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Instruction for Installation and Operation of
"He-Preduce" Rotary Gear Pumps
  The information contained hiren is of a general character and will be supplemented up on request by specific instruction appliying to the particular type of rotary gear pump bing operated. Satisfactory service can be reelized only up on strict adherence to these instructionů  


  Inspect and chake material received immieditaly and report any damage or shortage to us.  


The pump should be installed in a light, clean, dry location and so placed that it is easily accessible for inspection / maintanence. Suction piping should be full size, short and direct..


  The foundation should give permanent rigid support for the entire unit.

Concrete  foundation built up form solid ground will prove most satisfactory. ample allowance should be provided for grout in building the  foundation.

Foundation  bolts  of the specified size should  be accurately located according to drowings when the concerete is poured.


Correct alignment is absolutely essential for successful   operation  a flexible coupling will not as compensate as allgnmient . Rotary pumping  units should be aligned as accurately as if the coupling were solid.the flexbile coupling will then serve its purpose, ie. To prevent the compensate for slight changes in allignment which may occur during normal operation..


Pump are usually shipped on their baseplates and it is seldom necessary to remove the pump and driver from the baseplate while  levelling. The pumping unit should be placed on the foundation supported by wedges placed near the foundation bolts. Remove the paint from the  projections of the baseplate pads up on which the pump feet  are supported. Place sprit level on these pads and adjust the wedges under the daseplate to bring the pump to the shaft level. The drever  half coupling in perfect alignment with the pump  half coupling the chacking of alignment can be accomplished by  the use of  a sttainght edge across the top and sides of the coupling.

If the coupling‘s flanges are not perfectly true or not of the same diameter, check the alignment by revolving coupling and checking at ech quarter turn. If any variation is found, proper allowance must be made in alligning the unit.  The clearance between the coupling the  halves should be set so that they cannot strike, rub or exert and thrust on either pump or driver…


Alignment must be checked after the pump has been completely piped up because pumps aref frequently sprung and pulled out of position by  drawing up flange bolts when the must the flanges are not squared up suction and discharge piping is properly supported to prevent a strain or pull on the pump. Pipe strains are a common cause of misalignment, hot bearings, wear and vibration…


  The baseplate should be grouted in before the piping connections are made. The grout should be worked in under the baseplate so as to support it fully throughout its whole area.  


It is a common experience that a faulty suction line is responsible for trouble with rotary pumps.  Suction piping should never be less in diameter than the full size of the pump  suction opening. It should be as short and direct as possible and thorughly clean. It should be uniformly graded up from the source of supply to the pump. When drawing liquids, long distances or on high suction lifts or when handling thick, viscous liquids, the diameeter of the suction  pipe should  be greater than the opening in the pump to convey the liquid with minimum pipe friction loss…

If the static suction lift plus  suction pipe frection is equal to or greater than the equivalent of atmosheric pressure,the pump will not fill,resulting in reduced or entere loss of capacity….

When pumping highly  volatile liquids such as butane,propane, hot oils etc.,there must be sufficient static head on the suction in addition to the atmospheric pressure to prevent vapourization of liquid  within the pump. Reqid wear or seizing will result if these pump are allowed to run dry.

The suction line should be perfectly air-tight, a leak will result in reduced or entire loss of capacity….

A strainer is recommeded if the liquid contains foreign material. Abrasives in the liquid will cause rapid wear, the  strainer should have anet area of rom three to four times the suction pipe area and should permit easy cleaning.


Always carry the discharge up through a riser approximately five times the diameter. This prevents gas or air pockets in  the pump and will act. As a  seal in high vaccum service. A valve on the top of the riser be used a a vent when starting the pum.

To protect the pump against excessive pressure caused by increased pipe friction in could weather or accidental closing of valve in discharge line, a  relief valve is provided.this relief valve should be set slightly higher then maximum pump  discharge pressure  but not more than 10%...


Generally  standard pump are provided with gland packing. Do not thighten the glands to tightly, as a slight leakage will help to lubricate the packing.


Befor starting up for the first tim, prime the pump to the gear for effective  suction.

These pump are run and tested on oil. Unless specified on the order, the oil is lift in the pump to protect the internal mechanism  against corrosion. If  this oil will be detrimental to the system, it will be necessary to dismantle the pump, clean all parts thoroughly and fill the pump with the liquid to be pumped.

Never start or run the pump dry. This will inevitably cause galling, seizing or destructive wear between the rotors and casing…


  Direction of rotation is marked with an arrow on the pump.

When the direction of rotation  is to be reversed, the back cover of the pump should be rotated at 180*.


Before starting of, prime the pump and then check the prime mover for correct rotation. Check pressure on the inlet and outlet and side to be sure that they conform to specifications and that the pump will deliver full capacity without overloading the driver.

It is advisable to start operation at a  reduced load gradually increasing to maximum service conditions.




  • Alignment of the pump and motor should be checked.
  • Suction line should be checked for no air leakage and jamming of the dirt in filter.
  • If there is a pressure drop, the relief valve should be further  screwed until desired pressure is achieved.  If this does not give result, then there shouldb be  a  considerable wear in the rotors which should be replaced.
  • Leakage if any, on end cover should be eliminated by  tightening bolts.


  1. If the pressure drop is too much, the gears alongwith the shaft should be chenged  due to excess wear on them.
  2. On dismantling, if the  body shows wear, then  it  should be sent back to us for replacement.


If the pump gets jammed in running position, in that case loosen all the bolts by half a turn and try to rotate the pump shaft with pipe spanner. If  it rotates, then start the pump and allow it to run smoothly and tightenthe bolts slowly till there is no jamming.

If the rotor dose not rotate, then dismantling is necessary.

Where the pump is excessively heated in the initial running and jamming is caused, allow it to cool down to the temperature till the  jamming is eliminated

At the time of commissioning, under no circumstances the pump should be dismantled due to any fault whatsoever  without consulting the manufacturer.

At the commissioning stage, if the shaft is found tight, try to rotate the shaft with the help of a pipe wrench, then tightness should be considered as normal and the pump can standrd without any trouble.


  1. Unbolt the side  covers and push out assembly  of the rotor making note of the packing.

2. Remove all the burrs in body bore, on body faces as well as on rotors. Insert the rotors first in the body and check for free rotation.

3. Put appropriate packings with grease and then fit the cover with bolts.

4. Free rotation of the shaft should be checked with a small pipe wrench. If shaft is   found tight, loosen cover bolts by quarter turn and start the pump. When it runs smoothly, tighten the bolts equally and slowly . If seizure occurs, add one more packing.

5. If excessive wear is found on gear-teeth, complete set is to be replaced.

6. Minor scring in body bore will not affect pump performance to a great extent, but if heavy scoring is found, body should be replaced.


Falut Cause Remedy
1. a. Pump does not prime 1. Rotation wrong Check rotation if if necessary, change connections on motor.
  2. Pumps is dry Fill pump initially with oil.
  3. Suction line is not tight Tighten all bolts and nuts on suction, side. If necessary, pressure test suction line.
  4. Relief valve not, tight Remove valve and check set if necessary grind it.
b. In the case of working, against closed discharge line Evacuated air can not-note pass through the, pressurised oil colum & streams back in to,- suction line. Arrange deaeration cock on discharge side of pump. When pump is started, open this cock untill all air is exhausted and, then close. In the case of such arrang,- ements, a non-return valve is necessary, on the discharge is suggested so that the suction line, when switching off pump remains full.
2. LOSS OF OUT PUT 1. Speed to slow Check speed by means of tachometar. Check frequency and voltage on motor name plate. Check pump as in the case of overload, speed can be dropped.
  2. Relif valve opens too, soon. Remove valve cover and adjusting screw. if spring is fatigued, replace. Tank care, when adjusting that the pressure rise, with closed discharge valve does not, overload the pump.
  3. Suction line frection great Fit vaccum guage and check suction lift, which should not be more then, 8-6 mlc.
  a. Suction pipe too small
b. Suction line too long
c. Suction filter blocked
d. Viscocity too high
In the case of the items, a, b & d, only, a, - larger suction line or a reduction in, lenth can help. In case of © clean THE filter elements.
3.PUMP IS NOISY Badly aligned coupling Disconnect pump from motor and align coupling.
a. Mechanical noise 2. Gear flanks are damaged by foreiign bodies. Remove gear and correct damaged ,- flanks with oil stone. Finally do lapping.
  3. Delivery against low press,- in the case of thin liquids. Load gear flanks by closing discharge valve giving approximantely 15-20 psi,- noise will be eliminated.
b. Hydrolic or pneumatic noise. 4. The pumped medium contains air Determine whether air is drawn through, leak or whether retarn line is unsuitable in the line case of a circulating pump. In , such a case it is also nacessary the retu,- rn pipe terminates below liquid level.
  5. Cavitation due to:-  
  a. Too high suction Reduce the suction lift.
  b. Excessive speed in the case,- of very viscous liquids

Reduce speed

4. Motor is heating up. 1. Rong connection of motor, or only two phases. Connect motor according to name plate, - and check voltages in all three phases.
  2. Motor overloaded Check amp motor by means of an ameter.
  3. Pump seizing Disconnect motor and check that the , - the pump can be turned by hand.
  4. Delivery pressure too high Connect pressure guage onthedischarge branch and check whether delivery, - pressure is in accordance with the name, - plate of the pump.
  5. Viscocity too high Check viscocity at pumping temperature , - and compare with name plate of the pump.
  6. Misaligment Re-align coupling.
5. Fluctuating delivery 1. Frothing medim Avoid air entry in the oil. (see that in the, - case of cerculating pumps, the return , line oil level.)
6. Pump seized 1. Excessive pressure due to Check relif valve pressure at closed , - discharge valve so that it opens approxi, - mately at 10% above working pressure.
  2. Foregingn body in pumped Dismantle pump. Remove foreign body.  If, - necessary, do lapping on seized area. If, necessary fit suction fitter.
  3. Insufficient lubricating quality of pumped medium Check whether pump medium has lost its, lubricating properties due to elevated, temperature.
7. Relief valve chattering Valve is jammed Fit new spring, check valve for easy, - movement in the valve seat.
Quick Contact
Mr. Pravin M. Gajjar
Mr. Alpesh P. Gajjar
Mr. Vishal A Gajjar