Minimum Distance Between Pumps

Hello gsuhas

It depends on various factors.

1. Type of pumps
2. Size of pumps
3. Location of each of the pumps
4. If the usage is water wells, the characteristics of the artesian basin/ground-water need to be known to allow for re-charging of the basin/well/s.
5. Quantity of water being pumped/extracted.
6. Other factors - yet to be advised by yourself.

Reply here, with

Kind Regards....

Thanks Spark

The pumps are semisubmerged (vertical) centrifugal pumps, with motor above ground and pumps under water in sump. The pump size is 400 mm and pumping 850 m^3/hr at discharge head of 25 metres.

Due to space constraints, I want to install those near to each other, without starvation.

I could not find any reference for this parameter anywhere in technical lteratures regarding pumps.

Guidance/ experience will be highly appreciated.

Regards,

If the storage capacity of your sump is large enough to supply both pumps the intakes should be OK at one pipe diameter away from each other.

If the sump cannot keep a reasonable water level up to the intakes then your pumps are to large, run one at a time.

You could put an accumulator between the two discharges, this will take any surge or flow difference between the two pumps.

Without knowing how your well is designed and what baffles it has if any I believe that at these flow rates at least a metre between pumps. You state that these are vertical centrifugal pumps in which case the size of the volutes should prevent them being installed any closer together than this. It would be preferable to install a baffle between them to prevent interference. The other problem you may have is vortexing if the intakes are not far enough below the surface anti vortex plates may be required. Especially if the inflow into the well does not keep say 1m above the inlet to the pump. Some more detail would assist in giving you a more comprehensive answer as the design of intakes and sumps for high flow rates is critical for the pumps to operate without problems. ie sump dimensions inlet to sump (is it straight) size of inlet or velocity of inflow obstructions or conditions that could cause turbulence etc.

Thanks coconutpete

This almost gives answer to my question. Still add some more data:

As you say correctly, (in which case the size of the volutes should prevent them being installed any closer together than this,) the pumps can not be put closer than 900 mm center to center as the casing diameter is 850 mm. I am keeping this distance 1 metre.

The sump is big enough, minimum water height above strainer of pump will be 900 mm. Total sump capacity when filled full to 3m height is almost 350 m^3

One of the pump casing will be almost touching the wall of the sump. I am also thinking of putting the baffle between two pumps, so that those will not interfere with each other.

Any more suggestions after this additional data?

Hi all,

I think that you need to read the Hydraulic Institute Standard. You will find a specific item about "Sump Pump Design".

Regards

Ernesto

Hey,

Remember about the situation when the liquid is beeing pumped to the tank from one side...if the firts pumps will start to do it s job the second one will heat up.

Well, that will depend upon the availability of standard pipe fittings of the required diameter, which has been withheld from the forum. Standard bends of a particular radius and tees of a standard configuration will push the pumps away to a pipe centres distance. However not even the size was shared with the forum. In the absence of any information whatsoever, the minimum distance is zero, i.e. they can be touching.