1. COMPANY INTRODUTION

1.1 BOSCH GROUP

Introduction to Bosch group

Bosch is one of the world’s biggest private industrial corporations. The name

Bosch is not just famous for automotive technology products like gasoline / diesel /

chassis systems, starters & generators, electrical drives, steering systems and car

electronics – it is also a leader in the areas of automation technology, car multimedia

systems, packaging technology, power tools, thermo technology, household

appliances, and security systems.

Founded in 1886 in Germany, as a ‘Workshop for Precision Mechanics and

Electrical Engineering’ by Robert Bosch, the Bosch today is the largest automotive

technology supplier in the world. Headquartered in Stuttgart, Germany, Bosch has

some 283,000 associates worldwide, and generated annual sales revenue of 45.1

billion Euros. Each year, Bosch spends more than billion Euros, or eight percent of its

sales revenue, for research and development, and applies for over 3,000 patents

worldwide. With all its products and services, Bosch enhances the quality of life by

providing solutions which are both innovative and beneficial. Bosch is active in every

continent with 300 subsidiaries and regional companies in over 60 countries. If its

sales and service partners are included, then Bosch is represented by 13,000 service

centers in roughly 150 countries. This worldwide development, manufacturing, and

sales network are the foundation for further growth.

Development of other Business Sectors:

The Bosch Group is active in the following fields:

Automotive technology

Automation technology

Packaging technology

Solar energy

Power tools

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Heating technology

Household appliances

Security systems

Bosch Groupies present at 131 locations in 30 countries.

The divisions are

Gasoline Systems

Diesel Systems

Chassis Systems Brakes

Chassis Systems Control

Electrical Drives

Starter Motors and Generators

Car Multimedia

Automotive Electronics

Automotive Aftermarket

Steering Systems

Strategic objectives of Diesel System:

Strengthen earnings performance

Bolster and expand worldwide market position

Achieve additional growth with new, innovative business areas

Enhance the quality of products and services

Staff motivation

Process orientation

Social engagement

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2. BOSCH LIMITED (RBIN):

RBIN (formerly MICO, Motor Industries Company limited) is the largest

subsidiary of Bosch in India, founded in 1951. It is the largest auto-component

manufacturer in India with a turnover of over Rs6700crores in 2014 with total

employee strength of approx. 11774. Robert Bosch GmbH holds around 70% stake in

RBIN and is making a sizeable investment to introduce and manufacture World-Class

Technology products for the Indian market, spanning across 1000 towns and cities

with over 4000 authorized representations which ensure widespread availability of

both products and services.

RBIN facilitates superior product availability and countrywide after sales

services. Bosch Limited operates in all the business sectors of Bosch - Automotive

technology, Industrial technology, Consumer goods and Building technology. It

manufactures and trades products as diverse as common rail injector and components,

diesel and gasoline fuel injection equipment, industrial equipment, auto-electrical,

gear pumps, power tools, packaging machines, special purpose machines, security

systems, Starter –Generator (SG) and Gasoline Systems (GS) and Automotive

Aftermarket (AA). The company is headquartered at Bangalore with manufacturing

facilities in Bangalore, Nasik, Naganathapura, Jaipur and Goa.

2.1 BOSCH Limited in India

In India, Bosch is a leading supplier of technology and services, and has a

strong presence in the country at numerous locations in diverse industry segments -

both automotive and non-automotive. Bosch has grown over the years to 11

manufacturing sites and 4 development centers. RBIN manufactures and trades in all

the three business sectors of Bosch. It has a strong nationwide service network which

spans across 1,000 towns and cities with over 4,000 authorized centers to ensure

widespread availability of both products and services.

RBIN is the largest auto component manufacturer and one of the largest Indo-

German companies in India. From the year Bosch entered India it has focused on

state-of-the-art technology and continued commitment to world-class quality. RBIN is

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the country’s largest manufacturer of diesel fuel injection equipment and one of the

largest in the world.

It manufactures and trades products as diverse as diesel and gasoline fuel

injection systems, auto-electrical, industrial equipment, special purpose machines,

packaging machines, electric power tools and security systems. The major products of

RBIN are Fuel Injection Equipments (for Diesel engines), Auto electrical, Power

Tools, SPM, household appliances and so on. The Company has developed excellent

R&D and manufacturing capabilities, a strong customer base and its market

leadership is testimony to the high quality of technology. As Bosch focuses on

developing technology hubs in Asia, RBIN is gearing up to meet these challenges.

Bosch was awarded as “Auto component manufacturer” in 2005. Its customers

includes all Indian Auto majors like TATA Motors, Mahindra & Mahindra, Ashok

Leyland, Force Motor India, Volvo-Eicher, Escorts Ltd, Kirloskar Oil Engines, Indian

Railways, Defence Ministry of India and many more. It exports to international

customers like Mercedes Benz, John Deere, Peugeot, Daimler Chrysler, Volkswagen,

Renault, Ford, General Motors, Daewoo, Hyundai, FIAT, Nissan Motors Spain,

Cummins, Duetz, and Lombardini USA & proving prominent presence in the

International market.

Bosch’s slogan ‘Invented for Life’ is part of its long tradition, through which it

communicates the group’s core competencies and vision, that include technological

leadership, modernity, dynamics, quality and customer orientation.

RBIN is headquartered in Bangalore with manufacturing facilities in

Bangalore, Nashik, Naganathapura and Jaipur. All the four plants are TS 16949 and

ISO 14001 certified.

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2.2 BOSCHVISION, MISSION & VALUES

The Vision:

NaPMission

Leadership in Production and Logistics of Cost effective diesel injectors

through Innovative solutions and best in class Quality

We are the most preferred partner to our customers based on our

reliability and leadership in technology and quality We focus on our core competencies and continuous improvement for

sustainedand profitable growth

We involve, empower and motivate our peopleto shape our future

together

We,alongwith our business partners,are cost competitivethrough

lean and effective processes We commit ourselves towards environment protection & social

responsibility

NaPVision

Bosch Values:

Bosch has always been a company driven by its values. The Bosch values are

the foundation upon which we build our future. They guide our actions and tell us

what is important to us and what we are committed to.

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Bosch Values

1. Future & Result Focus

2. Responsibility

3. Initiative & Determination

4. Openness & Trust

5. Fairness

6. Reliability, Credibility & Legality

7. Cultural Diversity

2.3 BPS - Bosch Production System:

The Bosch success story stems from innovative products and a claim of high

quality. It is based principally on forward-looking production technologies. The key

objective is to provide their customers with products that have perfect quality and

competitive prices, and that meet customer requirements. The "Bosch Production

System (BPS)" aligns all production and logistics processes with common principles

that are systematic and uniform throughout the world. The aim here is to avoid

wastage in production and all associated business processes.

The Three layers:

The BPS is structured in three layers. At the top, is the objective to develop

"Best-in-Class" processes and establish them in Bosch world. The second layer

describes the eight principles that are obligatory guidelines for designing all sub-

processes. They are structured description on how to apply the modules. The modules

- in the third layer - are required to implement the principles at local operative level.

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Objectives:

The objective is to achieve a uniform, structured improvement with respect to

quality (Q), costs (K), and delivery service (L) along the entire added-value chain.

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Figure 11: BPS – Concept &

Structure

PRINCIPLES:

Principles describe a solution-finding framework that applies to all sub-

processes. This ensures that all sub-processes are based on a uniform objective

applicable to the entire added-value chain. The principles also ensure that the right

modules are applied to the right extent at the right time. The BPS principles are shown

in the figure

Modules:

Modules are tools that implement the principles in all subareas.

2.4 BOSCH LIMITED: NASIK PLANT (NAP):

The pilot plant at Nasik started in 1969 and from 1974, manufacturing of

Nozzles and Injectors was started at the present location. The plant is spread on

405,060 sq m, having 5 manufacturing hangers occupying 55,560 sq m. Nasik Plant

of Bosch (NaP formerly known as MICO-Bosch) is one of the important

establishments of Bosch in India since last 30 years. Nasik plant is specialized in

manufacture of components of fuel injection equipment, especially Nozzles and

Injectors for automobile industries, both in conventional (non-Euro) and Euro series

applications. The product application is in automotive, stationary engines, marine and

in locomotive segments for both inland & export markets. With the constant efforts

for excellence in Quality and delivery commitments, the plant received good

acceptance by customers in Europe, South East Asia. At present the export customer

is about 25% of the plant output. The plant is committed to continue its efforts for

total customer satisfaction in areas of Quality, Cost and Delivery.

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2.4.1 Organizational Relationships:

Stakeholder comprises of their customers, employees, shareholders, business

partners, and society.

RBIN, RB-DS, DS/IN:

NaP management is jointly led by a Technical & a Commercial Head who

report to DS/IN Management. Common corporate functions such as Legal, Finance,

Sales, Marketing, Product development, HR, Direct material purchasing etc. are

appropriately integrated with the plant though they are located at Bosch Bangalore.

Customers:

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S. No. Product Description Started InEmission

Norm

1 Nozzle holder & Nozzles 1969

2 DLL Nozzle (DI) 1974

3 BS-2 Nozzle Holder – P type 2000 BS2

4 KCA Injectors (Export) 2002Euro 4

5 Bx Injectors (Export) 2003

6 NBFE Injector 2008 BS 2

7 CRI Components 2006

8 CR Injector 2008 BS4

9 CR Nozzle 2009 BS4

10CR Injector (Low cost) 2010 BS3/4

Main products of NaP are injection nozzles and injectors with a good mix of

conventional and contemporary technologies. NaP products are supplied to inland and

export markets-both for Original Equipment and Aftermarket. They operate directly

with OEMs.

2.5.1Key needs of Customer:

Their customers are demanding and rely on the innovative products and

technical support of Bosch to collaborate with them to manufacture their products.

Timely delivery, flexibility and fast response are the key demands of their customers.

2.5.2Product Information:

The plant operation has grown remarkably and steadily in last 40 years. Due to

introduction of CMVR norms by government of India since 2006, it was expected that

the conventional products will decline (PLC) in the market. To overcome this, various

new products (Table) were introduced to meet customer expectations as per the

introduction of emission norms for vehicles.

Competitive Environment

RB-DS is a market leader for its major products. They are the biggest

manufacturer within DS for conventional type nozzles and injectors). NaP is

balancing between the conventional and contemporary products by having a good mix

of products from both the generations.

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Product DescriptionNaP Market

ShareCompetitor

Common Rail Injector

(CRI)

85% Local spurious market ,Delphi

and low cost Chinese market

Nozzle holder ( NHA) 85% Delphi , Siemens

2.6 Competitive Advantage:

Their major competitive advantages are market position, delivery

commitment, cost competitiveness and technological leadership.

2.7 Strategic Challenges:

They review and refine their vision annually since 2006 and implement related

strategies to achieve the same. They have defined five strategy themes derived from

their vision which remain to be their strategic challenges. To meet these challenges

they have defined ten strategic activities.

2.8 Accreditations:

1. TS 16949:2002 for QMS

2. ISO 14001:2004 for EMS

3. OHSAS 18001:2007

3. CARBON

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3.1 Basic properties of carbon:

Insoluble in water, chain of carbon capped with hydrogen to from hydrocarbon

It is 6th most abundant element on the planet. It is used in making diamonds,

pencils and lubricants.

Vacancy of carbon is 4.

3.2 Physical properties of carbon:

Electrically conductive

Black

Hardness: 1-2 moh.

Crystal have hexagonal symmetry

Density: 2.09-2.23 g/cm3

Dissolves in molten nickel

Melting point : 3600-3700℃

Boiling point: 5100 K, 4827℃

Pure forms of carbon: graphite, coal, diamond.

Atomic mass : 12.011

3.3 Pressure measurement methods:

Absolute pressure: it is zero reference against perfect vacuum, it is equal to

Gauge pressure + Atmospheric pressure

Gauge pressure : it is zero reference against ambient air pressure is equal to

Absolute pressure – Atmospheric pressure

Differential pressure : it is difference in pressure between two points.

3.4 Type of pressure:

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a) Positive pressure:

Positive pressure is when a room inside the building is held at a higher

pressure than the surrounding.

It is used to clean room application to prevent air bone contaminants from

outside the room leaking in.

Application:

1. It is used in therapy to improve the healing process of venous ulcer and fistula

wounds.

2. Preservation of food.

3. Control low B.P. naturally.

b) Negative pressure:

Negative pressure is when a room inside the building is held at lower pressure

than the surrounding.

It is used in hospital isolations room to prevent airborne viruses or bacteria

from escaping the room into other rooms.

Negative pressure measured in negative inches of mercury.

Applications:

1. Furnace pressure control.

2. Industrial ventilation system.

3. Air filtrations.

4. Process engineering.

3.5 Effect of negative pressure:

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Flow reversal or back drafting.

Lighting a fire is impossible.

People feel ill when at home and better after being outside or away from the

house.

A lack of fresh air, a musty smell, lingering odours around the house.

3.6 Device used to measure negative pressure:

1. Milliamp signal transmitter

2. Voltage signal transducer

3. Millivolt signal sensor

4. Pressure gauge

5. Loggers

4. VACUUM

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4.1 What is Vacuum?

A vacuum is a space entirely devoid of matter. In practice we talk

about a vacuum when the air pressure in a space lies below atmospheric

pressure.

4.2 Units of vacuum:

1. Milometer’s of mercury or also called tort.

2. Pascal

3. Mill bar

4. Atm.

5. Micron

TABLE NO.1 RANGES OF VACUUM:

Vacuum

level

Ultra high

vacuum

Very high

vacuum

High

vacuum

Medium

vacuum

Low

vacuum

Pressure in

torr

10−16−10−10 10−10−10−6 10−6-10−3 10−3-10 10-103

5. VACUUM FURNACE

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It is type of furnace that can heat material typically metals, to very high

temp. and carryout process such as brazing, sintering and heat treatment with

high consistency and low contamination. Vacuum furnaces are widely used in

heat treatment processes, and vary widely in capacity and size. Equipment has

consistently been improved over the last 30 years such that vacuum processing

has become a widely used application in the Aerospace and Automotive

Industry. Vacuum is considered to be any pressure which is below

atmospheric pressure and in industrial applications may be expressed as torr,

microns or millibars.

5.1 Vacuum effects:

The effects of treating components in a vacuum are two fold

1. In the medium-high vacuum region the partial pressure of the residual air in the

furnace particularly O2-H2O is significantly reduced and will provide an environment

to process components with little or no surface oxidation. The reduction of residual

Nitrogen (N2) is also beneficial for materials, which would otherwise form nitrides.

2. Decomposition of existing oxides in the surface of components may occur

depending on the temperature and material type.

General purpose of furnace: General purpose of furnace to designed to provide years

of continues service.

5.2 Different components used in furnace:

1. Furnace assembly.

2. Heat zone

3. Power supply

4. Evacuation system

5. Inert gas system

5.3 Types of process carried out in vacuum furnace:

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5.3.1 Annealing:

Annealing is one type of heat treatment comprising heating up to a specific

temperature, holding and cooling down slowly. Such processes are generally used to

obtain a softer structure of the part and to optimise material structure for subsequent

working steps (machining, forming). Parameters depend on the material and the

desired structure.

Purpose of process:

1. To reduce internal stresses.

2. To reduce hardness and increases ductility.

3. Refine grain size.

4. Improve machinability.

5. Improve homogeneity of material

5.3.2 Normalizing:

It is heat treatment process for making material softer but does not produce the

uniform material properties of annealing. In this process the metal is heating to a

specific temp. And holding for long time and then cooling to room temp. by using

air as cooling medium.

5.3.3 Hardening and Tempering:

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Hardening is process in which steel is heated to a temperature above the

critical point, held at this temperature and quenched (rapidly cooled) in water, oil or

molten salt baths. As earlier mentioned that if a piece of steel is heated above its

upper critical temperature and plunged into water to cool it an extremely hard, needle-

shaped structure known as marten site is formed. In other words, sudden quenching of

steel greatly increases its hardness.

After hardening steel must be tempered to:

1. Reduce brittleness,

2. Relieve the internal stresses, and

3. Obtain pre-determined mechanical properties.

The hardening process is based on a very important metallurgical reaction.

5.3.4 Case Hardening:

One of the important processes is the case hardening or carburizing process.

Parts are heated up to 900 °C - 1.000 °C and by adding specific gases (hydrocarbons)

into the atmosphere of the furnace the part's surface is enriched by absorbing carbon.

Following this treatment the part is quenched in order to achieve the required

properties. This results in higher resistance to stresses and friction on the component's

surface. The core of the part remains somewhat softer and more ductile which allows

the part to carry high stresses through its entire life.

For example, all gear parts for transmissions are treated this way.

5.3.5 Quenching or Austempering:

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This is the second method that can be used to overcome the restrictions of

conventional quench and tempering. The quench is interrupted at a higher temperature

than for Mar tempering to allow the metal at the centre of the part to reach the same

temperature as the surface. By maintaining that temperature, both the centre and the

surface are allowed to transform to Bainite and are then cooled to room temperature.

Advantages of Quenching:

(1) Less distortion and cracking than martempering,

(2) No need for final tempering (less time consuming and more energy

efficient)

(3) Improvement of toughness (impact resistance is higher than the

conventional quench and temp.)

(4) Improved ductility

Quenching media: The quenching media in general use are: Water, Brine, Oils, Air,

Molten salt.

Water: it is probably the most widely used as it simple and effective, it cools at the

rate of 982°C per second It tends, however, to form bubble. On the surface of

the metal being quenched an causes soft spots, so a brine solution is often

used to prevent this trouble.

Brine: it is very rapid cooling agent and may tend to cause distortion of the parts , as

will water.

Oil: it is used when there is any risk of distortion although it is more suitable for

alloy than plain carbon steels.

Air blast: when the risk of distortion is great, quenching must be carried.

Types of quenching:

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1. Direct quenching

2. Time quenching

3. Selective quenching

4. Spray quenching

5. Fog quenching

6. Interrupted quenching

5.3.6 Tempering:

The material should be tempere dimmediately after quenching.Quenching

should be stopped at a temperature of 50–70℃ (120–160℉)and tempering should

be done atonce. If this is not possible, thematerial must be kept warm, e.g. in a

special “hot cabinet” a waiting tempering.

Types of tempering:

1. Low temperature tempering (100-200℃¿

2. Medium temperature tempering (200-500℃¿

3. High temperature tempering (500-700℃¿

5.3.7 Carburizing Processes:

In vacuum carburizing, propane or acetylene are usually selected for all

carburizing processes without any specific geometrical requirements. However, it has

been proven that acetylene offers better carbon efficiency compared to propane

because of its instability and higher carbon content per mol of gas. Therefore, by

using acetylene, densely packed loads, especially parts with complicated shapes can

be carburized at high, reproducible quality.

Types of carburizing:

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1. Solid carburizing (925-950℃)

2. Gas carburizing (900-925℃)

3. Liquid carburizing (900-925℃)

Advantages of Carburizing:

1. Fast carbon transfer

2. No surface oxidation

3. Good case depth uniformity

4. Integration into manufacturing lines

5. Small consumption of carburizing gas

6. No formation of furnace atmosphere

7. High carburizing temperatures possible

5.3.8 Nitriding:

Nitriding is performed by exposing the parts to some media rich in nitrogen

under certain physical conditions that will result in the diffusion of nitrogen atoms

into the steel and the formation of nitrides. The part surface will then be harder and

have a higher wear resistance in its outer layer. In the case of corrosion resistant steel

with high-chromium content, it is very important to take into consideration the fact

that nitriding has a detrimental effect on the corrosion resistance of the material. In

other cases nitriding can have a positive effect on the corrosion resistance.

Appropriate steel to be nitride are usually medium-carbon steel with nitride-forming

elements such as chromium, aluminium, molybdenum and vanadium. The core should

act as a stable substrate regarding mechanical properties and microstructure. This

means that for hardened material it is necessary to temper above the nitriding

temperature in order to avoid softening of the core during the nitriding process. It

should be noted that a nitride surface cannot be machined with

6. FLANGES AND FITTINGS

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All vacuum systems require connections with either pumping systems or

different peripheral accessories such as vacuum gauges, valves, etc...

While these connections have to preserve vacuum integrity, they also have to be

modular to allow flexibility and required maintenance. All vacuum applications

involve flanges and fittings with stringent requirements regarding materials,

dimensions, tightness, conductance, etc...

FIG.NO.1 FLANG AND FITTINGES

6.1 Range of Flanges and Fittings:

In order to address the vacuum industries requirements, Alcatel offers a large

range of accessories based on the 3 most popular standards used in vacuum

technology.

• ISO-KF Flanges and Fittings

• ISO-K Flanges and Fittings

• CF Flanges and Fittings

For each standard, Alcatel offers the normalized nominal diameters generally used.

Moreover Alcatel offers other diameters historically used in the vacuum industry.

This offer includes a large range of accessories for each standard such as elbows, tees,

4-way crosses, flexible couplings, reducers and also some special adapters from one

standard to another.

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According to the working pressure, the tightness and the conductance

required, fittings will be made with one of the following standards.

TABLE NO.2 FLANGES AND FITTING, THE ALCATEL OFFER:

6.2 ISO-KF Flanges and Fittings:

ISO-KF Flanges and Fittings allow quick release and tight connections from

10 to 50 mm nominal diameters. With 2 flanges coupled together by a centring ring

with an O-ring and a clamp (Fig. 1 & 2), this kind of connection provides many

advantages such as:

• Easy and quick mounting

• Assembly without any tools

• Unlimited orientation

• Easy interchangeability

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FIG.2 ISO-KF FLANGES AND FITTINGS

6.3 Stainless steel series:

Used in high vacuum, corrosive or high temperature applications, stainless

steel flanges and fittings offer, according to the seal material, a large range of high

performances:

• Use with NBR O-ring

- Baked temperature: 80 °C

- Pressure range: 10-7 mbar

• Use with FPM O-ring

- Baked temperature: 150 °C

- Pressure range: 10-7 mbar

• Use with metal seal

(Aluminium, Braided aluminium, Indium)

- Baked temperature: 200 °C

- Pressure range: 10-9 mbar

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- Maximum overpressure: 5 bars

Metallic seals involve the use of special clamps such as chains or half flanges without

cantering ring due to the metallic seal characteristics. (Fig. 3)

6.4 Connections between different diameters ISO-KF Flanges:

10, 20 and 32 mm nominal diameter flanges have the same external

dimensions as 16, 25 and 40 mm, so the 10/16, 20/25, 32/40 connections are very

easy, using an adapter ring with the O-ring . These connections are also very easy

with a metallic seal because they are centred on the flange outside diameters.

For other different diameters, a conventional reducer must be used.

FIG.3 CONNECTIONS BETWEEN DIFFERENT DIAMETERS ISO-KF FLANGES

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6.4.1 Aluminium clamps:

FIG.4 ALUMINIUM CLAMP

6.4.2 Aluminium clamps with ratchet closure:

FIG.5 ALLUMINIUM CLAMP WITH RATCHET CLOSURE

6.4.3 Aluminium chain clamps for metallic seal:

FIG.6 ALUMINIUM CHAIN CLAMP FOR METALLIC SEAL

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6.4.4 Centering rings with O-Ring:

FIG.7 CENTERING RINGS WITH O-RING

6.4.5 Centering rings without O-Ring:

FIG.8 CENTERING RINGS WITHOUT O-RING

6.4.6 Adapting centering rings with O-Rings:

FIG.9 ADAPTING CENTERING RINGS WITH O-RING

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6.4.7 Elbows:

FIG.10 ELBOWS

6.4.8 Tees:

FIG.11 TEES

6.4.9 Crosses:

FIG.12 CROSSES

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7. LEAKAGE

A leak means an unintended crack, hole or porosity in an enveloping wall or

joint which must contain or exclude different fluids and gasses allowing the escape of

closed medium.

7.1 What is a vacuum leak?

A leak is an opening such as a crack or hole that allows a substance to be

admitted to or to escape from a confined space. A vacuum system leak allows air to

be admitted into the vacuum vessel. Suspect areas on vacuum furnaces include

threaded and brazed joints, fittings that have been improperly sealed or installed, and

damaged (cut, worn, melted, or dirty) O-ring seals, especially around doors.

Components that rotate or reciprocate are other prime leak sites.

7.2 Leakage in vacuum systems:

When a vacuum suction gripper cannot fully seal the system against

atmospheric air, we talk about leaking systems. This might be caused, for example, by

rough and uneven work piece surfaces or air-permeable work piece materials.

Remedial actions to achieve the required vacuum:

• Use of high-performance ejectors

• Reduction of the suction cup diameter

Ideally, when using vacuum applications in handling technology, the work piece

surfaces on which the suction cups have to rest should be smooth and impervious. A

suction cup fits tightly against this type of surface. When a vacuum is generated, the

sealing rim of the suction cup can fully seal the system against external atmospheric

air. We therefore describe this as a leak-proof system. The holding force of the

suction gripper on the work piece increases as the vacuum level in the system

increases compared with the external atmospheric pressure. Unfortunately, these ideal

surface conditions do not always exist on the work pieces to be moved.

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7.3 Potential sources of vacuum system leaks:

Type Potential Source

1. Actual (real) leaks:

Compression seals

Welds and brazed joints

Shaft seals and bellows on valves

Flexible connectors in piping

Threaded joints on vacuum gauge and plugs, for

example.

Static gasket seals on sight ports, feed through,

manifolds, and air-operated cylinder glands

2. Internal (through) leaks:

Process gas delivery system

Vent gas exit system

Seals between adjacent internal volumes

Improper gas ballast, gas purge, partial pressure control

systems, and backfill valves.

3. Virtual (outgassing) leaks:

Residual solvents

Residual liquids (water, cooling fluids) in blind holes

and

Restricted passageways.

Pockets of trapped gases or liquids

High-vapour-pressure materials

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7.4 Why do I need to leak test?

Everything leaks. And although a leak may be extremely small, it still may

pose a problem. Leaks can be inherent in the material, created during the

manufacturing process, be introduced during maintenance or repair, or occur over

time due to wear, fatigue, and stress. The possible source of a leak may be revealed by

the answer to the question, “What was the last area worked on or

modified?”However, the question that really matters is this: “Can the system tolerate

the leak?” In other words, can the process and equipment survive and be unaffected

by the leak? The answer is almost always, “No.”

7.5 How do I run a leak test?

A furnace leak-up rate test does not locate the leak, it only quantifies it. The

furnace must be clean, cold, empty, and outgassed to obtain a true leak-up rate value.

If it isn’t, which is often the case; a conditioning cycle should be run.

7.6 Leak testing:

To perform a leak-up rate check, pump the furnace down to ultimate pressure

with the heat turned off and the furnace cold, at 70°F (20°C) or below. Record the

vacuum level and the time. Next, isolate the furnace from the pumping system by

closing the vacuum valve(s) to the chamber. Allow at least an hour to obtain an

accurate leak-up rate. (This step is often shortened to just 5–30 minutes, but this is

poor practice and should be avoided.) Record the time and vacuum level. The leak-up

rate is the difference in the vacuum levels divided by the elapsed time and is

expressed in microns/h (mbar/h). For most vacuum applications, a leak-up rate above

10 microns/h (0.013 mbar/h) in the heating chamber is unacceptable— the leaks must

be found and corrected. Note that leak-up rates between 50 and 100 microns/h (0.067

and 0.13 mbar/h) are not uncommon for oil-quench tanks.

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7.7 Test methods:

There are three general categories of leak detection procedures:

• Effect-of-leak types: pressure decay (differential, increase), vacuum decay

• Amount-of-leak types: mass flow (inside/out, outside/in, accumulation), carrier gas,

residual gas analysis (RGA)

• Traditional types: immersion, sniffing The most common procedures for detecting

Leaks in vacuum furnaces are the solvent and mass spectrometer procedures.

Descriptions follow.

7.7.1 Helium Leak Detectors

History and principle:

At the origin of the helium leak detection method was the”Manhattan Project”

and the unprecedented leak-tightness requirements needed by the uranium enrichment

plants. The required sensitivity needed for the leak checking led to the choice of a

mass spectrometer designed by Dr. A.O.C. Nier tunedon the helium mass. Because of

its industrial use, the material choice turned out to be unbearably fragile and after

many complaints by the users, a new metallic version was developed and constructed.

The sensitivity of the apparatus was in 1946 ~10-7 Pa. m3.s-1 and it increased to ~10-

10 Pa. m3.s-1. by 1970. Nowadays the quoted sensitivity of the most sensitive

detectors is ~10-13 Pa .m3..S-1, a factor 106 gain within 50 years. The central piece

of the helium leak detector is the cell in which the residual gas is ionised and the

resulting ions accelerated and filtered in a mass spectrometer. Most of the current

detectors use, as in the original design, a magnetic sector to separate the helium ions

from the other gases. Permanent magnets are generally used to generate the magnetic

field. The adjustment needed for the selection of the helium peak is made by varying

the ion energy. A schematic layout of a helium leak detection .

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FIG.NO. 13 HELIAM LEAK DETECTION

To detect small leaks, the currents to be measured are very small: At the

highest sensitivity (in the 10-13 Pa .m3..s-1 range), currents as low as femtoamperes

have to be measured. This is achieved thanks to the use of an electron multiplier in the

most modern detectors. If the cell of a leak detector is not much different from the

original design, the pumping system has considerably changed, the original diffusion

pumps now being replaced by turbo molecular pumps or dry molecular-drag pumps.

The sensitivity of the helium leak detector is given by the ratio between the helium

flow through the leak and the partial pressure increase in the cell. In order to increase

the sensitivity, the pumping speed of the tracer gas has to be reduced. This must be

done without diminishing the pumping speed for the other gases (mainly water as leak

detection usually takes place in unbaked systems) in order to keep the appropriate

operating pressure for the filament emitting the ionising electrons. Selective pumping

is therefore needed to provide a high pumping speed for water and a low

pumping speed for helium.

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FIG.NO.14 LEAK CHEAKING A DOOR ASSEMBLY

7.7.2 Tracer Gas:

In the case of small leaks, the energy of the gas flow is insufficient to generate

measurable mechanical effects. In that case a greater sensitivity is obtained by relying

on the variation of physical properties of the residual gas for which accurate and

sensitive measurement methods are available. When the composition of the residual

gas is modified by the injection in the vicinity of the leak, of a gas (the tracer gas)

changing locally the air composition, these properties are altered and this alteration

can be measured for determining the size and the position of a leak. The tracer gas

must have the following properties [4], for the case of helium leak detection:

Be unique in the mass spectrum of the residual gas in the system and practically non-

existent in the normal surrounding atmosphere. Be readily removable from the system

by pumping and should not contaminate the systems Have a low viscosity. Many

properties of the residual gas can be used to monitor its composition changes. The

most widely used are the heat conductivity, the ionisation cross section, the pumping

speed and the conductance. The variation of heat conductivity is traced using a Pirani

gauge and using alcohol, helium or carbon dioxide. The pressure variation on the

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gauge will be positive for helium and negative for alcohol or carbon dioxide. The

variation in ionisation cross section can be used by monitoring the signal of an

ionisation gauge and this method, very useful in accelerators.

7.7.3 Comparing Pump Down Cycle:

A relatively simple leak detection method is to compare the pump down cycle

with a previous cycle made when the system was in a good working order. If the

vacuum level improves with each successive pump down, then out gassing should be

suspected. Out gassing can also be detected in large vacuum furnaces when large

pressure spikes occur or when pressure rises during the heating portion of process

cycle.

FIG.NO.15 COMPAIRING PUMP DOWN CYCLE

7.7.4 Performing Vacuum Decay Measurement:

Another simple leak detection method involves performing a vacuum decay

measurement. This test is accomplished by closing the valve between the vacuum

pump and the chamber, stopping the evacuation process. After a short stabilization

time, pressure can be observed to look for a pressure rise or vacuum decay. The

vacuum decay rate is defined as the difference in the vacuum levels at the beginning

and the end of the measurement divided by the elapsed time. It is normally expressed

in microns/hour. For most vacuum applications, a vacuum decay rate above 10

microns/hour in the heating chamber is unacceptable. Both of these methods are

affected by the overall cleanliness of the furnace.

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8. PROBLEM DEFINATION OF EXISTING LEAK

DETECTION

The main problem in helium leak detection system, it requires minimum -1 bar

pressure for detection of vacuum leakage. It cannot work when pressure is above -1

bar pressure in vacuum furnace. So we need another method for finding leakage in

above -1 bar pressure.

Another problem is maintenance cost and running cost is too much.

It also need highly skilled operator for operating this detector.

8.1 SOLUTION FOR PROBLEM

With respect to above information, solution is that to prepare a device such

that it should have to accomplish the following conditions.

1. device should work above -1 bar pressure

2. it should take less time for leak detection

3. it should be movable

4. easy to operate

5. size of machine should be compact

Hence from above reference we decide to prepare a device named as ‘vacuum

leak detection with smoke.’

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9. SMOOK GENRATOR

While using smoke generators to produce training smoke is a common training

option, it is critical that instructors take into account several issues regarding smoke

machine design and function, smoke quality, smoke properties, and the way in which

training smoke is used during their drills. The following report aims to provide insight

into various aspects surrounding smoke generator use and function with the ultimate

goal of promoting responsible and safe operation.

9.1 Smoke Production

There are basically two ways to produce training smoke:

1. Smoke can be produced through a chemical reaction of certain compounds, similar

to the way in which smoke arises from ordinary combustion processes;

2. Smoke can be produced by the spraying of certain liquids, during which liquid

particles are produced.

Smoke that is produced through the first method (a chemical reaction) is commonly

known as "pyrotechnic" smoke. There are typically several compounds added to a

special chemical “fuel” that are designed to improve the properties of the smoke.

Smoke generated in this way will usually contain resultant compounds that are

harmful to human health. Since only a small amount of chemical fuel is needed to

create significant levels of smoke, thus providing the advantages of portability and

flexibility, this type of smoke generation is popular in military applications. However,

due to the obvious health hazards involved, it is not recommended for normal training

situations where unprotected persons may be exposed. In the second method of

producing smoke through an aerosol process, a specially formulated "smoke liquid" is

used in combination with a smoke generation heater through which the smoke fluid is

sprayed. Here, the term 'smoke' is somewhat of a misnomer since the visual effect is

produced by a fine liquid mist, whereas in reality actual smoke consists of small solid

particles. Other typical terms for this type of “smoke” include “haze” and “fog”.

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9.2 How Smoke machines work

Smoke generators are often used in theatres and nightclubs. There are also

professional applications, such as fire drills or the detection of leaks in piping.

When comparing smoke generators, the following considerations must be taken into

account:

• The smoke production: how much and what type of smoke do you need? How much

smoke can the machine (continuously) produce? What is the efficiency – in other

words how much smoke liquid does the machine need to produce a given amount of

smoke?

• The operating mechanisms. How do you want to operate the machine?

• Electrical consumption: how much power is available at the location where the

Machine will be used mostly?

• Utilization. How do you transport the machine? How will the machine be refilled?

Smoke generator is rectangular box it contains one inlet and one outlet. It contains

circular heater inside rectangular box its heating capacity is 1100℃. Circular heater

contains glass wool which absorbs oil and produces smoke. With the help of

compressed air this smoke is spread on defected part with the help of air gun.

FIG.NO.16 SMOKE GENERATOR BOX

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10.ATK-MQ7-SMOKE SENSOR

FIG.NO.17 SMOCK SENSOR

10.1 Overview

Sensitive material of MQ-7 gas sensor is SnO2, which with lower conductivity

in clean air. When the target combustible gas exist, the sensor’s conductivity is higher

along with the gas concentration rising. Please use simple electro circuit,

Convert change of conductivity to correspond output signal of gas concentration.

MQ-7 gas sensor has high sensitivity used in to carbon monoxide, also could

be used to Methane and other combustible steam, it is with low cost and suitable for

different application

10.2 Features

Operating voltage: 5V

Provide both digital and analog output

Adjustable sensitivity

Output LED indicator

Compatible with Arduino and Microcontroller

Onboard holes for easy installation

High sensitivity to carbon monoxide

Stable and long life

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10.3 Applications

Consumer electronics

They are used in gas detecting equipment for carbon

monoxide(CO)

10.4 Specifications:

TABLE NO.3 SENSOR SPECIFICATIONS

Parameter Min Type Max Units

Working Voltage 4.5 5 8 Volts

Range 0-4.6 Volts

10.5 Pin Diagram: 3

TABLE NO.4 PIN DIAGRAM

Pin Pin Name Pin Name

+5V I/N Regulated 5V supply input

GND GND Ground level of power supply

DO O/P Digital Output to external devices

AO O/P Analog Output to ADC

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FIG.NO.18 SMOCK SENSOR CONNECTIONS

Initially the sensor gives high output so power on the sensor for 15minites

because it needs initially heating voltage then and then it gives proper output. More

info refers the datasheet for the same. Recommend separate power supply because its

required more current to heat.

10.6 Sensitivity adjustment

41

Resistance value of MQ-7 is difference to various kinds and various

concentration gases. So, when using these components, sensitivity adjustment is very

necessary. We recommend that you calibrate the detector for 200ppm CO in air and

use value of Load resistance that (RL) about 10 KΩ (5KΩ to 47 KΩ).

When accurately measuring, the proper alarm point for the gas detector should be

determined after considering the temperature and humidity influence. The sensitivity

adjusting program:

a. Connect the sensor to the application circuit.

b. Turn on the power; keep preheating through electricity over 48 hours.

c. Adjust the load resistance RL until you get a signal value which is respond to a

Certain carbon monoxide concentration at the end point of 90 seconds.

d. Adjust the another load resistance RL until you get a signal value which is respond

to a CO concentration at the end point of 60 seconds.

11. ADVANTAGES AND DISADVANTAGES

42

11.1 Advantages:

1. Its versatile device which used for leak detection of various

vacuum furnes in the range of above -1bar pressure.

2. It is portable device.

3. It doesn’t required skilled operator.

4. Adjustable sensitivity.

5 .Provide both digital and analog output

6. MQ-7 smoke sensor has high sensitivity used in to carbon

monoxide, also could be used to Methane and other

combustible steam, it is with low cost and suitable for different

application.

11.2 Disadvantages:

1. Leak detection range is limited.

2. Device uses smoke for leak detection which can be harmful to

human health.

3. It is uneconomical.

12 PROJECT COST

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TABLE NO.5 PROJECT COST

Sr. No. Device/material Cost (in Rs)

1. Circular heater

2. Rectangular metal box

3. Air gun

4. Pressure regulator

5. Gasket

6. Vacuum fittings

7. Hoses

8. Flexible pipe

9. KF40 fittings

10. Tee fittings

11. Smoke sensor

12. Other (welding/drilling)

TOTAL COST

13. CONCLUSION

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The various methods that can be used for the leak detection of accelerator

systems cover the large range of possible leaks from the broken feed through to the

tiny leaks appearing after bake out.

Despite the quality of the equipment now commercially available, leak

detection remains an exercise, which, generally, is still difficult and requires well

trained technicians with a good knowledge of the vacuum system on which they

intervene. Even with the best technicians using the most sophisticated equipment,

emergency leak testing is always a time consuming and very expensive activity. For

these reasons careful mechanical design and construction according to the rules of

good vacuum practice must be applied. Preliminary tests of components must be

made before installation: they are always much easier to carry out and avoid the costly

installation and demounting of faulty equipment. Lastly these somewhat theoretical

considerations on leak detection are a minute part of all the knowledge required to

become “a subtle leak hunter” and which is only accessible “the hard way” by

practice.

14. REFERENCES

45

14.1 Books:

[1] A. Roth, Vacuum Technology, New York, Elsevier Science Publishers, 1990.

[2] J.F. O’Hanlon, A Users Guide to Vacuum Technology, New York, John Wiley &

Sons, 1989.

[3] J.M. Lafferty, Foundations of Vacuum Science and Technology, New York, John

Wiley & Sons, 1998.

[4] A. Nerken, J. Vac. Sci. Technol., A9, 3, 2036, 1991.

[5] A.O. Nier, C.M. Stevens, A. Hustrulid and T.A. Abott, J. Appl. Phys. 18, 30,

1947.

[6] W. Becker, Vak. Tech., 8, 203, 1968.

[7] M.H. Hablanaian and W.E. Briggs, Proc. Int. Vac., Congr. 7th, Vienna, 199, 1977.

[8] M.H. Hablanaian and W.K. Huber, Proc. Int. Vac., Congr. 7th, Vienna, 199, 1977.

[9] International Standards Organization, 1 rue de Varembé, CP56, CH1211 Geneva

20, Switzerland, http://www.iso.ch ISO3530:1979.

[10] C. Benvenuti and J.C. Decroux, Le Vide, 162, 243, 1972.

[11]Practical Vacuum Techniques, by W.F.Brunner and T.H. Batzer: Krieger, 1974.

[12]A User’s Guide to Vacuum Technology, by J.F. O’Hanlon: John Wiley & Sons.

[13] High Vacuum Technology: A Practical Guide, by Marsbed H. Hablanian: Marcel

Dekker Inc., 1990.

[14] “Basic Vacuum Practice,” 3rd Ed.: Varian Vacuum Products Training Dept.,

Varian Assoc., 1992.

[15] “Leak Detection Applications & Techniques”: training course, Varian Inc.

Vacuum Technologies.

14.2 Website

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http://www.vicleakdetection.com/

http://www.pfeiffer-vacuum.com/en

http://www.cincinnati-test.com/

http://www.vac-eng.com/

http://www.heliumleakdetection.net/

http://www.sensorsONE.com/

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