psi wont stay up 5

[palecactus]

hello,
im working on a test station to measure water flow of irrigation parts at 20 psi . problem is that when i start testing parts that put out 14 gph and higher (up to 60gph) i cant get to 20 psi. i have a pressure releif valve in front of the regulator and the small procon series 1 pump has a pressure releif vale too. am i putting out the same amount of water that im putting in on the larger volume parts? would a larger pump be the answer?
any help would be appreciated.

 

[JStephen]

It looks to me like a higher capacity pump would be the answer. Check if you can get flow curves of gpm vs pressure or the equivalent beforehand.

 

[BigInch]

Two things you need to specify for your pump; Head and Flow.
You need a pump that can deliver a 50 ft discharge head (apx 20 psi with water) at the maximum flowrate you want to be able to run through your test station.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[palecactus]

thanks for the help!
happy new year!

 

[GregLamberson]

Another thing is you may have air trapped in the system and as you know, air is not nearly as compressible as water, so if you do have air entrapped you will have some difficulty getting up to pressure.

Normally this is the case when pressure testing systems to higher pressure, I assume even at the lower pressure air is still an issue. You will need some vents at the high points of the system to bleed the air out.

Greg Lamberson
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[zdas04]

"air is not nearly as compressible as water"??? Is that what you really meant to say?

Air is pretty compressible and in this case it would delay the pressure traverse across the system through the liquid having to compress the gas.

David

 

[BigInch]

There's no air.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[palecactus]

how about changing the systems main filter?

 

[palecactus]

pump releif valve set at 250...press releif valve for main reg set at 105...max press is 148.3 dead headed. when outlet is o-pened and part is applied rated @ 24gph, psi wont go past 4.4psi.

 

[palecactus]

sorry... pressure relief for main reg is wide open (250psi) deadheaded and max press is 148.3 w/ main reg closed.

 

[GregLamberson]

David

When you test a pipeline system and there is air in the system you cannot get a good test or get up to test pressure. That is the reason you must evacuate all of the air from the system and do air volume calculations to validate it.

Air is compressible, but in a closed system not nearly as much so as water. Air will cause you big headaches when hydrotesting.

Greg Lamberson
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[zdas04]

Air will indeed cause you big headaches while hydrotesting. It is very compressible (a couple of orders of magnitude more compressible than water) and not as susseptible to changing pressure with temperature as water. When you pressure up a system that contains significant air (either free or entrained), the system will not respond in the typical liquid-full manner.

David

 

[FACS]

Air is compressible, but in a closed system not nearly as much so as water. Air will cause you big headaches when hydrotesting.

You are saying water is compressible? More compressible than air?

Charlie

http://www.facsco.com

 

[BigInch]

There's no air in this system.
Don't go off on that tangent.

We all know water is slightly compressible and air very much so.





BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[JRLAKE]

It's pretty clear that the pump is undersized.

 

[FACS]

The pump is fine, check your motor to be sure it is the right horsepower.

http://proconpumps.com/Series 1.htm

The pump is not undersized.

tell us exactly how it is set up... from supply to outlet, what is in between?

Charlie

http://www.facsco.com

 

[BigInch]

"I can't get to 20 psi... at 14 to 60 gpH

The OP's statement implies that all he wants to do is to get to 20 psi, ie 50 ft head at ONE GPM maximum. That flow and head is micro watt power and probably not the kind of pump where you have the option to buy a new motor. Neither is it the kind of pump or motor worth spending any time on repairing.

Its not the motor. I feel if the motor was turning, he wouldn't be writing us. If its turning at all, its making 0.02 horsepower and that's all it needs to make to get 20 psi and 1 gpm with the right pump.

If this garden fountain pump doesn't work, he needs to scrap it and buy a new unit.... one with the right head and flow. That will be the only cost effective solution.

No air, probably no clogged filter, probably no motor problem. End of story.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[FACS]

pump releif valve set at 250...press releif valve for main reg set at 105...max press is 148.3 dead headed. when outlet is o-pened and part is applied rated @ 24gph, psi wont go past 4.4psi.

what do you mean when you say that "outlet is opened and part is applied"?

Is the pump generating pressure at dead head?

Charlie

http://www.facsco.com

 

[BigInch]

Delete my posts.
I see that Palecactus can't get his facts straight.


BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[FACS]

LOL.... BigInch.... I wish we could delete our own posts....

Palecactus,

Sounds to me, from what I read... that the system does not NEED to go past 4.4 psi.

Perhaps if the oulet valve was postiioned at the outlet of the "part". Then, the outlet valve is slowly closed to increase the pressure......

maybe, yet I'm lost.

Charlie

http://www.facsco.com