The pump suddenly stops delivering flow
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An additional standby pump was added to the pump; during trial operation, both pressure and flow rates were normal. However, after two hours of operation, there was no flow rate left and the outlet pressure fluctuated, so it was necessary to switch back to the standby pump. Tested again the next day. Still, there was no internet connection suddenly after two hours. The pressure in the storage tank is above 100 KPA, the liquid level is 3 to 4 meters, the temperature of the medium is 25 degrees Celsius, and it is C5. The only change is that the pump inlet has 4 more elbows than the original pump, as well as an upper U-tube, to detect cavitation or air entrainment. No abnormalities were found when the inlet filter was removed. It’s quite strange.
There are four additional elbows and one inverted U-shaped tube; the medium being transported is the easily vaporizable C5. It is likely that after some time of transportation, the liquid level in the storage tank dropped, and moreover, the resistance losses in the pipelines due to fluid flow increased, resulting in too low pressure at the pump’s suction inlet and thus causing pump cavitation.
Personally, I think it is the installation of the pump inlet elbow and U-tube that causes excessive inlet resistance, which can lead to cavitation in the pump. Try to reduce this inlet resistance by lowering the installation height or the temperature of the process fluid.
Check whether the temperature of the pump head is extremely high when the flow rate is low A high value indicates cavitation
Check whether the temperature of the pump head is too high, as well as the pressure difference across the inlet filter.
I think it might be because the increased resistance due to numerous elbows caused air to accumulate in the pump, preventing it from pumping liquid.
I’ve found the cause; it’s not gas – there’s none in the raw materials, and there’s no issue with the remaining gas volume either. Think about it; it’s very interesting.
Check the pump’s net positive suction head; also, see if there is any change in height at those four elbows, and determine whether the pump’s output volume is too low.
The problem should be at the inverted U shape. I don’t know what the use of setting this thing is? The principle of a communicating vessel: if the liquid level is low, can’t there be enough pressure? :lol
Reply to 7# fengl73: It’s likely that air is leaking from some part of the U-tube, which is preventing feeding! Think about other reasons!