Air Eliminator Causes Cavitation?
Air Eliminator Causes Cavitation?
(OP)
Pumping Jet-A fuel from one storgae tank to another,
we have the following setup:
Tank ->
Floating Suction ->
Check valve ->
Strainer ->
Positive Displacement Pump ->
Air Eliminator (NEW) ->
Filter/Separator ->
Relaxation Chamber ->
Meter ->
Tank
Everything has been working fine, but the owner insisted we add a bulk air eliminator, which we installed immediately after the pump. Now, when the discharging tank fuel level drops below a certain value we get cavitation in the pump.
When the cavitation happens, the vacuum at the pump inlet will have been holding steady at 3"-5" Hg, and then will very quickly jump up to over 10" Hg. This does not indicate normal conditions because the vacuum should increase linearly with the decreasing fuel level in the discharging tank. Do you agree?
Does anyone have any experience with any situation where changes on the pressure side of a positive displacement pump caused problems on the suction side?





RE: Air Eliminator Causes Cavitation?
how is the air separator piped and why is it upstream of the relaxation chamber?
RE: Air Eliminator Causes Cavitation?
The air eliminator is a 30-gallon pressure vessel with two floats. One at mid-height opens the discharge valve when it gets submerged by fuel. Then second, near the top, closes the air vent at the top when it gets submerged.
We will have run up to 8000 gallons through the system when the problem occurs, so I don't think it's related to air. For example, we might empty several compartments of a transport, each time getting a slug of air, and not get the problem. Or, we might run a similar volume of fuel from one tank to another, with no air entrainment at all. By this time the eliminator should be in steady state.
The eliminator is upstream of the filter/separator and relax chamber to minimize the chance of fires in the filter. Sometimes, though usually for much larger systems, compressing air and vapors in an empty filter can cause this problem.
RE: Air Eliminator Causes Cavitation?
RE: Air Eliminator Causes Cavitation?
RE: Air Eliminator Causes Cavitation?
RE: Air Eliminator Causes Cavitation?
RE: Air Eliminator Causes Cavitation?