Centrifugal pump flow is insufficient
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Travaini centrifugal pump, the medium is gasoline, the flow rate is 33.3m3/h, the lift is 41 meters, it uses a 7.5kW motor, and the process flow is:: Gasoline storage tank - gate valve - electric valve - basket filter - centrifugal pump - one-way valve - ball valve - flow meter - nozzle - absorption tower (as shown below) The fault phenomenon is insufficient outlet pressure and flow. There will be a friction sound when it is first started, but it will normalize after a while. At present, the basket filter (cleaned), centrifugal pump coupling (hexagonal foot pad replaced), one-way valve (no abnormality) have been checked. Please tell me how you should troubleshoot, thank you!
From the flow chart, 8 should be the flow meter? If so, you have to consider whether the opening of 10 is too large? Also, the opening of the outlet valve should not be opened too large at startup, or from a small opening. When the pump pressure is raised to normal pressure, wait for the flow rate of the flow meter, gradually open the outlet valve larger according to the flow rate, adjust the 10 return valve, and adjust the flow rate while ensuring the working pressure of the pump. It may be an issue with the order of operations, for reference. Oh, and the valve on the pipeline between symbols 6 and 7 also affects the flow rate.
From your description, I personally feel that it is caused by the inlet of your pump not pumping enough volume. As a centrifugal pump, generally the inlet valve is required to be fully open before starting, and the outlet valve is fully closed. After starting, the outlet valve is gradually opened to the required pressure and flow. As for the function of valve 10, it is either a return line or a minimum flow line (the pipe size cannot be seen, if the latter should not be large, the pipe should not be large). ) will not be opened under normal circumstances. Another question is whether the mesh number of your filter is too small. It is recommended to change it to a larger size. We have encountered a similar situation here before, that is, the mesh number of the imported filter is too small, causing insufficient suction force of the pump.
I can’t see the diameter of the inlet pipe and the mesh number of the basket filter. I guess it could be due to the following reasons:: 1. The inlet pipeline is thin, or the inlet pipeline is long, the flow rate is high or the pressure drop is high, resulting in insufficient cavitation margin in the system. ； 2. Gasoline contains light components and is easy to vaporize. ； 3. The mesh number of the filter is too high, causing resistance. ； 4. The pump selection does not meet the system cavitation margin. ； 5. The return flow is too large, causing the pump suction volume to be too high and the liquid supply to be insufficient.
Recently, one of our pumps has insufficient water supply. After checking, I found that the flow control valve is out of order. For your reference.
Use the elimination method, remove the filter and run it to see if there is any improvement.
It may be that cavitation occurred during startup. You can determine whether the sound is friction or cavitation. Insufficient pressure and insufficient flow are either caused by pump problems or cavitation, otherwise insufficient flow and pressure should be high.
Judging from the phenomenon, it is caused by insufficient inlet flow. You can check whether the filter, valve and pipeline in front of the pump are not smooth.
1. Is the medium dirty? If it is very dirty, the filter may be clogged in an instant and cannot be measured. 2. Is the medium inlet temperature too high and the pump inlet pressure low, leading to cavitation? 3. Open the ring clearance and check whether the pump impeller is worn. 4. The most basic thing is to pay attention to the exhaust.
Is your pump a pipeline pump, a canned pump or a magnetic pump? Is the electric valve fully open?