The pump doesn’t work
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Today, when starting the pump, it was found that the pump (a regular centrifugal pump) would not rotate (the crank rotation was normal). The filter on the inlet pipeline was cleaned, and the outlet pipeline was inspected as well, with no problems detected. Then, suspecting a problem with the pump’s impeller or impeller nut, the pump was disassembled, and everything was found to be normal! Then the pump was started again, but still no pressure. It’s really confusing... I’d be very grateful if fellow sailors could help analyze what might be the cause
Motor reversal； The motor speed is insufficient ； The inlet pipeline has holes for air intake ； http://bbs.hcbbs.com/viewthread.php?tid=120735 This post was last edited by jilinzhengda on 2009-4-10 02:09 ]
Personally, I think it’s caused by the reverse rotation of speed.
Check whether the motor is reversing； After starting the pump, check whether the outlet pressure rises (with the outlet valve closed), then open the valve to verify if there is any blockage at the outlet ； Pump in and discharge the condensate, then open it to check whether there is fluid flowing through, determine the flow rate, and verify that the inlet is not blocked ； Have the impeller and main shaft come loose? ； In the case of a hot oil pump, check whether an excessive amount of seal oil injection is causing the pump to go into vacuum. I’ll jot down a few points here; I’m not sure if they will be helpful. The specific reasons need to be identified step by step on site. Wish you resolve the issue soon. This post was last edited by gmdyes on 2009-4-10 08:49]
There are many possible reasons for no measurement being taken. The original poster should describe the specific circumstances in which no measurement is taken, such as the outlet pressure and current before the outlet valve is opened after the pump starts up, as well as the outlet pressure, current, and flow rate after the valve is opened. Information on the pump’s vibration and noise levels is also relevant. The more detailed the information provided, the more accurate Haiyou’s analysis will be.
Check the inhalation volume and inhalation pressure
For normal cranking, run it idle to check the rotation direction and sound of the motor and pump (inspect basic conditions such as pump installation and stability). Fill the inlet side of the pump and start it (the centrifugal pump), then check the outlet pressure. The lack of pressure is caused by the pump, or by problems with the inlet pipeline – such as air entering the system or insufficient liquid supply at the inlet. Once things return to normal, if the flow rate at the outlet is still low, check whether there are restrictions in the inlet pipeline, air in the system, or limitations in the pump’s capacity
⒈Vent the pump to eliminate air locking. ⒉Increase the pump inlet pressure to eliminate cavitation. ⒊Reduce the feed temperature to prevent cavitation.
Check the forward and reverse rotation of the motor. The vapor phase must be vented before starting the pump. Open a little of the outlet valve before starting the pump to avoid pressure buildup that could cause cavitation. The C4 pump here used to have this problem all the time, and the solution was to vent a large amount of fluid.
Generally, first check whether the motor rotates in one direction or the other, then swap the wires; otherwise, if there is air inside, that will cause problems.
1. Cavitation may be occurring. 2. There may be air inside the pump (not completely removed)
1. Check the motor rotation direction. 2. Check for any foreign objects blocking the inlet. 3. Check the sealing condition of the inlet pipe
1 Motor reversal 2 Coupling broken 3 Pump not filled, air lock