Upload
loni-gogoi
View
162
Download
0
Embed Size (px)
Citation preview
INTERNSHIP PROJECT
ON
“TO STUDY ABOUT AIR PRESSURE LOSSES IN CAR PRESS SHOP
IN TERMS OF MONEY (RUPEES) DUE TO AIR LEAKAGE AND
THE WAYS TO RECTIFY IT.”
SUBMITTED BY:
Mr. Ashim Khound (10ATME103)
Ms. Loni Gogoi (10ATME098)
Mechanical Engineering Department
Institute of Chartered Financial Analysts of India (ICFAI) University
Agartala-799210, Tripura.
UNDER THE SUPERVISION OF:
Mr. Mir Mobarak Hossain
Production Engineer of Car Press Shop
Hindustan Motors Private Limited
AT
Hindustan Motors Private Limited
Hind Motor- 712233, Dist. Hoogly
West Bengal, India
An Internship Program - III station of
Faculty of Science & Technology, ICFAI University (March, 2014)
INTERNSHIP PROJECT
ON
“TO STUDY ABOUT AIR PRESSURE LOSSES IN CAR PRESS SHOP
IN TERMS OF MONEY (RUPEES) DUE TO AIR LEAKAGE AND
THE WAYS TO RECTIFY IT.”
SUBMITTED BY:
Name(s) of the Student(s) ID.No.(s) Discipline (S)
Mr. Ashim Khound 10ATME103 Mechanical
Ms. Loni Gogoi 10ATME098 Mechanical
Prepared in partial fulfillment of the
Internship Program – III Course
AT
Hindustan Motors Private Limited
Hind Motor- 712233, Dist. Hoogly
West Bengal, India
An Internship Program - III station of
Faculty of Science & Technology, ICFAI University (March, 2014)
Faculty of Science & Technology, ICFAI University
Station: Hindustan Motors Pvt. Ltd. Centre: Uttarpara, Hoogly
Duration: 02 Jan ‟14 to 31 Mar ‟14 Date of Start: 02 Jan ‟14
Date of Submission: 31 Mar „14
Title of the Project: TO STUDY ABOUT AIR PRESSURE LOSSES IN CAR
PRESS SHOP IN TERMS OF MONEY (RUPEES) DUE TO AIR
LEAKAGE AND THE WAYS TO RECTIFY IT
ID No./Name(s)/ 10ATME103/Mr. Ashim Khound/Mechanical
Discipline(s)/of 10ATME098/Ms. Loni Gogoi /Mechanical
the student(s) :
Name(s) and Mr. Mir Mobarak Hossain
designation(s) Production Engineer of Car Press Shop
of the expert(s): Hindustan Motors Private Limited
Name(s) of the Mr. Arindam Sinha
IP Faculty:
Project Areas: Press shop of Hindustan Motors, Uttarpara Plant
Abstract: The project is related to the air pressure losses through pipes,
valves etc. in Car Press Shop
Signature(s) of Student(s) Signature of IP Faculty
Date: Date:
DECLARATION
I hereby declare that the project entitled “To study about air pressure losses in Car Press
Shop in terms of money (Rupees) due to air leakage and the ways to rectify it”
submitted is my original work and the project has formed the basis for the award of B-
Tech degree (Mechanical Engineering) 2010-2014.
Mr. Ashim Khound
Ms. Loni Gogoi
Place: Hindustan Motors Pvt. Ltd., Hind Motor
ENDROSEMENT FROM THE SUPERVISOR
The work presented here was carried out under my supervision, from 02.01.2014 to
31.03.2014.
(Mr. Mir Mobarak Hossain)
Production Engineer of Car Press Shop
Hindustan Motors Pvt. Ltd.
(Mr. Rohit Saini)
H.O.D of Car Press Shop
Hindustan Motors Pvt. Ltd.
The Institute of Chartered Financial Analysts of India (ICFAI)
University
Agartala-799210 , Tripura
CERTIFICATE
This is to certify that this project report is the bonafide work of “ASHIM KHOUND and
LONI GOGOI” student of B-Tech, final year (8th
semester), Mechanical Engineering
Department, The ICFAI University Tripura, in partial fulfillment of the requirements for
the Internship Program III, who carried out the project work under my supervision.
SIGNATURE OF GUIDE IN-CHARGE:
DATE: 31 March „14
PLACE: Hindustan Motors Pvt. Ltd., Hind Motor
ACKNOWLEDGMENT
This report is completed with the full support of this industry, college faculty and friends.
I would like to acknowledge and extend my heart felt gratitude who have helped for the
completion of this report.
We are thankful to Mr. Rohit Saini, H.O.D of Car Press Shop, for his guidance during the
completion of this Final Project report.
With the biggest contribution to this report, I would like to thank Mr. Mir Mobarak
Hossain, Production Engineer of Car Press Shop, for his full support and guidance with
stimulating suggestions and encouragement to go ahead in all the time of learning session
and report work.
We are also thankful to the Training Department of Hindustan Motors Pvt. Ltd , along
with Mrs.Saswati Som Bhandari, HR of the Training Dept. & Mr.Sandip Roy to allow
us to undergo our Internship Program .We would like to acknowledge Mr.Shiv Shankar
Chauhan, Maintenance Engineer of Car Press Shop without whom our project would
have been incomplete.
We are gratetful to Mr. Arindam Sinha, Project Faculty Guide & Mrs.Swarnali Nath
Choudhury, IP Co-ordinator of The ICFAI University Tripura ,for allowing use to take
this project and providing us guidance at each every step in preparing this report.
At last, I would like to thank my co-partners who supported us and helped us for this
project.
Ashim Khound
Loni Gogoi
INDEX
TOPIC PAGE NO.
CHAPTER 1: BRIEF DESCRIPTION OF HINDUSTAN MOTORS 1
CHAPTER 2: INTRODUCTION TO PRESS 2
2.1 MACHINES OF CAR PRESS SHOP 3
CHAPTER 3: PNEUMATICS SYSTEM 6
3.1 ADVANTAGES OF PNEUMATICS
CHAPTER 4: COMPRESSOR 7
4.1 WORKING PRINCIPLE OF AIR RECIPROCATING COMPRESSOR 7
4.2 COMPRESSOR USED IN CAR PRESS SHOP 7
4.3 PARTS INVOLVED IN A COMPRESSOR 9
CHAPTER 5: COMPRESSED AIR 13
5.1 USE OF COMPRESSED AIR
CHAPTER 6: SYMMETRIC AIR LINE DIAGRAM IN CPS 15
CHAPTER 7: LEAKAGE 16
7.1 ESTIMATING AMOUNT OF LEAKAGE 16
7.2 AIR LEAK DETECTION: 17
CHAPTER 8: COST CALCULATION 19
CHAPTER 9: LOSS ANALYSIS 23
CHAPTER 10:RECTIFICATION 31
CHAPTER 11: CONCLUSION 32
REFERENCE 33
Chapter 1: BRIEF DESCRIPTION OF HINDUSTAN MOTORS Pvt.
Ltd.
Hindustan Motors Limited was established during the pre-Independence era at Port Okha in
Gujarat. Operations were moved in 1948 to Uttarpara in district Hooghly, West Bengal, where the
company began the production of the iconic Ambassador. It was established by Mr. B.M Birla of
industrious Birla family. Equipped with integrated facilities such as press shop, forge shop, foundry,
machine shop, aggregate assembly units for engines, axles etc and a strong R&D wing, the company
currently manufactures the Ambassador (1500 and 2000 CC Diesel, 1800 CC Petrol, CNG and LPG
variants) in the passenger car segment and light commercial vehicle 1-tonne payload mini-truck Winner
(2000cc diesel and CNG) at its Uttarpara.
The first and only integrated automobile plant in India, the Uttarpara factory, popularly known
as Hind Motor, also manufactures automotive and forged components. The armoring division under
Hindustan Motors Finance Corporation Ltd., a fully owned subsidiary of HM, is also based out of the
Uttarpara plant. It is one of the leading bullet-proof fabricators for Ambassador cars and Mitsubishi
Pajeros. The production unit of HM basically deals with the manufacturing and production of different
body parts of ambassadors. Hindustan Motors directly takes cares of institution marketing customers.
Hindustan Motors has various dealer networks all over the country for trade business.
Hindustan Motors is committed to core values of quality, safety, environmental care and holistic
customer orientation.
Chapter 2: INTRODUCTION TO CAR PRESS SHOP
A power press is a machine that supplies force to a die used to blank, form, or shape metal or
nonmetallic material. Thus, a press is a component of a manufacturing system that combines the press,
die, material, and feeding method to produce a part. Presses are composed of frame, bed, or bolster plate
and a reciprocating member called a ram or slide, which exerts force upon the work material through
special tools mounted on the ram and bed. Energy stored in the rotating flywheel of a mechanical press
(or supplied by a hydraulic system in a hydraulic press, or supplied by pneumatic cylinder in a
pneumatic press) is transferred to the ram to provide linear movement.
Power presses can be classified according to:
1. Energy Supply
A. Mechanical presses
B. Hydraulic presses
C. Pneumatic presses
D. Steam presses
E. Electromagnetic presses
2. Function
A. Energy-producing machines
B. Force-producing machines
C. Stroke-controlled machines
3. Construction
A. C-frame presses or gap-frame
B. Closed-frame presses or O-frame
C. 2-Pillar type
D. 4-Pillar type
4. Operation
A. Single-Action Press
B. Double-Action Press
C. Triple-Action Press
D. Multi-slide Press
Pneumatic Presses: These type employs pressurized air using compressor as actuator and several valves to generate a high
compressive force acting on the male element it‟s look like the hydraulic presses but it deal with lower
pressure requirements i.e. it generate lower acting forces.
2.1 The following machines are present in the Car Press Shop:
1. Press Machine: A press machine is a machine tool that changes the shape of a workpiece by the
application of pressure.
Fig: Press Machine
2 Hand Shearing:
Fig. Hand Shearing
3 Hand Drilling: In the pneumatic drill is a sequence of air tubes that join to the pile driver, and
then to the drill bit at the base. The compressed air, delivered from the diesel-powered
compressor, enters the drill and moves via the air tube circuit system. The air motion pushes the
pile driver down onto the drill bit, making the drill bit to strike into the surface being drilled. The
downward motion of the drill, in combination with the vibration of the drill hitting into the
surface, makes a valve inside the air tubing to reverse. This valve's inversion causes the air to
flow in the contrary direction; the new stream of air causes the drill to hit back away from the
earth. The valve then flips once more, and the air flow, mixed with the power of gravity, forces
and pulls the drill bit back to the surface.
Fig. Hand Drilling
4 Spot Welding: Spot welding is a process in which contacting metal surfaces joined by the heat
obtained from resistance to electric current. Work pieces are held together under pressure exerted
by electrodes. In our press shop in spot welding motor is driven by the air.
Fig. Spot Welding
5 Punch Machine: Punching is a metal forming process that uses a punch press to force a tool,
called a punch, through the workpiece to create a hole via shearing. The punch often passes
through the work into a die. A punch (or moving blade) is used to push the workpiece against
the die (or fixed blade), which is fixed. Usually the clearance between the two is 5 to 40% of the
thickness of the material, but dependent on the material.
Fig. Punch Machine
6 Pneumatic Shearing Machine: - In this type of shearing machine steel sheets of size 1mm-3mm
are cut. Shearing, also known as die cutting, is a process which cuts stock without the formation
of chips or the use of burning or melting. If the cutting blades are straight the process is called
shearing; if the cutting blades are curved then they are shearing-type operations. The most
commonly sheared materials are in the form of sheet metal or plates, however rods can also be
sheared. Shearing-type operations include: blanking, piercing, rollslitting, and trimming
Fig: Pneumatic shearing machine
Chapter 3: PNEUMATICS SYSTEM
Pneumatics is that branch of technology, which deals with the study and application of use of
pressurized air to affect mechanical motion.
“Pneumos” means “Air” and “Tics” means “Technology”.
The compressed air is used as the working medium, normally at a pressure of 6-8bars (also can be
extended up to 15bar) and a maximum force up to 50KN can be obtained. Pneumatics is used
extensively in industry as well as in many everyday applications. It has many distinct advantages in
terms of energy consumption, cost and safety. Pneumatic power is used in industry, where factory
machines are commonly plumbed for compressed air (other compressed inert gases can also be used).
Pneumatics also has applications in dentistry, construction, mining, and other areas.
Pneumatic systems in fixed installations such as factories use compressed air because a sustainable
supply can be made by compressing atmospheric air. The air usually has moisture removed and a small
quantity of oil added at the compressor, to avoid corrosion of mechanical components and to lubricate
them.
3.1 ADVANTAGES OF PNEUMATICS SYSTEM:
1. Simplicity of Design and Control: Machines are designed using standard cylinders and other
components. Control is as easy as ON-OFF type.
2. Storage: Compressed Gas can be stored, allowing the use of machines when electrical power is
lost.
3. Safety: Very low chance of fire (compared to hydraulic oil). Machines can be designed to be
overload safe.
4. Reliability: Pneumatic systems tend to have long operating lives and require very little
maintenance because gas is compressible; the equipment is less likely to be damaged by friction.
Chapter 4: COMPRESSOR
An air compressor is a device that converts power (usually from an electric motor, a diesel
engine or a gasoline engine) into kinetic energy by compressing and pressurizing air, which, on
command, can be released in quick bursts. There are numerous methods of air compression, divided into
either positive-displacement or negative-displacement types. Air compressors are essential mechanical
equipment for homeowners (air conditioners and refrigerators), commercial businesses, jet engines,
refining industries, manufacturing and automotive industries. In reality, air compressors have been
utilized in industries in more than a century. It is a multi-talented device utilized to supply the
compressed air and/or power in a specified space. It is being used in any purpose which requires air in
decreased volume or increased force. Air Compressor is consists of two main components – the
compressing mechanism and power source.
Here in the Car press shop, we have seen five reciprocating compressors having 28.32 m3/min
volumetric flow, 10 kg/ cm2 pressure and runs at 760 r.p.m. It is a two stage compressor.
4.1 WORKING PRINCIPLE OF AIR RECIPROCATING COMPRESSOR
In Single stage compressor, each cylinder is fitted with suction and delivery valve. The suction
air filters mounted both the cylinder so that air can enter a both ends of the piston during the forward and
backward stroke. The piston is moving in the cylinder, quantity of air sucked at the front side is
compressed to the required pressure when the piston travels towards the front end cover and similarly
when the piston travels towards the rear end of the cylinder.
In two stage compressor, after compression of the air from the first stage cylinder passes through
delivery valve to the water cooled heat exchanger provided in between the first and second stage. There
it is cooled very near to the atmospheric temperature and it is sucked by the second stage trough the
suction valve. In the second stage cylinder the air is compresses again to the required pressure then to
the aftercooler, if provided and finally to the air receiver.
Reciprocating (Piston) Air Compressor – uses piston in compressing air and keeping in storage
tank. Based on the quantity of compression stages, this type may be single-stage or double-stage. In a
single stage, one piston is utilized in compressing air, whereas in the double-stage, there are two pistons
used in air compression.
4.2 COMPRESSOR USED IN CAR PRESS SHOP
According to working – Reciprocating Compressor
According to action- Double Action
According to number of stages-Multi Stage
I. According to actions: Reciprocating Compressor
Working principle of air reciprocating compressor: In Single stage compressor, each cylinder is
fitted with suction and delivery valve. The suction air filters mounted both the cylinder so that air can
enter a both ends of the piston during the forward and backward stroke. The piston is moving in the
cylinder, quantity of air sucked at the front side is compressed to the required pressure when the piston
travels towards the front end cover and similarly when the piston travels towards the rear end of the
cylinder.
In two stage compressor, after compression of the air from the first stage cylinder passes through
delivery valve to the water cooled heat exchanger provided in between the first and second stage. There
it is cooled very near to the atmospheric temperature and it is sucked by the second stage trough the
suction valve. In the second stage cylinder the air is compresses again to the required pressure then to
the aftercooler, if provided and finally to the air receiver.
Reciprocating (Piston) Air Compressor – uses piston in compressing air and keeping in storage
tank. Based on the quantity of compression stages, this type may be single-stage or double-stage. In a
single stage, one piston is utilized in compressing air, whereas in the double-stage, there are two pistons
used in air compression.
II. According to actions: Double Actions
A double-acting cylinder has no spring inside to return it to its original position. It needs two air
supplies, one to outstroke the piston and the other to instroke the piston.
The symbol for a double-acting cylinder is shown below.
Fig : Double Acting Cylinder
To outstroke a double-acting cylinder we need compressed air to push against the piston inside
the cylinder. As this happens, any air on the other side of the piston is forced out. This causes the
double-acting cylinder to outstroke. When the piston has fully outstroke it is said to be positive.
Fig. Outstroke of the Piston
To instroke a double-acting cylinder we need to reverse this action. We supply the compressed
air to the other side of the piston. As the air pushes the piston back to its original position, any air on the
other side is again forced out. This causes the piston to instroke and it is said to be negative.
Fig. Instroke of the Piston
Double-acting cylinders are used more often in pneumatic systems than single-acting cylinders. They are
able to produce bigger forces and we can make use of the outstroke and instroke for pushing and pulling.
III. According to Actions: Multi-Stage Compressor
In a two stge compressor as we know that air is taken from the atmosphere in the low pressure
cylinder during its suction stroke at intake pressure P1 and temperature T1. The air after compression in
the low pressure cylinder from atmospheric pressure to low pressure compressor is delivered to the
intercooler at pressure P2 and temperature T2.Now, the air is pulled in the intercooler from low pressure
compressor to intercooler at constant pressure P2 and temperature T3.After that the air enter in the high
pressure cylinder during its suction stroke. Finally the air after further compression in the high pressure
cylinder from the intercooler to high pressure compressor is delivered at pressure P3 and temperature
T4.
4.3 PARTS INVOLVED IN A COMPRESSOR:
1. INTERCOOLER : An intercooler is any mechanical device used to cool a fluid, including
liquids or gases, between stages of a multi-stage heating process, typically a heat exchanger
that removes waste heat in a gas compressor. They are used in many applications, including
air compressors, air conditioners, refrigerators, and gas turbines, and are widely known in
automotive use as an air-to-air or air-to-liquid cooler for forced induction (turbocharged or
supercharged) internal combustion engines to improve their volumetric efficiency by
increasing intake air charge density through nearly isobaric (constant pressure) cooling.
Fig. Intercooler
2. AFTERCOOLER: Aftercoolers are heat exchangers for cooling the discharge from air
compressor. They use either air or water and are an effective means of removing moisture from
compressed air. Aftercoolers control the amount of water vapour into liquid form. In a
distribution or process manufacturing system, liquid water can cause significant damage to the
equipment that uses compressed air. An aftercooler is necessary to ensure the proper
functionality of pneumatic or air handing devices that are a part of process manufacturing
systems. Aftercoolers can use either air-cooled or water-cooled mechanisms.
Fig. Aftercooler
3. OIL PUMP: The lubricating oil pump feeds lubricating oil to the main bearings, connecting rod
bearings and cross heads of one side i.e. to the opposite side of the crank shaft rotation.
4. RECEIVER: Air receivers are tanks used for compressed air storage. It decreases wear and tear
on the compression module, capacity control system and motor by reducing excessive
compressor cycle. It also separate some of the moisture, oil and solid particles that might be
present from the air as it come from the compressor or that may be carried over from the after
cooler. Receivers also eliminate pulsations from the discharge line.
Fig. Receiver
5. FILTER: Air filters, often referred to as line filters, are used to remove contaminates from
compressed air after compression has taken place. A leaving a standard screw or piston
compressor will generally have high water content, as well as a high concentration of oil and
other contaminates. There are many different types of filters, suitable for different pneumatics
applications.
Fig. Filter
6. DRIER: A compressed air drier is a device for removing water vapor from compressed air.
Compressed air dryers are commonly found in a wide range of industrial and commercial
facilities. When sudden large air demands occur, dry air receivers should have adequate capacity
to minimize a drop in system air pressure.
Fig. Drier
7. VALVES: A valve is a device that regulates, directs or controls the flow of a fluid (gases,
liquids, fluidized solids or slurries) by opening, closing or partially obstructing various
passageways. Valves are technically valves fitting but are usually discussed as a separate
category. In an open valve, fluid flows in a direction from higher pressure to lower pressure.
Fig. Valve
Chapter 5: COMPRESSED AIR
Compressed air, commonly called Industry's Fourth Utility, is air that is condensed and
contained at a pressure that is greater than the atmosphere. The process takes a given mass of air, which
occupies a given volume of space, and reduces it into a smaller space. In that space, greater air mass
produces greater pressure. The pressure comes from this air trying to return to its original volume. It is
used in many different manufacturing operations. A typical compressed air system operating at 100 psig
(7 bar) will compress the air down to 1/8 of its original volume.
5.1 USE OF COMPRESSED AIR:
Compressed air supplies power for many different manufacturing operations. At a pressure of
100 psig (7 bar), compressed air serves as a utility. It supplies motive force, and is preferred to
electricity because it is safer and more convenient. There are numerous industries that use compressed
air for various applications. Here in the Car Press Shop, compressor is supplying the compressed air at
5.8 bar with 800 cfm.
For maintenance work, plants can use air-operated drills, screwdrivers, and wrenches, provided that the
air outlets are well placed throughout the plant. Painting can be done using paint-spraying systems.
On the Production Line: Pneumatic tools are convenient for industrial production because they have a
low weight-to-power ratio, and they may be used for long periods of time without overheating and with
low maintenance costs. Chipping and scaling hammers are used in railroads, oil refineries, chemical
refineries, shipyards, and many other industries for general application. They are also used in the
foundry for cleaning large castings, and to remove weld scale, rust, and paint in other industries.
Additionally, these hammers are good for cutting and sculpturing stone.
Pneumatic drills can be used for all classes of reaming, tapping, and drilling anytime that the work
cannot easily be carried to the drill press and for all classes of breast drill work. These air-powered drills
are also often used for operating special boring bars, and in emergencies, for independent drive of a
machine tool where required horsepower is within their capacity.
Grinding, wire brushing, polishing, sanding, shot blasting and buffing are performed efficiently with
compressed air in the automotive, aircraft, rail car, locomotive, vessel shops, shipbuilding, other heavy
machinery, and other industries. The primary goals are to finish surfaces and prepare them for finishing
operations. Two of the most basic assembly operations, driving screws and turning up nuts, are
performed more efficiently because of pneumatic screwdrivers and nut runners.
Air Motors, Vacuum, & Other Auxiliary Devices: Air motors are often used as a power source in
operations involving flammable or explosive liquids, vapor, or dust, and can operate in hot, corrosive, or
wet atmospheres without damage. Their speeds may be easily changed; they will start and stop rapidly
and are not damaged by stalling and overloading. Air motors power (fig. CA1-4) many hand-held air
tools and air hoists. They are used in various applications in underground tunnels and mines and in
industrial areas where there are flammable liquids or gas. They also drive many pumps used in
construction and many positioning apparatuses used in manufacturing.
Pneumatic auxiliary production equipment is used extensively. Positioners, feeders, clamps, air chucks,
presses, air knives and many other devices powered by air cylinders increase production efficiency.
Pneumatic cylinders plus ratchets or stops provide reciprocating or rotating interrupted motions much
more economically than by traditional mechanical tools. In finishing and packaging areas, pneumatic
devices are used for many applications, such as dry powder transporting and fluidizing, liquid padding,
carton stapling, and appliance sanding. Blast cleaning and finishing are other widely used compressed
air applications.
The compressed air is used to run the following machines:
Press Machines
Hand Shearing
Hand Drilling
Spot Welding
Punch Machine
Pneumatic Shearing Machine
Chapter 6: SYMMETRIC AIR LINE DIAGRAM IN CPS
Fig.: Symmetric diagram of the distribution of air pressure from the compressor house to car
press shop.
Chapter 7: LEAKAGE
Leaks can be a significant source of wasted energy in an industrial compressed air
system, sometimes wasting 20-30% of a compressor's output. A typical plant that has not been
well maintained will likely have a leak rate equal to 20% of total compressed air production
capacity. On the other hand, proactive leak detection and repair can reduce leaks to less than
10% of compressor output.
In addition to being a source of wasted energy, leaks can also contribute to other operating
losses. Leaks cause a drop in system pressure, which can make air tools function less efficiently,
adversely affecting production. In addition, by forcing the equipment to cycle more frequently,
leaks shorten the life of almost all system equipment (including the compressor package itself).
Increased running time can also lead to additional maintenance requirements and increased
unscheduled downtime. Finally, leaks can lead to adding unnecessary compressor capacity.
There are two types of air leaks, planned and unplanned. The planned air leaks are the ones that
have been designed into the system. These leaks are the blowing, drying, sparging etc. used in
the production process. Many times these have been installed as a quick fix for a production
problem. Some leaks take the form of "coolers", which are used to cool production staff or
equipment. The unplanned leaks are the ongoing maintenance issues and can appear in any part
of the system. These leaks require an ongoing air leak detection and repair program.
Most common problem areas are:
Couplings, hoses, tubes, and fittings. Tubes and push-to-lock fittings are common
problems.
Disconnects. O-rings required to complete the seal may be missing.
Filters, regulators and lubricators (FRLs). Low first-cost improperly installed FRLs often
leak.
Open condensate traps. Improperly operating solenoids and dirty seals are often problem
areas.
Pipe joints. Missed welds are a common problem.
Control and shut-off valves. Worn packing through the stem can cause leaks.
Point of use devices. Old or poorly maintained tools can have internal leaks.
Flanges. Missed welds are a common problem.
Cylinder rod packing. Worn packing materials can cause leaks.
Thread sealants. Incorrect and/or improperly applied thread sealants cause leaks. Use the
highest quality materials and apply them per the instructions.
7.1 ESTIMATING AMOUNT OF LEAKAGE:
For compressors that have start/stop controls, there is an easy way to estimate the amount of
leakage in the system. This method involves starting the compressor when there are no demands on the
system (when all the air-operated end-use equipment is turned off). A number of measurements are
taken to determine the average time it takes to load and unload the compressor. The compressor will
load and unload because the air leaks will cause the compressor to cycle on and off as the pressure drops
from air escaping through the leaks. Total leakage (percentage) can be calculated as follows:
Leakage (%) = [(T x 100)/(T + t)]
Where: T = on-load time (minutes)
t = off-load time (minutes)
Leakage will be expressed in terms of the percentage of compressor capacity lost. The percentage lost to
leakage should be less than 10% in a well-maintained system. Poorly maintained systems can have
losses as high as 20-30% of air capacity and power.
Leakage can be estimated in systems with other control strategies if there is a pressure gauge
downstream of the receiver. This method requires an estimate of total system volume, including any
downstream secondary air receivers, air mains, and piping (V, in cubic feet). The system is started and
brought to the normal operating pressure (P1). Measurements should then be taken of the time (T) it
takes for the system to drop to a lower pressure (P2), which should be a point equal to about one-half the
operating pressure.
Leakage can be calculated as follows:
Leakage (cfm free air) = (V x (P1-P2)/T x 14.7) x 1.25
Where: V is in cubic feet
P1 and P2 are in psig
T is in minutes
The 1.25 multiplier corrects leakage to normal system pressure, allowing for reduced leakage with
falling system pressure. Again, leakage of greater than 10% indicates that the system can likely be
improved. These tests should be carried out quarterly as part of a regular leak detection and repair
program.
7.2 AIR LEAK DETECTION:
Since air leaks are almost impossible to see, other methods must be used to locate them. The best
way to detect leaks is to by hearing the high frequency hissing sounds associated with air leaks which
can recognize the air leakage. A simpler method is to apply soapy water with a paint brush to suspect
areas. Although reliable, this method can be time consuming.
Leaks in pressure and vacuum systems can be in: Compressed air storage
Compressed air distribution system
Compressor valves
Heat exchangers
Condensers
Valves
Pipes
We observed different air leakages from compressor house to Car Press Shop. Below figure is showing
some of the air leakages.
CHAPTER 8: COST ANALYSIS
From the schematic diagram of compressor shown above, let
P1 = Inlet pressure of air entering the L.P cylinder
V1= Volume of the L.P cylinder
P2 = Pressure of the air leaving L.P Cylinder or inlet pressure entering the H.P cylinder
V2= Volume of the H.P cylinder
P3= Pressure of leaving the H.P cylinder
n= polytropic index for both the cylinder
Now,
1). When intercooling is complete:
We know that work done per cycle in L.P cylinder,
Similarly, work done per cycle in compressing air in H.P cylinder,
Therefore, total work done per cycle,
W3= W1 + W2
2). When intercooling is complete,
P1V1= P2V2
Now,
……. (i)
Now, if compressor should work minimum on the working substance, then dW/dP2 = 0
Let [n/ (n-1)] = a
Substituting these values to eqn (i)
,i.e. for two stage
compressor
Now, Substituting
8.1 Data as collected:
I. P1= 1.013 bar = 1.013*105 N/m
2
II. Inlet volume flow rate of the compressor= 1000 CFM
Outlet volume flow rate of the compressor=800 CFM
Where, r.p.m of the compressor= 760
So, 760 revolution volume flow rate = 1000 CFM
1 revolution volume flow rate = 1000/760 CFM
= 1.31 CFM
So, V1= 1.31 CFM = 0.0370 m3/min
III. P3= 5.8 bar = 5.8*105 N/m
2
IV. V2 = 800/760 CFM = 1.05CFM = 0.0297 m3/min
V. P2 = (P3P1)1/2
= (5.8*105*1.0135*10
5)1/2
VI. n= 1.4
So,
= [{1.4/(1.4-1)}*1.013*105*0.037*{(5.8/1.013)
[(1.4-1)/(2*1.4)]-1}]
= 0.0371*105
N-m/min
So, Power needed,
P= 2*W*N/60
= 2*0.0371*105*760/60
= 93.986 kW
Total Working Time = 7.5 hrs
Total Working Time for a Non Production Day = 2.5 hrs
Industrial Tariff = Rs.8
So, Total cost needed = P*Working hr.* Industrial Tariff
= 93.986*7.5*8
Total cost required to run the compressor = Rs. 5639.16
Now, for getting 5.8 bar pressure at outlet we need Rs. 5639.16 /day
So, for 1 bar, cost need= 5639.16/5.8
= Rs.972.26 /day
Also, for getting 800 cfm cost needed = Rs. 5639.16
So, for 1 cfm, cost need = 5639.16/800
= Rs.7.04 /day
VII. Volumetric flow rate, Q= V*A
Q= 800cfm
=800*0.000472 m3/s
= 0.377552 m3/s
Radius,r= 7.01 cm
Area, A= 153.94*10-4
m2
Therefore,
0.377552 m3/s= V * 153.94*10
-4 m
2
Velocity, V= 24.52 m/s
CHAPTER 9: LOSS ANALYSIS
9.1 Leakage points:
1. From Compressor to main line:
Pcompressor= 5.8 bar
Pmain line= 5.5 bar
∆Paverage= 0.3 bar
Cost= Rs. 972.26* 0.3 bar
= Rs. 291.678
2. From main line to line 1:
Pmachine 1= 5 bar
Pmachine 2= 5 bar
Pmachine 3= 5.2 bar
Pmachine 4= 5.2 bar
Pmachine 5= 5 bar
Pmachine 6= 5 bar
∆Paverage= 0.65 bar
Cost= Rs. 972.26* 0.65 bar
= Rs. 631.969
3. From main line to line 2:
Pmachine 1= 5 bar
Pmachine 4= 5 bar
Pmachine 5= 5 bar
∆ Paverage= 0.5 bar
Cost= Rs. 972.26* 0.5 bar
= Rs. 486.13
4. From main line to line 3:
Pmachine 1= 5 bar
Pmachine 3= 5.2 bar
Pmachine 5= 5 bar
Pmachine 6= 5 bar
∆Paverage= 0.45 bar
Cost= Rs. 972.26* 0.45 bar
= Rs. 437.517
5. From main line to line 4:
Pmachine 1= 5.2 bar
Pmachine 4= 5.5 bar
Pmachine 7= 5.5 bar
∆Paverage= 0.3 bar
Cost= Rs. 972.26* 0.3 bar
= Rs. 291.678
6. From main line to Shearing Section:
Diameter, Dpipe= 0.25 cm
Area, Apipe= (∏/4* d2)
=0.05 *10-4
m2
Velocity, V= 24.52 m/s
Q= 24.52 * 0.05 *10-4
m3/s
= 1.226*10-4
m3/s
= 0.26 cfm
Cost= Rs. 7.04 * 0.26
= Rs. 1.83
7. Punch Machine:
Diameter, Dleakage= 0.3 cm
Area, Aleakage= 0.07 *10-4
m2
Velocity, V= 24.52 m/s
Q= 24.52 * 0.07*10-4
m3/s
=1.7164*10-4
m3/s
= 0.364 cfm
CostPer Leakage= Rs. 7.04 * 0.364
= Rs. 2.56
No. of leakage points= 15
Cost= Rs. 2.56*15
= Rs. 38.4
8. Hand Shear and Drilling:
Diameter, Dleakage= 0.27cm
Area, Aleakage= 0.06 *10-4
m2
Velocity, V= 24.52 m/s
Q= 24.52 * 0.06*10-4
m3/s
=1.4712*10-4
m3/s
= 0.312 cfm
CostPer Leakage = Rs. 7.04*0.312
= Rs. 2.19
No. of leakage points= 5
Cost= Rs. 2.19*5
= Rs.10.97
9. Shearing Machine:
Diameter, Dleakage= 0.25cm
Area, Aleakage= 0.05 *10-4
m2
Velocity, V= 24.52 m/s
Q= 24.52 * 0.05*10-4
m3/s
=1.226*10-4
m3/s
= 0.26 cfm
CostPer Leakage= Rs. 7.04 * 0.26
= Rs. 1.83
No. of leakage points= 4
Cost= Rs. 1.83*4
= Rs. 7.32
Total cost of losses = Rs. 291.678 + Rs. 631.969 + Rs. 486.13 + Rs. 437.517 + Rs. 291.678 +
Rs. 1.83 + Rs. 38.4 + Rs.10.97+ Rs. 7.32
Total cost of losses = Rs. 2197.492
Total cost utilized per day = Total cost required to run the compressor - Total cost of losses
Total cost utilized per day = Rs. 5639.16 - 2197.492
Total cost utilized per day = Rs. 3441.668
Therefore, utilization percentage = ( Total cost utilized per day/Total cost required to run the
compressor per day )*100 %
=(3441.668/5639.16)*100 %
= 61. 03 %
And, Losses Percentage = ( Total cost of losses per day/Total cost required to run the
compressor per day)*100 %
=(2197.492/5639.16)*100 %
= 38.97 %
Tabular form analysis of all the lossess in the CPS :
Leakage Location Total Pressure loss Total cfm loss Total Cost
Loss
Compressor to main line 0.3 bar 41.43 cfm Rs. 291.678
From main line to line 1 0.65 bar 89.77 cfm Rs. 631.969
From main line to line 2 0.5 bar 69.05 cfm Rs. 486.13
From main line to line 3 0.45 bar 62.15 cfm Rs. 437.517
From main line to line 4 0.3 bar 41.43 cfm Rs. 291.678
Main line to Shearing Section 0.0018 bar 0.26 cfm Rs. 1.83
Punch Machine 0.04 bar 0.364 cfm Rs. 38.4
Hand Shear and Drilling 0.011 bar 0.312 cfm
Rs.10.97
Shearing Machine 0.00753 bar 0.26 cfm Rs. 7.32
Total Loss in CPS Rs. 2197.492
Total cost utilized per day Rs. 3441.668
Total cost required to run the compressor per day Rs. 5639.16
utilization percentage Rs. 61. 03 %
Losses Percentage Rs. 38.97 %
15 DAYS DATA COLLECTION WITH UTILIZATION % AND LOSSES %
:
0
1000
2000
3000
4000
5000
6000
Total cost needed (Rs.)
Total cost of losses (Rs.)
Graph to show the total cost needed V/S its losses in terms of money (Rupees)
0
1000
2000
3000
4000
5000
6000
Total cost needed (Rs.)
Total cost utilized (Rs.)
Graph to show the total cost needed V/S its utilisation in terms of
money(Rupees)
0
500
1000
1500
2000
2500
3000
3500
4000
Total cost of losses(Rs.)
Total cost utilized(Rs.)
Graph to show the total cost of losses V/S its utilisation in terms of money
(Rupees)
CHAPTER 10: RECTIFICATION
Leaks occur most often at joints and connections. Stopping leaks can be as simple as tightening a
connection or as complex as replacing faulty equipment such as couplings, fittings, pipe sections, hoses,
joints, drains, and traps. In many cases leaks are caused by bad or improperly applied thread sealant.
Select high quality fittings, disconnects, hose, tubing, and install them properly with appropriate thread
sealant.
Non-operating equipment can be an additional source of leaks. Equipment no longer in uses
hould be isolated with a valve in the distribution system another way to reduce leaks is to lower the
demand air pressure of the system. The lower the pressure differential across an orifice or leak, the
lower the rate of flow, so reduced system pressure will result in reduced leakage rates. Stabilizing the
system header pressure at its lowest practical range will minimize the leakage rate for the system.
Problems associated with leaks:
Drops in system pressure
Air tools function less efficiently
Decreased system equipment and compressor longevity
Additional maintenance
Adds unnecessary compressor capacity
Benefits of fixing leakage:
Reliable and predictable production is ensured
Small leaks can be caught before they grow
Purchase of additional air compressors avoided
System pressure maintained
Increased productivity
Lower maintenance costs
Improved safety for workers
CHAPTER 11: CONCLUSION
The project works with an aim to study the losses of air pressure leakage and to rectify it. It has
met its aim by finding the per day cost of the air pressure used and its per day utilization .Hence we
could find a greater amount of loss in terms of money for which the company undergoes a big loss per
day due to its leakage.
Proper steps must be taken to minimize the daily leakage through air pressure in the car press
shop. It must be daily checked by the maintenance department so that proper preventive measures can be
taken at proper time.
Once leaks have been repaired, the compressor control system should be re-evaluated to realize
the total savings potential.
REFERENCE
1. http://www.pressuredrop.net/compressor/pressure/air
2. http://www.comressedairtutor.net/tutorials/compressed/air
3. http://www.leakage.net/air
4. http://www.airleakage.net/compreesor
5. http://www.airpressure.net/leakage
6. Orlov,P; Fundamentals of air pressure, Vol. 2, McGraw-Hill Education, New York,1977