Axially Split

7/30/2019 Axially Split

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MATHER AND PLATT

OPERATION AND MAINTENANCE MANUAL

1

OPERATION

AND

MAINTENANCE

MANUAL

FOR

CENTRIFUGAL PUMPS

MATHER AND PLATT PUMPS LTD.

FLUID ENGINEERING GROUP

CHINCHWAD, PUNE - 411 019.INDIA.


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PUMP TYPE. : SPLIT CASING PUMPS.

PRODUCT RANGES. : LE-ME, ST-SN, LONO-MED PUMPS.

PRODUCT VARIATIONS : HORIZONTAL CLOSE COUPLED,

VERTICAL DRY PIT CLOSE COUPLED,

VERT. DRY PIT WITH INTERMEDIATE SHAFTING.

SERVICE : WATER SUPPLY, STORM WATER, IRRIGATION,

DRAINAGE, COOLING WATER, FLOOD CONTROL,

PAPER STOCK, ETC.

NOTE: THIS MANUAL IS TO BE REFERRED ALONG WITH G.A. / C.S.

DRAWINGS.

MANUFACTURER

MATHER AND PLATT PUMPS LTD.

CHINCHWAD, PUNE

MAHARASHTRA STATE , INDIA

PIN - 411 019.


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FOREWORD

The information contained in this manual is intended for the interest and use of the

Engineers responsible for the erection, commissioning and maintenance of the

mechanical equipments described in this manual.

This manual should be studied before the plant is run for the first time and thereafter be

readily available for reference.

In a case where there is any doubt as to the functioning or adjustment of any parts of

the equipment, or in the event of any trouble which cannot be remedied by reference to

the information contained in this manual, the Fluid Engg. Group of MATHER + PLATT

PUMPS LTD., should be consulted immediately at their Pune address mentioned below.

In communicating with the Company, the Pump Serial Number specified on the

nameplate should always be quoted.


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REMARKS

To avoid ambiguity in the use of the word `replace' the words `replace' and `renew' are

used in this manual in the following context:

Replace - To put back, in its existing state, a part or component that has previously

been removed.

Renew - To substitute a new part or component for a worn or damage one.

Warnings, cautions, and notes are included in the manual. In principle, these are written

as follows:

WARNING:

This gives warning to the operator or maintenance crew that certain tasks may be

dangerous to personnel, and gives recommended safety precautions to be observed.

CAUTION:

This cautions the operator or maintenance crew that certain operations may cause

damage to the plant if the caution is not observed.

NOTE:

This gives miscellaneous additional information where necessary to clarify any

instructions.


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CONTENTS

SECTION TITLE PAGE NOS.

CHAPTER 1 - PUMP DESCRIPTION 05

CHAPTER 2 - ERECTION 08

CHAPTER 3 - OPERATING INSTRUCTIONS 18

CHAPTER 4 - ROUTINE MAINTENANCE 22

CHAPTER 5 - OVERHAUL 23

APPENDIX I - STUFFING BOX PACKING & REPACKING 28

ANNEXURE I - FAULT FINDING 29

ANNEXURE II - LUBRICATION CHART 32

ANNEXURE III - MAXIMUM RUNNING CEARANCE 33

ANNEXURE IV - DETAILS OF MAINTENANCE WORK-

CARRIED OUT. 34


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Chapter: 1

PUMP DESCRIPTION.

1. INTRODUCTION :The pump is installed on concrete platform in dry sump on sole plate / base plate.

The flow of liquid through suction bend (vertical shaft pump) or suction pipe

(horizontal shaft pump) communicates directly with the eye or centre of impeller.

The rotating impeller vanes transfer liquid at high velocity into pump casing where

specially designed volute brings about a reduction in the velocity of liquid. In this

way the kinetic energy imparted to liquid by rotating impeller is converted into

pressure energy & liquid is discharged through delivery branch.

2. GENERAL DESCRIPTION :

2.1 Casing :

The pump casing is of single/double volute design, two halves of which are bolted

together along the pump axis. Gaskets are provided between the split flanges of top

and bottom casing.

The suction and delivery branches of the pump are cast integral with bottom half

casing, which also incorporate the mounting feet. Tappings are drilled in suction and

delivery branches for connecting the pressure gauges and providing casing drain.Tappings are provided in top half casing for taking water seal connection on both the

stuffing boxes.

Sometimes the pump is installed with vertical shaft. In such installation if the pump is

of large size, the top half of pump casing is provided with runner at bottom .These

runner slides on rails horizontally. So during overhauling, the top casing can easily

moved in to & fro direction.

2.2. Casing neck Ring :

To minimize the amount of leakage between the high and low pressure areas ofthe pump casing neck rings are fitted. These rings are machined to close tolerances

to provide fine running clearances at the impeller necks and are renewable to allow

the clearances to be restored periodically as wear advances.


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2.3. Locating and Doweling :

The pump is held in place on to a soleplate by holding down screws. Soleplate is held by

foundation bolts and grouted in foundation. Two half casings are located by dowel pins

provided on their split flanges. Bearing housings are also located on the casing with

dowels.

2.4. Rotating Element:

The rotating element consists of a shaft on to which is keyed the double entry impeller.

Renewable shaft sleeves, which abut the impeller hub, protect the shaft from corrosion

and erosion. The impeller is locked by sleeve nuts which have their threads handed to

prevent them from unscrewing by the rotation of the shaft.

In horizontal shaft pump, the pump rotor is supported on bearings on eighter sides. The

total thrust developed by rotating element is carried by grease / oil lubricated antifriction

bearing at non-driving end.

In vertical shaft pump the thrust bearing is located at driving end. At non-driving end

FINOSTOS B bearing bush is provided. The antifriction bearing is provided with grease

lubrication & bush bearing is with water lubrication.

2.5. Shaft Sealing:

Shaft sealing is achieved by means of graphited cotton gland packing. Flushing liquid

for stuffing box is tapped from pump casing as shown in C/S drawing.

Mechanical seal is provided when asked for and the arrangement and flushing plan is

indicated in C.S.drawing.

2.6. Coupling:

Flexible coupling is used to transmit the power from motor to pump shaft. The type of

coupling used is indicated in the G.A. drawing.

2.7 Intermediate shafting (if applicable):

When the motor is mounted on separate floor away from pump, it is coupled with pump

shaft by intermediate shafting. Solid or hollow tube shafting is provided as per the

requirement. Intermediate bearings are provided, when the distance is large. The

position of intermediate bearings and support plate details are shown in the General

Arrangement Drawing. Rigid supporting structure has to be provided at each

intermediate bearing location. Alignment of connecting shafts and rigidity of intermediate

bearing support structure are important to restrict vibrations within acceptable limit.


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2.8 Bearings- intermediate shafting (if applicable) :

The solid intermediate shafting is supported by antifriction thrust bearing assembly

provided the motor stool. If the distance between pump and motor shaft is very large,

intermediate bearings are provided at intervals shown in G.A. drawing.

The weight of Hollow intermediate shafting is distributed on pump, motor and

intermediate shaft bearings.


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Chapter: 2

Erection

1. Introduction : This section provides instructions on the recommended methods ofinstalling pumping sets on to concrete foundations. Careful attention must be paid to

the customer's and contractor's installation drawings during the erection procedures

to ensure that the pumping set is accurately positioned on the correct datum levels.

The erection of the pump set may be divided into five stages, namely preparing the

foundations, installing the pump, installing the drive unit, alignment and coupling the

drive and connecting the pipe work.

The installation of the pump cannot be done in a continuous sequence because two

time periods are required to permit grout to set; the first period occurs after thesoleplate has been leveled and foundation bolts half grouted and the second is after

full grouting prior to the connection of the pipe work. The installation of the drive unit

must be in accordance with the instructions of motor manufacturer. This manual

contains procedure for erection of pump only.

2. Reception And Storage :

Following procedure should be adopted after receipt of pump at site.

2.1. Safety :

Before commencing handling of the equipment, suitable protective clothing andsafety equipments must be worn and site standing orders, safety instructions and

similar directives must be observed.

2.2. Lifting :

Ensure that the capacity of any lifting tackle is adequate for the loads involved and

that their test certificates are current valid and not time expired.

When lifting the pump in combination with the soleplate, the lifting tackle should be

attached to the lifting lugs provided on the soleplate side member. To lift the pump

from the soleplate, the lifting slings should pass beneath the pump body. Pumpshould never be lifted with slings engaged below the bearing housings.


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2.3. Reception:

On reception after unloading the pump should be inspected and Mather & Platt

Pumps Ltd. and or Insurance Company and Transport Company should be

immediately informed of any damage and shortage.

2.4. Storage and Conservation:

Any pump, which will not be installed immediately on reception, should have all the

corrosion protection made good. The inlet and outlet flanges should be blanked off

and the open ends of any small-bore pipes should be covered. Where the condition

of abrasive grit are severe, the

Region around the shaft seal and bearings should be protected. Ensure that the

storage area will support the pump weight, particularly on ground, which softens

during rain.

Pumps, which are sheeted over with plastic or tarpaulin, should have an anti-scuff

barrier of sacking or similar durable material beneath the covering to prevent the

finish from wind chaffing. Boxes containing accessories should be protected by

tarpaulin cover.

Projections of the shaft should be protected properly from mechanical damage. After

inspection unless the pump is required to be taken up immediately for erection, it

should be repacked in its case and stored away from exposure to rain and damp

surrounding. If the pump is required to be stored for a considerable period, it is

recommended that all the exposed parts of the pump be well protected with suitable

anti-corrosives. If pump is to be taken for erection immediately, clean any anti-

corrosion protection from the mounting surfaces using a rag moistened with white

spirit. Do not use chlorinated solvents, such as carbon tetrachloride and

trichloroethylene because they are a corrosion risk when used on ferrous material.

If these chemicals are present for any reason, a `No Smoking' rule must be strictly

observed.

Warning:

CHLORINATED SOLVENT FUMES + TOBACCO SMOKE = TOXIC GAS.


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For storage of drive unit refer instruction manual of its manufacturer.

3. Cleaning:

If the pump is being taken up for the erection, clean any anticorrosive protection

from the mounting surfaces using a rag moistened with white spirit. Do not use

chlorinated solvents

Such as carbon tetrachloride and trichloroethylene.

3.1 Erection On Concrete Foundations:

The installation of the pump cannot be done in a continuous sequence because two

time periods are required to permit the grout to set. The first period occurs after

soleplate has been leveled and foundation bolts half grouted. The second time lag

occurs after full grouting of soleplate, which is after alignment of pump and driving

unit prior to piping.

4. Preparing the Foundation:

4.1 Foundation Requirements.

A suitable foundation for the pump must be prepared with pockets to accommodate

the foundation bolts. The strength of the foundations must be adequate for the

loads imposed and depends upon the local soil conditions.

The top surface over which the soleplate / base plate rests must be left rough to

assist in keying of the final grout and sufficient allowance must be made for the

thickness of the steel packing and levelling shims beneath the soleplate, the

requirement being approximately 25 mm.

Foundation work is usually completed before the pump arrives on site but it is

mentioned here because it is logical to begin the erection procedure sequentially.

4.2. Soleplate / Base plate Erection:

Mather & Platt soleplate / base plate has machined surfaces on both top and bottom.

Therefore no distortion of the soleplate / base plate can be caused by the weight of

the unit when supported on a levelled surface. But initially the foundation surface

will be rough to key the final grout and the soleplate / base plate could distort if

mounted directly on this uneven surface. To avoid this distortion and to provide a

suitable base for leveling, steel packing blocks must be positioned at suitable

intervals on the foundation surface, a minimum requirement being one on each side

of every foundation bolt Ensure the surface beneath each packing block is solid

by crushing any protrusion or alternatively each block may be placed on a thin

screed of cement.


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4.3 Levelling the Soleplate / Base plate :

1. Lift the soleplate / base plate and lower it on the foundation. Insert the foundation

bolts through the holes in the soleplate and screw a nut on to each bolt until the bolt

protrudes through the nut by a length, which is sufficient to accommodate a lock nut.

2. Level the soleplate / base plate as follows:

a) Place an engineers level (sensitive to an error of 0.05 mm per 250 mm) on the

machined surfaces of the soleplate / base plate, or on the leveling pads if provided.

NOTE: - These machined surfaces where level is being checked must be clean and

free from paint, burrs etc.

b) Adjust the level of the soleplate / base plate by inserting shims between the soleplate

/ base plate and the packer plate until the soleplate / base plate is leveled and

supported on all the packing blocks at the height required for the connection of

suction and discharge branches. For checking the levels across two pads, I-beam

type straight edge should be used extensively in conjunctions with engineers

level. Level should be achieved within 0.05 mm per 250 mm. Also ensure that

elevation of soleplate / base plate is adjusted suitably as shown in General

Arrangement Drawing.

c) When the soleplate / base plate is leveled, grout in the foundation bolts. Care should

be taken so as not to disturb the verticality of foundation bolts. For grouting use rich

mix of 1:1:2 of cement, sand and gravel. Alternatively quick setting grout mix such

as ACC's SHRIMPCOM -20 or equivalent can be used.

d) When the grout has set, gently but firmly tighten the foundation bolts; then screw on

and tighten the lock nuts. Care must be taken not to distort the soleplate or loosen

the foundation bolts in the grout by excessive tightening.

3. Carefully re-check the level of the bed and make adjustments that are necessary by

fine shimming.

4. Erection Of Pump: (Refer GA Drg)

Pump is dispatched in assembled condition with pump half coupling fitted on pump

shaft. The erection of pump and in case of vertical shaft pump, intermediate shafting

motor stool and thrust bearing is done in following sequence.

1. Clean soleplate & pump pads thoroughly free from rust, burr etc.


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2. Lift the pumping unit & slowly lower down on to the soleplate / base plate & tighten

the fasteners.

3. Check the alignment on the face of pump half coupling.

Following steps are applicable to vertical shaft pump with solid shafting and

shaft enclosing tube:

1. Fit the support stool to pump casing

2. Keep the bottom shaft tube, if provided, on horizontal platform.

3. Insert the intermediate shaft through bottom shaft tube.

4. Fit intermediate bearing housings on both end of bottom shaft tube.

5. Fit self-aligning ball bearings with adaptor sleeves, lock nuts & washers on both end

of intermediate shaft. Tighten the lock nuts.

6. Fit intermediate bearing end covers to bearing housings on both sides.

7. Fit flexible coupling on lower end of intermediate shaft.

8. Lift the bottom shaft tube & lower it on support stool.

9. Tighten the screws between support stool & shaft tube.

10. Assemble the flexible coupling half on intermediate shaft with pump half coupling.

11. Check freeness of rotor by rotating the intermediate shaft.

12. Assemble the top shaft with intermediate shaft through solid muff coupling.

13. Fit the Thrust bearing housing on upper end of top shaft tube.

14. Lift top shaft tube & lower it on bottom shaft tube & tighten the screws.

15. Lift the motor stool locate it on sole plate & tighten the screws.

16. Locate the clamping plate in proper position & align the top shaft tube by tightening

the screws on retaining plate.

17. Fit the thrust collar on top shaft.

18. Fit thrust bearing in housing. The position of thrust bearing on top shaft is adjusted

by suitable machining of thrust collar.

19. Fit the adjusting ring on top shaft.

20. Fit the flexible coupling half on top of the top shaft & check the alignment.

21. Fit flexible coupling half on motor shaft.

22. Lift motor & lower on to the motor stool & tighten the fasteners.

23. Maintain gap of 7 mm between two halves of flexing coupling by suitable machining

of adjusting ring below flexible coupling on top shaft.

24. Complete bearing lubrication and cooling piping as shown in GA drawings.


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Sometimes incase of solid intermediate shafting or cardon shafting the

intermediate bearings are supported on support structure provided at site. The

position of intermediate bearings and support plate details are shown in the

General Arrangement Drawing. Rigid supporting structure has to be provided at

each intermediate bearing location. Alignment of connecting shafts and rigidity of

intermediate bearing support structure are important to restrict vibrations within

acceptable limit.


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4. Completion Of Erection:

4.1Pipe work:

No stress must be imposed on the pump casing; either by the weight of the pipes or by

tightening up badly fitted pipes. Experience has shown that such stress can seriously

affect the alignment of the pump unit. All pipe work attached to the pump must be fully

supported and the mating faces of the pipe flanges must abut parallel with all bolt holes

coinciding. It is important therefore, that the alignment of a pump and its motor is re-

checked after the pipes are finally fitted. Any deviations in alignment must be corrected

by re-setting or supporting the pipes.

4.2. Suction Conditions:

The suction pipe should be as short as possible. An arrangement of suction pipe work,

which is common to two or more pumps operating on suction lift, is not recommended. If

such an arrangement is unavoidable, any points of possible air ingress, such as valve

and glands, should

Be liquid sealed and isolating valves should be fitted at appropriate points. The diameter

of the suction pipe required, depends upon its length and bears no fixed relation to the

diameter of the suction branch of the pump. The size of the pipe must be such that

friction losses are kept to a minimum. For example a long suction pipe (or one with

numerous bends) which passes a given quantity of liquid must be of larger bore than a

short straight one passing the same quantity of liquid. When the suction pipe is

increased to a size larger than the bore of the pump suction branch, the form of taper

pipe used must not allow the formation of air pockets. To avoid the formation of air

pockets, the installation of the suction pipe work must be arranged under the following

conditions:

a) With as few bends as possible.

b) It must be completely air tight.

c) There must be a gradual rise towards the pump. The inlet of the suction pipe must lie

well below the lowest possible water level and it must be fitted with the strainer. The

strainer must be clear off the bottom and sides of well or sump so that deposits of

sediment or grit are not drawn into the pump. The strainer must be of rugged

construction with holes in the side, suitable for type of liquid to be passed. For clean

liquid the cumulative area of these holes must not be less than twice the area of the

bore of the pump suction branch. Where the liquid is known to contain a high


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Percentage of solids, the cumulative area of the holes must be much greater; it may

even be necessary to provide special apparatus, such as traveling screens, to ensure

that the pump is kept free of solid foreign matter. As these pumps are generally

expected to operate on positive head, foot valve is not necessary. However, at site,

if liquid level falls below the minimum water level mentioned in the drawing, the pump

should not be started.

4.3 Sump Design:

The design of suction sump has great influence on trouble free & smooth operation of

pump. The special attention must be paid to sump design when two or more no. Of

pumps are operated in combinations of working + standby conditions. It is

recommended that when space & site constraints do not allow the suction sump

design as per recommendation of HIS or BHRA, the suction sump design should be

verified by a model study. Whenever model study has been carried out previously for

optimizing suction sump design, its recommendation regarding corrective structures

should be fully implemented.

4.4 Delivery Conditions

A suitable valve should be fitted in the delivery pipe as near to the pump as possible.

Unless the pump is to deal with only small quantities of liquid at a low delivery head, or

where back surge is likely to occur, a non-return valve must be fitted in the delivery

line as close to the pump delivery branch as possible. A by-pass valve fitted to non-

return valves is often an advantage, although this is not always required. Pressure

gauges should be fitted to the tapping provided in the pump suction and discharge

branches. These will give useful indication of the pump behavior.

4.5 Alignment of Driving and Driven Unit:

Refer Appendix 1 of this instruction manual for alignment procedures and tolerances.

5.0 Delayed Commissioning:

When commissioning is delayed, it is recommended that the pump set be periodically

rotated through a minimum of two complete revolutions.


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Note: - Prior to each occasion, check that the pump casing is full of pumped fluid. The

period between these revolutions depends upon site condition

a) Ideal conditions are defined as clean, dry, and free from vibrations (for example a

service pump in an air-conditioned office building) and these conditions require that

the pump be rotated twice per week.

b) Adverse conditions being those of extreme vibrations (for example a pump which is

standing near a reciprocating compressor and both machines are mounted on the

same steel structure) and these conditions require that the pump be rotated every two

hours. When the environment is not clean and dry, further advice should be sought

from Mather & Platt Pumps Limited.


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Chapter: 3

Operating Instructions.

1. Introduction:This chapter covers the commissioning and operation of the pump only. For

commissioning of motor instruction manual of motor manufacturer should be

referred.

2. Commissioning:

This section is written assuming that a new pump is being commissioned. It is

recommended that similar procedure be adopted after each major overhaul.

2.1. Pipe work Flushing:

Before the pumps are brought into service, either on initial commissioning or onre-commissioning after overhaul, the pipe work associated with the pumps must be

flushed through. This will clear deposits or scales which may have accumulated in

the pipes, and which could damage the internal components of the pumps.

2.2.Cleaning Bearings: Where possible, especially if the unit has been in store for a

long period before commissioning, the bearings should be cleaned and flushed out

with clean white spirit or good quality paraffin. Waste should not be used for this

purpose, as particles of foreign matter may be left behind which would cause

damage when the bearing is in service. Bearings should be then filled withrecommended grade and quality of fresh lubricant.

2.3.Checking Motor Rotation: Disconnect the drive coupling and run the motor to

check its direction of rotation. A directional arrow is provided on the pump unit.

2.4. Priming: The efficient operation of a centrifugal pump depends upon fine running

clearances, which are lubricated by the pumped liquid. Any attempt to run the pump

dry or partially full may result in seizure of the rotating internal components. These

pumps must therefore be properly primed before starting.

These pumps are not self-priming type and if a pump fails to generate its rated

pressure on starting, it must be stopped at once, the cause ascertained and the

pump re-primed before restarting.


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2.5. Pumps Operating on Flooded Suction Head: When these pumps operate on a

flooded suction head, all that is required to prime them is to open the air release

valve situated on top of the pump casing, open the pump inlet isolating valve and

vent the air out of the casing. When the liquid issues from the air vent, free of air,

the pump is properly primed. The air vent must be closed after priming and before

the pumping set is started.

2.6. Pumps Operating on Negative Suction Head: There are two methods of priming

pumps that draw their liquid from an elevation lower than the pump inlet branch:

1. If the inlet pipe work is fitted with a non-return foot valve, the pump casing and inlet

pipe work can be filled with liquid from an external source under pressure. The

pressure imposed on the pump by this method must not exceed that for which the

pump is designed. In certain cases priming can be achieved by flooding back from

the delivery side of the pump.

2. By exhausting air or gas from the pump casing. To enable this method to be used,

the gland arrangement must be sufficiently gas-tight or they should be liquid sealed

from an external supply. For operation details of gas exhausts reference should be

made to the manufacturers instructions. Some form of priming indicator is usually

fitted to indicate when the priming operation is complete.

3. Pre-Commissioning Checks:

a) Ensure that sufficient fluid is available at the pump suction for satisfactory operation

of the pump. Efficient operation of the pump depends upon the running clearance,

which are lubricated by pumped liquid. Any attempt to run the pumps dry or partially

full will result in seizure of internal rotating components.

b) Check that the inlet isolating valve is open and that the delivery valve is closed.

c) Ensure that bearings have been filled with proper grade of lubricant.

d) Check that there is no blockage in the strainer at the end of the suction line.

e) Check for free rotation of the unit when coupled.

f) Check that suction and delivery pressure gauges are connected. Test and make

available any alarm, signals, interlock systems and any of the protective devices

incorporated in the auxiliary and main pumping control system.


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g) Check that all electrical checks on motor, relay setting in panel etc have been carried

out in accordance with the instructions of motor manufacturer.

h) Ensure that stuffing box sealing water seal connection is provided as shown in GA

Drawing.

4. Normal Starting Procedure:

a) When all the foregoing pre-start checks are satisfactory, depress the appropriate

`START' button on the control panel and run the pump at its rated speed.

b) Check that the pump is rotating in the correct direction. This is indicated by a

direction arrow on the pump casing.

c) Check the ammeter reading to ensure that the motor is not being overloaded.

d) Check that the pumping unit is generating not less than its rated delivery pressure

indicated in the data sheet/name plate.

Caution: If the pumping unit fails to generate at least its rated delivery pressure it

must be stopped immediately, the cause ascertained, the fault rectified and the

pumping unit re-primed before restarting.

e) Ensure that the stuffing box is not overheating and that there is slight leakage from

the gland.

f) Check that the bearing is not overheating.

Note: - If the bearings are overheating its cause should be investigated immediately.

g) If the foregoing checks are satisfactory, open the delivery valve slowly and bring the

pump gradually up-to its rated parameters based on pressure gauge and ammeter

readings.

h) Check that the driving unit is not being overloaded during valve opening.

Note: Overloading may occur if the pump is discharging into an empty system when

the delivery head will be temporarily lower than that for which the pump is designed.

Careful regulation of the discharge valve until the system is fully charged will prevent

this.

i) Check vibration of pump set and ensure that vibration level is within limits specified in

Hydraulic Institute Standard of America. Check that noise level is within stipulated

limits.


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5. Running Checks:

Make the following checks at regular intervals. It is recommended that they be made

at every change of shift, but this may be amended by the station superintendent to

suit routine requirements.

a) Check the suction and discharge pressure gauge for normal operating pressure, if

there is significant drop in the suction or discharge pressure the pump may have lost

its supply. In the event of this fault occurring, the pump must be stopped

immediately and the cause of liquid loss eliminated.

b) Check the stuffing box assembly for overheating.

c) Check the pump and motor for overheating, excessive vibration and noise. Report

any faults. During first commissioning, the pumps may be run for 8 hours trial

operation and all the parameters like delivery pressure, current, bearing

temperature, etc. Be recorded periodically.

6. Normal Shutdown:

a) Close the delivery valve to reduce the load on the driving unit.

b) Depress the appropriate STOP button on the control panel.

c) When the pump has come to rest, close the suction-isolating valve.

d) Isolate any ancillary supplies.

7. Emergency Shutdown: In the event of any malfunction of the equipment, trip the

pump set. When the pump has come to rest, close the suction & discharge valves,

isolate the driving unit power supply & rectify the fault.


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Chapter: 4

Routine Maintenance.

Centrifugal pump requires very little routine maintenance beyond periodic replenishingof grease in the bearing assemblies. However, serious troubles can be often avoided by

regular observation and analysis of various working parameters. Some of the routine

maintenance checks for this purpose are as under:

1. To keep daily logbook records of working parameters like suction and discharge

pressure, flow rate, current drawn, bearing temperature, etc. Any sudden change

should be a signal for investigation.

2. Bearings will normally run at a temperature of 30-35 DEG C above ambient temp.

Temperature slightly above this figure is acceptable provided it remains constant. Iftemperature exceeds 80 Deg C, the pump must be stopped and bearings

inspected.

3. Vibration readings should be taken once in a fortnight and values compared with that

of previous records.

4. Check that there is sufficient leakage from the gland packing to ensure proper cooling

and lubrication.

5. Pump bearings should be replenished with correct grade of grease after every 170

Hrs. Grease should be changed completely after every 1700 hours or as required bysite condition. Recommended type and grade of grease is indicated in Annexure II.

6. Fault Finding - Many of the common faults which occur on centrifugal pumps and

which can be diagnosed by observations are given in the chart under Annexure I.

After a long period of service, wear will occur in parts of the pump, necessitating the

renewal of a few components. Parts, those are most likely to be affected are

impeller/ wearing ring, bearing, neck rings, impeller distance sleeves and stuffing box

bushes. Logbook records will indicate wear as gradual deterioration of performance is

noticed. Once this is known, pumps should be taken for overhaul.


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Chapter: 5

Overhaul

1. General Information:

It is inevitable after long service that certain components will become worn.Frequently it is more economical to renew the worn components completely, but

where site machining and engineering facilities are available most components can

be restored if wear is not too far advanced.

It is impossible to be mandatory regarding the periods at which major overhauls

should be undertaken as this will be dependent upon the fluid being pumped, the

site operating conditions, and the length of operational availability required.

The determination of when major overhaul should be carried out will depend upon

the performance of the pump, i.e. its rate of deterioration by reference toinstrumentation, during the current operational period. If the hydraulic or mechanical

performance has deteriorated to such an extent that no further deterioration can be

tolerated during the next operational period, wearable components should be

renewed.

If related pair of components show a marked degree of wear in relation to the rest

of the unit, then it may be sufficient to renew only the heavily worn components. If

the wear is uniform throughout the pump, then all wearable components may require

renewal.Measurements should be taken and recorded of all wearable components at the

first, and every subsequent overhaul period. Reference to these records will enable

an accurate assessment of the rate of wear to be made, and a reasonably accurate

forecast regarding when a particular component may require renewal can be made.

Information regarding original design dimensions and clearances is furnished in

data sheet. Any other information if needed can be obtained on application from

Mather & Platt Pumps Ltd., Service Department, Chinchwad, and Pune 19. Such

request must quote nameplate number and type of the pump in question.The parts most likely to be affected are:

1. Impeller Necks.2. Stuffing Box Bush.3. Bearings.4. Casing Neck Rings.


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Before commencing dismantling operations, ensure that the following tools and tackles

are available:

1. A crane / chain pulley block suitable for handling the weight of pumping unit.

2. A selection of ring and open-ended spanners in British, American, and Metric sizes.

3. Eye-bolts in British and Metric sizes.

4. Cotton rope, wire rope and slings.

5. Hardwood and metal packing blocks.

6. Miscellaneous tools including a set of Allen keys, drills, pin drivers, files etc.

7. Extractor / puller for bearing and coupling.

2. Dismantling The Pump:

Following steps are applicable to vertical shaft pump with solid shafting and

shaft enclosing tube:

1. Isolate the pump motor electrically

2. Remove all lubrication & auxiliary piping.

3. Isolate the pump system by closing suction and delivery valve.

4. Dismantle the flexible couplings (i.e. Couplings between motor & top shaft & between

intermediate shaft & pump shaft.)

5. Remove the motor off the motor stool.

6. Remove the flexible coupling from top shaft.

7. Remove the thrust bearing, retaining plate, motor stool, top shaft tube, top shaft, and

bottom shaft tube assembly in proper sequence.

8. Remove support stool.

9. Remove all split flange nuts and the two dowel pins.

10. Remove nuts of gland & bottom bearing end cover.

11. After removing all fasteners joining top & bottom casing, slide the top casing away

from bottom casing.

12. Remove all the fawners joining bearing end cover (inner & outer) to bearing housing

& between top & bottom of bearing housing.

13. Rotating element can now be lifted clear off the casing along with casing rings and

bearings. Ensure that it is lifted off the casing evenly and does not twist, otherwise

the casing rings may be damaged. Place and support the rotor on wooden cradle in

horizontal position. Pump half coupling can now be withdrawn from the spindle; if


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Necessary by using proper tackle like coupling puller. The coupling has a parallel

bore and with a transition fit. Remove the coupling key.

3. Dismantling The Rotating Element:

To completely dismantle the rotating element proceed as follows:

1. Remove lock nut, lock washer of thrust bearing.

2. Remove the bearings using some form of extractor or puller

NOTE: - Unnecessary removal of the bearings should be avoided because removal of

the bearing can damage it and cause deterioration of the interference fit. Except

where removal is necessary to give access to the other parts, bearing should be

removed only if they need close inspection. Symptoms, which will indicate the state

of bearing, are the condition of the lubricant, the bearing running temperature, noise

level and vibration during operation.

3. Take off the casing rings & bearing bush & bearing carrier.

4. Unscrew and remove the sleeve nuts on both side and slide off the impeller

distance sleeve. If difficulty is experienced in withdrawing the sleeves, they may be

drawn off with the impeller. It may be even advisable to apply some heat for easy

withdrawal.

5. Remove the impeller. It may be necessary to apply heat to the impeller for removal.

Apply heat uniformly from the shrouds inwards towards the hub. Before removing

the impeller put a reference mark on the shaft for ease of re-assembly at correct

centre position.

4. Examination Of Internal Components:

With the pump and rotating element dismantled, the internal components and

clearances can be checked.

4.1. Casing neck ring:

Use an internal micrometer to measure the bore of casing ring, taking

measurements at intervals around the circumference to check for uneven wear. A

comparison between this dimension and that of the impeller neck will indicate the

amount of diametrical clearance between the casing neck ring and the impeller

neck. If this clearance is 150% or more than the original design clearance, or if the

deterioration in hydraulic performances has been such that no further deterioration

can be tolerated during the next operation period,


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The impeller-wearing ring to casing neck ring clearance must be restored to the

original design value by fitting small- in-bore neck rings, bored out to suit the

diameter of the impeller.

4.2. Shaft Sleeves:

The shaft sleeve should be examined to see if it is grooved or generally worn. The

outside diameter of the sleeve should be measured and a comparison made with the

bore of the stuffing box bush through which the sleeve passes. The amount of

clearance between the two can thus be checked to determine whether or not it is

within acceptable limits.

4.3. Impeller:

1. Inspect the impeller as follows:

a) Examine the impeller for damage.

b) For corrosive pitting.

c) Cavitations pitting.

d) Bent or cracked vanes, inlet and outlet vane end wear.

Any of the above may be repaired, or cause the impeller to be scrapped. Further

information should be sought from M + P, Service Dept. Chinchwad Works, Pune

before any decision on repair work is taken.

4.4 Stuffing Box Bush:

Check bore of stuffing box bush and compare with sleeve diameter. If clearance is

excessive, the bush should be renewed.

4.5 Spindle:

Check the spindle for trueness. Check bearing journal diameters for undue wear or

grooving. Light grooving on journal area must be polished off.

5. Re-assembly Of Rotating Element :

If rotating element has been completely dismantled, the correct position for the

impeller must be established as marked on the shaft prior to dismantling. Then

commence re-assembly as under.

1. Fit the impeller key in the key way of the spindle.

2. Fit the impeller on the spindle in correct position.

3. Fit the shaft sleeve on both sides of impeller to engage with impeller key and tighten

the sleeve nuts.


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4. Slide the casing ring on the spindle on both sides.

5. Slide the stuffing box bush on driving end side & bearing bush along with bearing

bush carrier on non-driving end side.

6. Fit the thrust bearing on driving end side along with thrust collar, lock nut & washer.

Note: - While assembling stainless steel component molybdenum-disulphide paste

should be applied to prevent galling / seizure and also to facilitate easy removal in

future.

6.. Re-assembly Of The Pump :

6.1. Ensure that casing is clean, dry and free from foreign matter. Clean casing ring and

stuffing box bush seating thoroughly and ensure they have no burrs.

6.2. Carefully lower the element into the bottom half casing.

6.3 Ensure that casing rings enter their half grooves in the bottom half casing.

6.4. Fit the dowel pins of the bearing housing and ensure that the spindle rotates

freely and then tighten all the bearing fixing setscrews.

Caution: If the shaft does not rotate freely, the cause must be investigated and the

fault rectified.

6.5. Fix inner & outer bearing end covers to driving end bearing housing & bottom to

casing at non-driving end by setscrews.

6.6. Cut a gasket from 0.25 mm thick black joint paper or similar gasket material and

locate on flange of bottom half casing.

6.7. Slide the top half casing towards bottom half casing.

6.8. Fit the split flange studs. Align dowel holes and fit dowel pins before tightening the

nuts.

The nuts must be tightened evenly in the diagonally opposite sequence.

Caution : During the tightening up procedure a careful check must be made to

ensure that the rotating element continues to rotate freely . Any sign of stiffness

or bending must be investigated immediately and the cause eliminated.

6.9 Insert gland packing. Fit studs and gland.

6.10.Reconnect sealing water lines to stuffing boxes.

6.11.Now the remaining assembly of pump is done in same way as described in

chapter-2.


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APPENDIX- I

STUFFING BOX PACKING AND REPACKING

( Refer Cross Sectional Drawing )

This operation is of extreme importance. It is often left to a comparatively unskilled

operator to insert the stuffing box packing or to fit an additional ring of packing. This

should not be allowed; packing and repacking of stuffing box should be done with

greatest skill and care.

The packing supplied with pumps by Mather & Platt Ltd. is packed in a separate box

and should be fitted at site as under:

1. The stuffing box and gland sleeve should be thoroughly cleaned and full entry of

gland into Stuffing box must be checked.

2. Insert leak-off-Bush in the stuffing box and check if it is aligned with its connection.

3. Check if each ring of packing length passes round the shaft and meets end to

end, the ends being cut square.

4. The packing ring should be inserted into the stuffing box. Each ring should be

pushed into position individually. The joint of each ring must be positioned at 180o

from joint of its neighbor.

5. Fit gland square with stuffing box and gland nuts should be screwed up to little

more than finger tightness.

While repackaging, if packing is available in complete coil from or rope form, then

the quantity required for immediate use only should be taken. Each ring of

required length should be cut so that it passes once round the shaft and meets end

to end, the ends being cut square. Packing should be handled with care and it

should not be allowed to pick-up dust or abrasive foreign matter by coming into

contact with floors or dirty benches.

It is bad practice to hammer packing to facilitate the insertion.


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ANNEXURE I

FAULT FINDING CHART

Symptom Possible cause of trouble and remedies

(Each number is defined in the list below)

Pump does not deliver water. 1,2,3,4,6,11,14,16,17,22,23Insufficient capacity delivered. 2,3,4,5,6,7,8,9,10,11,14,17,20,22,23,29,30,31

Insufficient pressure developed. 5,14,16,17,20,22,29,30,31

Pump loses prime after starting. 2,3,5,6,7,8,11,12,13

Pump requires excessive power. 15,16,17,18,19,20,23,24,26,27,29,33,34,37

Stuffing box leaks excessively. 12,13,24,26,32,33,34,35,36,38,39,40

Pump vibrates or it is noisy. 2,3,4,9,10,11,21, 23,24,25,26,27,28,30,35,41,42,43,44,45,46,47

Bearings have short life. 24,26,27,28,35,36,41,42,43,44,45,46,47

Pump overheats and seizes. 1,4,21,22,24,27,28,35,36,41

Suction troubles Remedies

1. Pump not primed. Ensure that casing fully filled and water comesout from air cock.

2. Pump or suction pipe not completelyfilled with liquid.

Check leaking foot valve in case of negative suction.

3. Suction lift too high. Reduce by lowering pump elevation or increase waterlevel.

4. Insufficient margin between pressureand vapor pressure.

Check that NPSH available is at least 1-meter suctionmore than NPSH required.

5. Excessive amount of air or in liquid. Check the reasons and eliminate. Gas entrapped gas iliquid. Air may be passing through suction joints.

6. Air pocket in suction line. Ensure pipe fully filled, no concentric bend fornegative suction.

7. Air leaks into suction line. Tighten pipe joints with solution.

8. Air leaks into pump through stuffingboxes.

Ensure stuffing box sealing.

9. Foot valve too small or leaking. Replace / Attend.

10.Foot valve partially clogged. Clean.

11.Inlet of suction pipe not sufficientlysubmerged.

Ensure adequate submergence that foot valve is.not exposed.

12.Water seal pipe clogged. Clean or change.

13.Logging ring is improperly located instuffing box, preventing sealing fluid

from entering to form seal.

Position logging ring centrally under sealing holes ofstuffing box.

14.Speed too low. Check motor RPM, supply frequency Motor nameplate,speed should be as specified on pump nameplate.

15.Speed too high. Check motor RPM, supply frequency.

16.Direction of rotating wrong. Check correct direction of rotation for motor beforecoupling to motor.

17.Total head of system higherthan design head of pump.

Check the causes and refer to M&P. Measure withpressure gauge.


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18.Total head of system lowerthan pump design head.

Check the causes and refer to M&P. Measure withpressure gauge.

19.Specific gravity of liquiddifferent from design.

Refer to M&P.

20.Viscosity of liquid different fromdesign.

Refer to M&P.

21.Operation at very low capacity. Check the causes and refer to M&P, OperatePump at rated duty.

22.Parallel operation of pumpsunsuitable for such operation.

Refer to M&P with characteristics curves of pump.

Mechanical troubles Remedies

23.Foreign matter in impeller. Open and clean.

24.Misalignment. Check with Dial gauge should be within limits and witho

undue pipe stresses25.Foundations not rigid Check vibration on Base frame, check hollowness

26.Shaft bent Dismantle and check, Replace shaft

27.Rotating part rubbing onstationary part

Incorrect assembly, correct assembly

28.Bearing worn Check lubrication, shaft run out, alignment, replace ifrequired

29.Wearing rings worn Replace

30.Impeller damaged Replace

31.Casing gasket defective,permitting internal leakage

Replace

32.Shaft or shaft sleeves wornor scored at packing

Replace

33.Packing improperly installed Use correct grade and size of packing

34.Type of packing incorrect foroperating condition

Use correct grade and size of packing

35.Shaft running out of centrebecause of worn bearings ormisalignment

Rectify

36.Rotor out of balance, causingvibration

Balance the rotor

37.Gland too tight, resulting in noflow of liquid to lubricate

packing

Adjust gland. Check sealing water flow

38.Cooling liquid not beingProvided to water cooledstuffing boxes

Provide

39.Excessive clearance at bottom ofstuffing box between shaft andcasing, causing packing to beforced into the pump

Check pump assembly.

40.Dirt or grit in sealing, liquid leading to Provide clean liquid for flushing


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scoring of shaft or shaft sleeve

41.Excessive thrust caused bymechanical failure inside pump or byfailure of hydraulic balancingdevice, if any (in case of multistagepump etc.)

Check pump operation and assembly.

42.Excessive grease or oil in antifrictionbearing housing or lack of cooling,causing excessive bearingtemperature

Attend.

43.Lack of lubrication Provide proper lubrication.

44.Improper installation of antifrictionbearings (damage, incorrectassembly of stacked bearings, use ofunmatched bearings as a pair, etc.)

Rectify or replace bearing.

45.Dirt in bearings Investigate the cause and clean bearing

46.Rusting of bearings from water inhousing

Arrest water ingress.

47.Excessive cooling of water-cooled bearing, resulting incondensation of atmosphericmoisture in bearing housing

Reduce cooling water flow


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ANNEXURE II

LUBRICATION CHART

RECOMMENDED BRANDS OF OILS AND GREASE FOR

M + P CENTRIFUGAL PUMPS

Manufacturer Oil Brand

Oil Lubricated

bearing

Grease

Grease Lubricated Bearing

Indian Oil Corporation Servo System-46 Servogem-2/3

Hindustan Petroleum Enclo-46 Lithon-2/3

Bharat Petroleum Hydral-46 Multipurpose Grease-3

Note: For oil Lubrication : 1. ISO Grade 46 oil.

2. All above oils are compatible with each other when

fresh.

3. It is unsafe to mix oil of two or more grades for use in

Bearings.

4. Number 46 is Viscosity at 40 degree centigrade in

centistokes.

For Grease Lubrication : 1. Only lithium base Grease to be used.

2. Numbers mentioned stands for consistency.

3. Grease of two different grades should not be used

.


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ANNEXURE III

MAXIMUM RUNNING CLEARANCE:

DIAMETER DIAMETRIC DIAMETER DIAMETRIC

FROM UP TO CLEARANCE FROM UP TO CLEARANCE

mm mm Mm mm Mm Mm

30 49.99 0.314 450 474.99 0.910

50 64.99 0.356 475 499.99 0.940

65 79.99 0.376 500 524.99 0.980

80 89.99 0.419 525 549.99 1.010

90 99.99 0.439 550 574.99 1.030

100 114.99 0.469 575 599.99 1.060

115 119.99 0.489 600 624.99 1.080

120 124.99 0.503 625 629.99 1.080

125 149.99 0.533 630 649.99 1.155

150 174.99 0.553 650 674.99 1.180

175 179.99 0.583 675 699.99 1.205

180 199.99 0.598 700 724.99 1.230

200 224.99 0.618 725 749.99 1.255

225 249.99 0.648 750 774.99 1.280

250 274.99 0.683 775 799.99 1.305

275 299.99 0.713 800 824.99 1.355

300 314.99 0.733 825 849.99 1.380

315 324.99 0.746 850 874.99 1.405

325 349.99 0.776 875 899.99 1.430

350 374.99 0.796 900 924.99 1.455

375 399.99 0.826 925 949.99 1.480

400 424.99 0.860 950 974.99 1.505

425 449.99 0.890 975 999.99 1.530


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ANNEXURE IVDETAILS OF MAINTENANCE WORK CARRIED OUT

SR.NO. DATE EQUIPMENT

NO.

DETAILS SIGN

NAME

REMARKS

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