Operation status of the shielded pump
Thread Content
I would like to ask what could be the reasons for a shielded pump to stop operating suddenly? Medium: Propane, Isopentane ； Inlet temperature: normal temperature; Inlet pressure: 8 kilograms ； Operating current: 70-80A, outlet pressure 30-35 kg ； When starting the pump, the current is sometimes too high or too low; the exact reason is unknown
If there are no issues with the electrical and mechanical aspects, it’s possible that there are fluctuations in the pump’s flow rate, or that the specific gravity or viscosity of the medium has changed
Did you forget to close the pump’s outlet valve?
It’s impossible to tell, but sometimes when there is less isopentane, the current level tends to be higher
The opening degree of the outlet valve hasn’t changed; it’s just an unexplained surge in current
With less medium, there’s no need to explain – the traffic has decreased! There’s nothing that can’t be determined here; the control panel has current monitoring, and current levels indicate the flow rate. It seems the problem lies in the process itself.
The possibility of a process-related issue was also considered, but after observing for some time, it was found that the opening degree of the manual valves in the process flow remained unchanged, and both the liquid level and current were stable； But after running for a while, the current will fluctuate occasionally!
Is it the non-condensable gas content at the inlet, or is there water present?
Is it possible that there are occasional periods of inactivity, which leads to large fluctuations in traffic?； Is this medium completely liquid at room temperature, or is it a gas-liquid mixture? After how long of operation does this occur in shielded pumps? Has this happened before? Were there any changes in the process parameters during this period? Is there a bearing monitoring gauge or indicator light on the pump, and what is the wear condition of the bearings? You can refer to these aspects and analyze them further.
It depends on the pump conditions and the inlet and outlet valves
If the flow rate is too high, it will cause the overload switch of the motor to trip; if the flow rate is too low, the thermal switch in the motor of the shielded pump will break circuit. Check again to see whether the pressure at the pump inlet is sufficient to ensure that the material is fully liquefied and can be drawn in smoothly. If tripping still occurs without an obvious reason, it is likely that the graphite bearings of this shielded pump have reached the end of their useful life.