TECHNICAL SUPPORT


Common Problem

Common problems and solutions for metering pump piping systems

 

Question 1: When there is no pressure at the outlet of the metering pump, the actual flow rate of the pump is much larger than the rated flow rate, and when the flow rate is adjusted, the flow rate basically does not change.

 

Solution: Install a back pressure valve at the outlet of the metering pump; while stabilizing the pipeline pressure, the back pressure valve can stabilize the flow of the metering pump and ensure metering accuracy.

 

Problem 2: After turning on the pump, the outlet pipeline vibrates greatly.

 

Solution: Install a pulse damper at the outlet of the metering pump (if there is no pressure at the outlet of the metering pump, it is best to use it together with the back pressure valve). Due to inertial resistance, the fluid at the discharge end will produce a pulsating impact force on the pipeline at the moment the pump starts running. . This is a unique phenomenon of reciprocating pumps and is caused by sudden acceleration of the liquid in the pipeline. Pulse dampers can effectively prevent pipeline vibrations caused by pulses.

 

Problem three: After turning on the pump, liquid cannot be pumped out or the pressure cannot be pumped up, and the flow rate is unstable.

 

Solution: There are many reasons why the metering pump cannot pump out liquid, such as diaphragm damage, pipeline blockage, etc. When the motor and plunger are working normally, the reason why the metering pump cannot pump out the pressure is usually because there are impurities in the liquid, causing the metering pump to fail. The inlet and outlet valve balls and valve seats cannot be completely sealed, so the pressure cannot be pumped up and the flow rate is unstable. Therefore, it is recommended to install a filter to prevent impurities from entering the pipeline.

 

Question 4: (a) The liquid in the storage tank still flows out from the pump head after the pump is stopped. (b) Siphoning occurs when the metering pump is adding medicine.

 

Solution: Install a back pressure valve at the outlet of the metering pump; gravity flow is generally caused by the liquid level in the liquid storage tank being higher than the pump head of the metering pump, so gravity flow occurs. The back pressure valve can effectively prevent gravity flow or siphonage.

 

Question 5: The pressure fluctuation in the pump outlet pipeline is relatively large, which affects the measurement accuracy and the use of precision instruments.

 

The solution is to install a pulse damper near the pump outlet, preferably in conjunction with a back pressure valve. Installing a pulse damper with appropriate volume can reduce pulses by more than 90%, allowing the liquid behind the damper to flow out smoothly.