Scavenge pump check
Scavenge pump check
(OP)
Hi,
I am trying to check if the pump that I plan to use for a scavenge system is adequate for my system. I have calculated the NPSHA (10.2 ft.). The pump model is NDP-20BAV (Yamada) and it says that the max dry suction lift is 18 ft. What does this mean and how can I check if my pump will work?
Notes: I am pumping an air/oil mixture (scavenge). I took hvpa to be 0 ft. because it is oil.
Thank you for any advice.
Gabriel
I am trying to check if the pump that I plan to use for a scavenge system is adequate for my system. I have calculated the NPSHA (10.2 ft.). The pump model is NDP-20BAV (Yamada) and it says that the max dry suction lift is 18 ft. What does this mean and how can I check if my pump will work?
Notes: I am pumping an air/oil mixture (scavenge). I took hvpa to be 0 ft. because it is oil.
Thank you for any advice.
Gabriel





RE: Scavenge pump check
Therefore. If I installed the pump on the top of a sump and the liquid level is 17.9 feet BELOW the pump, this pump could suck it up the pipe during the priming cycle.
Don't rely on this number. It is performed under lab conditions with perfect seating of the balls and seats. As soon as these items begin to wear, this suction lift ability drops off. Also, your diaphragm life will be reduced if it has to pull an 18' suction lift. The vacuum created on the suction stroke will eventually fatigue the diaphragm.
RE: Scavenge pump check
RE: Scavenge pump check
This answered some of my questions. Will the manufacturer be able to provide the NPSHR? Is this a fixed value or does it depend on some variables?
Also, is it ok to assume that the vapor pressure of oil is equal to zero? (I have MIL-23699 Oil at 160 deg F).
Thanks again!
RE: Scavenge pump check
I can't answer your question on the vapor pressure because I don't know anything about that oil. However, I normally don't assume this kind of information at elevated temperatures.
RE: Scavenge pump check
I know my flow of 15.4 gpm. Other than that I have no idea.
Sorry if I don't know too much about design for pumps. I don't usually do too much work on pumps.
RE: Scavenge pump check
RE: Scavenge pump check
Thanks for all your help!
RE: Scavenge pump check
Thanks for any advice!
RE: Scavenge pump check
to answer your question - there are no suction capabilities shown on the curves you have posted.
The curve is clearly marked as "curve data is based on one-foot flooded suction; ambient temperature"
Contact the suppler with your problem - they should be able to help you.
JRLAKE - pumps don't suck - (maybe you can say that when they don't work)
" this pump could suck it up the pipe during the priming cycle."
RE: Scavenge pump check
RE: Scavenge pump check
RE: Scavenge pump check
Finally i could compare this to the manufacturers max discharge pressure.
Do you think this would be good? Because is there even an NPSHR for this type of pump?
RE: Scavenge pump check
RE: Scavenge pump check
RE: Scavenge pump check
2. Total head is discharge static head PLUS losses PLUS total suction losses.
You are currently running in circles, advise the total picture - inlet configuration and heights, inlet pipe details etc - discharge config.etc and NPSHr info for the pump.
You can assume what you like - but wishful thinking won't make it work if you have exceeded its limitations.
RE: Scavenge pump check
RE: Scavenge pump check
RE: Scavenge pump check