Double-screw pump failure
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The lubricating oil station for the main fan is equipped with 2 twin-screw pumps; the pressure at the pump outlets drops after a while before rising again. The inlet filters have been cleaned and no debris was found in them.
Typically, station filters are divided into pre-pump filters and post-pump filters; checking for issues with the pre-pump filter can provide some insight.
The inlet filter of the pump has been cleaned and there are no issues; the impurities detected in the fluid sample are also normal
Check the pressure control valve; this valve is typically used to control the flow back to the tank in order to regulate pressure. The control valve can operate in automatic or manual mode. If it can be controlled smoothly in manual mode, then it’s a problem with the control valve. A specialist in instrumentation can adjust the proportional-integral settings of the control valve so that the pressure can be controlled stably.
It was confirmed that all control valves are manual; the oil pressure rises gradually, and once it reaches a certain level, the curve drops in steps. Over and over again.
Is it related to the suppression of screw pumps?
Hello, first we need to identify the problem by separating the system from the screw pump, and then testing the inlet and outlet pressures of the screw pump. Run it for a while to see if those pressures change repeatedly! For reference!
Fluctuations in the pump outlet pressure are caused by insufficient oil supply. After checking that the filter is not clogged, examine the pipes and equipment ahead of the inlet for any leakage points. Small leakage points may not be visible to the naked eye, but they can allow air to enter, affecting the pump’s flow rate. It is recommended to conduct a pressure test on the pipes and equipment before the pump.
Check whether the oil level at the inlet is sufficient; a low oil level can also cause pressure fluctuations.
I’m not sure if there’s a secondary line at the oil pump outlet; generally, there is a solenoid valve used to control the pressure at the oil pump outlet. Check whether the solenoid valve activates when the pressure drops. However, it’s unlikely that the solenoid valve will happen to function in such a situation. If the oil pressure fluctuates, you can try removing the solenoid valve and using manual control to regulate the pressure