Can anyone help me spec a pump?

[liquidsords]

Our suction is 1" discharge is 2"
Right now our pump is designed for 30 gpm but we only need 2-4. Here's what we need

Flow: 2-4 gpm
Pressure: - 100 psi differential
Product: Jet fuel
Suction pressure available: 18 psi


Is this something I can buy off the shelf such as a simple ANSI pump?
Any help is greatly appreciated

 

[FACS]

Call Viking pump and make your suction line larger than your discharge.

Charlie

http://www.facsco.com

 

[liquidsords]

Thanks I called them. Anyone else?

Some more info:

Specific gravity is ~0.8, temperature is ~75 F, viscosity ~2.7

Suction pressure is currently at 18 psi, but it is coming through ~1000 equivalent feet of 1" pipe and will therefore drop proportionally with flow. This needs to be validated by engineering, but according to the Cameron Hydraulic Data book, loss in feet would be as follows:

1 gpm 1.41 feet
2 gpm 4.80 feet
3 gpm 9.48 feet
4 gpm 15.9 feet
5 gpm 23.4 feet
6 gpm 32.4 feet
7 gpm 42.6 feet
8 gpm 54.3 feet


If I am doing the calculations correctly, we currently have 18 psi which equates to (18 x 2.31/0.8) roughly 50 feet of head. Our existing pump was designed to operate at ~25 gpm. It also went dry when we ran it, meaning we were likely flowing at or above 7 gpm. It also cannot put up enough pressure

 

[dcasto]

Little pumps like this are off the shelf at McMasters Carr or Grainger

 

[TenPenny]

I'd look at a little 3 screw pump, like the IMO pumps. You may be pushing the lower limit of viscosity in your application, but I'd check it out...put a vfd on it, and you can control your flow quite well. Your flow rate is on the low end for an ANSI pump, although there are low-flow ANSI pumps (ie, the Goulds LF3196) that will probably do it, they're NOT very efficient....

 

[pumpking]

you could give us a go at

http://www.cdrpumps.co.uk

??

 

[liquidsords]

Why does the suction need to be larger than discharge?

 

[JRLAKE]

You need a larger suction than discharge for many reasons. Sufficient NPSH, inlet velocity, etc. I agree with FACS. A gear pump (Viking, Gorman Rupp, etc.) is the best pump for this application.

 

[Whyknot]

You make want to look at a small regen-turbine pump

 

[Artisi]

There is no rule that says suction diameter MUST be bigger than discharge although it is normally this way.

 

[pumpguykc]

YOUR SUCTION SHOULD ALWAYS BE THE SAME SIZE OR LARGER THAN YOUR DISCHARGE. FROM MY QUICK CALCS YOU ROUGHLY HAVE AROUND 7-8PSI FRICTION LOSS IN YOUR SUCTION LINE SO IF YOU HAVE 18PSI NPSHA YOU SHOULD BE GOOD AT A MAX FLOW RATE OF 4GPM. THIS IS BASED ON STRAIGHT RUN WITH NO ELBOWS. YOU NEED TO MAKE SURE YOU HAVE 10 X YOUR SUCTION LINE OF STRAIGHT PIPE. A GEAR PUMP IS NOT THE BEST PUMP FOR SUCH A THIN FLUID DUE TO WEAR ON THE PUMP. ALSO YOU NEED TO FIND OUT WHAT REQUIREMENTS YOU HAVE TO PUMP JET FUEL. IN ALL OF THE APPLICATIONS WE HAVE WORKED ON WITH JET FUEL IT REQUIRED AN API RATING. A REGEN TURBINE PUMP WILL WORK WELL IN AN APPLICATION LIKE THIS BUT AGAIN THAT DEPENDS ON YOUR REQUIREMENTS. WITH A THIN FLUID LIKE THIS THERE TENDS TO BE SLIP INTERNALLY IN YOUR PUMP.