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Metering pump selection and use of precautions

Release Time:

Jan 23,2024

According to the GB/T7782-2008 "Metering Pump" standard, "the flow metering accuracy of the pump under rated conditions and the maximum relative stroke length shall not be less than 1% of the soil". The ideal travel range of the pump when conveying general media, the piston metering pump and the hydraulic diaphragm pump are 30%~100%; The mechanical diaphragm metering pump is 40%~100%. When the range required by the process is ≤ 10%, the AC inverter can be added to reduce the speed and expand the range of use. The flow curve on the certificate is measured by the factory according to the normal temperature clear water performance test when leaving the factory, and the user should retest according to the actual working conditions and recalibrate the relationship curve between the stroke and the flow rate, so as to accurately adjust the flow rate during operation.

1. Metering accuracy and flow calibration:
According to the GB/T7782-2008 "Metering Pump" standard, "the flow metering accuracy of the pump under rated conditions and the maximum relative stroke length shall not be less than 1% of the soil". The ideal travel range of the pump when conveying general media, the piston metering pump and the hydraulic diaphragm pump are 30%~100%; The mechanical diaphragm metering pump is 40%~100%. When the range required by the process is ≤ 10%, the AC inverter can be added to reduce the speed and expand the range of use. The flow curve on the certificate is measured by the factory according to the normal temperature clear water performance test when leaving the factory, and the user should retest according to the actual working conditions and recalibrate the relationship curve between the stroke and the flow rate, so as to accurately adjust the flow rate during operation.

2. the installation height of the metering pump:

For normal temperature media with physical properties similar to clean water, the installation height from the center to the liquid level is about 2 meters, and the diaphragm pump is about 1 meter. When the pump cylinder cavity is filled with liquid medium, the suction performance of the pump can be improved, the installation height of the piston pump is 6~7 meters, the mechanical diaphragm pump is 2~3 meters, and the hydraulic diaphragm pump is 4~45 meters.

3. Problems that should be paid attention to in the metering pump pipeline system:
1. The inner diameter of the pump inlet pipe should not be less than the inner diameter of the pump valve suction. The inlet pipeline of the pump should be shortened as much as possible and the resistance parts such as elbows and valves should be reduced, and the "Q" shaped arrangement of upward bending should not be allowed to avoid gas storage.

2. In order to ensure the safety of the pump and pipeline system, a safety valve should be set on the outlet pipeline.
3. Due to the large pulsation of the flow output of the most pump, it is recommended that the outlet is equipped with a buffer or a multi-metering system with less pulsation. When the inlet flow rate is 300, it is recommended that the inlet side should also be equipped with a buffer.

4. When the outlet pressure is close to or lower than the inlet pressure, a back pressure valve should be set on the outlet pipeline. Or set up a pressure stabilizing device on the inlet pipeline.

4. Precautions for metering pump ordering:
1. When ordering metering pumps, in addition to conventional products, the "metering pump teaching form" should be filled in as an attachment to the contract to ensure that the selected model meets the requirements of users.

2. If the flow rate of the liquid containing mud or solid particles is conveyed, it will change and may cause damage to the pump.

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