Final Report at Hindustan Motors by Ashim Khound and Loni Gogoi

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


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


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


Cost= Rs. 972.26* 0.65 bar

= Rs. 631.969


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


Pmachine 1= 5 bar

Pmachine 3= 5.2 bar

Pmachine 5= 5 bar

Pmachine 6= 5 bar


Cost= Rs. 972.26* 0.45 bar

= Rs. 437.517


Pmachine 1= 5.2 bar

Pmachine 4= 5.5 bar

Pmachine 7= 5.5 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


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


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


m2


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


Cost= Rs. 2.19*5

= Rs.10.97

9. Shearing Machine:

Diameter, Dleakage= 0.25cm


m2


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


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




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

http://www.comressedairtutor.net/tutorials/compressed/air

http://www.leakage.net/air

http://www.airleakage.net/compreesor

http://www.airpressure.net/leakage

Final Report at Hindustan Motors by Ashim Khound and Loni Gogoi

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Transcript of Final Report at Hindustan Motors by Ashim Khound and Loni Gogoi