Loking fo a low flow/low NPSH Pump

[eaw1]

Folks, I am looking for suitable type, vednor or manufacturuer for a pump of the following specs. Any help appreciated


> Capacity 17 GPM
> Normal Suction Pressure 0-3 psig
> Discharge Pressure 20-25 psig
> Pump suction and casing must be rated for 100 psig
> Temperature rating for pump -20 F to 100 F
> NPSHa 0.56 ft
> Pumping Fluid is hydrocarbon and water, SG 0.75-1.0 and viscosity 0.82
> cP
> 2" outlet and inlet, 300# rated flanges
> Pneumatic (120 PSIG utility air ) or Electrical (480 V, 3 phase , 60 Hz, Induction type motor)
> Marine Environment (Offshore)
> Class 1 Div 2
> MUST be API 610, 7674, 675, 676 compliant

 

[moltenmetal]

0.56 ft NPSHA? Good luck...

 

[MJCronin]

eeeeww..

Try an air operated diaphragm pump...

They are variable speed, can operate under all kinds of suction conditions and can handle the modest flow and pressures that you you state.

By the may... they consume a lot of compressed air if operated continuously.

-MJC

 

[nickelkid]

A gear pump like vikingpump.com may be a fit (and a little overkill considering your viscosity). Larger gear pumps that meet your spec's (API, Flanged, etc...) can be slowed down with gear reducers to deal with low NPSHa.

A half a foot NPSH available is really low. With a minimum 0 psig suction and minimum 0.75 SG I do not see how you arrive at 0.56 ft NPSHa.

 

[TBP]

Try Roth Pump, they may have something.

 

[nickelkid]

Roth has a nice product, but not API compliant.

 

[Glenfiddich]

(Roth) turbine pump.

 

[nickelkid]

Roth turbine pump NPSHr is 0.5 ft, that gives a 0.06 ft margin. I would like to see vendor experiences with that.

 

[eaw1]

thanks guys, what about prgressive cavity pumps or canned pumps, do you gusy have experiecne in these ?

 

[nickelkid]

Progressive cavity could be a fit, very forgiving if the pumpage has solids.

Canned motor can be trouble make if misapplied; a champ is the right application.

 

[schnipp]

Gear pump may not be able to handle the lack of viscosity. We use them in heavy solid syrups and they do not pump water, may be because the solids increase the clearances too much.

I've always stayed clear of progressive cavity as I've heard the liners can sometimes come loose in big chunks. Not good in the food industry. If you have a filter down stream, though, it may work.

 

[djack77494]

PD pumps like gear and progressive cavity pumps can handle some vapor entrainment and tend to be more forgiving than centrifugals in that regard. So, if you may fall short of the NPSHr from time to time, it may be best to select a PD pump.

 

[786392]

I believe; since laboratories small vacume suction pumps are most usually the PD type. I second djack77494 from practical standpoint.

Best Regards
Qalander(Chem)

 

[lastminuteman]

Hi,

I suggest you look up Roth Pump Company on the Net. They offer a line of Regenerative Turbine pumps that they claim work with 6" NPSH.

 

[chemicalengineerthai]

1)If can not avoid, Modify the suction elevation to improve NPSHa, You can not find the good pump for this service, but I think you may wrong calculation in NPSHa, I guess you should have at least 3 FT, Please check again, I also work for oily water pump offshore from open drain drum.

2) This oily water ( rich water/ & only time by time has some oil, no need API pump Just use ANSI pump much cheaper/low maintenance, and safe enough to operate in utility/safe zone.