turn. Ratcheting screwdrivers have an internal ball-bearing mechanism that allows the user to make multiple turns of the screw with an easy back-and-forth wrist action.
By switching a button on the screwdriver the ratcheting action can be changed from one direction to the others so that it is applicable to insert screws like clockwise directional motion and remove screws by the counter-clockwise direction of motion.
Yankee screwdriver operates on a spring-loaded ratcheting principle that has a specific ratcheting screwdriver mechanism. The tip of a Yankee screwdriver in the screw head and pushes firmly toward the screw Instead of using wrist action to turn the screwdriver. The pressure causes the screwdriver shank to turn and the tension spring inside pushes the handle back to make it to the starting position.
Right Angle Screwdriver
They are designed to turn at right angles.
The 8 pieces right-angle screwdriver is designed to get into areas with only 1 in. of clearance. The convenient ratcheting mechanism provides ample torque for tightening and loosening hardware. The screwdrivers come with 7 hex bits. Designed to get into hard-to-reach areas – requires only 1 in. of clearance! Includes 7 hex bits: PH1, PH2, PH3, 3/16 in., 1/4 in., T15, and T20 Convenient ratcheting mechanism.
It has forged steel handle and precision tips that can be inserted anywhere even in the narrow locations. Tips are precision formed to fit the fastener and Shaft is forged from high strength alloy steel. It meets ANSI specifications and has 90-degree offset bits that enable the user to get around obstructions Includes 4 different bit sizes.
It is used at several place like:
Manufacture of furniture, electronics, carpentry, and jewelry.
Square Recess typically used in the manufacture of furniture due to the efficiency of the drive.
Torx typically used in the electronics and automotive industries.
Hex typically used in the manufacture of furniture.
Some electronics manufacturers use this drive to prevent users from tampering with their products.
Spanner typically used with electronics, restroom doors, and elevators.
So here we have studied all the different types of screwdriver in detail. Do share this article with your friends and family.
In this article, we will study Definition, Types, Working Principle, Advantages, Disadvantages, and Application [Notes with PDF] of Cam and Follower.
Note: You can download PDF of this article at the end.
Let’s start with the definition of Cam,
Table of Contents
What is Cam?
When the two links are connected either along a line or at a point, it is called a higher pair. Two such higher pair mechanisms will be included in a cam-follower system. A higher pair mechanism is known as cam and follower.
For the smooth functioning of a cam- follower mechanism, it is imperative that the follower should move smoothly without requiring too much input power, which means the follower should not jam, during its movement.
In an IC engine the valves have to be kept open; first, then close it and keep it closed, all these timing operations can be easily set by having cam-follower mechanisms. In the case of linkages, we study about planar linkages or two- dimensional linkages and more.
Now moving to different types of Cam,
Types of CAM:
Disc or Plate Cam
Disc or Plate Cam:
A disc or plate cam is a type of cams in which follower moves radially from the center of rotation of the cam. These cams are very popular due to their simple design and compactness that can be fitted into remote places. The application of Disc or Plate Cam is in I.C engines and machine tools.
A Cylindrical cam is the cam in which the cylinder rotates about its axis has a circumferential contour cut on the cylinder surface. They are also of two types in the first types a groove is cut on the surface of the cam and the roller and has a positive oscillating motion. Another one is having a cylinder as the working surface. In this type of cam spring-loaded follower translates along the parallel axis to the rotating cylinder.
Translating cam is the type of cam in which cam can move in a horizontal plane. The follower attached too, it has the motion constrained with the help of the spring. Some times groove cams are used in which the follower motion is achieved without the use of the spring.
If the input link also called cam rotates as angular motion, then cam has rotational or angular motion and then we call it a radial cam.
This profiled body is called the cam. This has a revolute pair with the fixed link that is the foundation or fixed link. Cam is the revoluting link. There is a revolute pair between fixed link and the cam and the output link is the follower. If this cam rotates depending on the profile or shape of the cam, the follower will have translatory motion along with this prismatic pair between fixed link and the follower.
So uniform rotary motion of this cam will have oscillation of the follower along with the guide.
If the cam has a linear motion, then we call it a wedge cam. Wedge cam has a four-link mechanism, first is the fixed link, the cam which looks like a wedge is the other link. It depends on the profile of this wedge, as this cam oscillates in the horizontal direction, the follower will oscillate along the vertical direction along with this prismatic pair or this guide.
Now we are moving to follower,
What is a Follower?
A follower is a translating or oscillating mechanical member that follows the motion of the cam. It can touch the surface profile of the cam or can be spring-loaded. It can have the uniform velocity or can have uniform acceleration motion. Complicated output motion can be achieved with the help of the follower motion.
Types of Follower:
Oscillating or Rotating follower
Translating or Reciprocating follower
Knife Edge Follower
Flat Faced or Mushroom Follower
Spherical faced Follower
If the follower has linear motion, then we call it as a translating follower. Now for the translating follower, that is the axis of that prismatic pair passes through the cam centre, then we call it radially translating. We call it a radial translating follower when the follower axis passes through the centre of the camshaft. If it has a little offset, that means the axis of the translation of the follower does not pass through the cam centre, then we call it as an offset translating follower.
The cam rotates as before but this is the follower due to the shape of the cam, the follower undergoes an oscillatory motion and the follower is hinged at this point. So, this is called an oscillating follower.
If the follower has just a knife-edge with the cam then we call it a knife-edge follower. the knife-edge is only theoretical because knife-edge follower is never used because of the very high wear rate. Contact-stress will be extremely high
The follower is hinged to a roller and this roller is in contact with the cam, this is called roller follower. This is the cam that rotates and the follower which is hinged here oscillates. it is used when a large force has to be transmitted like in stationary IC engines. If there is not enough space to use a large roller because this pin has to be sufficiently big to transmit the force between the cam and the follower and the roller has to be bigger than the pin at least twice as big as the pin, then the roller needs a lot of space.
Flat face follower:
The follower surface which is in contact with the cam is in the form of a flat surface is called flat face follower. The follower surface, instead of flat, can be also a curved surface. This is the cam that rotates and the follower which is hinged here oscillates, so this is called curved-face. If space is restricted then we can use flat face follower, if the force involved is not too large as we used in the case of automobiles.
Cam and Follower Nomenclature or Terminology:
Tracepoint is a point on the follower, which describes the follower movement. For roller follower, it is the centre of the roller. So the tracepoint is the roller centre, which means the movement of the follower will be described in terms of the motion of this roller centre.
If it is a flat face follower, then tracepoint we use is the point on the follower’s face which is in contact with the cam surface when the follower is at one of the extreme positions, we normally use that extreme position when the follower is closest to the cam center.
Base circle is the smallest circle that can be drawn with the cam centre as the centre and touching the cam profile, this circle we call as a base circle. So the radius of the base circle we call, Rb, that is called base circle radius.
To define the pitch curve, think of kinematic inversion. In the kinematic inversion, this is a four-link mechanism, fixed link, cam, roller, and follower.
In this four-link mechanism, this link is fixed, but in the kinematic chain, if we make a kinematic inversion holding cam fixed. the locus of the center of the roller will generate a curve which is parallel to the cam profile.
This is the locus of the tracepoint or roller center, after kinematic inversion with cam fixed.
The smallest circle that can be drawn with the cam center as the center and tangential to the pitch curve. This circle has a centre at the cam-shaft axis and tangential to the pitch curve. This circle is called the prime circle. If base circle radius is Rb and Rr is roller radius, then the prime circle radius is Rp = Rb + Rr.
The common normal between the roller and the cam is passing through the roller center and normal to the cam profile.
If we neglect the friction, the force that the cam exerts on the rollers is along this common normal. So this is the direction of the force between the cam and the roller in the absence of friction. But in the vertical direction, pushing the roller along this direction, so this angle should not be too large. So the angle between these two directions between the normal contact force and the direction of the follower movement is called pressure angle. This angle is denoted by φ. Obviously, for the smooth movement of the follower, the φmax should be less than the maximum value φ allowable. The φ will keep on changing depending on the cam profile and normally for a translating roller follower φmax should be less than 30. The pressure angle should be low while overcoming the spring force and this positive offset ensures that the pressure angle reduces during the motion. It compresses the spring and increases the force while the follower is coming down.
Cam and Follower Working Principle:
A normal force acts in the X direction and a normal force acts in the Y direction and these two normal forces balance the cocking moment, the moment due to this force Fn.
The friction force which will try to oppose this vertical motion will be μ times the normal force. Normal force as N, then this will be μN. During upward motion, the follower has to overcome not only these two friction forces, but it also has to overcome the spring force.
Large Fn is necessary to overcome the friction force and the vertical component of the Fn will overcome these two friction forces and the spring force, whereas during the downward movement the spring force is helping the follower to come down, so the contact force will be less.
The vertical component will be Fn cos φ, if the φ is very large then this vertical component will be reduced. As a result, during the upward movement, the pressure angle should be low and during the return movement, φ can be large, so φmax is more critical during the upward movement.
While designing a cam-follower system, translating follower does not jam in its prismatic guide. The chances of the restriction to the movement of the oscillating follower are much less.
Cam and Follower Advantages:
Cam and follower bearing are that they always distribute evenly, regardless of the configuration of the unit.
A wide range of linear motions is available from cams and followers.
Cam follower can absorb more shock than normal and can reduce distortion.
They are highly versatile.
Cam and Follower Disadvantages:
Backlash between the cam-follower and the cam.
This must be stopped to prevent much damage when there is a crashing of the machine.
More expensive to manufacture and machine require greater precision.
The negative radius of curvature is not possible.
Cam and Follower Application:
Feed mechanism in lathe machine.
Inlet and exhaust valve of the IC engine.
Jigs and fixtures.
This is a complete article on Cam and Follower. If you like this article then do not forget to share with your friends and family. Till then thank you much for reading. We will meet in other articles.
This article includes Definition, Types, Working, Advantages, Disadvantages, and Application [Notes with PDF] of Radiator.
Note: At the end of the article you can easily download whole article in PDF format.
Let us start with the definition of radiator first,
Table of Contents
Radiators are used to convert thermal energy from one mode to another for the purpose of cooling and heating. Radiators function in automobiles, buildings as well as in electronics. The radiator acts as a source of heat to the surrounding but might be its the purpose of heating the environment, it acts as a coolant source for automotive engine cooling.
Radiators transfer most of their heat via convection rather than thermal radiation. If there are large temperature differences, it can cause distortion of the engine components. The radiator will do the cooling purposes because the temperature of the burning gases in the engine cylinder reaches up to 1500 to 2000°C.
If the heat is not dissipated there can be a failure of the cylinder material. Radiators can reduce the chances of piston seizure and keep the temperature minimum.
Radiator Main Parts or Construction:
We will study one by one in detail,
Due to absorbing heat from the engine coolant get hot, the liquid expands and creates pressure in the radiator additionally. The pressure causes the coolant to get higher than the pressure cap, in order to prevent leakage excess coolant needs to be captured somewhere. The excess fluid flows into the pipe and goes into the overflow tank.
When the driver parks turn off the engines the vehicle and the heat dissipates which causes the coolant. The coolant will then contract instead of expanding; resulting in the volume of the coolant.
The vacuum effect will take place where the pressure decrease allows the excess coolant in the overflow tank to flow back so it can return to the radiator. Tanks could also be made of brass, plastic, a polyamide).
Just after it has passed through the heat radiating tubes and fins in the body of the radiator the bottom tank receives the cooling water.
The significant temperature takes place. From the block, the thermostat releases water at 180 degrees Faranhite. That water can lose as 100 def. F. depending on the ambient air temperature and the efficiency of the radiator by the time it reaches the bottom tank.
The water pump holds this cooled water. It will back into the block where it is again heated up.
On its way to the opposite tank, as the coolant passes through the radiator tubes, it transfers heat to the tubes that transfer the heat to the fins that are attached between the rows. The fins head the heat flow to the ambient air.
Radiator tubes are made up of brass. The use of aluminum increased, eventually taking over the vast majority of vehicular radiator applications.
Since the coolant expands the high coolant temperature leads to an increase in pressure in the cooling system. Coolant is press in the tank that will increase the pressure in the tank.
A pressure relief valve in the filler cap opens. It allows air to escape. Partial vacuum forms in the cooling system when the coolant temperature returns to normal. This causes a vacuum in the tank because the Coolant is extracted from the tank.
Fins are surfaces that are used to increase the rate of heat transfer to or from the environment and they extend from the surface by increasing convection.
Fins increase the surface area and can be an economical solution to heat transfer problems.
Types of radiators:
Cellular Type Core.
It is the series combination of upper and lower tanks through which water passes. Fins are attached to improve heat transfer around the tubes. Outside of the tubes, the air is passed between the fins that absorbing heat from the water.
The water passes through all the tubes the cooling effect of the entire tube is lost if one of the tubes becomes clogged. On a cellular radiator, the clogging of any passage results in a loss but of a small part of the total cooling surface.
The tubular radiator type operates with convection and radiation heating. The tabular type radiators are designed for heating of church interior, garages, public toilets, locker rooms.
The tubular radiator type is manufactured from steel that is powder painted and mounted with stainless tubular heating element attached in insulation plates.
This type of radiator should only operate with full power because it becomes rather hot on the surface. It Should be equipped with protection grate. The radiator is equipped with a heating element. The electrical board has got the reconnection.
The radiators are equipped with brackets and are designed for placing under the bench and along the wall.
Cellular Type Core:
Air passes through the tubes and the water flows in the spaces between them in cellular type core. The core contains a large number of air cells that are surrounded by the radiator. It is known as a honeycomb radiator because of its appearance as the cells in front are hexagonal in form.
On a cellular radiator, passage clogging results in a loss but small areas will be affected by it. It consists of many small tubes equipped with a honeycomb-like structure of fins to dissipate heat rapidly and cools hot liquid from the engine.
Radiator Working Principle:
The radiator is a pretty simple device. Aluminum radiators are used nowadays. It has a tank on both sides, and there is a transmission cooler inside the tank. This radiator has aluminum mesh. Aluminum ports have two ports inlets as well as an outlet port.
There are tubes that mounted in a parallel arrangement inside the radiator. And the aluminum fins are attached to all of the tubes. The Radiator working is very simple. In the radiator, the coolant flows from the inlet to the outlet through many tubes mounted in a parallel arrangement. The hot water enters the radiator through the inlet port. And a fan is attached behind the radiator to cool down the hot water in the tubes.
The fan blows the air and cools down the water. So the water is going to come out cooler than it entered before and then go back to the engine. Now it does that air is going to be feeding through this radiator. The aluminum fins are attached to the tubes this called tabulator.
Now the tubes are filled with hot coolant coming from the engine. So they’re going to give off heat to this aluminum coat by passing air through the fan, it cools the aluminum coat.
If the smooth flow through the tubes, only the fluid would be cooled directly that actually touching the tubes. Now it is going to send out to the cooler and then go back to the engine.
The radiator core is usually made up of flattened aluminum tubes with aluminum strips that zigzag between the tubes. These fins transfer the heat in the tubes to the air stream, to be carried away from the vehicle.
One is mounted towards the top of the radiator to let the coolant in while the other is mounted at the bottom of the radiator on the other tank to let the coolant back out.
On top of the radiator is an additional opening that is capped off by the radiator cap.
In a liquid-cooled internal combustion engine motorcycles and cars, the radiator is connected to channels running through the engine and, through which a liquid (coolant) is pumped in the cylinder head.
More commonly a mixture of water and antifreeze is used as the liquid. Antifreeze is ethylene glycol or propylene glycol.
It is of good heat dissipation. It obviously saves material and energy.
Good performance of oxidation corrosion resistance
they are highly responsive.
They are environmentally friendly to produce, so they are less polluting.
They are easy to mold, and so you can find some very cool and unusual designs.
One of the major advantages of radiators is that ceramic, cast iron, and other materials used to construct them will hold on to heat.
Heat loss takes place if not used and maintained properly.
It needs an adequate amount of airflow in the room in order for a radiator to properly work.
The heats from the unit will simply sit around the unit, which can reduce the comfort levels within your home and create drafts and cold spots.
Hot: radiators can grow extremely hot to the touch while working especially if you have small children or pets in the house.
In this Planer Machine article, we will study Definition, Parts, Working, Types, Operation, Advantages, Disadvantages, and Application.
Note: At the end of the article you can download PDF of Planer Machine.
So now lets start with the Introduction first,
Table of Contents
Planer Machine Introduction:
The principle of the planner machine is the concept of relative tool-work motions. Reciprocation of the tool or job and the slow, intermittent transverse feed motions are imparted to the job or tool by the fast straight path cutting motion.
Al the operations done in planning machines can be done in the shaping machine. Stroke length, larger size, and higher rigidity enable the planing machines to do more heavy-duty work on large jobs and their long surfaces.
It produces planes and flat surfaces with a single-point cutting tool. A planer machine is large and massive as compared to a shaper machine. The planer can do machining heavy workpiece, which cannot be done on a shaper surface.
Planer Machine Definition:
Planer Machine is a machine in which unwanted material is cut from the workpiece to produce a flat surface on the workpiece. Unlike Shaper Machine, in this machine, more than one tool can be set and perform an operation.
Now let’s see the construction or Parts of Planer Machine,
Planer Machine Parts:
The following Construction or Main Parts of Planer Machine are:
Column or Housing
The bed of a planer having cross ribs similar to box-like casting. It is heavy in weight and very large in size also it supports the column and moving parts of the machine.
The bed is made generally longer than the length of the table, almost twice the length. So that the full length of the table may across it. To support the table guideways may be provided on a very large machine.
The guideways should be horizontal and parallel to each other. The guideways are lubricated properly and to ensure a continuous and adequate supply of lubricants in modern machines, oil under pressure is pumped into the different parts of the guideways.
Column or Housing:
The housings also called columns like vertical structures placed on each side of the bed and are attached to the sides of the bed. They are heavily mechanized to continue severe forces due to cutting.
Cross rail may be made to slide up and down for accommodating different heights of work to the front face of each housing is accurately machined to provide precision ways.
Two side-tool head also slide upon it. Planer housing encloses the Crossrail elevating screw, vertical and crossfeed screws for tool heads, counterbalancing weight for the Crossrail.
The planer screws can be operated by hand or power.
The table of the planer supports the workpiece and reciprocates along with the ways of the bed. The planer table is a heavy rectangular casting that has T-slots provided on the entire length of the table so that the work and work holding devices attached to it.
In the end, a hollow space is left which acts as a carrier for collecting chips. Works can also rest upon the troughs of the planer.
The table is made up of one single casting but it is divided by the table of planer there are two separate tables mounted upon the bed ways.
Hydraulic bumpers are attached to the end of the bed to stop the table from overrunning that will give the cushioning effect. If the table overruns, a large cutting tool bolted along the underside of the table which will take a deep cut on a replaceable block absorbing the kinetic energy of the moving table.
The Crossrail is a casting that connects the two housings. Crossrail provides rigidity to the machine. It occupies the face of the housing and can be clamped at the position by manual, hydraulic devices.
The Crossrail when clamped should remain absolutely parallel to the top surface of the table, i.e. It must be horizontal irrespective of its position.
Two tool heads are mounted which are called railhead. It has screws for vertical and crossfeed of the tool heads and a screw for elevating the rail. The planer screws can be operated by hand or power.
Tool head is a component assembled to saddle, which has the tool post in it. The tool post is attached to the head so that on to and from of the table the cutting tool force is raised.
The cutting edge of the tool will be saved as of being damage and permits the automatic supply to function with no intrusion.
It has Saddle, Swivel base, Vertical Slide, Apron, Clapper box, Clapper block, Toolpost, Down feed screw, Apron, clamping bolt, Apron swiveling pin, Mechanism for cross and down-feed of the tool.
Driving and Feed Mechanism:
The feeding mechanism of the tool head is by the hand of power in a crosswise or in a vertical direction. The drive mechanism is located under the table and The motor drive is at one side of the planer.
The size of the planer is specified by the maximum length of the stroke and it is also specified by the largest rectangular size that can be machined.
Now we study working of Planer Machine,
Planer Machine Working Principle:
The worktable can be move and the tool head of the machine is in a stationary position. The workpiece is fixed on the work table and
The single point cutting tool is attached to the tool head and now we switch on the machine that means power supply to the machine and the worktable moves forward.
Hence it cuts the material and it is called cutting stroke. The worktable moves downward there is no cutting of material so this is called the return stroke. The process will be continued unless you change the power supply or others.
Planer Machine Mechanism:
Kinematics and its mechanism involve transformation and transmission of rotation of the motor into reciprocating motion of the work table and the transverse motions of the tools.
The reciprocation motion of the table that gives cutting motion to the job, is obtained by a rack-pinion mechanism. The rack is fitted with the table and the pinion is fitted on the output shaft of the speed gearbox.
The blocks hold the cutting tools that move horizontally along the rail by the screw-nut system and the rail is again moved up and down by screw-nut pair different from it.
The belts are used as drivers to reciprocate the table alternatively. The greater arc of contact on the larger pulley is used to drive the table.
Greater power and less speed is required during the cutting stroke and is done by connecting the cross belt with a larger diameter pulley which is fed on the shaft.
The power from the shaft transmits through pinion P and spur gear.
Now moving to types,
Planer Machine Types:
There are five different types of Planer Machine:
Double Housing Planer Machine
Pit Planer Machine
Open Side Machine
Edge Planer Machine and
Divided Table Planer Machine
Double Housing Planer Machine:
Most of the workshops use a double housing planer machine. Double housing planers have a long heavy base with machined guideways accurate on which a table reciprocates. The bed length is greater than twice the length of the table.
Two vertical housings are mounted one housing: One on each side and these are connected at the top by a cross member. It has a horizontal cross rail that carries two tool heads slides over the vertical faces of the machine housing.
Tool heads are moved by hand or power in the cross or vertical direction for the feeding operation. Double housing planer is a high speed, heavy-duty as well as rigid machines.
It has a high degree of surface finish. Work is mounted on a table which reciprocates while the tool is held on the machine frame. It can make deep cuts and heavy feeds can be applied to finish the work in a short time. The tool is stationery and work is moving. Heavier, stronger, and larger tools are used.
Throughout the stroke cutting and return, speeds are uniform. Double housing Planer consumes a power of 150 horsepower and the double housing holds the large floor area.
Pit Planer Machine:
Pit planer has a massive construction in which the table is kept in a pit and kept stationary. The crosses rail reciprocates on a horizontal rail mounted on both sides of the table.
The table of the planer is leveled with the floor, so heavy work can be loaded. It has two tool heads and these can be moved horizontally and vertically to have the feed. By means of a motor, a driving screw is used for driving the column.
Open Side Planer Machine:
One housing on one side of the base is attached or clamped on which a cross rail on a table moves.
The open side planer machine has three tool heads mounted on the machine. Single housing will bear the entire load, Therefore it should be rigid and robust to face the forces.
It can slide along the guideways of the housing in the vertical direction which carries the tool heads.
Edge Planer Machine:
Edge planer is also called plate planer and is used for bevelling and squaring the edges of steel plates used for pressure vessels in different applications and in the ship buildings industry.
The table holds the work that remains in a stationary position. The workpiece can be attached by air-operated clamps. The tool-head that mounts on the carriage moves along two horizontal guideways.
Divided Table Planer Machine
Divided table Planer Machine has two tables on the bed that can reciprocate separately or jointly. This will saves the idle time when you set the work.
Divided type planer is mostly suitable for mass production work that can Machine is to be done identically, the work on one of the tables is loaded, the other part can reciprocate the cutting tool for the finishing process.
Finishing the work can be done after the table is stopped and the finished job is ejected by shifting the table to the end. Heavy and large jobs are clamped together therefore given the reciprocating movement by the tool.
Now we will study Advantages, Disadvantages and Application.
Planer Machine Advantages:
The following advantages of Planer Machine as follows:
It has Greater accuracy,
Good surface finish,
More than one tool can perform on the workpiece at a time and
Low maintenance is required.
Planer Machine Disadvantages:
The following disadvantages of Planer Machine as follows:
The cost of the machine is on the higher side.
The power consumption is quite more.
The skilled worker required.
Only tool single point is used.
Planer Machine Application:
The following application of Planer Machine as follows:
The Planer machine is used for Flat surfaces on the workpiece.
Cutting angular surfaces is one of the major applications.
In this article, we will study Definition, Parts or Construction, Working Principle, Advantages, Disadvantages, and Application of Laser Beam Machining.
And most important you can download the whole document in PDF format at the end of the articles.
LASER: It stands for Light Amplification Stimulated Emission of Radiation.
The different types of Laser are Solid-state, Gas, and Semiconductor. At high power lasers required for machining and welding, The solid-state lasers used.
We will study in depth. Lets start with the definition first,
Table of Contents
Laser Beam Machining Definition:
Laser Beam Machining is a non-conventional machining process in which the workpiece is being holed by the laser machining process. To remove the material from the workpiece the process used thermal energy.
Now we are moving to construction or Main Parts, So
Laser Beam Machining Parts or Construction:
Laser Machining consists of following Main Parts:
Laser Light Beam
The electric current or power is supplied to the system. A high voltage power system is used in laser beam machining. It will give initial power to the system after that reaction starts in a laser that will machine the material. There is a high voltage supply so that pulses can be initiated easily
During the major portion of the cycle, a capacitor bank charges and releases the energy during the flashing process. The capacitor is used for the pulsed mode for charging and discharging.
It is the electric arc lamp that is used to produce extremely intense production of white light which is a coherent high-intensity beam. It is filled with gases that ionize to form great energy that will melt and vaporizes the material of the workpiece.
Reflecting Mirror are two main types of internal and external. Internal mirrors also called a resonator that is used to generate maintain and amplify the laser beam. It is used to direct the laser beam towards the workpiece.
Laser Light Beam:
It is the beam of radiation produced by the laser through the process of optical amplification based on the coherence of light created by the bombarding of active material.
Ruby laser produces a series of coherent pulses which is deep red in color. It achieves by the concept of population inversion. It is a three-level solid-state laser.
Lenses are used to focus the laser beam onto the workpiece. First laser light will enter into the expanding lens and then into the collimating lens which makes the light rays parallel and the expanding lens expands the laser beams to the desired size.
The workpiece can be metallic or non-metallic. In this machining process, any material can be machined.
Laser Beam Machining Working Principle:
Laser Machining is based on the LASER and conversion or process of Electric Energy into Light Energy and into Thermal Energy.
Negatively charged electrons in the atomic model rotate around the positively charged nucleus in orbital paths. It depends on the number of electrons, electron structure, neighboring atoms, and the electromagnetic field.
Every orbital of electrons is associated with different energy levels. An atom is considered to be at ground level at absolute zero temperature at this, all electrons occupy their lowest potential energy.
The electrons at the ground state move to a higher state of energy by absorbing energy like an increase in electronic vibration at elevated temperatures.
High voltage is applied at the ends that leads to discharge and gas plasma will be formed. Population inversion and lasing action will take takes place due to energy transformation.
The laser has one 100% reflector and the other one is partial reflector.100% the reflector directs the photons inside the gas tube and the partial reflector allows only some part of the laser beam that will be used for processing of materials.
The laser beam produced is focused on the workpiece that has to be machined. When the laser strikes the workpiece, the thermal energy impinges on the workpiece.
This will heat then melt, vaporize, and finally, the material will be removed from the workpiece. So laser machining is a thermal material removal process that uses a coherent beam of light to machine the workpiece very precisely.
In the laser machining process, MRR (Material Removal Rate) depends on the wavelength used because it will decide the amount of energy impinged on it.
Laser Beam Machining Application:
The following application are:
Laser Machining is used for making very small holes, Welding of non-conductive and refractory material.
It is best suited for brittle material with low conductivity and Ceramic, Cloth, and Wood.
Laser Machining also used in surgery, micro-drilling operation.
Spectroscopic Science and Photography in medical science.
It is also used in mass macro machining production.
Cutting complex profiles for both thin and hard materials.
It is used to make tiny holes. Example: Nipples of the baby feeder.
Laser Beam Machining Advantages:
The following advantages of LBM are:
In Laser Beam Machining any material including non-metal also can be machined.
Extremely small holes with good accuracy can be machined.
The tool wear rate is very low.
There is no mechanical force on the work.
Soft materials like plastic, rubber can be machined easily.
It is a very flexible and easily automated machine.
The heat-affected zone is very small.
Laser Machining gives a very good surface finish.
Heat treated and magnetic materials can be welded, without losing their properties.
The precise location can be ensured on the workpiece.
Laser Beam Machining Disadvantages:
The following disadvantages of LBM are:
Laser Machining cannot be used to produce a blind hole and also not able to drill too deep holes.
The machined holes are not round and straight.
The capital and maintenance cost is high.
There is a problem with safety hazards.
The overall efficiency of the Laser beam machining is low.
It is limited to thin sheets.
The metal-removing rate is also low.
The flash lamp life is short.
There is a limited amount of metal removing during the process.
Lathe Machine is one of the oldest machine tools in the production machine. This Machine is also known as the “mother of all machines“.
Today we will study Definition, Parts, Types, Operation, Specification, advantages, disadvantages, and application [Notes with PDF] of Lathe machine.
Note: At the end of article you can download whole document in PDF format easily.
Let’s start by Introduction first,
Table of Contents
Lathe Machine Introduction:
Lathe machine is probably the oldest machine tool know to mankind. Its first use date back to 1300 BC in Egypt. The first lathe was a simple Lathe which is now called a two-person lathe. In this one person would turn the wood workpiece using rope and the other person would shape the workpiece using a sharp tool.
This design was further improved by the Ancient Romans who added the turning bow and lather the paddle (as there in the sewing machine) was added.
Further during the industrial revolution Steam Engines and water wheel were attached to the Lathe to turn the workpiece to a higher speed which made the work faster and easier.
Then, In 1950 servo mechanism was used to control the lathe machine. From this crude begging and over a period of more than two centuries, the modern engine lathe has evolved.
Now we have the most advanced form of the Lathe which is the CNC Lathe. HENRY MAUDSLAY, a British Engineer is considered as the inventor of a lathe.
Lathe Machine Definition:
A lathe machine is a machine tool which removes the undesired material from a rotating workpiece in the form of chips with the help of a tool which is traversed across the work and can be feed deep into the work.
It one of the most versatile and widely used machine tools all over the world.
This is also known as the ‘Mother of all Machines’. Nowadays, Lathe Machine has become a general-purpose machine tool, employed in production and repair work, because it permits a large variety of operations to be performed on it.
Lathe Machine Parts:
The Lathe Machine consists of following Main Parts:
I have also shown the different parts in the diagram.
let’s start from Bed first,
The bed of the lathe machine is the base on which all the other parts of the lathe are mounted. The bed is made from Cast iron or nickel cast iron alloy and is supported on broad box-section columns.
Its upper surface is either scraped or grounded and the guiding and the sliding surfaces are provided.
The bed consists of heavy metal slides running lengthwise, with ways or v’s forced upon them. It is rigidly supported by cross griths.
The three major units mounted on a bed are:
The scrapped or the
ground guiding along with the sliding surfaces on the lathe bed ensure the
accuracy of the alignment of these three units.
The headstock is present on the left end of the bed. The main function of the headstock is to transmit power to the different parts of the lathe.
It supports the main spindle in the bearing and aligns it properly. It also houses a necessary transmission mechanism with speed changing levers to obtain different speeds.
Accessories mounted on the headstock spindle are:
Three jaw chuck.
Four jaw chuck.
Lathe center and lathe dog.
The tailstock is a movable casting located opposite to the headstock on the way of the bed.
The basic function of the tailstock is:
To support the other end of the work when being machined.
To hold a tool for performing operations like drilling, reaming, tapping, etc.
It consists of the dead centers, the adjusting screws, and the handwheel. The body of the tailstock is adjustable on the base which is mounted on the guideways of the bed and can be moved.
Carriage is located between headstock and tailstock. The basic function of the carriage is to support, guide, and feed the tool against the job during operation.
It consists of 5 main parts:
It is an H-shaped casting mounted on the top of the lathe ways. It provides support to cross-slide, compound rest, and tool post.
slide is provided with a female dovetail on one side and assembled on the top
of the saddle with its male dovetail.
The top surface of the cross slide is provided with T slots to enable fixing of rear tool post or coolant attachment. Carriage basically provides a mounted or automatic cross-movement for the cutting tool.
rest is present on the top of the cross slide. It supports the tool post and
cutting tool in its various positions.
Compound rest is necessary for turning angles and boring short tapers and forms on forming tools.
The tool post is mounted on the compound rest. It is used to hold various cutting tool holders. The holders rest on a wedge which is shaped on the bottom to fit into a concave-shaped ring (segmental type),
Which permits the height of the cutting edge to be adjusted by tilting the tool. It is fixed on the top slide. It gets its movement by the movement of the saddle, cross slide, and top slide.
The three types of tool post which are commonly used are:
Ring and rocker tool post: It consists of a circular tool post with a slot for accommodating the tool or tool holder.
Quick change tool post
Squarehead tool post.
The Apron is fastened to the saddle and hangs over the front of the bed. Apron consists of the gears and clutches for transmitting motion from the feed rod to the carriage, and the split nut which engages with the lead screw during cutting threads.
Two types of Apron are extensively used:
Incorporating drop worm mechanism.
Friction or dog clutches.
Chuck is basically used to hold the workpiece, particularly of short length and large diameter or of irregular shape which can’t be conveniently mounted between centers. It can be attached to the lathe by screwing on the spindle nose.
Four different types of chucks are most commonly used in Lathe:
Independent or four-jaw chuck
Three jaw or universal chuck
Collect chuck and
Independent or four-jaw chuck:
It is used for irregular shapes, rough castings of square or octagonal in such jobs, where a hole is to be positioned off the center. It consists of four jaws and each jaw is independently actuated and adjusted by a key for holding the job.
Three jaw or universal chuck:
It consists of three jaws that move simultaneously by turning a key and the workpiece automatically remains in the center of the chuck opening. It is used for holding a round, hexagonal bar or other symmetric work.
It is mostly used in the places where production work is required such as in Capstan Lathe or automats.It is used for holding the bars of small sizes (below 63mm).
They are of permanent magnet type or electrically operated. In Lathe, it does not have widespread use.
Feed rod is a power transmission mechanism used for precise linear movement of the carriage along the longitudinal axis of the lathe. In some lathe machines instead of feed rod lead screws are used.
The lead screw is used mostly in the case when the threading operation is to be performed on a lathe. As we know for threading operation requires rotational movement of the job (workpiece) and the linear movement of the tool (tool post).
So rotation of the job is obtained by the chuck and the desired linear motion of the tool-post (as the lead screw drives the saddle when it is engaged) is provided with the help of a lead screw.
Lathe Machine Working Principle:
A Lathe works on the principle of rotating the workpiece and a fixed cutting tool.
The workpiece is held between two rigid and strong supports called a center or in a chuck or in faceplate which revolves.
Lathe removes the undesired material from a rotating workpiece in the form of chips with the help of a tool that is transverse across the work and can be fed deep in the work.
The main function of the lathe is to
remove the metal from a job to give it the required shape and size.
The normal cutting operations are
performed with the cutting tool fed either parallel or at right angles to the
axis of the work.
The cutting tool can be fed at an angle relative to the axis of the work for machining tapers and angles.
Products made by Lathe Machine:
A variety of products can be made from the lathe machine and that are Nuts, bolts, piston, ram, pump part, electric motor parts, sleeves, Aircraft parts, gun barrels, candlesticks, train parts, cue sticks, wooden bowls, baseball bat, crankshaft andmany more things.
Lathe Machine Types:
There are 10 different types of Lathe Machine and those are:
Engine Lathe or Center Lathe
Gap bed lathe
Hollow spindle Lathe
Vertical Turret Lathe and
CNC Lathe Machine.
Engine Lathe or Center Lathe Machine:
The engine lathe is the most important tool in the Lathe family and by far the most widely used type of Lathe machine.
Its name is derived from the fact that early machine tools were driven by separate Engines or central engines with overhead belts and shafts.
The operations which can be performed by the Engine Lathe machine are Turning, facing, grooving, knurling, threading, and many more operations that can be performed by it.
Engine lathe consists of headstock, Tailstock, bed, saddle, carriage and other parts.
The headstock encloses the spindle and motor. It also consists of the gear and pulleys, which are used to change the gear speed and the feed rate.
The tailstock is provided to facilitate holding the work between centers and permit the use of tools like drills, taps, etc.
The cutting tool can be fed both in the cross and longitudinal direction with reference to the lathe axis with the help of the feed rod and the lead screw.
The Engine Lathe is available in sizes to handle to 1m diameter jobs and 1 to 4m long.
Turret Lathe Machine:
It is a production machine that is used for the production of products on a large scale. It basically handles heavy-duty workpieces. The distinguishing feature of this type of lathe is that the Tailstock is replaced by hexagonal Turret.
In this, several tools are set up on a revolving turret to facilitate in performing a large number of operations on a job with minimum wastage of time.
The turret usually accommodates 6 tools for different operations like drilling, countersinking, reaming, tapping, etc, which can be brought into successively working positions by indexing the turret. Turret lathe is basically used for repetitive batch production.
Capstan Lathe Machine:
It is similar to the Turret lathe. Used for the mass production of the light-duty workpiece. It incorporates a capstan slide which moves on the auxiliary slide and can be clamped in any position.
This is best suited for the production of the small parts because of its lightweight and short stroke of capstan slide.
Speed Lathe Machine:
This is the simplest form of the lathe and consists of a simple Headstock, tailstock, and a tool post. Having no gearbox, lead screw, and carriage. Very high speed of the headstock spindle. The speed of the spindle ranges from 1200 to 3600rpm.
Tools are hand-operated. Cone-pulley is the only source provided for speed variation of the spindle.
Speed Lathes are intensively used in woodturning, metal spinning, and polishing operation.
Tool Room lathe Machine:
Tool Room lathe is a modern engine lathe that is equipped with all the necessary accessories for the accurate tool room work. It is best suited for the production of small tools, dies, gauges, etc.
It is a geared head driven machine with considerable rage in spindle speed and feeds. Its speed can range from very low to a very high speed of up to 2500 rpm.
Bench Lathe Machine:
Bench Lathe machine is a type of small lathe machine which has all the parts of the engine Lathe and speed lathe.
It is mounted on a workbench and is used for doing small precision and light jobs.
Special purpose Lathe machine Machine:
Special purpose lathe machine is used for performing the specific special tasks which cannot be performed by an ordinary lathe. Some type of special-purpose Lathe are as follow:
Gap bed lathe Machine:
In gap bed lathe, a gap is provided over the bed near the headstock to handle the job having flanges or some other protruding parts.
Mostly a removable portion is provided in
the bed so that when it is not required it can be inserted.
Wheel lathe Machine:
Wheel lathes are a special-purpose lathe machine that is used for finishing the journals and turning the tread on locomotive wheels.
T- Lathe machine Machine:
T- Lathe machine is a type of machine which has a T shaped bed and is used in the aerospace industry for the machining of the rotors of the jet engine.
Automatic Lathe Machine:
As the name suggests automatic Lathe machine is a machine in which the complete work and the job handling movements required for the completion of the job are done automatically.
They are heavy-duty, mass production, and a high-speed machine.
CNC Lathe Machine:
Computer Numeric Control (CNC) is the most advanced form of the lathe machine. CNC lathe machine produces the most accurate products as compared to the other type of lathe machine.
In this machine, programs are being fed to the computer system which controls the overall working of the lathe.
It is used for large scale production. Semi-skilled workers are required for the operation of this machine.
Lathe Machine Operation:
The operations performed on Lathe Machine are:
Thread cutting operation
Counter Boring Operation
Countersinking Operation and
Let’s start discussing them one by one:
Turning is the most common operation performed on the lathe. Turning is a machining operation in which the diameter of the workpiece is being reduced by removing the excess material from the outer diameter of the job (workpiece) which is mostly cylindrical or conical in shape.
Turning operation results in the good surface finish of the metal.
The various type of
turning operation are:
Tapered Turning is a machining process in which the cylindrical jobs are being machined to produce a conical surface. In taper Turning the tapered component will be produced.
The various methods used for Taper Turning are:
Compound Rest Method
Taper Turning Attachment method
Form tool Method.
Let’s discuss each
method in brief:
Taper Turning Attachment Method:
In taper turning attachment method the slideways are tilted by an angle equal to the taper angle of the component so that the saddle is automatically tilted and when the saddle is moving on the slideways it produces a tapered component.
It can be used for both internal, external operations.
Up to 0.1degree accuracy can be produced.
Maximum taper angle which can be produced is 8 degree.
The maximum taper length of the component in one sitting is 235mm.
Compound Rest Method:
In compound Rest Method the compound rest is swiveled by an angle equal to the required taper angle on the component. Any taper angle can be produced by this method and both internal and external taper turning operations can be performed by this method.
The method is used for producing only external tapers. In this method, the tailstock is moved from its middle position to one side of the bed, which makes the workpiece tilted with respect to the lathe axis and feed.
Thus, when the tool moves it cuts the workpiece at an angle to the axis creating a taper.
Form Tool method:
The form tool method is used for producing external tapers only. The form tool method is a type of method in which the shape of the tool is the same as that of the shape of the component to be produced. Whatever the angle on the tool that can be produced on the component.
Accuracy produced on the component depends upon the accuracy present on the tool. It is mostly used in the chamfering operation.
Shoulder Turning is used in the case where several diameters are to be turned on the work piece. The surface forming the step from one diameter to the other is called the shoulder.
There are four types of shoulder:
A right-cut tool is used to make the square shoulder.
Facing is a process in which the end of the workpiece is being machined by the tool which is at a right angle to the axis of the rotation of the workpiece.
Facing is frequently the first operation performed in the production of the workpiece and often the last. We can relate it to the phrase” ending-up”, which will help us in remembering its sequence.
Thread cutting operation:
Thread cutting is a type of operation in which the threads are being cut on the internal and the outer surface of the workpiece as per the requirement.
In the thread cutting operation, only the automatic feed is given.
The automatic feed required for the thread cutting operation is given by using a lead screw and the feed gearbox.
toothed gear is used for producing Metric threads on engine Lathe.
The feed of the lead screw has to be changed in order to get the different pitch of thread on the job.
JOB SPEED: Job speed during threading is up to 1/4th of the job speed during turning.
Parting is an operation in which the deep groves are being made on the parent material to remove the specific portion from the parent material resulting in dividing the workpiece into two or more parts.
Chamfering is the operation of beveling the extreme end of a workpiece. Chamfering is provided for:
To enable the nut to pass freely on the threaded workpiece.
Protect the end of the workpiece from being damaged.
Chamfering is done usually after knurling, thread cutting, etc…
The process of making the surface of the workpiece rough by embossing (impressing) a diamond-shaped regular pattern on the surface by making use of a knurling tool is called a knurling operation.
Knurling is done at a lower speed and plenty of oil is used. Knurling provides an effective gripping surface on a workpiece to prevent it from slipping when operated with hand.
Drilling operation is a type of machining operation which is used to remove the material from the workpiece by making use of drill bit, which is held stationary in the Tailstock. Finally creating a hole in the workpiece.
Drill bits are generally made up of high-speed steels and carbon steels.
Boring is an internal turning operation used for enlarging the existing holes by some amount.
It can further be divided as:
boring is an internal turning operation used for enlarging the end of the
Counter Sinking is the operation of the conical enlargement of the end of the hole. It requires a large size drill bit then that required for the hole.
It is a machining process that is done after drilling to make internal holes of a very accurate diameter. This operation helps to remove a very small amount of material from the holes which are already drilled.
Now we will study Specification of Lathe Machine,
Lathe Machine Specification:
In order to specify the lathe Machine completely the following parameter should be included:
The length between the two centers:
Height of the center:
Swing Diameter over the bed:
Maximum bar diameter:
Tailstock sleeve travel.
Metric thread pitches.
Motor horsepower and RPM.
Shipping dimension: (length x width x height x weight).
a) The length between the two centers:
It is the measure of the maximum length of the workpiece that can be fixed between the lathe center.
b) Height of the center:
The distance between the lathe axis and the lathe bed is called the height of the center.
c) Swing Diameter over the bed:
It is the maximum diameter of the workpiece that can we turned on a lathe without hitting the lathe bed.
d) Maximum bar diameter:
It is the maximum
diameter of the workpiece that can be passed through the hole in the headstock.
Other factors for the lathe specification are:
Tailstock sleeve travel.
Metric thread pitches.
Motor horsepower and RPM.
Shipping dimension: (length x width x height x weight).
Application of Lathe Machine:
The following application of Lathe Machine are:
In the automobile industry mainly in the crankshaft, woodturning, Glass turning operation, for forming screw threads, also used for reclamation of the parts, and many more.
A CNC lathe finds extensive use in the several tasks being performed by it in various industries like:
of the Lathe machine:
Lathe Machine has numerous advantages, some of them are:
The lathe is a High-quality product.
It has a high speed.
It also Saves time and
1. High-Quality Products: Lathe machine, especially the CNC Lathe machine, produce final products with high quality.
2. High Speed: The machining in the lathe can be done at a very high speed especially in automatic and CNC lathe machines.
3. Saves time: Lathe machine because of its extensive high speed and high accuracy saves a lot of time, resulting in the increased production.
4. Saves Money: Lathe machine helps in reducing the cost of machining because fewer operators are required for machining.
Disadvantages of Lathe Machine:
Lathe Machine has some disadvantages too, some of them are:
The Initial cost is very high.
The high skilled worker required for the initial setup.
CNC machines can not use for small production.
This is all about Definition, Introduction, Parts, Types, Application, Advantages, Disadvantages, and [Notes with PDF] of Lathe Machine.
In this article we will study the Definition, Construction or Parts, Working Principle, Advantages, Disadvantages and Application [Notes & PDF] of Pelton Wheel Turbine in detail.
So lets start with the definition,
Table of Contents
Pelton Wheel Turbine Definition:
Pelton Wheel Turbine is the type of impulse or hydraulic turbine which is used for high heads for the generation of power. In this, the jet after leaving the nozzle runs in the open air and strikes the bucket or vane.
Now come to construction or Main parts of Pelton Turbine,
Pelton Wheel Turbine Construction or Parts:
The following construction or parts of Pelton wheel Turbine:
Runner or Rotor
Now we will study one by one in detail,
The Pelton wheel casing prevents the splashing of water and it will provide a discharge of water from the nozzle to the tailrace.
The casing surrounding the wheel has no hydraulic function to perform, unlike the reaction turbine where the casing plays an important hydraulic function.
Needle Spear will control the water flow and it moves insides the nozzle and provides smooth flow so there can be very less energy loss.
When the nozzle is completely closed by moving the spear in the forward direction the amount of water striking the runner is reduced is zero but the runner due to inertia continues revolving for a long time.
To stop the runner to rest in a short time a breaking jet is provided which directs the water on the bucket. this is called breaking jet.
Runner or Rotor:
A Pelton wheel has a runner that rotates and has kinetic energy, at the periphery of the runner equally spaced hemispherical or double ellipsoidal buckets.
All the potential energy is converted into kinetic energy before it strikes jet hits the rotor blades
These are the channels or pipelines from high head source water is transferred to the actual power station
Governing of Pelton turbine is done by means of oil pressure governor, which consists of the following parts:
The spear rod or needle.
Pipes connecting the oil sump with the control valve and control valve with servomotor.
The centrifugal governor or pendulum which is driven by a belt or gear from the turbine shaft.
The control valve or the distribution valve or relay valve.
The servomotor also called the relay cylinder.
When the load on the generator decreases, the speed of the generator increases this increases the speed of the turbine beyond the normal speed.
The centrifugal governor which is connected to the turbine’s main shaft will be rotating at an increased speed. Due to an increase in the speed of the centrifugal governor, the flyballs move outward due to the increased centrifugal force on them.
Due to the upward movement of the flyballs, the sleeve will also move upward. A horizontal level supported over a fulcrum connects the sleeve and the piston rod of the control valve.
As the sleeve moves up, the lever turns about the fulcrum, and the piston rod of the control valve moves downward. Close the valve V1 and open the valve V2.
The piston along with the piston rod and spear will move towards the right. This will decrease the area of the flow of water at the outlet of the nozzle. This decrease in the area of flow will reduce the rate of flow of water.
Pelton Wheel Turbine Working Principle:
The working principle is water is coming from the storage reservoir through a penstock to the Inlet of the nozzle which is the inlet of the turbine so the hydraulic energy of the water is mainly converted into kinetic energy.
The water releases in the form of a jet from the nozzle and strikes on the vanes for a very small time duration.
Since a very high force is exerted on the vanes by the jet of water for a very small time duration so these turbines are known as Impulse turbines.
Bucket changes the direction of run/flow of water jet and momentum transfer takes place.
All events happen in open air i.e at atmospheric pressure. The nozzle is used to convert the head available with water into a dynamic head and the water comes out from the nozzle in the form of a jet.
As the jet strikes over the runner vane, it will apply a large magnitude force for a small amount of time over the runner called Pelton force the Pelton force will rotate the runner.
Hydraulic Efficiency of Pelton Turbine:
Water may be allowed to enter a part or whole of the wheel circumference and the wheel/turbine does not run full and air has free access to the buckets.
Always installed above the tailrace. No draft tube is used either remaining constant or reduces slightly due to friction
V1= absolute velocity of the jet before striking the bucket
V2 = velocity of the jet leaving the bucket (absolute)
u1= absolute velocity of bucket considered along the direction tangential to the pitch circle
Vr1=velocity of the incoming jet relative to the bucket
β = angle between v2 with the direction of motion of vane at the outlet
ϕ = angle made by vr2 with the direction of motion of vane at the outlet, vane angle at the outlet
The parts assemble of the Pelton turbine is very easy. No complexity here.
The water striking and leaving the runner at atmospheric pressure only.
This is a tangential flow turbine. It can move in axial flow or radial flow direction.
Pelton Wheel Turbine Disadvantages:
The following disadvantages of Pelton Wheel Turbine is:
In the Pelton turbine, the variation in the operating head cannot be easily controlled because it works at high heads.
The ratio of maximum and minimum operating heads can be even less.
The operating head cannot be utilized when the variation in the tailwater level is relatively large when compared to the total head.
The mechanical efficiency of the Pelton wheel decreases faster compare to the Francis turbine.
The size of the runner, generator, powerhouse required is large and not economical if the Pelton turbine is used instead of the Francis turbine for the same power generation.
Pelton Wheel Turbine Application:
The following application of Pelton Wheel Turbine is:
The Pelton Turbine wheel turbine is used in Hydro Power Plant where Less discharge and High Heads are required.
This is used to get more velocity of the fluid for maximum power and efficiency [Because the turbine and wheel are designed in such a way that the water jet velocity is twice the rotating bucket velocity].
Hello user, In the last article I have discussed the Mechanical Properties of Material you can read that article. But Today I will discuss other properties which are Thermal properties of Material.
Before moving to our main topic let us have the meaning of the word ‘Thermal’ first, The word ‘Thermal’ means Temperature and Heat.
What is Temperature and Heat Definition?
The tempearture definition is, Temperature is a degree of measuring the hotness and coldness.
Whereas Heat is the energy that is transferred across the boundary of the system to change in the difference between the system and surroundings.
Note: Heat and Temperature are two different quantities. What we are giving in the water is called Heat and the rising in the water is called Temperature.
E.g. I have taken a metal and kept it in the sun, then I am giving in heat and the increase in the level of degree of hotness and coldness is temperature.
So these are the way that specific material will change the temperature and their states.
Now coming to our main topic Thermal Properties of Material,
Thermal Properties of Material:
The different thermal properties of Material are follows:
Thermal shock resistance
This is a property that tells which material gets heated very quickly. So Specific heat is the quantity of heat that we need to change 1 unit degree in unit mass. It is denoted by ‘S’ and unit is joule/kg Kelvin.
Q = Energy content
Note: Specific heat varies for all materials
For example, We use water instead of ice as a coolant in the radiator because the water’s specific heat is higher, the water can absorb more heat as a comparison to ice.
So Specific heat has varied by changing the phase
SP. Heat of water = 1 SP. Heat of Ice = 0.5 SP. Heat of vapor = 0.4
The Heat capacity is the property of the material by which the material is known by absorbing the heat inside itself, and it tells how much heat energy we need to bring in 1-degree unit change.
In this, we say the amount of heat needed to change the entire substance to 1 degree. It is denoted by (H) and Unit is joule/Kelvin.
Mathematical expression :
H= m*s= ∆Q/∆t
Whenever we put heat energy in a material, it expands, which we call it thermal expansion. That is, there is a change in his dimension and this change comes in all directions.
If we see it in the linear direction, then we will call it the Linear Expansion, If you look in an area, then there will be area expansion, if you talk in volume, then it will say volume expansion.
Thermal expansion depends on interatomic forces. On increasing the temperature, the space between the molecules increases, which also increases their dimension.
Because we gave more temperature and its energy increased which also caused vibration in the molecule and it started expanding.
Effect of thermal conductivity in solid, liquid, and gas:
In solid, Pure solid metal has the highest thermal conductivity because pure metal has free-electron present, Which works to transfer heat by gaining heat,
While fluid liquid gas has low thermal conductivity due to inter-molecular collagen.
Effect of temperature on thermal conductivity of solids:
As the temperature of the solid increases than thermal conductivity decreases in solids. As the metal is heated, the temperature will increase and it will transfer less heat from its.
But In aluminum and uranium, as the temperature increases, thermal conductivity also increases. that’s why we use aluminum in the kitchen.
Effect of temperature on thermal conductivity of fluids:
The liquid’s thermal conductivity will decrease as the temperature will rise in the liquid, because their density continuously decrease.
But water exception is the case, it does not happen with water, if the temperature increases in water, thermal conductivity will also increase.
Effect of temperature on thermal conductivity of gases:
The thermal conductivity of the gases will increase as we increment the temperature. As the molecular weight of the gases increases, the thermal conductivity decreases.
The melting point is the temperature of a material where it changes from a solid phase to a liquid phase. The melting point of pure metal is fixed while it varies for alloys.
It also depends on its bonding forces How strong is the bonding force, the higher the melting point. Covalent bonds have the highest melting point then ionic, and last metallic molecular bonds.
A low melting point is used for safety devices like fuse wire, fuse plug, and boiler safety devices.
The ratio of our thermal conductivity and heat capacity is called thermal diffusivity. In thermal diffusivity, it tells us, if we supply heat to the material, then how soon it will distribute the heat to the other end of the material.
This means if the diffusivity of our material is very high, then the supply of heat to the material will distribute the heat at high speed.
E.g. We have a rod, we heat it from a corner, so its temperature is 100 degrees there.
So if our thermal diffusivity is high, our metal will be 100 degrees Celsius at the other end also in a short time. Means will distribute the heat very quickly.
Material having a high value of thermal diffusivity acknowledges very quickly to change in the thermal environment for set up the steady-state.
So here we finally studied all the material properties of thermal. If you have any doubt let me know in the comment section. And if you found helpful then please share it on social places like Facebook, WhatsApp.
Hello reader, In this article, we will read the Definition, Classification of the valve, and their functions. So first Let’s start with the Definition of Valve.
Definition of Valves:
A valve is a component that controls and regulates the fluid or directs the flow of a fluid by various kinds of closing, opening, or by partially cut off fluid flow. So to controls the flow and pressure of fluid within a system, we used valves.
Now our main topic valve types,
There are various types of valve for different operation and those are:
Pressure Relief Valve
The gate valve is a regular type valve that is used in any process plant. Here flow of fluid is controlled in linear motion. Gate valves are either in a fully open or fully closed position.
It is used in nearly all fluid services functioning as air, fuel gas, feedwater, lube oil, steam, hydrocarbon, and close to every system.
It has to provide a good shut off. It will not be used as a regulating or control valve because when we start to open the gate valves, the passage is slowly opened and Similarly slowly gets closed.
So that a lot of vibration and noise is created at the time of initialization and also the wear of the disc is obtained which causes disc damage which increases the risk of leakage.
So that’s why It will be either in the fully open position or in the fully closed position.
In gate valves there are different types and those are:.
Solid Wedge Gate
Flexible Wedge Gate
Split wedge or Parallel disks Gate
OS & Y Gate or (Rising Stem) of gate valves
Solid Wedge Gate Valve:
The solid wedge disk type is very strong and has very good simplicity so it is very common and widely used in plants. A solid wedge is very much flexible to install in any position. This is appropriate for almost all fluids.
It may also be used in a turbulent flow. It is one of the oldest design which is still used in various places.
The problem in this is that whenever there is a thermal expansion [Thermal Properties of Material] in this gate, the risk of getting choked increases.
So A solid wedge gate does not reimburse for changes in seat alignment due to thermal expansion or pipe loads.
This kind of disk design is most permitting to overcome the leakage. It is also used in high-temperature service, where Solid wedge is subjected to thermal locking.
Thermal locking is a situation where a wedge stays between the seats because of the expansion of the metal. These gate valves are generally used in passable to lower pressure-temperature applications.
Flexible Wedge Gate:
A one-piece solid disk with a cut throughout the perimeter is known as a flexible wedge gate. Its cuts dimensions vary in shape, size, and depth. To simplify the problem of the solid wedge, we use a flexible wedge design.
Here we cut Peripheral in the middle of its disc which gives this disk the flexibility And whenever there is any thermal expansion, a flexible wedge design will manage.
The problem is that it is not strong like a solid wedge because it has a peripheral cut in it.
For more flexibility, we consider a cast-in recess or wider and deeper cut on wedge perimeter but one of its drawbacks is that it is compromised with strength.
So this design provides better leak tightness and upgrades seat alignment. It also enhances the performance of thermal binding possible.
In steam systems, the flexible gate valves are used. There are chances of various distortion in the valves due to thermal expansion of the steam line which causes it to lead in thermal binding.
So as per this problem, we use a flexible gate to overcome the problem of thermal binding.
And one of the disadvantages of flexible gates is that it collects the fluid In the disk, which may result in weaken in disk and corrosion occurs.
Split wedge or Parallel disks Gate:
We use split dishes to fix the problem of both solid disk wedges and flexible wedge gate. So It consists of two disks that connect parallel to each other.
Normally they are spring-loaded and it is always stuck with the seat of the body of the gate, there is also another type of split disk is parallel in the shape of a disk.
Split wedge disk means it consists of two solid pieces with the help of a special mechanism where both pieces are confined in together.
If the disk’s one-half is out of positioning then the disk is free to regulate itself to the seating surface. It may be in a wedge shape or a parallel disk type where parallel disks are spring-loaded which helps in to contact with seats and provides bi-directional sealing.
The split wedge is also used for regulating noncondensing liquids and gasses at normal and high temperatures.
Thermal binding has prevented through the help of Freedom of movement of the disk. When a line is cold the valves may have been closed. which means it does not create thermal blinding whenever a line is get heated by fluid and expand.
OS & Y Gate Valve or (Rising Stem) of Gate valves:
OS & Y termed as outside stem and yoke or outside screw and yoke. It is one of the valves used to control the flow of water to fire sprinkler systems.
These valves are operated by opening and closing via a gate, and to regulate the lowers into the rises out of valves.
Water allows flowing through the valves when the gate is raising whereas lowering the gate halt the water flowing through the valves.
Globe valve Used to start-stop and regulate the fluid in it. Globe stopper occurs at a place in the system where we have to control the fluid flow, and also take into account the leakage and tightness of the system.
It is costlier than gate valves. But it provides good leakproof and tightness than gate valves. Normally the globe valves used as a control valve.
It is also used for cooling water systems, also used in transport the fuel oil, and lube oil. Its shape is in globular at the bottom side that’s why we called it a globe.
There are three types of Globe valve:
Z types globe:
Z-type globe body is the simplest design of the valve. This globular body contains a Z-shaped partition inside the tap.
The Z-type globular body is design to consider and simplifies the problems in manufacturing, installation, and repair.
These valves do not consider pressure drop but throttling is required.
Y type globe:
The Y-type valves design are used to solve the high-pressure drop problem in Z-type valves.
So due to simplifying the problem of Z-type, we configure the Y-type, where seats are angled at 45° to the axis of the pipe.
So These valves are used in high pressure and many other reproving services.
This valves able to turns the flow of fluid direction by 90 degrees without the use of an elbow and extra weld of pipe.
A Disk has open in opposition to the rise and down of the disk. In the case of fluctuating the globe valves have been used, it also competent to operate the slugging effect.
The check valves are used to prevent the backflow in the piping system. check valves allow the flow to pass in one direction.
Whenever back pressure is created in the system, Then the check spigot automatically shuts off And prevents the flow of the fluid.
This is also a nonreturn valve. So the check valves are able to check and intercept the flow of reversal.
There are three types of Check valve:
It is used in low fluid velocities and where flow reversal is not continual. It is used on the discharge side of the pressure relief valves.
In this checking device, a disc, piston, and a ball are used for checking in. A lift check is to be placed in a horizontal or vertical position.
Pressure drops are very high in this system so we used the Lift check plug which is suitable for the small pipeline.
It is stem operated and controlled manually or through a motor. These valves are available in various sizes of ranging from 6mm to 600 mm. The construction of material can be cast iron, steel, ductile iron, and corrosion-resistant alloys.
The plug valves is a quarter-turn rotary valve. In this, the disc rotates in a circular motion and uses valves to open or close.
It is called plug valves because its disc is in the plug shape and it also contains a passage.
It contains leakage of almost negligible. Plug valve has been used in vacuum services, and as can use in high-pressure services and also in high temperature.
Lubricated plug valves use a lubricant mainly consists of a base oil and viscosity improver which is injected to reduce friction and seal ports under pressure between the face of the plug and the seat body.
Lubricant is generally recommended by valves manufacturers for the process fluid, and the resealed occurs in valves after only a few cycles, whereas in some scenario, it happens after every cycle.
A high maintenance plug valves are used in most operations because it performs very efficiently in applications that have very rare or exceptional operations such as to carry mildly abrasive particle-like gas pipeline systems, dirty upstream applications, etc.
Non-lubricated plug employs a tapered or cone-shape which works as a wedge(chock) and the body cavity presses against a polymeric sleeve.
The sleeve is used to reduces the friction between the body and plug mechanism.
Non-lubricated plug valves are used where minimum maintenance is required. such them in sulfur, hydrogen fluoride, and the liquid where these can be solidified and trapped and potentially jam the valves.
So these valves are limited by the chemical and temperature compatibility of the non-metallic materials they are made of.
There are three types of non-lubricated plug valves:
Elastomer sleeved plug
Fully lined plug
The eccentric plug design is advantageous for applications that need a higher seating force and minimal friction from open to close conditions.
The design of plug valves has a half plug used for very wide applications to control the flow such as sewage, sludges and slurries, air, and clean and dirty water, and a variety of other services.
The expanding plug valve is used to prevent product contamination where double isolation does not require.
It uses various components that help to expand and provides the work of two double blocks has done in one valve.
This valve rotates between the open and closed positions and defends both seals from the flow path.
The ball valve is Rotary Turn Quarter Valve. It is in the shape of a ball. This is a quick-acting type This means we can turn off it in 0 or 90 degrees.
The ball spigot is lighter and smaller in the size and rating compare to the gate valve.
We control it as we like through the Plunger handle ourselves either clockwise or anticlockwise for on and off the valve.
We used it in the pipeline in domestic houses or in domestic uses of pipes.
The different Ball valves types:
PVC ball and
stainless steel ballValve.
The butterfly valve is also a quarter-turn rotary motion valve. It also helps in regulating flow start-stop.
Its biggest benefit is that its body is very thin so that it gives it the least space in the piping system, due to this the butterfly valve is used in many applications.
It is very compact and lightweight and it takes considerably less space as compared to other valves.
So it is very easy and fast to open. In this, the disk moves like a butterfly in a closed space.
Butterfly valve types:
Wafer Type Butterfly
Lug Type Butterfly and
Double Flange Butterfly
The needle valve design is similar to a globe valve. Its biggest difference is that its disk looks Needle-like pointed.
This is normally used in an instrument where the need for an accurate flow of fluid is necessary. This is used in a small diameter pipe.
It is very much used in applications where very low pressure can be controlled.
Applications: It is used in every industry with a wide range of applications such as: for control or metering of steam, oil, gas, water, air, or other non-viscous liquids is required.
The pinch valve has a simple mechanism and It has 1 pinch tube. This pinch tube is made of Normally rubber and in this, we can turn the Valve on and off using the pinch mechanism.
Its biggest benefit is that we can use it in a solid particle that has a lot of slurry in it.
Pinch valve types:
OM Mechanical Pinch Sleeves.
OV Mechanical Pinch.
VM Air Operated Pinch.
VF Air Operated Pinch.
VT Air Operated Tanker Pinch.
VMF Air Operated Pinch.
VMP Air Operated Pinch.
Pressure relief valve:
The pressure relief releases the pressure whenever an overpressure event occurs in the pressure relief piping system or in the equipment, and the vacuum that is created by it is getting abolished by vacuum valves and protect the piping system.
In this paper, we will study the definition, Construction, Working principle, Advantages, Disadvantages, and Application of Lancashire Boiler.
Make sure if you want to download the PDF version then at the end of the article you will get it.
Now we will understand the definition of Lancashire Boiler,
Table of Contents
Lancashire Boiler Definition:
Lancashire Boiler is an internal fire tube boiler and similar to the cornish boiler in which the flue gases are in the tube and water is surrounding them. As the temperature is maximum so the water gets converted into the steam and that steam used at several places for different operations. The Lancashire boiler is used in the marine or locomotive industry.
Now come to construction of Lancashire Boiler,
Lancashire Boiler Parts or Construction:
Lancashire Boiler consists of following Main Parts:
Feed check valve
Water Level Indicator
Blow off valve
Steam stop valve
Now let us study one by one in detail,
The shape of the shell is in cylindrical and it is the outermost part of the Lancashire boiler. The other parts of the Lancashire boiler are present inside the boiler shell.
Safety Valves prevents from the boiler busting. A safety Valve is used to Blow off the steam when their pressure is exceeded.
It is a device that is used for getting information related to boiler pressure. When the pressure is maximum and minimum it will indicate the value of pressure inside the boiler.
Water Level Indicator:
It is an important part of the system it helps to regulate the flow of water into the boiler and it checks the level of water in the system when there is less water and needed than with the use of a feed pump the water is supplied.
Blow off valve:
The blow-off valve is used to remove the wastes that are sediment or muds which are accumulated at the bottom of the boiler. These muds need to be fixed because it can create problems during operation.
Steam stop valve:
The main function of the steam stop valve is to stop the steam flowing from the boiler to the steam pipe.
At the fire door, the solid fuel is placed and have to ignite them for burning to produce flue gases inside the boiler. From the fire door, the solid fuel is ignited.
Feed check valve:
It is like controlling the flow of water into the boiler and also prevent the backflow of the water from the boiler to the pump.
Fusible plug work is similar to safety valve that helps from bursting.
The fusible valve is used when the safety valve does not work and the boiler pressure exceeds the pressure limit then The steam generated from the boiler goes out of the boiler and prevents from bursting.
The fuel is burnt and it converted into ashes and that ash comes into the ash pit. The ash pit collects the whole ashes after the solid fuel coal is burnt.
The economizer is an external and mechanical component that is used to increase the efficiency of the boiler.
The work of the economizer is to pre-heat the water by taking the residual heat which is flue gases.
When the boiler gets any problem like wear and tear or any parts is not working or it may be any problem then a Boiler skilled operator is entered the boiler to fix the problem.
This is similar to an economizer that helps to increase boiler efficiency. It recovers heat in the exhaust gases by heating the air supplied to the furnace.
The superheater is used to superheat the steam that is generated in the boiler. It gets heat from the flue gases. Here the temperature is much higher.
Now working of Lancashire Boiler,
Lancashire Boiler Working Principle:
The Lancashire Boiler works on the principle of Heat Exchanger. Heat Exchanger is a device that is used for the transfer of heat between two or more than two fluids.
The solid fuel that is coal is placed at the grate for burning and producing heat. The water is pumped into the system by using a feed pump.
Now supplying the heat to the coal to start burning. When it burns it produces flue gases and that flue gas is sent to the fire tube of the boiler.
Here the water is surrounding the tube. The flue gases have maximum temperature and also with the use of superheater, it increases the temperature.
So that the water starts evaporating and is fully converted into the saturated steam and meanwhile some amount of flue gases is also passing through the bottom and side passage that also helps to heat the water.
The amount of steam generated is controlled by the steam regulating and stop valve. And meanwhile with the use of a water level indicator, will check the water level if the water is required then we have to supply the water.
At the grate, there is an arc in which the burning coal ashes stores so that it can not mix with the flue gases.
Through the chimney the waste gases is released to the environment.
Now for better efficiency, we use a device that is an economizer. The economizer helps the water to preheat and then it entered into the system.
Generally, the boiler length is 8 to 9 meters and 2 to 3 meters in boiler diameter. The pressure range is 16 bar. The steam production rate is 9000 kg/hr. Depending on the type of fuel used the efficiency varies.
Features of Lancashire Boiler:
The features of Lancashire Boiler includes:
Lancashire boiler, overall efficiency is higher than a fire tube boiler.
The component which is in the boiler can be inspected during the operation also and when there is no operation then we can easily inspect the component.
If the tubes get infected it can be replaced easily.
There is a minimum draught loss compared with other boilers.
To promote the circulation of water the water tube kept at 10 to 10 degrees Celsius.
Lancashire Boiler Advantages:
There are some advantages and those are:
The clean and inspection are easy in this boiler.
The operation is easy.
Maintenance is less required.
It is a natural circulation boiler therefore the consumption of electricity is less.
It has a high thermal efficiency of around 90 percent.
Lancashire boiler can easily meet the load requirement.
Lancashire Boiler Disadvantages:
The disadvantages of Lancashire boiler is:
More space required for this boiler because the size is big.
The steam generation is not high like other fire tube boiler.
Grates area is limited because It is situated at the inlet of the fire tube, which has a small diameter.
There is having a problem with leakage.
For a steam generation, it takes much time.
Lancashire Boiler Application:
The following application of Lancashire Boiler is:
The Lancashire boiler used in industries like sugar mill and tire industries.
The amount of steam generated from this boiler is used to drive steam turbines, which helps to generate electricity.
It is also used in the locomotive system and marine engine too.
The Mechanical properties of a material affect how they behave as it loaded.
The Mechanical properties of a material are those which affect the mechanical strength and ability of a material to be molded in a suitable shape
Mechanical Properties of Material:
The Mechanical Properties includes Elasticity, Plasticity, Ductility, Malleability, Hardness, Toughness, Brittleness, Tenacity, Fatigue, Fatigue resistance, Impact Resistance property, Machineability, Strength, Strain Energy, Resilience, Proof Resilience, Modulus of Resilience, Creep, Rupture, and Modulus of Toughness.
Now we will study one by one in simple and understandable language.
Such property of material from which if we pull it and leave it, then it will come back in its shape again, it is called Elasticity. This property is useful for materials used in tools and machines.
E.g. steel is more elastic than rubber.
Such a property of material from which if we pull but it cannot regain its original position when leaving it, then it is called plasticity.
Eg: This property of the material is compulsory for forgings, in stamping images on coins and ornamental work.
Such property of a material that we can pull and make it into long wire form, we call it Ductility. A ductile material needs to both strong and plastic. e.g. The ductile material used in mild steel, copper, aluminum, nickel, zinc, tin, and lead.
If we beat any metal that causes it to spread and form into a sheet form, So we call this property Malleability. A malleable material needs to be plastic but it is not essential to be strong.
E.g. Malleable material is used in engineering practice is lead, soft steel., wrought iron, copper, and aluminum.
Suppose there is a metal and we have to scratch it, The harder the scratch is, the harder our material will be considered.
Suppose we have a material called iron and on the other side is silver aluminum So if we impact on both, the highest impact will be on aluminum because it is a weak metal and its hardness is less.
But if we talk about iron, It will be more difficult to scratch on the sheet of iron if we compare it with aluminum, so hardness will be more of iron. So a hard material that we cannot easily scratch, is equally hard.
The hardness of a metal is determined by various of tests :
Brinell hardness test
Rockwell hardness test
Vickers hardness test (also called Diamond Pyramid ) test, and
Material that if we bend or twist, how much energy can absorb before it breaks is called Toughness.
The toughness of the material has been decreased when it is heated. So Toughness is properties that provide information about the capacity to absorb maximum energy. In this, we suddenly impact and check how much energy is absorbed at that time.
The toughness of metal is determined by Impact testing machine.
It has a pendulum that suddenly attacks the material, and connects its maximum energy absorbing capacity.
Impact testing has done by two types
Suppose we have a material and we impact it and it should be broken, without deform is called Brittleness. Or If we pull such a material, it breaks instead of pulling it, we call it Brittleness. e.g. Cast iron is a brittle material.
Such material on which we apply pressure, bend, and pull, but do not break it in that condition is called Tenacity.
When a material loads more than a specific load, then there is a chance of failure But in fatigue, Any material fails even at low load if we apply a repetitive load. This failure is known as fatigue.
Fatigue value is many times less than that stress, in which a material has to fail in actual. The factor of fatigue on materials: Less strength, life, and Durability.
E.g. Fatigue property is used for observing In designing shafts, connecting rod, springs, gears, etc.
Causes of fatigue in the material: 1. Dynamic forces 2. Repetitive load/stress
In spite of repetitive loads on a material, it is not broken then it is its fatigue property. E.g. Road
Let’s say we took the material and hit it with a hammer, So the more he can bear the injury of that hammer without breaking, as much his impact resistance will be high.
Such a material that is easy to work on, such as cutting, using a tool, and machining, we call it machinability. E.g. Brass can be easily machined than steel.
If we put a load on metal, it is without changing its shape or if it is able to bear it without breaking it then it is called its strength. So the ability or capacity of a material to withstand or support a load without fracture is called its strength.
If we put a load in a body or material, then the body is elastic up to a particular limit in the stress-strain curve, so the energy that the body stores up to that elastic limit is called Strain energy.
Such material in which the strain energy is stored in the body till the elastic limit only, is called as the resilience. so it is the property of a material to absorb energy and to resist shock and impact loads. This property is essential for spring materials.
How much maximum strain energy stored in material up to the elastic limit is called proof resilience.
Modulus of Resilience
If we divide the proof resilience from the volume of body, then it will come out with the Modulus of Resilience.
When we put the material under constant load, for a long time, at high temperature, then the deformation that happens inside it, is called Creep. It is also known as cold flow. Creep is used for examine in designing internal combustion engines, boilers, and turbines.
Rupture meaning is a break or burst suddenly. Stress rupture testing is similar to creep testing except that the stresses are higher than those used in creep testing.
E.g. pipe or container
Modulus of Toughness
It is defined as the ability of a material to absorb energy in plastic deformation or fracture point.
Hello, reader in the last article we explained the piston of the engine in detail. The connecting rod is also a part of an IC Engine. Today we will study the Definition, Parts, Types, Function, and Material.
And at the end of the article you can download PDF version.
So lets start with the definition first,
Table of Contents
Connecting rod Definition:
The connecting rod is defined as it is a mechanical component that helps to connect the piston and crankshaft of the engine. In other words, you can say it acts as an intermediate member between the piston and the cylinder.
Connecting rod Parts or Construction:
The following construction is:
Bolt and nut
It connects to one side with the pistol pin and the other side connects with the crank.
Small and Bigger End:
The rod which is facing the piston side is termed as a small end. And which is on the crank side is termed as a bigger end.
There is a bearing insert inside the bigger end which is attached to the cap, which is called the bearing insert.
Apart from this, both the bolt and nut acts to connect the connecting rod and cap. And we use a section beam which we call a shank. The cross-section of the rod can be rectangular, tubular, and be a circular section.
The length of the rod depends on the ratio of (l/r) Where, l = length of the shank and r = radius of the shank.
If the length is low then the l/r ratio will also be low, Due to this, the rod will increase in angularity due to which the side thrust on the piston will increase which causes increasing linear wear.
In the same way, if the length is more then the ratio of l / k will be more. Due to this, the angularity of the rod will decrease, so due to this, the side thrust on the piston will also decrease which causes less wear is obtained in the cylinder.
Note: The higher the length, the more the engine size will also increase, so the ratio of l/r is kept between 4 and 5.
Bush and bearing:
Bush and bearing are installed at both ends of the connecting road. The phosphor bronze bush is placed near the small end of the rod and the piston pin is connected with the smallest end piston.
The big end stays connected with the crank and the big end of the rod is divided into two half which we can easily mount above the crank bearing shell.
And then after connecting the rod with the crank in the last, both sides of the big end are joined with the help of nuts and bolts. So by combining all these we prepare the connecting rod.
Connecting rod Function:
The pull and push in the piston receive the piston pin, then the connecting rod acts as the transfer of the pull and pushes from the piston pin to the crank pin. That is, in any internal combustion engine with the help of it, the reciprocating motion is converted to rotary motion.
In the design requirements of the rod, the bearings are connected with the cap so that we have accurate and smooth rotation. Same as bush near the smaller end to fit to get accurate and smooth motion.
So It is connected to the piston pin or gudgeon pin on one side. And connected to the crankshaft on the other side, so the movement of the piston gives to the crank through the rod.
Connecting Rod Material:
These are the five materials which we use in the connecting rod:
Mild carbon steel,
Alloy cast iron,
Graphite cast iron and
Manufacturing process: It is made from the drop forging process.
Connecting rod Lubrication Function:
Bearing is attached to both ends of the rod so we lubricate the bearing in two ways.
Splash lubrication is done in the bearings in the big end of the crankshaft. And pressure lubrication is done in the small end bearing.
In splash lubrication, a sprout is placed at an angle, so that whenever the rod is down, the sprout is inserted into the lubricating oil.
So that the lubricating oil reaches the end of the bearings through the sprout. So when this rod goes up, the sprout causes the oil to splash, so we call it to splash lubrication.
In pressure lubrication, the end of the connecting rod has a hole near the bearing, And there the oil pressure is sent for lubrication which we call pressure lubrication.
Connecting rod Types:
This mainly of two types depending on the structure
Single piece and
Two pieces or split piece of connecting rod
Single piece connecting rod:
The big end of a single rod is made in one part instead of two. A needle bearing is fitted in it
Two-piece or split piece of connecting rod:
This type of connecting rod in which consists big end is made up of 2 pieces
Let us also know about the bush and bearing of the connecting rod:
A bush made of bronze or gunmetal is fitted between the connecting rod’s small end and piston. The bearing on the big end is made up of :
Low carbon steel
Copper lead alloy
Copper tin alloy
Tin antimony alloy
Tin antimony copper alloy
Lead indium alloy
Lead bronze alloy
And tin aluminum alloy
Apart from this, the bearing is in 2 pieces, it is placed near the big end of the rods. The flange is used to prevent the moment between the two pieces.
It is mainly two types
Running bearing clearance
Side bearing clearance
Running bearing clearance It is the clearance between bearing and the crank surface.
Side bearing clearance This is the clearance between the crankpin and the crank arm (Big end) thrust side.
Connecting Rod Inspection:
Normally the connecting rod is not crooked but can sometimes be bent due to preignition and detonation. Then it is inspected while fixing it.