Jianghu came to the rescue, and the water pressure of the centrifugal pump was getting lower and lower.
Thread Content
When the inlet valve is fully opened, cavitation makes a crackling sound. When the outlet valve is closed, the sound disappears. At this time, the outlet pressure is 2.2 kg. However, after a day or two of running after it is opened, the pressure fluctuates high and low, and the pressure gauge needle swings wildly. I felt that there was air intake somewhere, so I replaced the valve soft joints on the air intake pipe, but the problem was still not solved. The mechanical seal did not leak. Logically speaking, the mechanical seal has positive pressure and will only leak water and not suck air in. I forgot the guidance of teachers Haiyou.
1. Find a way to increase the inlet pressure； 2. Check the inlet filter
Replenish: If the pressure still drops after checking and cleaning the inlet filter, and there is no problem with the pump itself, it is recommended to look for the cause from the process, especially whether there is foreign matter or scale in the pipeline and tank in front of the pump inlet.
If possible, measure the pressure difference between the inlet and outlet of the filter.
It seems that everyone has the same opinion. The inlet is not smooth, the pump cannot pump anything, or the phenomenon you mentioned will occur intermittently.
The inlet filter has just been disassembled and inspected, and there is no clogging or foreign matter. This pump shares an inlet pipe with another pump. The other pump runs normally, except this one.
If the other pump is normal, it means that there is no problem with the inlet main pipe before branching. To check the inlet branch pipe of the problematic pump, not only the filter, but also the inside of the pipe should be checked. There may also be large objects stuck in the pipe. In addition, are these two pumps one on and one on standby? Is it the same model? Is the inlet piping symmetrical? When a problem occurs, are the two pumps turned on at the same time or separately? If they are opened at the same time, is there any problem of water grabbing? If there are no problems, it means there is a mechanical failure in the pump itself.
What is the rated lift of your water pump? How much lift is actually used? Is there cavitation caused by large flow rate?
So if you close the valve, the flow rate will be reduced and the pump will work normally.
It is recommended to use the method of observing the current. The current of the two pumps is close to the same by controlling the opening of the outlet valve and try again. The suction valves of the two pumps must be fully open, but the outlet valve must not be opened too large within the rated current range, otherwise the current will be exceeded. Give it a try.