Questions about mass flow meters

As long as the operating conditions of the flow meter are met, there will be no problem; since your outlet valve is not open and there is no flow in the pipeline, the measured density remains constant. At least a return pipe should be added

Installing a densitometer on the reflux line can

I also think there should at least be a return pipe, and the mass flow meter is too close to the pump

The main concern raised by the poster regarding this issue is whether the mass flow meter installed at the pump outlet can operate under pressure with the valve downstream of the meter closed, while the pump is running. Based on the measurement principle of mass flow meters, it is necessary to keep them away from sources of vibration; vibrations at the pump outlet are inevitable, and they may affect the meter’s measurements, resulting in fluctuations in the values. The operator controls the pump outlet valve by referring to the density value displayed by the mass flow meter. Why not add a separate densitometer? Place a valve in front of the flow meter, add a return pipe in front of the valve, and install a densitometer on the return pipe. In this way, when the pump is running, the valve in front of the flow meter is closed, so it has no effect on the flow meter.

Now that the pump has stopped, the density of the mass flow meter still hasn’t changed. Could it be that the prolonged pressure buildup has caused damage to the flow meter?

As long as there is no overpressure, it has no impact

It has no impact on the flow meter; the key point is that even if there is gas inside, you can’t push it out

This procedure isn’t correct, right? Normally, the pump should be started first before the control valve is opened, and the flow meter should remain in use throughout