Seeking advice on the issue of the circulating water pump not functioning properly
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Our facility has 9 circulating water pump units for cooling towers, and pump No. 2 is not functioning properly at the moment. The main issues are as follows: when the pump is started after filling it with liquid, the outlet pressure is around 0.6 MPa; however, once the outlet valve is slowly opened, the pressure drops to around 0.1 MPa. Upon inspection, no corrosion was found in the pump’s internal rings or impeller, and there was no blockage at the inlet. Due to slight internal leakage in the pump’s outlet valve, a large amount of gas continuously leaked in from the outlet after the pump was reinstalled, which is why the pump could not function properly. This circulating water system operates at 0.45-0.5 MPa, with 7 pumps currently in use. Could the experts please analyze the specific reasons and solutions?
Is there no popping sound of cavitation inside the pump?
There is an internal leakage at the pump’s outlet; gas keeps leaking in from the pump outlet after filling it. The air release valve on top of the pump casing remains open throughout operation. Initially, when the outlet valve was not opened, there was almost no sound, but as soon as the outlet valve was opened to 5% of its full position, pressure dropped and a cracking noise appeared.
Air is being drawn in. Inspect the pump inlet pipeline.
If the inlet flow is insufficient, first reduce the opening of the inlet valves of the other pumps (not too much). Once this pump is operating properly, gradually increase the opening of the inlet valves of the other pumps to ensure a uniform distribution of water flow
I’ve never encountered this situation; I agree with the people above. Perhaps the inlet valve isn’t open.
Maybe the valve at the inlet is not fully closed. Ahhh, I’ve seen similar problems before; it was a manual valve, and it seemed to be fully open, but in reality the valve disc was slightly ajar. For a pipe of this thickness, use a flashlight to check the valve disc
I am extremely grateful for everyone’s help. The problem with this pump is mainly internal leakage in the outlet valve; in other pumps, the compressed gas enters the pump body and causes a \"gas lock\" phenomenon. I installed a vent valve at the top of the pump casing, kept the outlet closed, and after starting the pump I opened the vent until no more gas was discharged. Open the outlet valve for normal operation.