1. How and Why Machines Work
By:- Dr. Gaurav Kumar Gugliani
2. • Unit 1:
• Introduction to Mechanical Engineering: what is Mechanical
Engineering,Engineering Way of Thinking, identification of main parts of a
technical problem, Modeling & estimation,Mechanical Engineering
(ME):Developing the mechanical solutions of a problem using basic, applied, &
experimental means. Explore what is a Machine and Mechanism,
understanding elements, links , pairs and mechanisms and formation of
various systems in a Machine, why the machines are used, Machines and their
contribution in the development of society, MechanicalAdvantage. Flow
Balances in a Machine such as (Mass, Energy , Momentum,Power ), Control
volume approach, Mass balance in a MachineExample : filling and emptyingof
a vessel with a fluid, Hydraulic Cylinders, Ballons etc.. A brief Classification of
Machines .
•
• Unit II :
•
• Basics of operations of an Engine : How and why an engine ( its function &
working) its utility and contribution in the development of society, a brief
description of component parts of an engine, The performance parameters of
an engine, Thermodynamic analysis of an engine, Market specifications of an
engine, Fault finding (diagnosis & Maintenance), Spare parts of an engine,
Single cylinder and Multi Cylinder engines, Working of a locomotive engine
system its specifications, diference between an earthmover and locomotive.
•
3. • Unit III:
•
• Basic hydraulic machines & components: Pumps : Hydraulic pump and motor equations,
Reciprocating and centrifugal pumps:utility of a pump , Component parts of a pump , Market
specifications , working of a pump, installation of a pump on a sumpwell technical
requirements and procedure, NPSH, Manometric efficiency, Head and discharge of a pump
and practical significance of these terms, Pump ,Motor and cylinder (Mass,energy and Power
flow balance), Control volume approach, SFEE & Bernoulli’s Equation, Submersible Pump its
assembly , working and installation,
• Maintenance techniques of a pump , Hydraulic Turbines An overview.
•
• Unit-IV:
• Power Transmission systems in Machines, Belt, Rope & chain drives: their industrial
applications, Gear trains, Sun and planet gear train, Epicyclic Gear train, Train ratio
calculations, Alarm clock gear train : technical analysis, Tractor transmission system analysis,
Threaded mechanisms involved in power transmission and load lifting, Analysis of torque on
a rotor of a DC Machine, How keep the machines moving an analysis : Mechanical and
electrical power transmission.
•
• Unit–V:
• Machine components : elements: various types of Nuts and Bolts used in engineering
practice thier trade specifications, rivets, cotter, pins, screws,shafts, cluthes, bearings market
specifications etc.
•
• Sealing and packings : gaskets, rings, valves and their industrial applications, various types of
pipes.
4. What is Mechanical Engineering?
Mechanical engineering is a discipline of engineering that applies the principles of
physics and materials science for analysis, design, manufacturing, and maintenance
of mechanical systems. It is the branch of engineering that involves the production
and usage of heat and mechanical power for the design, production, and operation
of machines and tools. It is one of the oldest and broadest engineering disciplines.
Why study Mechanical Engineering?
If you’re interested in the design, development, installation, operation or
maintenance of just about anything that has moveable parts then mechanical
engineering could be the programme of study for you
5. What is Mechanism?
It is combination of a number of bodies assembled in such a way that the motion of one
causes constrained and predictable motion of the others is known as a mechanism. Thus,
the function of a mechanism is to transmit and modify a motion.
Examples: Typewriter, Spring Toys, clock, watches , Slider crank Mechanism etc.
What is Machine ?
A machine is a mechanism or a combination of mechanism which apart from imparting
definite motions to the parts, also transmits and modifies the available mechanical energy
into some kind of desired work. It is neighter a source of energy nor a producer of work
but helps in proper utilization of the same. The motive power has to be derived from
external sources.
Examples: Engine, Compressor, Pump, Steam Engines Etc.
7. Mechanism Classification:
Kinematics: It deals with the relative motions of different parts of a mechanism
without taking into consideration the forces producing the motions. Thus, it is
the study, from a geometric point of view, to know the displacement, velocity
and acceleration of a part of a mechanism.
Dynamics: It involves the calculations of forces impressed upon different parts of
a mechanism. The forces can be either static or dynamic.
Dynamics is further classified into static and kinetics.
Kinetics is the study of forces when the body is in motion
statics deals with forces when the body is in stationary condition.
9. Link (element):
A resistant body or a group of resistant bodies with rigid connections preventing
their relative movement is known as Link.
A link may also be defined as a member or a combination of members of a
mechanism, connecting other members and having motion relative to them. Thus,
a link may consist of one or more resistant bodies.
Example: A slider crank mechanism has four link, viz., frame and guides, crank,
connecting-rod and slider.
The crank link may have a crankshaft and flywheel also, forming one link having no
relative motion between them.
Types of Link (It is depend upon the number of turning pair at its end):
Binary
Ternary
Quarternary
10.
11. Kinematics Pair: A kinematic pair or simply a pair is a joint of two links having
relative motion between them.
Classification of kinematic Pairs are based on:
Nature of contact
• Lower Pair
• Higher Pair
Nature of mechanical constraint
Closed Pair
Unclosed Pair
Nature of relative motion
Sliding Pair
Turning Pair
Rolling Pair
Screw Pair (Helical Pair)
Spherical Pair
12.
13. Closed Pair: When the element of the pair are held together mechanically, it is
known as a closed pair. The two elements are geometrically identical; one is
solid and other is hollow or open. The latter not only envelope the former but
also encloses it. The contact between the two can be broken only by
destruction of at least one of the members.
Unclosed pair: when two links of a pair are in contact either due to force of
gravity or some spring action., they constitute an undisclosed pair.
14. Sliding pair: If two links have a sliding motion relative to each other, they form
a sliding pair. Eg. A rectangular rod in a rectangular hole in a prism.
Turning pair: When one link has a turning or revolving motion relative to the
other, they constitute a turning or revolving pair. E.g. All pair in slider and
crank mechanism except slider and guide pair
Rolling pair: When the links of a pair have a rolling motion to each other, they
form a rolling pair, e.g., a rolling wheel on a flat surface, ball and roller
bearings etc.
Screw Pair: If two mating links have a turning as well as sliding motion
between, they form a screw pair. Eg. Lead screw in a lathe machine
Spherical Pair: When one link in the form of a sphere turn inside a fixed link, it
is a spherical pair. E.g. ball and socket joint
15. Based on application, machines are classified into three main types:
1. Machines generating mechanical energy: The machines generating mechanical energy are
also called as prime movers. These machines convert some form of energy like heat,
hydraulic, electrical, etc into mechanical energy or work. The most popular example of these
machines is the internal combustion engine in which the chemical energy of the fuel is
converted into heat energy which in turn is converted into mechanical work in the form of
the rotation of the wheels of the vehicle. Some other examples of this group of machines
are gas turbines, water turbines, steam engine etc.
2. Machines transforming mechanical energy: These machines are called converting machines
because they convert mechanical energy into other form of energy like electricity, hydraulic
energy etc. Some examples of these machines are electric generator in which the rotation of
the shaft is converted into electrical energy, and hydraulic pump in which the rotation
energy of the rotors is converted into the hydraulic energy of the fluid.
3. Machines utilizing mechanical energy: These machines receive mechanical energy and
utilize it for various applications. Some examples of these machines are lathe machine that
utilizes the mechanical energy to cut metals and washing machine that utilizes the rotation
of the rotor for washing the clothes.
16. Flow Balance Equation:
Mass Balance Equation: The law of conservation of mass or principle of mass
conservation states that for isolated system, the mass of the system must remain
constant over time.
Energy Balance Equation : First Law of Thermodynamics is the statement of
conservation of energy: the law of conservation of energy states that the
total energy of an isolated system remains constant; it is said to be conserved over
time. This law means that energy can neither be created nor destroyed; rather, it can
only be transformed or transferred from one form to another.
Momentum Equation: Based on Newton 2nd Law: The principle of conservation of
momentum states that in an isolated system, two objects that collide have the same
combined momentum before and after the collision. That is, momentum is not
destroyed in the collision, but transferred between the two objects. In an isolated
system, momentum is always conserved in a collision. In the example of you catching
a baseball, the momentum from the ball is transferred into your hand.
Net force acting on the fluid mass= change in momentum of the flow per unit time
in that direction
17. System : A system is defined as a fixed, identifiable quantity of mass; the system boundaries
separate the system from the surroundings. The boundaries of the system may be fixed or
movable; however, no mass crosses the system boundaries.
Control Volume: A control volume is an arbitrary volume in space through which fluid flows.
The geometric boundary of the control volume is called the control surface. The control
surface may be real or imaginary; it may be at rest or in motion
18. Example: A reducing water pipe section has an inlet diameter of 50 mm and exit
diameter of 30 mm. If the steady inlet speed (averaged across the inlet area) is 2.5
m/s, find the exit speed.
20. ENGINE & WORKING PRINCIPLES
A heat engine is a machine, which converts heat energy into mechanical energy. The
combustion of fuel such as coal, petrol, diesel generates heat. This heat is supplied
to a working substance at high temperature. By the expansion of this substance in
suitable machines, heat energy is converted into useful work. Heat engines can be
further divided into two types: (i) External combustion and (ii) Internal combustion.
In a steam engine the combustion of fuel takes place outside the engine and the
steam thus formed is used to run the engine. Thus, it is known as external
combustion engine.
In the case of internal combustion engine, the combustion of fuel takes place inside
the engine cylinder itself. The IC engine can be further classified as: (i) stationary or
mobile, (ii) horizontal or vertical and (iii) low, medium or high speed. The two distinct
types of IC engines used for either mobile or stationary operations are: (i) diesel and
(ii) carburettor.
21.
22. Spark Ignition (Carburetor Type) IC Engine
In this engine liquid fuel is atomized, vaporized and mixed with air in correct
proportion before being taken to the engine cylinder through the intake
manifolds. The ignition of the mixture is caused by an electric spark and is
known as spark ignition.
Compression Ignition (Diesel Type) IC Engine In this only the liquid fuel is
injected in the cylinder under high pressure.
23. Drawback of Single Cylinder Engine
A single-cylinder engine gives only one power stroke per revolution (two-stroke cycle) or two
revolutions (four-stroke cycle). Hence, the torque pulses are widely spaced, and engine vibration
and smoothness are significant problems.
Multicylinder Engine:
As rated power increases, the advantages of smaller cylinders in regard to size, weight, and
improved engine balance and smoothness point toward increasing the number of cylinders per
engine.
An upper limit on cylinder size is dictated by dynamic considerations: the inertial forces that are
created by accelerating and decelerating the reciprocating masses of the piston and connecting
rod would quickly limit the maximum speed of the engine. Thus, the displaced volume is spread
out amongst several smaller cylinders. The increased frequency of power strokes with a
multicylinder engine produces much smoother torque characteristics.
Multicylinder engines can also achieve a much better state of balance than single-cylinder
engines. A force must be applied to the piston to accelerate it during the first half of its travel
from bottom-center or top-center. The piston then exerts a force as it decelerates during the
second part of the stroke. It is desirable to cancel these inertia forces through the choice of
number and arrangement of cylinders to achieve a primary balance. Note, however, that the
motion of the piston is more rapid during the upper half of its stroke than during the lower half
(a consequence of the connecting rod and crank mechanism evident from Fig. 1-1; see also Sec.
2.2). The resulting inequality in piston acceleration and deceleration produces corresponding
differences in inertia forces generated. Certain combinations of cylinder number and
arrangement will balance out these secondary inertia force effects.
24. The ignition of diesel fuel pushes pistons connected to an electric generator. The
resulting electricity powers motors connected to the wheels of the locomotive. A
“diesel” internal combustion engine uses the heat generated from the compression of air
during the upward cycles of the stroke to ignite the fuel. The inventor Dr. Rudolph Diesel
designed this type of engine. It was patented in 1892.
Diesel fuel is stored in a fuel tank and delivered to the engine by an electric fuel pump.
Diesel fuel has become the preferred fuel for railroad locomotive use due to its lower
volatility, lower cost, and common availability.
The diesel engine (A) is the main component of the diesel-electric locomotive. It is an
internal combustion engine comprised of several cylinders connected to a common
crankshaft. Fuel is ignited by the intense compression, pushing the piston down. The
piston’s movement turns a crankshaft.
How Diesel Locomotive work
25. The diesel engine is connected to the main generator (B), which converts the engine’s
mechanical power to electrical power. The electricity is then distributed to traction
motors (C) through circuits established by various switchgear components.
Because it is always turning, whether the locomotive is moving or not, the main
generator’s output is controlled by the excitation field current to its windings.
The engineer controls the power output of the locomotive by using an electrically-
controlled throttle. As it is opened, more fuel is injected into the engine’s cylinders,
increasing its mechanical power output. Main generator excitation increases,
increasing its electrical output.
Each traction motor (C) is directly geared to a pair of driving wheels. The use of
electricity as the “transmission” for the locomotive is far more reliable than using a
mechanical transmission and clutch. Starting a heavy train from a dead stop would
burn out a clutch in a brief time.
How Diesel Locomotive Work
26. Depends on the train. Trains will generally be either diesel, diesel-electric, electric, or
occasionally a combination of them.
A diesel train is essentially a big bus on rails. A diesel engine directly drives the wheels through a
gearbox.
More common is diesel-electric, where a diesel engine drives a generator. The power from that
generator drives electric motors mounted on the bogies.
Electric trains take power from an overhead line and/or a third/fourth rail. Some fancy power
electronics are used to drive electric motors on the bogies. One major advantage is that they
can use regenerative braking, where the train actually uses its kinetic energy to generate
electricity (slowing itself in the process) and then return that power to the supply system. If
planned correctly so that one train is accelerating in a section while another brakes this can
result in significant cost savings for operators (and a much lower carbon footprint).
Typically passenger trains are electric and freight trains are diesel-electric, but that’s a gross
oversimplification.
28. Component Parts of Centrifugal Pump
Impeller: An impeller is a wheel (or rotor) with a series of backward curved vanes
(or blades). It is mounted on a shaft which is usually coupled to an electric motor.
The impellers are of following three types:
Shrouded or closed impeller
Semi-open impeller
Open impeller
Casing: The casing is an airtight chamber surrounding the pump impeller. It
contain suction and discharge arrangements, supporting for bearings, and
facilitates to house the rotor assembly.
The essential purpose of casing are:
To guide water to and from the impeller,
To partially convert the kinetic energy into pressure energy
Types of casing
Volute casing
Vortex casing
Casing with guides blades
Suction Pipe : The pipe which connects the centre/ eye of the impeller to sump
from which liquid is to be lifted is known as suction pipes
Delivery Pipe: The pipe which is connected at its lower end to the outlet of the
pump and it delivers the liquid to the required height is known as delivery pipe
29.
30.
31.
32. Net Positive Suction Head
NPSH is a term used to check cavitations in the pump
Hsv = Ha-Hs-Hv
Where: Hsv: NPSH
Ha: Atmospheric pressure head
Hs: Suction Pressure head
Hv: Vapour pressure head
33.
34. Head of a Pump:
(a)Static head (b) Manometric head (c) Gross head
36. The difference in total head across the pump known as manometric head, is always less than the
quantity because of the energy dissipated in eddies due to friction.
The ratio of manometric head H and the work head imparted by the rotor on the
fluid (usually known as Euler head) is termed as manometric efficiency . It represents the
effectiveness of the pump in increasing the total energy of the fluid from the energy given to it by
the impeller. Therefore, we can write
Work done per unit weight of the fluid=
37. Routine maintenance (Can be made during pump
operation)
Perform the following tasks whenever you perform routine
maintenance:
Clean bearing bracket from any oil if found.
Check oil drain plug.
Lubricate the bearings.
Inspect suction and discharge flanges for any leak.
Inspect pump casing for any unusual damage signs.
Inspect the seal.
If the pump is offline check the coupling and its shims for
any damage.
Make sure that the coupling guard s well tightened to
pump base plate.
Check that motor alignment bolts are all in place.
46. Gear Train:
When two or more gears are made to mesh with each other to transmit power from
one shaft to another. Such a combination is called gear train or train of toothed
wheels. The nature of the train used depends upon the velocity ratio required and
the relative position of the axes of shafts. A gear train may consist of spur, bevel or
spiral gears.
Types of Gear Trains
1. Simple gear train,
2. Compound gear train
3. Reverted gear train
4. Epicyclic gear train
47. Simple Gear Train When there is only one gear on each shaft, it is known as simple gear
train. The gears are represented by their pitch circles. When the distance between the
two shafts is small, the two gears 1 and 2 are made to mesh with each other to transmit
motion from one shaft to the other. Since the gear 1 drives the gear 2, therefore gear 1
is called the driver and the gear 2 is called the driven or follower. It may be noted that
the motion of the driven gear is opposite to the motion of driving gear
48. Compound Gear Train:
When there are more than one gear on a shaft, it is called a compound train of gear.
whenever the distance between the driver and the driven or follower has to be
bridged over by intermediate gears and at the same time a great ( or much less )
speed ratio is required, then the advantage of intermediate gears is intensified by
providing compound gears on intermediate shafts. In this case, each intermediate
shaft has two gears rigidly fixed to it so that they may have the same speed.
49. Reverted Gear Train When the axes of the first gear (i.e. first driver) and the last gear (i.e.
last driven or follower) are co-axial, then the gear train is known as reverted gear train as
shown in Fig. 13.4. We see that gear 1 (i.e. first driver) drives the gear 2 (i.e. first driven or
follower) in the opposite direction. Since the gears 2 and 3 are mounted on the same
shaft, therefore they form a compound gear and the gear 3 will rotate in the same
direction as that of gear 2. The gear 3 (which is now the second driver) drives the gear 4
(i.e. the last driven or follower) in the same direction as that of gear 1. Thus we see that
in a reverted gear train, the motion of the first gear and the last gear is like.
50. Epicyclic gear train: In an epicyclic gear train, the axes of the shafts, over which the
gears are mounted, may move relative to a fixed axis. A simple epicyclic gear train is
shown in Fig. 13.6, where a gear A and the arm C have a common axis at O1 about
which they can rotate. The gear B meshes with gear A and has its axis on the arm at O2 ,
about which the gear B can rotate. It the arm is fixed, the gear train is simple and gear A
can drive gear B or vice- versa, but if gear A is fixed and the arm is rotated about the axis
of gear A (i.e. O1 ), then the gear B is forced to rotate upon and around gear A. Such a
motion is called epicyclic and the gear trains arranged in such a manner that one or
more of their members move upon and around another member are known as epicyclic
gear trains (epi. means upon and cyclic means around). The epicyclic gear trains may be
simple or compound. The epicyclic gear trains are useful for transmitting high velocity
ratios with gears of moderate size in a comparatively lesser space. The epicyclic gear
trains are used in the back gear of lathe, differential gears of the automobiles, hoists,
pulley blocks, wrist watches etc.
51. Compound Epicyclic Gear Train—Sun and Planet Gear: It consists of two co-axial shafts S1
and S2 , an annulus gear A which is fixed, the compound gear (or planet gear) B-C, the sun
gear D and the arm H. The annulus gear has internal teeth and the compound gear is
carried by the arm and revolves freely on a pin of the arm H. The sun gear is co-axial with
the annulus gear and the arm but independent of them. The annulus gear A meshes with
the gear B and the sun gear D meshes with the gear C. It may be noted that when the
annulus gear is fixed, the sun gear provides the drive and when the sun gear is fixed, the
annulus gear provides the drive. In both cases, the arm acts as a follower.
52. Train ratio calculations:
The speed ratio (or velocity ratio) of gear train is the ratio of the speed of the driver to the
speed of the driven or follower and ratio of speeds of any pair of gears in mesh is the inverse
of their number of teeth, therefore
It may be noted that ratio of the speed of the driven or follower to the speed of the
driver is known as train value of the gear train
53. It may be noted that when the number of intermediate gears are odd, the motion of
both the gears (i.e. driver and driven or follower) is like
if the number of intermediate gears are even, the motion of the driven or follower
will be in the opposite direction of the driver
we see that the speed ratio and the train value, in a simple train of gears, is
independent of the size and number of intermediate gears. These intermediate gears
are called idle gears, as they do not effect the speed ratio or train value of the system.
The idle gears are used for the following two purposes : 1. To connect gears where a
large centre distance is required, and 2. To obtain the desired direction of motion of
the driven gear (i.e. clockwise or anticlockwise).
54. Power Screw:
A power screw is a drive used in machinery to convert a rotary motion into a
linear motion for power transmission.
It produces uniform motion and the design of the power screw may be such that
(a) Either the screw or the nut is held at rest and the other member rotates as it
moves axially. A typical example of this is a screw clamp.
(b) Either the screw or the nut rotates but does not move axially. A typical
example for this is a press.
Applications:
Jack screws
lead screws of a lathe
screws for vices, presses etc.
55. Types of Power Screw
Square threads
Acme or Trapezoidal threads
Buttress Thread
Square threads: These threads have high efficiency but they are difficult to
manufacture and are expensive.
56. Acme or Trapezoidal Screw: These threads may be used in applications such as
lead screw of a lathe where loss of motion cannot be tolerated. The included angle
2φ = 290
57. Buttress Thread: This thread form can also be used for power screws but they can
transmit power only in one direction. Typical applications are screw jack, vices etc.
58. POWER TRANSMISSION SYSTEM
Transmission is a speed reducing mechanism, equipped with several gears (Fig. 1). It
may be called a sequence of gears and shafts, through which the engine power is
transmitted to the tractor wheels. The system consists of various devices that cause
forward and backward movement of tractor to suit different field condition. The
complete path of power from the engine to the wheels is called power train.
Function of power transmission system:
(i) to transmit power from the engine to the rear wheels of the tractor,
(ii) to make reduced speed available, to rear wheels of the tractor,
(iii) to alter the ratio of wheel speed and engine speed in order to suit the field
conditions and
(iv) to transmit power through right angle drive, because the crankshaft and rear axle
are normally at right angles to each other.
The power transmission system consists of:
(a) Clutch (b) Transmission gears (c) Differential (d) Final drive (e) Rear axle (f) Rear
wheels. Combination of all these components is responsible for transmission of
power.
66. Batteries for the EV
The batteries that are used for electric cars are rechargeable.
Flow of electrons can be reversed to “reload” the negative
electrode and makes the battery rechargeable.
67. Analysis of torque on a rotor of a DC Machine
Rotating Electrical Machine: D.C machines, Induction machines, Synchronous machines etc.
Work as: 1}Motor 2} Generator.
Consist of: 1} Driving Torque 2} Opposing Torque
Generator mode:
The driving torque is obtained by prime movers (Diesel Engine, Water Turbine, Steam
Turbine etc.)
The direction of rotation of the generator is same as the direction of the prime mover
torque.
A loaded electrical rotating machine always produces electromagnetic torque Te
Te together with small frictional torque is the opposing torque in generator mode.
This opposing torque is called the load torque, TL. If one wants to draw more electrical
power out of the generator, Te (hence TL) increases due to more armature current.
Therefore, prime mover torque must increase to balance TL for steady speed operation
with more fuel intake.
68. Motor Mode:
In case of motor mode, the driving torque is the electromagnetic torque, Te and
direction of rotation will be along the direction of Te.
Here the opposing torque will be due to mechanical load (such as pumps, lift, crane,
blower etc.) put on the shaft and small frictional torque.
In this case also the opposing torque is called the load torque TL.
For steady speed operation, Te = TL numerically and acts in opposite direction.
69. • If it is acting as a motor, electromagnetic torque Te acts along the direction of the
rotor rotation and the load torque TL acts in the opposite direction of rotation as
shown in the figure (a). If Te = TL motor runs steadily at constant speed. During
transient operation, if Te > TL, motor will accelerate and if Te < TL motor will
decelerate.
• On the other hand, if the machine is acting as a generator, the prime mover torque
Tpm acts along the direction of rotation while the electromagnetic torque, Te acts in
the opposite direction of rotation as shown in figure (b). Here also during transient
operation if Tpm > TL, the generator will accelerate and if Tpm < TL, the generator will
decelerate.
71. Bolt: A bolt contains two parts a shank and head. The cylindrical portion of
the bolt is known as the shank. The shank is threaded at the tail end for a
sufficient length so as to effectively engage with a nut.
The shape of the head is depended upon the purpose for which bolt is
required.
Nut: The nut is a type of a fastener which has a threaded hole in it. The
nut is always used in joining with a mating bolt to fasten various parts
together.
Nuts & Bolts
72. Various Types of Nuts and Bolts
Form of Bolts
Hexagonal-headed bolt
Square-headed bolt
Cylindrical or cheese-headed bolt
Cup-headed or round-headed bolt
T-headed bolt
Countersunk-headed bolt
Special Purpose Bolts
Stove bolt
Carriage bolt
Hook Bolt
Expansion bolt
Foundation or rag bolt
Eye-bolt
Stud
Forms of Nut
Hexagonal Nut
Square Nut
Ring Nut
Cap Nut
Cylindrical or Capstan Nut
Dome Nut
Wingnut or Thumb Nut
75. Rivets
Rivets are used to join together two or more sheets of metal permanently. In sheet
metal work riveting is done where: brazing is not suitable, the structure changes
owing to welding heat, the distortion due to welding cannot be easily removed etc.
Specification of rivets
Rivets are specified by their length, material, size and shape of head.
Rivet Materials
Rivets are made of ductile materials like low carbon sheet (mild steel), brass,
copper, yellow brass, aluminium are their alloys.
The length of the rivets ‘L” is indicated by the shank length.
Rivets are cylindrical rods having heads of various shapes.They are used for
assembling the parts of a work-piece together.
76. Types of Rivets and Use
1.Snap Head Rivet
2.Pan Head Rivet
3.Conical Head Rivet
4.Countersunk Head Rivet
5.Bifurcated Rivet
77. Cotter pins and wire clips are penetrating and coupling mechanical fasteners.
They are easy to install and remove. Cotter pins come in several forms, with each
designed for a specific kind of assembly. Some cotter pins are suitable for use as
shear pins.
Cotter Pin
•Split pin, a metal fastener with two tines that are bent during installation used
to fasten metal together, like with a staple or rivet
•Hairpin cotter pin, more commonly known as an "R-clip"
•Bowtie cotter pin, a vibration-proof type of R-clip that is shaped like a bowtie
•Circle cotter, a ring-shaped cotter pin
Types of Cotter Pins
78. The bearings are used to allow rotation or linear movement and to reduce
friction between two objects. The ease of movement (rotary or linear) reduces
friction and improves the speed and efficiency of the object.
The bearings are divided into two basic categories.
Radial bearings — Rotating shaft bracket
Thrust bearings — axial load support
Bearings
The most popular types of bearings are ball bearings,
Tapered Roller Bearings,
Ball Thrust Bearings,
Roller Thrust Bearings
etc.
79. According to ISO plan:
First number indicates width series 0,1,2,3,4,5 and 6 in increasing order.
Second number indicate Outer diameter 0,1,2,3, and 4 in ascending order.
Last two digit multiply by 5 gives inner diameter
80. A water pipe is any pipe or tube designed to transport treated
drinking water/potable water to consumers/building.
They differ according to sizes:-
1) Large diameter main pipes, which supply entire towns
2) Smaller branch lines that supply a street or group of buildings,
3) Small diameter pipes located within individual buildings
Pipes
81. • PIPES COME IN SEVERAL TYPES AND SIZES. THEY CAN BE DIVIDED
INTO THREE MAIN CATEGORIES:
• METALLIC PIPES INCLUDE STEEL PIPES, GALVANISED IRON PIPES AND
CAST IRON PIPES, COPPER PIPES .
• CEMENT PIPES INCLUDE CONCRETE CEMENT PIPES AND ASBESTOS
CEMENT PIPES.
• PLASTIC PIPES INCLUDE PLASTICISED POLYVINYL CHLORIDE (PVC)
PIPES
MATERIALS USED FOR CONSTRUCTION OF
PIPES
82. In piping, a Gasket is sealing material placed between connecting flanges to
create a static seal, which will maintain the leakage proof sealing in all
operating conditions.
The primary function of gaskets is to seal the irregularities of each face of the flange
so that there will be no leakage of the service fluid from the flange joint.
Types of Gaskets
There are three types of gaskets used in process piping.
Non-Metallic
Metallic
Composite
Gasket
83. Valves are mechanical devices that controls the flow and pressure within a system
or process. They are essential components of a piping system that conveys
liquids, gases, vapors, slurries etc..
Different types of valves are available:
gate,
globe,
plug,
ball,
butterfly,
check,
Valves
diaphragm,
pinch,
pressure
relief,
control valves etc.
84. FUNCTIONS FROM VALVES ARE:
•Stopping and starting flow
•Reduce or increase a flow
•Controlling the direction of flow
•Regulating a flow or process pressure
•Relieve a pipe system of a certain pressure
