Manufacturing Process of Centrifugal Pumps

A Study on Manufacturing Process of Centrifugal
Pumps in Milarns Pumps Limited

Pumps in Milarns Pumps Limited
Submitted By
………………………………………………………….
Md Rohel Uddin
Id# 15207024
Department of Mechanical Engineering
IUBAT—International University of Business Agriculture &
Technology
20 April 2019

iii
In the name of Allah, The Most
Beneficent, the Most Merciful
And the Most Gracious

iv
A Practicum Report Submitted to the Department of
Mechanical Engineering at IUBAT-International
University of Business Agriculture and Technology in
Partial Fulfillment of the Requirements for the Degree
Of Bachelor of Science in Mechanical Engineering

vi
PLACEMENT LETTER
CERTIFICATE FROM ORGANIZATION
Author’s Declaration

vii
This to inform that the Practicum Report ―A Study on Manufacturing Process of
Centrifugal Pumps at Milanars Pumps Ltd.I has been prepared only for academic
purpose. I also confirm that it has not been submitted elsewhere for any reward or
presentation or any other purpose.
……………………
ID # 15207024
Department of Mechanical Engineering
IUBAT—International University of Business Agriculture & Technology
ACKNOWLEDGEMENT

viii
Professor M Alimullah Miyan, PhD
Vice Chancellor and Founder of IUBAT.
Prof Dr Engr A Z A Saifullah
Professor & Chair, Department of Mechanical Engineering.
Prof Eng. Abdul Wadud
Professor & Coordinator, Department of Mechanical Engineering
Prof.Eng. Abdul Wadud
Internal Supervisor, Department of Mechanical Engineering
Md .Abdul Halim
Dicetor, Milnars Pumps Ltd.
Engr. Morshed Cho. Miraz
Inspection and Quality Control Engineer, Milnars Pumps Ltd.

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Pumps in Milarns Pumps Limited.
Candidate
………………………………
Md Rohel Uddin
ID:15207024
Supervisor
…………………………………………
Professor Abdul Wadud

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Abstract
Milnars Pumps Limited is one of the leading centrifugal pump manufacture company. It
is one of the largest manufacturers of Pump Company in our country. It was originally
founded in 1961 in the name of KSB Pumps Company Limited, During my internship
period, as a Trainee Engineer, my responsibilities were how to manufacturing process
of centrifugal pump in the workshop. The company underwent extensive and exhaustive
program. Under the program, Induction Furnace has been installed with decorated
laboratory for casting of quality stainless steel (SS), other alloy steel. In foundry shop
they cast volute casing, B.B Stole, Impeller, Suction cover of the centrifugal pump.
MPL pumps and its other products are manufactured according to DIN standard and to
highest design meeting international quality. So I hope my report in the centrifugal
pump is based on theoretical knowledge and as well as practical knowledge. This report
contains the basic parts and accessories of the Centrifugal pumps. The total shop of
Milnars pumps shop divided into four different shops those are Foundry shop, Machine
shop, Assembly Section, Testing Section. All this parts are described by the things they
are made and their working procedure. It is also about keeping the pumps in good
situation and when to check for maintenance and servicing. I hope I was able to include
all the parts and its description in this report

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Table of Contents
Chapter 1. Introduction.................................................................................................. 1
1.1 Introduction......................................................................................................... 1
1.2 Aim and Objectives............................................................................................... 1
1.2.1 Broad Objective............................................................................................. 1
1.2.2 Specific Objective .......................................................................................... 1
1.3 Metrology:........................................................................................................... 2
1.3.1 Sources of Data............................................................................................. 2
1.4 Limitations ........................................................................................................... 2
Chapter 2. (Company Profile).......................................................................................... 3
2.1 Introduction......................................................................................................... 3
2.2 Company Location................................................................................................ 6
2.3 Vision................................................................................................................... 6
2.4 Mission ................................................................................................................ 6
2.5 Social commitment............................................................................................... 7
2.6 MPL Code of Conduct............................................................................................ 7
2.7 Management structure ......................................................................................... 8
2.8 Message from Executive Chairman: ....................................................................... 9
2.9 Company product profile and their detail............................................................... 9
2.9.1 Product Profile .............................................................................................. 9
2.10 Product Details of MPL.........................................................................................10
2.10.1 Centrifugal pump..........................................................................................10
2.10.2 Sluice Valves.................................................................................................11
2.10.3 High pressure multistage pump.....................................................................12
2.10.4 Deepwell Turbine Pump................................................................................13
2.10.5 Submersible Pump........................................................................................14
2.11 Production Capacity of Milnars Pumps Ltd............................................................15
2.12 Commitment to Customer....................................................................................15
2.13 Certificate andAward and Social Activities............................................................15
Chapter 3. LITERATURE REVIEW ....................................................................................16
3.1 Literature Review.................................................................................................16
Chapter 4. The centrifugal Pump...................................................................................18
4.1 Definition of Pump...............................................................................................18
4.2 Classification of Pump..........................................................................................18
4.3 Classification of pumps mainly dividedinto two major categories:..........................19
4.3.1 Dynamic pumps / Kinetic pumps:...................................................................19

xii
4.3.2 Displacement Pumps / Positive displacement pumps:.....................................19
4.4 Definition of Centrifugal Pump .............................................................................22
4.5 Classification of Centrifugal Pump.........................................................................23
4.5.1 Axial Flow Pumps..........................................................................................23
4.5.2 Radial Flow Pumps........................................................................................23
4.5.3 Mixed flow pump .........................................................................................24
4.5.4 Vertical Pumps.............................................................................................24
4.6 Working Mechanism of a Centrifugal Pump...........................................................26
4.7 Different Type of Parts Centrifugal Pump ..............................................................26
4.7.1 Impeller.......................................................................................................27
4.7.2 Volute Casing...............................................................................................28
4.7.3 Suction Cover...............................................................................................28
4.7.4 Break Bearing Stool (B.B Stool)......................................................................29
4.7.5 Shaft sleeves................................................................................................29
4.7.6 Wear Ring....................................................................................................30
4.7.7 Gasket.........................................................................................................31
4.7.8 Ball bearing..................................................................................................31
4.7.9 Gland...........................................................................................................32
4.7.10 Coupling.......................................................................................................33
4.8 Introduction........................................................................................................34
4.8.1 Foundry Section...........................................................................................34
4.8.2 Machine Section...........................................................................................42
4.8.3 Assembly Section..........................................................................................49
4.8.4 Pump Testing Section....................................................................................51
Chapter 5. Problem and solution...................................................................................59
5.1 Problem and solution:..........................................................................................59
5.1.1 Centrifugal Pump Problems:..........................................................................60
Chapter 6. Conclusion and Recommendation..................................................................64
6.1 Conclusion...........................................................................................................64
6.2 Recommendation ................................................................................................65
6.3 Bibliography........................................................................................................66
6.4 Abbreviations......................................................................................................67
6.5 Pump Terminology...............................................................................................69

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List of Figures
Figure 2.1 Milnars pumps Ltd............................................................................................... 4
Figure 2.2 Machine Shop of MPL......................................................................................... 4
Figure 2.3 Foundry Shop...................................................................................................... 4
Figure 2.4 Assembly Shop ................................................................................................... 5
Figure 2.5 Testing Section.................................................................................................... 5
Figure 2.6 Management structure....................................................................................... 8
Figure 2.7 Chairman of MPL................................................................................................ 9
Figure 2.8 Centrifugal Pump ...............................................................................................10
Figure 2.9 Sluice Valve.......................................................................................................11
Figure 2.10 Sluice Valve.....................................................................................................11
Figure 2.11 High Pressure multistage Pump .........................................................................12
Figure 2.12 : Deepwell turbine pump ..................................................................................13
Figure 2.13: Submersible water pump..................................................................................14
Figure 4.1 Classification of pumps.......................................................................................18
Figure 4.2 Dynamic pumps .................................................................................................19
Figure 4.3 Displacement Pumps...........................................................................................20
Figure 4.4 Reciprocating pumps ..........................................................................................21
Figure 4.5 : Centrifugal pump..............................................................................................22
Figure 4.6 : Axial pump ......................................................................................................23
Figure 4.7 Radial flow pumps..............................................................................................23
Figure 4.8 Mixed flow pump ...............................................................................................24
Figure 4.9 Vertical pump.....................................................................................................24
Figure 4.10 Line shaft pump................................................................................................25
Figure 4.11 Submersible pumps...........................................................................................25
Figure 4.12 Centrifugal pump.............................................................................................26
Figure 4.13 main parts of pumps..........................................................................................27
Figure 4.14 Impeller ...........................................................................................................27
Figure 4.15 Volute Casing...................................................................................................28
Figure 4.16 Suction Cover...................................................................................................29
Figure 4.17 Break Bearing Stool..........................................................................................29
Figure 4.18 Shaft Sleeves....................................................................................................30
Figure 4.19 Wear Ring........................................................................................................30
Figure 4.20 Gasket..............................................................................................................31
Figure 4.21 Ball Bearing .....................................................................................................32
Figure 4.22 Gland...............................................................................................................32
Figure 4.23 Coupling ..........................................................................................................33
Figure 4.24 Master pattern...................................................................................................35
Figure 4.25 Core Making ....................................................................................................36
Figure 4.26 Sand prepared Machine .....................................................................................37
Figure 4.27 Sand making process.........................................................................................38
Figure 4.28 Induction Furnace.............................................................................................39
Figure 4.29 : Pouring ..........................................................................................................39
Figure 4.30 Finishing of Impeller.........................................................................................41
Figure 4.31 Lathe Machine Operation ..................................................................................42
Figure 4.32 Facing & Turing Operation...............................................................................43
figure 4.33 Drilling & Reaming operation ............................................................................43
Figure 4.34 Drilling Machine & its operation........................................................................44
Figure 4.35 Milling Machine & Its operation........................................................................44
Figure 4.36 Milling Machine ...............................................................................................45
Figure 4.37 Grinding Machine & its operation......................................................................45
Figure 4.38 Assembly Section of pump................................................................................49

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Figure 4.39 Assembly of pump............................................................................................50
Figure 4.40 Testing Section of pump....................................................................................51
Figure 4.41 Curve Efficiency..............................................................................................52
Figure 4.42 Pump flow capacity.........................................................................................53
Figure 4.43 Head and Capacity............................................................................................53
Figure 4.44 Head & Capacity ..............................................................................................54
Figure 4.45 NPSH and Capacity ..........................................................................................55
Figure 4.46 Overall rating ..................................................................................................55
Figure 4.48 Specific Speed..................................................................................................56
Figure 4.49 Specific Speed typical Curve .............................................................................57
Figure 4.50 System Curve ...................................................................................................57
Figure 4.51 Fluid flow curve ...............................................................................................58
Figure 4.52 Milnars Pumps curve ........................................................................................58
Figure 4.53 Total head and Capacity....................................................................................58
Figure 5.1 Problem and solution ..........................................................................................59
Figure 5.2 Problem and solution ..........................................................................................60

xvi
List of Tables
Table 2-1 Specification of Centrifugal pump ........................................................................11
Table 2-2 Specification of High pressure Centrifugal pump...................................................12
Table 2-3 Specification of Deepwell Turbine pump ..............................................................13
Table 2-4 Specification of Submersible pump.......................................................................14

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Chapter 1. Introduction
1.1 Introduction
Internship is the process of on-the-job training, which particularly beneficial for
students with major in technical courses. International University of Business
Agriculture and Technology (IUBAT) provide that glorious opportunity to their
students of having an internship within their bachelor program. For these purpose
industry people are invited to IUBAT to talk about their companies and
experiences, often some technical courses are entirely conducted by them. The four
month internship program is another, possibly most effective, way of achieving
industry orientation. Internship helps the students to link-up their academic
experience with industry practices. I have tried my best to combine the both
together. The company I was sent for internship is Milnars Pumps Ltd. It is one of
the leading pump Manufacture companies in Bangladesh.
1.2 Aim and Objectives
1.2.1 Broad Objective
The board objective of the report is to introducing with the Milnars Pump Ltd. and
also their production procedure, mainly the manufacturing process and the related
other aspects of the Milnars Pumps Ltd.
1.2.2 Specific Objective
1. To study about manufacturing process of centrifugal pumps.
2. To study metal casting process, pattern making and core making process of
centrifugal Pumps
3. To study about the Induction furnace for metal casting.
4. To study different type of machine operations.
5. To study about the assemblies of centrifugal Pumps.
6. To study about the testing process of centrifugal pump.
7. To suggest probable solution of the identified problem.

2
1.3 Metrology:
A qualitative research method has been used to carry out this study of practicum in
Milnars Pumps Ltd.
The method of manufacturing process is started from foundry section by the raw
metal casting, mold making, pattern making etc. After that it will come to the
machining section, turning, facing, knurling, and boring all kinds machining work
done by separate machine and processes. Rest of the work done by the assembly
shop and painting shop. After that a pump go throw the test bench for final
checking and quality control. I have collected information verbally from engineer
and technicians and some are collected from there data sheet, work log, client work
order, and testing data
1.3.1 Sources of Data
I have collected two types of data for prepare this report purpose. These are Primary
data which I collected from the factory, and Secondary data which I collected from out
of the factory.
Primary Data: I have collected primary data verbally from engineer and technicians
and some are collected from there operators Log Sheet, Machine catalog, Client Work
order the User Manual etc.
Secondary data: Secondary data has been collected from the Books, Journals,
Searchers papers, article, internet etc.
1.4 Limitations
During Practicum in Milnars Pumps Ltd, I have got a lots of information and they
are very much cooperative and they help us a lot. This report has been prepared for
only the Centrifugal Pump . Nothing is described about the other pumps like
turbine pump, reciprocating pump, rotary pump. I focused on the manufacturing
process only.
 Project time was insufficient.
 There was some safety problem.
 Updated tools is not sufficient.
 Technical term is not sufficient.
 Special tools is not sufficient & some spares parts have no available.

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Chapter 2. (Company Profile)
2.1 Introduction
Milnars Pumps Limited (MPL) has a history of over four decades. It was originally
founded in 1961 in the name of KSB Pumps Company Limited as an affiliate of
KSB Germany at time when the country was just on the verge of making a
breakthrough in agricultural production of food through small localized
mechanical Irrigation system. Its factory was established at Tongi, 20 Km north of
Dhaka City on an area covering about 3.50 acres. After 1972 independence of
Bangladesh, the parent company KSB Ag of Germany took direct control of the
management and renamed it as KSB Pumps Company (Bangladesh) Limited. Later
in 1980, after obtaining majority of share from KSB, its operation started under the
name MILNARS PUMPS LTD. Under the new management presently, MPL is
wholly owned by AFTAB GROUP. Aftab Group is one of the leading
multidisciplinary Industrial and business house of Bangladesh. Aftab Group is
involved in Banking, Engineering/manufacturing, agro - industrial productions,
garments,textile and multifarious trading activities in Bangladesh and real-estate
business in USA. The company has its own foundry in its premises at Tongi
Works. Backed-up with an on-job solid experience of more than four decades, the
MPL products are the result of forward looking techniques, modern machining and
accurate & precision tooling under the inspiring and dedicated professionalism of
its 12 highly qualified engineers and 175 skilled work personnel. Very recently,
the company underwent extensive and exhaustive program. Under the program,
Induction Furnace has been installed with well-equipped laboratory for casting of
quality stainless steel (SS), other alloy steel and sherardized graphite iron (SG)
products. This modern plant is the only and first of its kind in Bangladesh and can
meet the demand of casting of different type of products of different qualitative
specification required in pump valve and other machine part/component
manufacturing. MPL pumps and its other products are manufactured according to
DIN standard and to highest design meeting international quality. Every product
has to undergo comprehensive inspection and tests in company’s most modern test
bed in 2002. MPL obtained ISO9001:2000 certification for Quality Management
System, as the first and only Pump and casting industry in Bangladesh. MPL
current product lines what we believe to be among the best and finest available in
this part of the world. Hundreds and thousands of MPL pumps can be seen at work

4
all over Bangladesh in surface and ground water irrigation projects, Hydro
projects, And municipal water supplies as well as in various industrial enterprises.
Figure 2.1 Milnars pumps Ltd
Figure 2.2 Machine Shop of MPL
Figure 2.3 Foundry Shop

5
Figure 2.4 Assembly Shop
Figure 2.5 Testing Section

6
2.2 Company Location
Head Office
Uttara Bank Bhaban(5t h Floor)
90, Motijheel Commercial Area, Dhaka-1000
Bnagladesh, G.P.O Box No. 428
Fax : 880-2-9559431, 9563319
E-mail :sales@milnarspumps.com, milnars@bdmail.com
Web : www.milnarspumps.com
Phone : 9563526,9563436,9567203
Factory Location
Aftab Complex, Cherag Ali 89-90,Tongi I/A.
Gazipur-1704
Fax: 9815549 Phone: 9802385
2.3 Vision
The company’s vision is to make progress possible through excellence in
technology, integrity and unsurpassed customer services. The company principles
evolve around the idea of providing high quality customer services with reliability
and innovative practices through persistent teamwork of responsible employees.
The management of MPL strongly appreciates the diversity in the vast amount of
knowledge and experience their people bring with them to the company. They also
acknowledge the professional specialization of each company personnel and
believe that there is always something one can teach and learn from others; hence
they actively encourage everyone to work collaboratively together.
2.4 Mission
We manufacture and market a selected range of standard and engineered pumps
and castings of world class quality. Our efforts are directed to have delighted
customers in the water, sewage, oil, energy, and industry and building services
sectors. In line with the Group strategy, we are committed to develop into a center
of excellence in water application pumps and be a strong regional player. We want
to market valves, complete system solutions and foundry products including

7
patterns for captive, automotive and other industries. We will develop a world class
human resource with highly motivated and empowered employees.
2.5 Social commitment
MPL places particular value on social welfare and environmental protection.
Working under the name of MPL Care, our Corporate Social Responsibility
program is focused to provide a sustainable infrastructure and basic amenities to
underprivileged students at schools in the rural areas of Pakistan. Our commitment
towards our Country shines through the efforts we put in our business and our
corporate social responsibility.
2.6 MPL Code of Conduct
The Code of Conduct constitutes the basis of compliance activities at MPL. It describes
the key legal and business policy principles that we use in our relationships with
customers, suppliers and other business partners as well as our internal cooperation. It
also determines our conduct on financial markets and in the various countries in which
we work. The Code aims to support employees in their day-to-day work.

8
2.7 Management structure
Figure 2.6 Management structure

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2.8 Message from Executive Chairman:
Welcome to Milnars Pumps Limited We are thankful to Al-mighty Allah for his
kindness to us all.Milnars Pumps Ltd, is the oldest pump manufacturing company of
Bangladesh. Our aim is to continue our effort to get highest confidence and satisfaction
of our valued customer by continuous improvement of our service and quality. Support
from the valued customers of Milnars Pumps Ltd. have enabled us to meet the demands
of development and have made it possible to strengthen our commitment to growth and
set higher quality standards of management, technology, operations system human
and resources.
We always appreciate suggestions and comments from our customers for developing
our service and quality.
Regards for all our well-wishers.
Azharul Islam
2.9 Company product profile and their detail
2.9.1 Product Profile
2.9.1.1 Centrifugal Pump
2 Types
1. ETA 40- 20
2. ETA 150-26
2.9.1.2 Submersible Pump
2 Types
Figure 2.7 Chairman of MPL

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1. Sub-B7B
2. Sub-B12B
2.9.1.3 Turbine Pump
2.9.1.4 High Pressure Multistage Pump
2 Types
1. MOVI-30
2. MOVI-40
2.9.1.5 Domestic Pump
2.9.1.6 Sluice Valve
2.9.1.7 Non Return Valve
2.9.1.8 Jaw Plate
2.10 Product Details of MPL
2.10.1 Centrifugal pump
Materials of construction
Volute casing, Impeller, Suction cover, Bearing stool etc. are made of Cast
Iron(Bronze or SS for special requirement)Shaft made from cold drawn carbon
steel(SS for special requirement.
Figure 2.8 Centrifugal Pump

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Specifications
Table 2-1 Specification ofCentrifugal pump
Size NW 40 to 250 mm
Capacity Q Up To 550 m3
/h
Total Head H Up To 100 m
Discharge
Pressure
P Up To 8.50 bar
Temperature T -10° To 130° C
Speed N Up To 2900 rpm
Applications:
1. Organic and inorganic Liquids
2. Drugs and Pharmaceuticals
3. Refineries ,Fertilizer Plant, Petrochemical and Chemical.
4. Process Industries
5. Agriculture undertakings.
6. General water supply duities for Municipal.
2.10.2 Sluice Valves
Figure 2.10 Sluice Valve
Figure 2.9 Sluice Valve

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Materials of construction:
The selection of the correct material of construction for valves body from the wide
choice available is government by the pressure, the temperature and the nature of the
fluid flowing through the valves
Standard execution
 Body, dome, wedge gate, Stuffing box and hand wheel are of Cast Iron
 Face ring in body and on the gate are of Bronze, an alloy of high wearing
qualities material naturally developed for use in valves and fittings
 Spindle of forged bronze upto valve size NW 100 and stainless steel for NW
125, 150 & 200
2.10.3 High pressure multistage pump
Specifications
Table 2-2 Specification ofHigh pressure Centrifugal pump
Size NW 32 to 40 mm
Capacity Q Up To 42 m3
/hr
Total Head H Up To 400 m
Discharge
Pressure
P Up To 40 bar
Figure 2.11 High Pressure multistage Pump

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Temperature T -10° To 140° C
Applications:
Irrigation, water, General water supply, Fountains, Pressure Boosting , Pumping of
Boiler Feed water ,Cooling water and Hot water Circulation ,pumping of Condensates
,Fire Fighting etc.
2.10.4 Deepwell Turbine Pump
Specifications:
Table 2-3 Specification ofDeepwell Turbine pump
Well Diameter D 8" TO 20"
Delivery Size NW 3" TO 8"
Bowl Size A 5.5" TO 11"
Capacity Q Up to 300 m
Figure 2.12 : Deepwell turbine pump

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Total head H Up To 100 m
Application:
1. Agricultural undertakings.
2. General water supply duties for Municipal
3. Refineries, Fertilizer Plant, Petrochemical and Chemical
2.10.5 Submersible Pump
Specification:
Table 2-4 Specification ofSubmersible pump
Well
Diameter
D 6" To 14" Inc
Delivery
Size
WN 50 To 250 mm
Capacity Q Up To 360 𝒎 𝟑
/hr
Total head H Up To 450 M
Figure 2.13: Submersible water pump

15
Motor rating HP Up To 250 V
Application:
Agriculture Undertaking, Irrigation & Drainage, Drinking water supplies, Water supply
for Trade and Industry
2.11 Production Capacity of Milnars Pumps Ltd
Milnars Pumps Ltd. is involved in the assembly and manufacturing of pumps
which are essentially devices for lifting and movement or transfer of water or any
other fluid. The company’s present yearly production capacity is 20,000
Centrifugal pumps, 1,500 Deep Well Turbine Pumps, Submersible Pumps, High
Pressure Industrial Pumps and Domestic pumps of various design and capacities,
MPL also manufactures Sluice and Non-Return valves from diameter 37 mm to
200 mm sizes.
2.12 Commitment to Customer
Our success is based upon our customer focus. We listen to and connect with customer.
We anticipate their needs and make it easy for them to do business with us. We keep
promises. We offer internal and external customer value and quality services to enrich
lives and enhance business success. We treat them with dignity and respect.
2.13 Certificate and Award and Social Activities
In 2002, MPL obtained ISO9001:2000 certification for Quality Management
System, as the first and only Pump and casting industry in Bangladesh. MPL’s
current product lines what we believe to be among the best and finest available in
this part of the world. Hundreds and thousands of MPL pumps can be seen at work
all over Bangladesh in surface and ground water irrigation project, BWDB Hydro
projects, And Municipal Water Supplies as well as in various industrial enterprises.

16
Chapter 3. LITERATURE REVIEW
3.1 Literature Review
At present time, single and multistage centrifugal pumps are widely used in
industrial and mining sectors. Centrifugal slurry pumps are used for handling
different slurry mixtures. There are many design parameters for pumps, which
affects the characteristics of pump immensely. To achieve better performance for a
centrifugal pump, design parameters such as the number of blades for impeller-
diffuser, blade angle, blade height and diffuser, blade width, impeller diameter and
volute casing radius must be determined accurately, due to the complex liquid flow
through a slurry pump. A lot of papers have been published on various aspects of
wear in a slurry impeller or volute, performance corrections and derating, etc. The
readers of these papers are often left with the impression that the design of these
pumps is a combination of science and art. What are generally lacking in the
research work are the guidelines for the design of centrifugal slurry pumps. The
literature review of experimental and numerical evaluation of performance
characteristics of centrifugal pumps are given in this chapter.
The performance of centrifugal pump has been evaluated to determine their
dependence on various geometrical and dynamical parameters including the
effect of variation in rotational speed and numbers of blades. Using
computational simulation of fluid flow within the pump, the effect of
geometrical modifications has examined in relation to pressure pulsations.
Some literatures are as:
Minggao et al. (2009) have investigated the numerical research on
performance prediction for centrifugal pumps. Commercial FLUENT
software with standard k-ɛ model was used to simulate the performance of six
centrifugal pumps models at design flow rate and off design flow rate for the
improvement of performance and numerical calculation method. Every pump
made run at different specific speed.
Bacharoudis et al. (2009) investigated the parametric study of a centrifugal
pump impeller by varying the outlet blade angle. Simulation is carried out
using ANSYS FLUENT CFD Code with standard k-ɛ model. During the
study of the impeller performance, blade outlet angle changed. The
performance curve became smoother and flatter due to increase in the blade

17
angle at whole range of the flow rates. Due to increase in outlet blade angle
from 200 to 500, the increment in the head is more than 6 %.
Si et al. (2014) have studied the numerical investigation of pressure
fluctuation in centrifugal pump volute based on SAS model and
experimental validation. ANSYS CFX 14.5 software with SST k-ω
turbulen e odel w s used for si ul tion. Near the tongue region, pressure
fluctuation intensity is strongest and distribution is irregular in the pump
casing.

18
Chapter 4. The centrifugal Pump
4.1 Definition of Pump
A pump is a mechanical device that imparts energy to the fluids such as liquids and
gases or sometimes slurries by mechanical action. It is a hydraulic machine, which
translates into a hydraulic energy
Pumps are classified as rotary, reciprocating or centrifugal. Gear, vanes, lobes are
used by rotary pump to transfer fluid from inlet to outlet. Reciprocating Pumps are
those that use pistons or diaphragms for giving the pressure to the fluid. In
centrifugal pumps, fluid move by the action of centrifugal force which is imparted
by rotating elements is called impeller which raises the kinetic and pressure energy
of the fluid.
4.2 Classification of Pump
Figure 4.1 Classification of pumps

19
4.3 Classification of pumps mainly divided into two major categories:
1. Dynamic pumps / Kinetic pumps
2. Displacement Pumps / Positive displacement pumps
Definition of Dynamic/Kinetic pumps:
4.3.1 Dynamic pumps / Kinetic pumps:
Dynamic pumps impart velocity and pressure to the fluid as it moves past or through the
pump impeller and, subsequently, convert some of that velocity into additional pressure.
It is also called Kinetic pumps.
Figure 4.2 Dynamic pumps
4.3.2 Displacement Pumps / Positive displacement pumps:
Positive displacement pump (PDP) is a type of pump in which a moving fluid is
captured in a cavity and then discharges that fixed amount of fluid. The displacement of
fluid takes place by some parts like plunger, piston, diaphragm etc.

20
Figure 4.3 Displacement Pumps
The mainly Positive displacement pumps are subdivided into three categories as follow
a. Reciprocating pumps.
b. Rotary pumps.
c. Pneumatic pumps.
a. Reciprocating pumps:
Reciprocating pump, a piston or plunger moves up and down. During the suction stroke,
the pump cylinder fills with fresh liquid, and the discharge stroke displaces it through a
check valve into the discharge line.
Reciprocating pumps can develop very high pressures. Plunger, piston and diaphragm
pumps are under these type of pumps.

21
Figure 4.4 Reciprocating pumps
Plunger / piston type pumps:
The plunger contains the cross head, driven by a cams haft arrangement. The capacity
of the pump can be adjusted by changing the stroke, the rotating speed of the pump, or
both. The stroke of the pump is changed by the eccentric pin setting.
Diaphragm pumps :
These type of pumps are quite versatile, handling a wide variety of fluids like food
additives, chemicals, dry powders, slurries, pharmaceutical products, and wastewater
etc. The advantages in diaphragm pumps is the absence of seals or packing, meaning
they can be used in applications requiring zero leakage.
b. Rotary pumps:
The pump rotor of rotary pumps displaces the liquid either by rotating or by a rotating
and orbiting motion. The rotary pump mechanisms consisting of a casing with closely
fitted cams, lobes, or vanes , that provide a means for conveying a fluid. Vane, gear, and
lobe pumps are positive displacement rotary pumps.
c. Pneumatic Pumps:
Compressed air is used to move the liquid in pneumatic pumps. In pneumatic ejectors,
compressed air displaces the liquid from a gravity-fed pressure vessel through a check

22
valve into the discharge line in a series of surges spaced by the time required for the
tank or receiver to fill again.
4.4 Definition of Centrifugal Pump
Centrifugal pump is a device in which mechanical energy is converted into
the pressure energy by means of centrifugal force acting on the fluid.
Centrifugal pumps may be single or multi stage depending on the number of
the impeller. At present time there are various types of centrifugal pump
available in the market with single and double entry, with multiple rotor
stages. Efficiency of the pump depends on the application. Centrifugal pump
are used for many application and handle liquid and gases at relatively high
pressure and temperature. Rotor and volute are the two main component of
centrifugal pump. A centrifugal pump has two main components, a. The part
which gives energy to the fluid generally known as impeller is called rotor
and the part around which fluid moves is termed as casing. Efficiency of the
centrifugal pump depends on the shape of the impeller. Structure of specific
flow depends on the geometry of the pump. Recirculation and separation may
occur at part flow conditions and due to the formation of the vapour bubbles,
cavitations occur.
Due to the rotating impeller blade unsteadiness occurs in centrifugal pump
which pass through the stationary volute cutwater and diffuser blade.
Unsteady effects on the off design condition and with respect to time, it
effects the variation of mass flow through the centrifugal pump.
Figure 4.5 : Centrifugal pump

23
4.5 Classification of Centrifugal Pump
4.5.1 Axial Flow Pumps
Axial flow pumps, also called propeller pumps, are centrifugal pumps which move fluid
axially through an impeller. They provide high flow rate and low head, but some
models can be adjusted to run efficiently at different conditions by changing the
impeller pitch.
4.5.2 Radial Flow Pumps
Radial flow pumps are centrifugal pump at which the fluid handled leaves the
impeller in a radial direction. The radial outward movement of the flow in the impeller
causes higher centrifugal forces, which translate into higher discharge pressures but
typically smaller volume flow rates.
Figure 4.6 : Axial pump
Figure 4.7 Radial flow pumps

24
4.5.3 Mixed flow pump
Mixed flow pumps borrow characteristics from both radial flow and axial flow pumps
.As liquid flows through the impeller of a mixed flow pump, the impeller blades push
the liquid out away from the pump shaft and to the pump suction at an angle greater
than 90o.
4.5.4 Vertical Pumps
Vertical pumps were originally developed for well pumping. The bore size of the well
limits the outside diameter of the pump and so controls the overall pump design.
Vertical pumps can be subdivided
into three major categories:
a. Lines-shaft pumps
b. Submersible pumps
c. Horizontally mounted axial-flow
Figure 4.8 Mixed flow pump
Figure 4.9 Vertical pump

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Line-shaft Pumps
The driver is mounted on the discharge head for these type of motors. The line-
shafting extend through the column to the bowl assembly and transmits torque to the
pump rotor.
Figure 4.10 Line shaft pump
Submersible Pumps:
Submersible pumps are close-coupled pumps driven by a submersible motor and
designed for submerged installation in a wet well. The motor is mounted below the
bowl assembly and is directly coupled to the pump rotor shaft.
Figure 4.11 Submersible pumps

26
4.6 Working Mechanism of a Centrifugal Pump
Let us understanding in detail, How a Centrifugal pump works. Centrifugal pumps are
used to induce flow or raise a liquid from a low level to a higher level. These pumps
work on a very simple mechanism .A Centrifugal pump converts rotational energy ,
often from a motor , to energy in a moving fluid. The two main parts that are
responsible for the conversion of energy are the impeller and the Casing .The impeller
is the rotating part of the pump and the casing is the airtight passage which Surrounds
the impeller . In a centrifugal pump, fluid enters into the casing, falls on the impeller
blades at the eye of the impeller, and is whirled tangentially and
Radially outward until it leaves the impeller into the diffuser parts of the casing . While
passing through the impeller, the fluid is gaining both velocity and pressure.
4.7 Different Type of Parts Centrifugal Pump
1. Impeller 2. Volute Casing
3. Suction Cover 4.Break Bearing Stool
5. Impeller. 6. Shaft
7. Wear Ring 8.Gasket
9. Ball Bearing 10.Gland
11. Coupling 12.Buffer.
Figure 4.12 Centrifugal pump

27
4.7.1 Impeller
An impeller is a part of a pump or compressor that rotates at a high speed and acts as a
propeller to increase a fluid's pressure and flow rate. Impellers are made from various
metals such as steel, iron or bronze, as well as plastics. The impeller transfers energy to
the fluid as it passes through the pump, which increases the fluid's velocity at the
pump's discharge outlet.
There are three types of impellers
 Close Impeller
 Semi-open impeller.
 Open impeller
Figure 4.14 Impeller
Figure 4.13 main parts of pumps

28
4.7.2 Volute Casing
The casing contains the liquid and acts as a pressure containment vessel that directs the
flow of liquid in and out of the centrifugal pump. The volute is a curved funnel that
increases in area as it approaches the discharge port. The volute of a centrifugal pump is
the casing that receives the fluid being pumped by the impeller, slowing down the
fluid’s rate of flow. Therefore, according to Bernoulli’s principle , the volute converts
kinetic energy into pressure by reducing speed while increasing pressure. Some
centrifugal pumps contain diffusers. A diffuser is a set of stationary vanes that surround
the impeller. The diffuser directs the flow, allows more gradual expansion and
therefore increases the efficiency of the centrifugal pump.
4.7.3 Suction Cover
Suction cover is made by cast iron some time for special requirement it made by
stainless steel or Bronze. It mainly use for attesting suction pipe with coupling easily.
Inside of its create vacuum by impeller for this reason liquids are suck. Its size depends
on volute casing.
Figure 4.15 Volute Casing

29
Figure 17: Suction Cover
4.7.4 Break Bearing Stool (B.B Stool)
Break bearing Stool is made by cast iron. B.B Stool mainly uses for contains ball
bearings, oil seal, Lubricating oil and pump shaft. The electric motors rotating motion is
past form B.B stool by pump shaft. B.B stool fixed with base with buffer for avoid
vibration. Its size depends on volute casing.
4.7.5 Shaft sleeves
Pump shaft contain mainly impeller which fixed by key and slot. Electrical motors
rotating motion is transform by this shaft to impeller. Pump shaft is a moving part so It
is necessary to observe pump shafts designed and metal selection that it not twist or
Figure 4.16 Suction Cover
Figure 4.17 Break Bearing Stool

30
shear by any sudden load. Pump shaft made from cold drawn carbon steel some time for
special requirement pump shaft made from stainless steel.
Figure 19 : Shaft Sleeves
4.7.6 Wear Ring
Wear ring provides an easily and economically renewable leakage joint between the
impeller and the casing. Clearance becomes too large the pump efficiency will be
lowered causing heat and vibration problems. Most manufacturers require that you
disassemble the pump to check the wear ring clearance and replace the rings when this
clearance doubles.
Figure 4.18 Shaft Sleeves
Figure 4.19 Wear Ring

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4.7.7 Gasket
A gasket is a mechanical seal which fills the space between two or more mating
surfaces, generally to prevent leakage from or into the joined objects while under
compression. Gaskets allow "less-than-perfect" mating surfaces on machine parts
where they can fill irregularities. Gaskets are commonly produced by cutting from
sheet materials.Gaskets for specific applications, such as high pressure steam
systems, may contain asbestos. However, due to health hazards associated with
asbestos exposure, non-asbestos gasket materials are used when practical.It is
usually desirable that the gasket be made from a material that is to some degree
yielding such that it is able to deform and tightly fill the space it is designed for,
including any slight irregularities. A few gaskets require an application of sealant
directly to the gasket surface to function properly.
4.7.8 Ball bearing
The purpose of a ball bearing is to reduce rotational friction and support radial and axial
loads. A ball bearing is a type of rolling-element bearing that uses balls to maintain the
separation between the bearing races. It achieves this by using at least two races to
contain the balls and transmit the loads through the balls. In most applications, one race
is stationary and the other is attached to the rotating assembly (e.g., a hub or shaft). As
one of the bearing races rotates it causes the balls to rotate as well. Because the balls are
rolling they have a much lower coefficient of friction than if two flat surfaces were
sliding against each other.
Ball bearings tend to have lower load capacity for their size than other kinds of rolling-
element bearings due to the smaller contact area between the balls and races.
Figure 4.20 Gasket

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4.7.9 Gland
A gland is a general type of stuffing box, used to seal a rotating or reciprocating
shaft against a fluid. The most common example is in the head of a tap (faucet)
where the gland is usually packed with string which has been soaked in tallow or
similar grease. The gland nut allows the packing material to be compressed to form
a watertight seal and prevent water leaking up the shaft when the tap is turned on.
The gland at the rotating shaft of a centrifugal pump may be packed in a similar
way and graphite grease used to accommodate continuous operation. The linear
seal around the piston rod of a double acting steam piston is also known as a gland,
particularly in marine applications. Likewise the shaft of a hand pump or wind
pump is sealed with a gland where the shaft exits the borehole.
Other types of sealed connections without moving parts are also sometimes called
glands; for example, a cable gland or fitting that connects a flexible electrical
conduit to an enclosure, machine or bulkhead facilitates assembly and prevents
liquid or gas ingress.
Figure 4.21 Ball Bearing
Figure 4.22 Gland

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4.7.10 Coupling
The shaft coupling is the connecting element between the electric motor and the pump
hydraulic system. Slip-free shaft couplings employed in centrifugal pumps are divided
into rigid and flexible shaft couplings.
Figure 4.23 Coupling

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(Manufacturing Process of Centrifugal Pump)
4.8 Introduction
Millars Pumps Limited has different shop for different type of work. Manufacturing
process of a centrifugal pump is a combination of Casting, Machining, Assembly, and
Testing. From casting to Testing there are many working procedure to produce a ready
pump. I have classified there shop by 4 parts-
1. Foundry shop.
2. Machine Section.
3. Assembly & Painting Section
4. Testing Section
4.8.1 Foundry Section
Foundry shop is the place where the metal casting is prepared by melting and
pouring the molten metal into molds. A foundry is an operating plant which
manufactures castings of metal, both ferrous and non-ferrous. Metals are
processed by melting, pouring, and casting. Iron is the most common base
element processed in a modern foundry. However, other metals, such as,
aluminum, copper, tin, and zinc, can be processed.
Foundry section can have the following processes:
 Melting
 Furnace
 Mold making
 Pouring
 Shakeout
 Degating
 Heat treating
 Surface cleaning
 Finishing

35
4.8.1.1 MasterPattern from DesignEngineer
Milnars Pumps Limited used Wood Pattern, Cast Iron Pattern and Plastic Pattern for
making mold. Many of the parts are like- Impeller, Volute casing, BB Stool is made by
cast iron pattern. This patterns are made by a Master pattern, which is a form of plastic
object. The master pattern is made by the experienced engineer and pattern designer of
Milnars Pumps Ltd. Some the time, the master pattern is changed according to the
requirement of the production.
4.8.1.2 Pattern making work
A poor casting may be produced from a good pattern. But a good casting will not be
made from a poor pattern. In casting, a pattern is a replica of the object to be cast, used
to prepare the cavity into which molten material will be poured during the casting
process. Patterns used in sand casting may be made of wood, metal, plastics or other
materials. Patterns are made to exacting standards of construction, so that they can last
for a reasonable length of time, according to the quality grade of the pattern being built,
and so that they will reputably provide a dimensionally acceptable casting. Under
certain circumstances an original item may be adapted to be used as a pattern.
Figure 4.24 Master pattern

36
4.8.1.3 Pattern allowance
Pattern allowances in order to produce a casting of proper size and shape depend
partly on product design, mold design, shrinkage and contraction of the metal
being cast. A pattern is always made larger than the required size of the casting
considering the various allowances.
These are the allowances which are usually provided in a pattern.
 Shrinkage allowance
 Draft allowance
 Distortion or camber allowance
 Rapping or Shaking allowance
 Finishing allowance
4.8.1.4 Core making work
Cores are utilized for castings with internal cavities or passages. A core is a body
usually made of sand used to produce a cavity in or on a casting cores are placed in
the mold cavity before casting to from the interior surfaces of the casting.
Figure 4.25 Core Making

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4.8.1.5 Prepare a Mold
Good castings cannot be produced without good mold. Because importance of the
mold. The first step in the sand casting process is to create the mold for the casting.
In an expendable mold process, this step must be performed for each casting. A
sand mold is formed by packing sand into each half of the mold. The sand is
packed around the pattern, which is a replica of the external shape of the casting.
When the pattern is the cavity that will form the casting remains. Any internal
features of the casting that cannot be formed by the pattern are formed by separate
cores which are made of sand prior to the formation of the mold. Further details on
mole-making will be described in the next section. The mold-making time includes
positioning the pattern, packing the sand, and removing the pattern the mold-
making time is a affected by the size of the part, the number of cores, and the type
of sand mold. If the mold type requires heating or baking time, the mold-making
time is substantially increased. The use of lubricant also improves the flow the
metal and can improve the surface finish of the casting. The lubricant that is used is
chosen based upon the sand and molten metal temperature.
4.8.1.6 The sand casting may be made in are
1. Green sand mold
2. Dry sand mold
3. Loam sand mold
4. Core sand mold
Figure 4.26 Sand prepared Machine

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Figure 4.27 Sand making process
Common hand tool use in foundry shop, like
 Showel
 Trowel
 Riddle
 Rammer
 Hamer
 Swab
4.8.1.7 Induction furnace
Milnar’s pump company use induction furnace. Their product capacity 300 kg,
they use high voltage like more than 1400 centigrade. Principle of induction
melting is that a high voltage electrical source from a primary coil induces a low
voltage, high current in the metal or secondary coil. Induction heating is simply a
method of transferring heat energy.
Induction furnaces are ideal for melting and alloying a wide variety of metals with
minimum melt losses, however, little refining of the metal is possible. There are two
main types of induction furnace coreless and channel.

39
Induction furnaces are ideal for melting and alloying a wide variety of metals with
minimum melt losses, however, little refining of the metal is possible. There are two
main types of induction furnace coreless and channel.
4.8.1.8 Pouring
In a foundry, molten metal is poured into molds. Pouring can be accomplished
with gravity, or it may be assisted with a vacuum or pressurized gas. Many
modern foundries use robots or automatic pouring machines for pouring molten
metal. Traditionally, molds were poured by hand using ladles.
Figure 4.28 Induction Furnace
Figure 4.29 : Pouring

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4.8.1.9 Degasification
In the case of aluminum alloys, a degassing step is usually necessary to reduce the
amount of hydrogen dissolved in the liquid metal. If the hydrogen concentration in
the melt is too high, the resulting casting will be porous as the hydrogen comes out
of solution as the aluminum cools and solidifies. Porosity often seriously
deteriorates the mechanical properties of the metal.An efficient way of removing
hydrogen from the melt is to bubble argon or nitrogen through the melt. To do that,
several different types of equipment are used by foundries. When the bubbles go
up in the melt, they catch the dissolved hydrogen and bring it to the top surface.
4.8.1.10 Shakeout
The solidified metal component is then removed from its mold. Where the mold is
sand based, this can be done by shaking or tumbling. This frees the casting from
the sand, which is still attached to the metal runners and gates - which are the
channels through which the molten metal traveled to reach the component itself.
4.8.1.11 Degating
Injection molding is accomplished by the pressurized flow of molten plastic
through a channel system of runners and gates into the mold cavity where the part
is formed. The gate and runner typically remains attached to the part upon ejection
from the mold. Degating is the process of removing the molded part from the gate
and runner system. Degating can be accomplished by simply “snapping off” the
runner and gate system, using hand tools such as side cutters, employing dedicated
trimming fixtures, or by using special injection molding tooling such as the “cold-
runner” three plate mold and runnerless style injection molds. The cold-runner
three plate mold consists of three separate plates which form the complete mold.
These plates include the stripper plate, which contains the sprue, the middle or
cavity plate, which holds the cavity, runner and gate, and the movable plate, which
holds the molded part. This type of cold runner mold design automatically
separates the runner system from the part each time the mold opens.

41
4.8.1.12 Surface cleaning
After degating and heat treating, sand or other molding media may adhere to the
casting. To remove this surface is cleaned using a blasting process. This means a
granular media will be propelled against the surface of the casting to mechanically
knock away the adhering sand. The media may be blown with compressed air, or
may be hurled using a shot wheel. The media strikes the casting surface at high
velocity to dislodge the molding media (for example, sand, slag) from the casting
surface. Numerous materials may be used as media, including steel, iron, other
metal alloys, aluminum oxides, glass beads, walnut shells, baking powder among
others. The blasting media is selected to develop the color and reflectance of the
cast surface. Terms used to describe this process include cleaning, bead blasting,
and sand blasting. Shot preening may be used to further work-harden and finish the
surface.
4.8.1.13 Finishing
After completing all of casting the final step in the process usually involves
grinding, sanding, or machining the component in order to achieve the desired
dimensional accuracies, physical shape and surface finish.
Removing the remaining gate material, called a gate stub, is usually done using a
grinder or sanding. These processes are used because their material removal rates
are slow enough to control the amount of material. These steps are done prior to
any final machining.
After grinding, any surfaces that require tight dimensional control are machined.
Many castings are machined in CNC milling centers. The reason for this is that
these processes have better dimensional capability and repeatability than many
casting processes. However, it is not uncommon today for many components to be
used without machining. A few foundries provide other services before shipping
components to their customers. Painting components to prevent corrosion and
improve visual appeal is common. Some foundries will assemble their castings
into complete machines or sub-assemblies. Other foundries weld multiple castings
or wrought metals together to form a finished product.
More and more the process of finishing a casting is being achieved using robotic
machines which eliminate the need for a human to physically grind or break

42
parting lines, gating material or feeders. The introduction of these machines has
reduced injury to workers, costs of consumables whilst also reducing the time
necessary to finish a casting.
4.8.2 Machine Section
Machining is the process to achieve desire shape of the material by different type
machining work. Milnars Pump Limited has such kind of machine to do this task. Like
as, Lathe Machine, Milling Machine, Shaper Machine, Grinding Machine, and Drill
Machine. These machines are used for specific purpose, and their working process is
also different. I try to discuss about machine and its operation.
4.8.2.1 Lathe Machine & its Operation
Lathe is one of the most important machine tools in the machining section of Milnar
Pump Limited. A lathe operates on the principle of a rotating work piece and a fixed
cutting tool. The cutting tool is feed into the work piece, which rotates about its own
axis, causing the work piece to be formed to the desired shape. Lathe machine is also
known as ―the mother/father of the entire tool family.
Figure 4.31 Lathe Machine Operation

43
4.8.2.1.1 Facing
This operation is almost essential for all works. In this operation, as shown in fig., the
work piece is held in the chuck and the facing tool is fed from the center of the work
piece towards the outer surface or from the outer surface to the center, with the help of a
cross-slide
4.8.2.1.2 Plane Turning
It is an operation of removing excess amount of material from the surface the surface of
the cylinder work piece. In this operation, shown in fig., the work is held either in the
chuck or between centers & the longitudinal feed is given to the tool either by hand or
power
Figure 4.32 Facing & Turing Operation
4.8.2.1.3 Drilling
It is an operation of making a hole in a work piece with the help of a drill. In this case
as shown in figure the work piece, by rotating the tail stock hand wheel. The drill is fed
normally, into the rotating work piece, by rotating the tail stock hand wheel.
4.8.2.1.4 Reaming
It is an operation of finishing the previously drilled hole. In the operation as shown in
fig., a reamer is held in the tailstock and it is fed into the hole in the similar way as for
drilling.
figure 4.33 Drilling & Reaming operation

44
4.8.2.2 Drilling Machine & its operation
Drilling machine can be defined as a machine which makes a circular hole in the job by
removing volume of the metal from it with the help of a cutting tool called drill bit.
Figure 4.34 Drilling Machine & its operation
4.8.2.3 Milling Machine & operation
Milling is the process of machining flat, curved, or unregulated surfaces by feeding the
work piece against a rotating cutter containing a number of cutting edges. The milling
machine consists basically of a motor driven spindle, which mounts and revolves the
milling cutter, and a reciprocating adjustable worktable, which mounts and feeds the
work piece.
 Face Milling
 Side milling
 Plain milling
 Angular milling
 End Milling
 Saw milling.

45
4.8.2.4 Grinding machine & operation
A grinding machine, often shortened to grinder, is any of various power tools or
machine tools used for grinding, which is a type of machining using an abrasive wheel
as the cutting tool.
4.8.2.5 Operation of Pump parts
I try to discuss every separate parts name and needed Machine name and Its needed
operation.
Name of parts:
4.8.2.5.1 Shaft sleeves
Machine Name:
 Center Lathe machine
Figure 4.37 Grinding Machine & its operation
Figure 4.36 Milling Machine

46
 Saw machine
Needed Operation:
 Shaft cutting by the saw machine.
 Both side facing & centering
 Coupling side rough turning
 Impeller side step turning
 Coupling side finishing
 Impeller side finishing
 Impeller side grinding
 Coupling side grinding
 Both side key way.
Name of parts:
4.8.2.5.2 Volute Casing
Machine Name:
 Vertical lathe machine
 Drilling Machine.
Operation:
1st operation:
 Facing (Suction side)
 Boring for ring side
 Boring for shaft side
 Grooving.
2nd Operation:
 B.B stool side facing.
 Groving

47
 Khob facing
 knob out dia turning
3rd Operation:
 Drilling
 Taping
Name of parts:
4.8.2.5.3 Impeller
Machine Name:
 Center Lathe Machine
 Milling Machine
Operation:
1st Operation: B.B Stool side
 Ring side turning
 Ring face rough Cutting.
2nd Operation: Section Cover Side
 Ring facing
 Ring Turning
 Rough out dia cutting
3rd Operation:
 Ring out dia finishing
 Ring facing
 Face finishing.
 Knob facing
 Key way cutting
 Grinding

48
Name of Parts:
4.8.2.5.4 B.B Stool
Machine Name:
 Vertical Boring Lathe Machine
 Drilling Machine
Operation:
 Base surface facing
 Coller out dia facing
 Coller groove
 Bearing top side facing
 Drilling
 Taping
 Boring for Bearing.
Name of Parts:
Suction Cover
Machine Name:
 Centre Lathe Machine
 Drilling Machine
Operation:
 Facing
 turning
 Coller
 Groove
 Drilling.
Name of Parts:
4.8.2.5.5 Gland

49
Machine Name: Lathe Machine
Needed operation:
 Turning
 Facing
Name of parts:
4.8.2.5.6 Impeller Nut
Machine Name: Lathe Machine
Name of Operation:
 Facing
 Drilling
 Boring
 Threading.
When all parts are finishing their needed operation .Than all parts send are send in
assembly section
4.8.3 Assembly Section
Assembly and Painting is the last part of the manufacturing of Milnars pumps.
After assembly, a pump go throw the testing section, if its ok, then ready for sell, if it is
not than the pump is feedback to assembly section again. Sometimes maintenance work
is also occur in assembly section of Milnars Pump Ltd.
Figure 4.38 Assembly Section of pump

50
The main steps of pump assembly are:
1. Install bearings and oil seals on the shaft.
2. Install the shaft on the housing.
3. Put front and back covers and tighten the bolts.
4. Install mechanical seal on correct distance from the other end of the shaft.
5. Install flange coupling on the other end.
6. Install the impeller then put and tighten impeller lock-nut.
7. Install the suction volute housing, then put and tighten the bolts.
MPL Assembly procedure:
 Clean and inspect all pump parts (O-ring, seal seats, motor shaft, etc.).
 Apply sealant in bracket bore hole and possibly around seal case according to
sealant instructions. For SS seal, chamfer the edge of the bracket bore hole.
 Place carbon graphite seal into bracket while taking care not to damage carbon
graphite face.
 Place slinger (rubber washer) over motor shaft and mount bracket to motor.
 Carefully lubricate boot or O-ring around ceramic piece and press into impeller
(if ceramic has O-ring, the marked side goes in). Use glycerine for EPDM.
 Sparingly lubricate carbon graphite and ceramic sealing surfaces. Water,
glycerine or lightweight machine oil may be used, depending on the elastomers
used in the pump. Do not use silicon lubricants or grease!
Figure 4.39 Assembly of pump

51
 Thread impeller onto shaft and tighten. If required, remove motor end cap and
use a screwdriver on the back of motor shaft to prevent shaft rotation while
tightening. Replace motor end cap.
 Electrically, connect the motor so that the impeller will rotate CCW when facing
the pump with the motor toward the rear. Incorrect rotation will damage the
pump and void the warranty! For 3-phase power, electrically check rotation of
impeller with volute disassembled from bracket. If pump end is assembled and
rotation is incorrect, serious damage to pump end assembly will occur even if
the switch is "quickly bumped." If rotation is incorrect, simply exchange any
two leads.
 Seat O-ring in volute slot and assembly volute to bracket.
 Install drain plug with its O-ring in volute drain hole.
4.8.4 Pump Testing Section
Milnars Pump Ltd. used manual pump testing method by take reading from pressure
gauge, flow meter, water level scale and digital kw reading meter. They are taking
reading 10 times on a data sheet, and used some equation and curves to determine the
desired pump performance which I‘m describe below. Centrifugal pumps are among the
important equipment‘s in any process plant. In any refinery they are considered to be
equivalent to heart of a refinery, as they keep the flow running with a certain pressure
and quantity from one place to another, each pump has its own pump performance
curve.
Figure 4.40 Testing Section of pump

52
4.8.4.1 Pump performance curve
A performance curve is plotted to indicate the variation of pump differential head
against volumetric flow (gpm) of a liquid at an indicated rotational speed or velocity,
while consuming a specific quantity of horsepower (BHP). The performance curve is
actually four curves relating with each other on a common graph. These four curves are:
The Head-Flow Curve. It is called the H-Q Curve.The Energy Curve. It records Brake
Horsepower, BHP.The Pump‘s Minimum Requirement Curve. It‘s called Net Positive
Suction Head required, NPSHr.
4.8.4.2 Typical Procedure of Pump Performance Test
The purpose of pump performance test is to ensure that the actual performance of a
pump is typical to that set by supplier. Typical steps to be followed to conduct a pump
performance test are outlined below.
Prepare the original pump curve sent by supplier.
Make sure that the suction strainer is clean and the suction valve is fully open.
Ensure that discharge valve is fully closed.
Start the centrifugal pump take the reading of the discharge pressure, flow rate, suction
pressure and pump Ampere. (Finish this procedure in less than 1 min. As not to damage
the internal parts of the pump)
Open the discharge valve slightly till the flow rate reaches the first value indicated in
pump performance curve provided by pump supplier.
Write down the discharge pressure, flow rate, suction pressure and pump Ampere.
Figure 4.41 Curve Efficiency

53
Increase the opening of the discharge valve till you reach the next value indicated in
pump performance curve provided by pump supplier.
Open the discharge valve in small increments until it is fully open and take the readings
of the discharge pressure, flow rate, suction pressure and pump Ampere at each of the
steps. Equation:
Head H=Suction gauge reading×0.346+Delivery gauge reading ×10.21+0.34 (m)
Discharge Q={372-V notch high/304.8}2.47×2.52 (m3/hr) W.H.P= (Head
×Discharge×2.727/746) (kw) I.H.P= (Watt meter reading/.746) (kg) Efficiency
ηc=W.H.P/I.H.P
4.8.4.3 Head and Capacity Relationship
Head and Capacity
-A rating curve indicates the relationship between the head (pressure) developed by the
pump and the flow through the pump based on a particular speed and impeller diameter
when handling a liquid.
–As the capacity increases, the total head which the pump is capable of developing
decreases.
–In general, the highest head the Centrifugal Pump can develop is at the point where
there is no flow through the pump.
Figure 4.42 Pump flow capacity

54
BHP (Brake Horsepower) and Capacity
–For the Centrifugal pump to deliver the capacity we want, we must supply the pump
with a certain HP.
–Generally, the HP increases as we increase the capacity.
•BHP: is the total power required by a pump to do a specified amount of work.
BHP= 𝑄×𝑆𝑝.𝐺𝑟
3960×𝑒𝑓𝑓𝑖𝑐𝑒𝑛𝑐𝑦
• Efficiencies
– Efficiency of a pump can be calculated by:
Efficiency =
𝑄×𝑆𝑝.𝐺𝑟
3960×𝐻𝑃
× 100
Eff = Efficiency (%)
Q = Capacity delivered by the pump
H = Head developed by the pump
Sp. Gr = Specific Gravity of liquid being pumped
HP = Horsepower required by the pump
• 3960 is a constant linking a HP (33,000 ft lbs / min) to a US GPM (8.333 lbs).
33000
8.33
= 3960
NPSH and Capacity
Figure 4.44 Head & Capacity

55
–The curve shows the relationship between the capacity which the pump will deliver
and the NPSH (net positive suction head), which is required for proper operation
of the pump at that capacity.
–Lack of NPSH measured in Feet of
the liquid pumping, will cause the pump to operate improperly and cause cavitation.
Overall Rating
–By plotting all the characteristics of a Centrifugal Pump on one coordinate system, we
can define the capabilities and limitations of the pump.
Figure 4.45 NPSH and Capacity
Figure 4.46 Overall rating

56
Specific Speed:
Specific Speed is used to describe the geometry (shape) of a pump impeller.
–Performance of Centrifugal pump is expressed in terms of pump speed, total head and,
required flow. Specific Speed is calculated using the formula below at pump’s BEP.
Formula of Specific Speed=
𝑵√𝑸
𝑯 𝟓/𝟒
N=Speed of pump.
Q= Fluid flow
H=Head.
Figure 4.47 Specific Speed

57
System Curves
Pressure loss and Friction Loss
Simple System with Point A and B on same level.
Assume a line through which liquid is flowing and also assume heat exchangers,
valves and other items which add to total friction loss.
Friction loss through the system will increase as we increase the capacity (velocity).
Friction loss is proportional to the square of capacity.
At zero flow, there is no friction loss.
Figure 4.48 Specific Speed typical Curve
Figure 4.49 System Curve

58
-Point B is higher than Point A.
-Necessary to add energy to the fluid to get to Point B from A.
-The amount of energy required is exactly equal to the difference in elevation between
Point A and B, assuming friction loss as before
-Friction Curve will be the same in both systems because the friction loss is the same.
-We just added constant amount of head at any capacity to get the liquid from one point
to another.
Figure 4.51 Milnars Pumps curve
Figure 4.50 Fluid flow curve
Figure 4.52 Total head and Capacity

59
Chapter 5. Problem and solution
5.1 Problem and solution:
In order to correctly identify the problem it is important to gather as much information
relating to the process as follows
a. Reconfirm original duty requirements and / or system design
b. Check for any process changes i.e. pressure, temperature, fluid viscosity etc.
c. Check whether the system is undergoing routine maintenance.
d. How long did the pump operate before the problem
Figure 5.1 Problem and solution

60
e. Check the appearance and condition of the pump
f. Check when the pump was last serviced
g. Check for any changes in pump noise or vibration.
5.1.1 Centrifugal Pump Problems:
Typical pump problems include.
• No or low flow
• No or low pressure
• Excessive power consumption
• Excessive noise or vibration
• Seal leakage.
Typical causes are as follows:
Problem 1: No or low flow:
Causes Of problem:
a. Pump is not primed
b. The motor is turning pump in the wrong direction
c. Valves are closed or there is an obstruction in the suction or discharge pipework
Figure 5.2 Problem and solution

61
d. The end of the suction pipework is not submerged
e. A strainer or filter is clogged
f. Insufficient Net Positive Suction Head available (NPSHa)
g. Air leak in the suction pipe
h. No power to the pump
i. Pump speed too low
j. Pumped media viscosity is higher than expected
k. Pressure is higher than calculated
Solution of problem:
a. Increase suction line diameter.
b. Increase suction head.
c. Decrease fluid temperature - check effect of increased viscosity?
Problem 2: Noise and vibration
Causes Of problem:
a. Insufficient NPSH available.
b. Fluid vaporizing in suction line.
c. Air entering suction line.
d. Strainer or filter blocked.
e. Pump casing strained by pipework
a. Cool the pump casing.
b. Reduce fluid temperature.
c. Check seal face and elastomer temperature limitations.
Problem 3: Mechanical seal leakage
Causes Of problem:
a. Allowing the pump to run dry.
b. Vibration.

62
c. Hammering couplings onto the shaft.
d. Selecting the wrong mechanical seal materials
a. Increase fluid temperature.
b. Increase motor speed.
c. Check seal face viscosity limitations.
d. Increase flush flow rate.
e. Check that flush fluid flows freely into seal area.
Problem 4: Irregular discharge :
Causes Of problem:
a .Insufficient NPSH available
b. Fluid vaporizing in suction line.
c. Strainer or filter blocked.
d. Air entering suction line.
a. Increase suction line diameter.
b. Increase suction head.
c. Remake pipework joints.
d. Service fittings.
Problem 5: Pump motor falls to start
Causes of problem :
a. Blown fuse or tripped breaker
b. Open thermal overload in motor starter
c. Low line current

63
d. Open circuit in limit switches, timers or other control devices in pump motor starter
circuit
e. Motor damage
f. Replace fuse after correcting cause of overload
g. Reset after correcting cause of overload. If malfunction recurs, check heater size
h. Determine cause and correct
The voltage and frequency of the electrical current may be lower than that for which
motor was built or there may be defects in motor .The motor may not be ventilated
properly due to a poor location.

64
Chapter 6. Conclusion and Recommendation
6.1 Conclusion
As completed my attachment programme at Milnars Pumps Limited. I believed that, it
was great practical learning session of my engineering life. I am very thankful to my
honorable faculty and supervisor Prof Engr. Abdul Wadud and also grateful to Eng.
Morshed Cho. Miraz. Milnars Pumps Ltd. is one of the leading centrifugal pump
manufacture company in Bangladesh, which is started with the hand of KSB. As I have
done my attachment at MPL, now I can say that I have a clear concept about
manufacturing process and procedure of centrifugal pumps, as well as working principle
and testing of centrifugal pumps. MPL is a leading metal casting company in our
country. They can make centrifugal pump based on the customer requirements. MPL try
to make sure the quality of their product. I have learn a lot of practical and theoretical
information from there engineers and workers. MPL can maintain highest quality by
their high experienced engineers. Centrifugal Pump based on total head (not discharge
pressure) and flow rate. The flow rate will depend on maximum requirement. Total
head is the amount of energy that the pump needs to deliver to account for the elevation
difference and friction loss in system. Pump selection starts with acquiring detail
knowledge of the system. Just replacing an existing pump then of course there is no
problem. Replacing an existing pump with problems or looking for a pump for a new
application then we will need to know exactly how the systems is intended to work. We
should make our own sketch of the system that includes all the information on the MPL
plus elevations (max., min., in, out, equipment), path of highest total head, fluid
properties, max. and min. flow rates and anything pertinent to total head calculations.
Depending on the industry or plant that we work in, it will be forced to either select
ascertain type of pump or manufacturer or both. Manufacturers are normally a very
good source of information for final pump selection and it should always consult with
them, do our own selection first and confirm it with the manufacturer. They can help me
to select the right type, model, and speed if I have all the operating conditions and if not
they will rarely be able to help me. This form will help gather all the information
pertinent to operation and selection of the pump. Aside from the normal end suction
pump, vertical turbine and submersible pumps, there is a wide variety of specialized
pumps that should consider for application if some have unusual conditions. I have
passed a quality time with the stuff of MPL when I was there. I observed that MPL will

65
be in the leading of supplying pumps in the field of agricultural undertakings, irrigation
& drainage, general water supply.
Duties for municipal , community, industrial and pressure boosting, textile industries,
organic and inorganic corrosive liquids in chemical handling, pharmaceutical industries
and petrochemical plants etc. The practicum has been completed successfully by the
grace of Allah. Practicum sends to the expected destiny of practical life. The completion
of the practicum at ―Milnars Pumps Ltd. The impression that factory is of the most
modern input oriented machinery composite company in Bangladesh.
6.2 Recommendation
1. I think, they should Promote for popularity.
2. Modern technology should be used to increase production.
3. To reduce metal waste by operation and maintenance to get more benefit.
4. Workers need to focus more on security and work.
5. They should to ensure the customer requirements.
6. Need to create a suitable working environment.
7. Contest with another Company.
8. Ensure the demand of consumers to be constantly monitoring the market.

66
6.3 Bibliography
1. Centrifugal pump-https://en.wikipedia.org/wiki/Centrifugal_pump
2. An introduction to Centrifugal Pumps-
http://www.engineeringtoolbox.com/centrifugal-pumps-d_54.htm
3. Recirculation in Centrifugal Pumps – By: W. H. Fraser Paper presented at the
Winter Annual Meeting of ASME, Washington D.C- Nov 15-20, 1981.
4. Learning about NPSH Margin –
http://www.pumps.org/public/pump_resources/discussion/NPSH_Standard/pu
mp_NPSH_margin.htm
5. Pump shaft radial thrust alternative calculations (in Imperial dimensions) 13-2.
http://www.mcnallyinstitute.com
6. Bearings in Centrifugal Pumps – SKF Application Handbook.
7. Pump Controls – A dollars and sense approach by Kevin Tory, Manager,
applications and training, Cutler-Hammer, Eaton Corporation, Milwaukee,
Wisconsin- FHS (Fluid Handling Systems) – March 1999.
8. Adjustable Frequency Drives and Saving Energy – Part One – The Basics, The
Affinity Laws and Pump Applications – By, M. R. Branda – Cutler-Hammer
http://www.drivesmag.com
9. Centrifugal Pumps: Trouble shooting minimum flow and temperature rise
http://www.iglou.com/pitt/minimum.htm
10. Centrifugal Pump Specification and Selection – A System‘s Approach, StanT.
Shiels 5th International Pump Users Symposium Pump; –1988.
11. R.S Khurmi, A Text Book Of Hydraulics, Fluid Mechanics And Hydraulic
Machines- Nineteenth Edition, 2014- S. Chand & Company Ltd. Ramnagar,
New Delhi-110055

67
6.4 Abbreviations
B
BWDB- Bangladesh Water Development Board
D
DIN- Deutsches Institutfür Normung
E
ETA-Engine Turnover Assembly
H
H-Head
I
I.H.P-Indicated Hours Power
ISO-International Organization for Standardization
M
MPL-Milnars Pump Limited
N
NPSH-Net positive suction head
P
P- Pressure
PPM-Predictive and Preventative Maintenance
Q
Q-Discharge
R
R.P.M-Revolutions Per Minute
S
SS-Stainless steel

68
SG- Sherardized Graphite
T
QA- Quality Assurance
TQM- Total Quality Management

69
6.5 Pump Terminology
NPSH – Net positive suction head – total head at pump suction branch over and above
the vapor pressure of the liquid being pumped.
NPSHr – NPSH required – is a function of the pump design and is the lowest value of
NPSH at which the pump can be guaranteed to operate without significant cavitation.
There is no absolute criterion for determining what this minimum allowable NPSH
should be, but pump manufacturers normally select an arbitrary drop in total dynamic
head (differential head) of 3% as the normal value for determining NPSHr.
NPSHa — NPSH available – is a function of the system in which the pump operates
and is equal to the absolute pressure head on the liquid surface plus the static liquid
level above the pump centerline (negative for a suction lift) minus the absolute liquid
vapor pressure head at pumping temperature minus the suction friction head losses.
Cavitation – Process in which small bubbles are formed and implode violently; occurs
when NPSHa < NPSHr.
Density (specific weight of a fluid) – Weight per unit volume, often expressed as
pounds per cubic foot or grams per cubic centimeter.
Flooded Suction – Liquid flows to pump inlet from an elevated source by means of
gravity.
Flow – A measure of the liquid volume capacity of a pump. Given in gallons per minute
(GPM), litters per second and cubic meters per hour.
Head – A measure of pressure, expressed in meters for centrifugal pumps. Indicates the
height of a column of water being moved by the pump (without friction losses).
Pressure – The force exerted on the walls of a tank, pipe, etc. by a liquid. Normally
measured in pounds per square inch (psi) or kilopascals (kpa).
Prime – Charge of liquid required to begin pumping action when liquid source is lower
than pump. Held in pump by a foot valve on the intake line
or by a valve or chamber within the pump.
Self/Dry Priming – Pumps that draw liquid up from below pump inlet (suction lift), as
opposed to pumps requiring flooded suction.

70
Specific Gravity – The ratio of the weight of a given volume of liquid to pure water.
Pumping heavy liquids (specific gravity greater than 1.0) will require more drive
kilowatts.
Static Discharge Head – Maximum vertical distance (in meters) from pump to point of
discharge with no flow.
Strainer – A device installed in the inlet of a pump to prevent foreign particles from
damaging the internal parts.
Sump – A well or pit in which liquids collect below floor level; sometimes refers to an
oil or water reservoir.
Total Head – Sum of discharge head, suction lift, and friction loss.
Viscosity – The “thickness” of a liquid or its ability to flow. Most liquids decrease in
viscosity and flow more easily as they get warmer.
Valves
Bypass Valve – Internal to many pump heads that allow fluid to be circulated if a given
pressure limit is exceeded.
Check Valve – Allows liquid to flow in one direction only. Generally used in discharge
line to prevent reverse flow.
Foot Valve – A type of check valve with a built-in strainer. Used at point of liquid
intake to retain liquid in system, preventing loss of prime when liquid source is lower
than pump.
Relief Valve – Used at the discharge of a positive displacement pump. An adjustable,
spring loaded valve opens when a preset pressure is reached. Used to prevent excessive
pressure buildup that could damage the pump or motor.
Pump Installation Information
P ump-installStatic Head – The hydraulic pressure at a point in a fluid when the liquid is
at rest.
Friction Head – The loss in pressure or energy due to frictional losses in flow.
Discharge Head – The outlet pressure of a pump in operation.

71
Total Head – The total pressure difference between the inlet and outlet of a pump in
operation.
Suction Head – The inlet pressure of a pump when above atmospheric pressure.
Suction Lift – The inlet pressure of a pump when below atmospheric pressure.

Manufacturing Process of Centrifugal Pumps

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