A metering pump is a specialized pump used for measuring and transporting liquids. Most metering pumps use plunger pumps and diaphragm pumps(See reciprocating pump)And the structure of gear pumps, because they can maintain a constant flow rate regardless of discharge pressure. There are two types of metering pumps: adjustable flow and non adjustable flow, with the former having a wider applicability.

Advantages of metering pumpsMainly adjusted by changing the stroke length, such as changing the crank radius, the position of the stop point after the plunger returns, and the gap between the plunger rod and the crosshead connection. The flow rate can also be adjusted by changing the number of repetitions or using both methods simultaneously. Although the travel length can be adjusted from zero to the maximum value, in order to ensure measurement accuracy, it is generally limited to30 ~ 100%.

Advantages of metering pumpsIt is a single cylinder single action reciprocating pump with the highest pulsation rate of flow pressure. In order to eliminate pulsation, increase the stability of flow pressure, reduce pipeline vibration, and minimize the impact on process performance, it is generally recommended to install an accumulator with pulsation reduction function at the discharge port of the reciprocating pump. Sometimes, in order to improve the suction performance of the inlet, an accumulator is also installed at the inlet. From the perspective of reducing pulsation, the larger the volume of the accumulator, the better, but the larger it is, the less economical it is, so it should be controlled within a certain range. The volume selection of the accumulator for a metering pump is generally as follows: metering capacity per stroke(ml)multiply26, can be reduced90%Minimum volume of pulse damper required for pulsation(ml).

According to the structural form of the hydraulic end, metering pumps can be divided into plunger metering pumps and diaphragm metering pumps. Among them, plunger metering pumps are divided into ordinary valve pumps and valve free pumps. Diaphragm metering pumps are divided into mechanical diaphragm metering pumps, hydraulic diaphragm metering pumps, and bellows metering pumps. Metering pumps can be divided into electromagnetic driven metering pumps and motor-driven metering pumps according to their driving forms. In addition, there are metering pumps that use hydraulic drive, pneumatic drive and other driving forms.