pump bypass location
pump bypass location
(OP)
Hello, I am hoping for some good advice in an area I only know a little about. I am installing a 15hp centrifigual pump, 2inch inlet; 1 1/2inch outlet. I will be installing a spring loaded relief valve in the discharge line to regulate the pressure. Should relief valve discharge into the supply tank or the pump inlet? Thanks in advance for you help.





RE: pump bypass location
However, I have bypassed to the pump suction in the past without problems, depending on the system and the pump design.
RE: pump bypass location
actually I don't get the point with your post!
specially for the sentence "I will be installing a spring loaded relief valve in the discharge line to regulate the pressure"!!! keep in mind that we install relief valves for emergency cases as they are called elsewhere PSV for pressure safety valves! and NOT to regulate the pressure of the discharge line!
so please re-post with the complete data (that way we can help you better):
- liquid pumped
- viscosity, temperature and pressure of the liquid
- the height of the tank you are pumping from
- the height of the one that you'll pump to
- piping type (material) and length to compute the pressure losses.
kader
RE: pump bypass location
The terminology is sometimes confusing. But we commonly use relief valves specified as full-flow relief valves for pressure regulation on small systems. This is very common on small lube oil skids. A full-flow relief valve differs from a typical pop valve (PSV). The full-flow valve will crack open at a certain pressure and gradually open further as the pressure increases. It often has scored seats so it passes some flow even when fully closed. It does not "pop" open at a pre-determined set point. This makes it impossible to test and adjust using equipment commonly used to test PSV's. In most cases, the full-flow relief valve can only be field adjusted in the system at normal operating conditions.
Johnny Pellin
RE: pump bypass location
RE: pump bypass location
RE: pump bypass location
bsfc9 why don't you think about a much more simple solution?
I mean why don't you think to throttle the discharge line by installing a valve (a pressure control valve I would say).
Knowing the deltaP=10psi (which will be the pressure drop through the valve) that you are wondering, the viscosity of you fluid (1 cp for water) and the flow rate it would be "easy" to find out the valve that would do the job!
This doesn't answer your question but we'll open an another view or solution to your problem.
To answer your question "Should relief valve discharge into the supply tank or the pump inlet?"
I would say that both of the solutions are possible the difference would be only the pressure drop due to the piping (from tank to pump) that you'll avoid recycling directly to the pump inlet.
I advise you to read this article: "controlling centrifugal pumps" from http://www.driedger.ca/ce1_cp/CE1_CP.html
it treats the 2 points:
-throttling control
-recycling control
good luck!
RE: pump bypass location
Secondly, regarding kader007's post, I do not agree with his statement,
"Should relief valve discharge into the supply tank or the pump inlet?" I would say that both of the solutions are possible the difference would be only the pressure drop due to the piping (from tank to pump) that you'll avoid recycling directly to the pump inlet."
Recycling back to the pump suction results in a much more turbulent/less developed pump suction, and it fails to provide for any removal of heat. For a small inventory of liquid experiencing full recycle, this could result in rapid overheating with resulting pump problems. In my opinion, it is a thousand times better to return to the suction vessel if at all possible.
RE: pump bypass location
Just a thought...
Ash Fenn
www.cdrpumps.co.uk
RE: pump bypass location
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