Looking for the impossible?? 4

[barryn56]

I am looking for a high pressure (2000 psi), low rate (1.5 litres/min) water (brackish, possible small solids content) pump which has an overall diameter of 65mm or less (length not important, but ideally 3 metres or less), to operate at 120 deg C. Had no luck so far, except for a positive displacement (piston) pump, but this can't handle any solids (5 micron max). I thought a PCP would be available, but they all seem to be too large in diameter, or have a low pressure capability. Alternatively, some form of transfer pump, where the pumped fluids are separate from the pump working fluid, might be OK. Any help/contacts appreciated.
Thanks,
Barry
Brisbane, Australia

 

[micalbrch]

A PC pump is not a good choice for 2000 psi and some solids. I thought there are multistage centrifugals available like SUNDYNE (

http://www.sundyne.com)

but it seems that 2000 psi is too much for them. But there are small piston diaphragm pumps available from LEWA (

http://www.lewa.com)

or BRAN & LUEBBE (

http://www.bran-luebbe.com)

which can do that - at least it looks as if. 2000 psi is not a problem for these pumps, 120 °C neither for a pump with PTFE diaphragm and the solids concentration is easy to handle. The only problem might be the low flow but I think it is worth a try.

 

[Compositepro]

From your size requirement it sounds like a down-hole pump. Are you sure you require 2000 psi of differential pressure, i.e. lift, or is it operating at that ambient pressure? A gear pump would work, except for the solids. The ost appropriate design to handle solids would be something like a plunger pump with a hydraulically driven plunger. I don't know of any manufacturer, though.

 

[zdas04]

The HSP from Global Energy in Calgary (

http://www.global-energy.ca/)

would do the job except for the 65 mm max diameter. Their smallest pump is around 95 mm. They might be able to build you a custom pump, but it wouldn't be cheep.

David

 

[FACS]

So you can be clear on your terminology; "Brackish" means it has a mixture of Salt water and fresh water. It makes a difference because of the increased corrosive nature of salt. It looks by your definition that you are using "Brackish" to mean it may have solids in it.

And yeah, I could make one for you, but it would cost a fortune.


Charlie

http://www.facsco.com

 

[curtis26]

Did you look at the sister to the piston pump, the plunger pump? It is used for mine surry applications with up to 6 mm solids.

 

[barryn56]

Hi, and thanks guys, for the comments.
Micalbrch - I will check out the links. I thought PCP would be best due to the use of these pumps for lifting water in deep wells, but they are large diameter. The piston diaphragm pumps look very interesting if I cen find one small enough.

Compositepro - correct, it is a downhole pump and yes, I do need that level of differential. The pump will be used to inflate a packer against the differential at depth, and to pump from a low pressure to a high pressure environment. Gear pumps I looked at could not handle water at the pressure, and the solids, as you mention, would be a problem. Plunger pump would be good, but you are right - finding a supplier is a problem.

zdas04 - Thanks, I will check that out and ask them.

FACS - Brackish does mean saline, but only around 5 to 10kppm. Send me technical details and a quote if you're serious about building a pump.

Regards,

Barry

 

[barryn56]

Curtis26 - yes, the plunger pump looks good, but the size and supplier is an issue. Also driving it was another problem, as it needs a linear drive mechanism, causing a high loss of efficiency, and as we use batteries for the high current, this has not been overcome.

 

[barryn56]

Having checked these out, it still looks like there are no solutions - diaphragm pumps from the referenced manufacturers are too large, but would be ideal if I could find one small enough. Plungers are a problem to drive efficiently by electric motor, and also a size issue.

Looks like the custom build is the only way to go, at this stage. I am currently using a special hydraulic pump designed for water, but this needs very clean fluid and has other issues too, because a) it can't take differential pressure across the seals. This is solved by immersing the whole pump in the tank and using a magnetic drive coupling; b) it stalls the motor if there is a high pressure on the inlet. This solved by using a one way valve between the tank and outlet, which shorts the pump until it gets up to pressure; c) it produces a high delta P when flow is reversed and the pump not turning. As I need the pump out of the way when this happens, solution was to design a special shuttle valve to short backflow to the tank.
Finally, this only gives 1500 psi at best...

To give a better idea of what I need, I attached a file showing the current arrangement. Top is the motor, then the magnetic coupling, then the pump.

 

[micalbrch]

barryn: A triplex plunger pump meets flow and pressure with a corresponding gear motor (manually adjustable or VFD controlled). And efficiency is good. We just bought one for a flow between 66-380 l/h (= 1.1 - 6.3 l/min). We bought a SPECK pump (

http://www.speck-triplex.de).

We mount a manually adjustable gear motor to it and that works well.
We are pumping just clean water as a triplex plunger pump is sensitive to solids and the temperature is an issue too. But at least flow and pressure will work for sure. If you can get a PTFE plunger packing and PTFE or FPM seals the temperature issue will be solved, too.

 

[barryn56]

Thanks Micalbrch, but I don't think they'll fit in 65mm diameter!

 

[NickJ67]

At just 1.5 l/min I think it would be possible to make a PC pump within your 65mm but it would be long as it would need to be a 20 - 24 stage design. Making the rotor would be a challenge.... very long and very skinny. Making a transmision that can hadle the eccentric motion and thrust load would also be a challenge!

Nick

 

[barryn56]

Thanks NickJ67,
length isn't a problem, but agree that what I want seems really difficult to achieve. I'm thinking if there are some other options available, as this seems to be in the "too difficult" box.