Suction lift
Suction lift
(OP)
Hi. I'm designing a system using a Grundfos JP5 suction lift pump. It can be used to lift up to about 5. The suction pipe has to rise out of the reservoir and fall back down to the pump as shown in the sketch. I know that the lift the pumps needs to deal with is 2m + pipe friction losses, but how do I take the 2m height of the hump into account? I appreciate the issues I may have with keeping the pipe primed etc, but assuming the pipe is full of water when the pump is running, I want to know the suction lift that the pump has to be able to deal with.
Thanks very much
Thanks very much





RE: Suction lift
In order to keep the high point of the suction line primed, I would recommend that you consider an automatic vacuum pump that would kick in to evacuate any vapor. I have seen these as standard equipment on portable rental pumps that we used for temporary cooling water applications when the pump had to lift from the cooling tower sump down below. Unfortunately, I don't recall the manufacturer of that little vacuum pump or the supplier of the big rental pump.
Johnny Pellin
RE: Suction lift
RE: Suction lift
Johnny, was it perhaps a Cornell pump you saw? The have big pumps with a small diaphragm pump directly fitted on the suction side.
RE: Suction lift
I woild say 4m of lift plus friction loss.
Charlie
www.facsco.com
RE: Suction lift
Cheers,
John
RE: Suction lift
"The top of the organisation doesn't listen sufficiently to what the bottom is saying." Tony Hayward X-CEO BP
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.live.com
RE: Suction lift
Charlie
www.facsco.com
RE: Suction lift
RE: Suction lift
"The top of the organisation doesn't listen sufficiently to what the bottom is saying." Tony Hayward X-CEO BP
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.live.com
RE: Suction lift
Now whether the pump can operate within the 'system' in terms of initial prime, re-prime etc is another issue to which we do not have enough information to pass judgement.
RE: Suction lift
rmw
RE: Suction lift
RE: Suction lift
If the foot valve leaks a bit when the pump isn't running and air gets into the pipe and collects at the top, firstly is there a way i can assess how likely it is to either accumulate there or get sucked into the pump? The pipe internal diameter, flow rate and speed will be either 32 mm - 0.65 l/s - 0.8 m/s or 22 mm - 0.35 l/s - 0.92 m/s.
Secondly, what sort of valve/device would I used to get rid of trapped air?
Thanks again - maybe one day I'll know enough to give people advice!
RE: Suction lift
It is very difficult to find suitable valves to get the air out. There are some de-aeration valves available in the market (I know that company Grundfos has them) but they are not really performing well, especially not when the pump is operating. You need a pressure difference between pipe and atmosphere to get the air out. That means the pressure in the pipe must be higher than the atmospheric pressure which is unlikely the case in a pump's suction line.
RE: Suction lift
"The top of the organisation doesn't listen sufficiently to what the bottom is saying." Tony Hayward X-CEO BP
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.live.com