Reasons for flow fluctuations in diaphragm pumps
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The last edit to this post was made by *ao*ao1970 on 2018-3-16 at 10:16. As the title indicates, this device uses dual diaphragm pumps with variable frequency control to regulate flow rate; it can operate normally, but the flow rate experiences periodic fluctuations at irregular intervals. The medium used is similar to mineral oil, and the maximum fluctuation in flow rate is 0.2 KG/H. The flow rate was once adjusted by using the on-site stroke knob, and it seemed stable for a while, but now fluctuations have appeared again. Dear experts, is it a fault with the knob used to adjust the stroke on site? It hasn’t been opened for inspection, so everything is uncertain.
Did the vibration loosen the adjustment knob? The adjustment handle has a locking mechanism; you can check it.
The answer above is correct. Another possibility is that impurities affect the inlet and outlet sides, causing the ball valve to fail to seal properly, or that the output signal from the variable frequency motor is unstable
This requires checking step by step, as there are many potential issues with hydraulic diaphragm pumps. Problems that occur occasionally like this are hard to resolve, because once something is done, it takes some time to determine whether it has been done properly or not...
It is difficult to diagnose problems with pumps of this type; the mechanical piston section, the hydraulic system, check valves, and the entire conveying system all affect the actual flow rate.
I suspected that the ball valves at the pump inlet and outlet were not sealing properly; they were just replaced during maintenance last year. Moreover, we have three pumps, so it’s unlikely that all of them are faulty. The output signal of the variable-frequency motor has been measured and remains stable without a load connected.
The machinery, pistons, and hydraulic systems were not inspected; in other words, the pumps were not disassembled. All three of our pumps exhibit this issue.
I suspect it’s in the pump itself, but I’m not entirely sure; the key point is that it doesn’t have a serious impact on production, so no one pays attention to it.
Let’s check the entire system; I once encountered a situation where the pressure-relief valve on the atmospheric tube got stuck
You are referring to the container for storing the medium, right? I dealt with this issue from the start – the nitrogen sealing pressure was set at 40-60 KPA, and the pressure remained stable throughout.
From the appearance, it seems that the stroke adjustment knob isn’t locked