Question one: metering pump outlet pressure is not the case, the actual flow of the pump is much larger than the rated flow, and adjust the flow, the flow basically no change. Solution: Increase in the metering pump outlet back pressure valve, back pressure valve in the steady pipeline pressure at the same time, you can stabilize the metering pump flow to ensure measurement accuracy. Question two: After the pump, the export pipeline vibration more powerful. Solution: install a pulse damper at the metering pump outlet (if there is no pressure at the metering pump outlet, it is best to use the backpressure valve at the same time). Due to the inertial resistance at the discharge end, the pump will start pulsating impact force . This is a peculiar phenomenon of reciprocating pumps, caused by the sudden acceleration of the liquid in the pipe. Pulse damper can effectively prevent the pipeline caused by pulse vibration.