The hydraulic diaphragm metering pump is one of the piston diaphragm metering pumps. It is a new type of metering pump combined with the characteristics of the plunger metering pump and the diaphragm metering pump. The metering pump is in contact with the medium of the measured medium, and the driving part is a hydraulic plunger.

Hydraulic diaphragm metering pump uses the hydraulic oil to drive diaphragm evenly, which overcomes the disadvantage of too much stress on the diaphragm of the pump under the mechanical direct drive mode, and improves the diaphragm life and the upper limit of the working pressure. Below the diaphragm metering pump manufacturers tell you how to stabilize the metering pump flow and measurement accuracy.

In the diaphragm metering pump, the reciprocating movement of the plunger is transmitted to the diaphragm through the fluid of the hydraulic chamber between the plunger and the diaphragm. In order to maintain the normal movement of the diaphragm to hydraulic cavity closed space liquid (usually with hydraulic oil) the volume remains constant. So as to ensure the volume formed by the movement of the diaphragm is always equal to the stroke volume of the plunger pump to maintain the stability of the flow; but in the actual operation process of pump in the plunger seal will inevitably produce at the same time there may be a gas leak into the hydraulic chamber. In addition, when the volume of oil filling or discharge excessive line pressure rises accident it may change the hydraulic fluid, thus affecting the flow stability, reduces the measurement accuracy of the pump. In order to solve the problem of how to stabilize the measurement accuracy of metering pump metering pump flow, how stable, using the three valve device actually refers to the so-called the combination includes three functions of compensation, discharge and safety protection device or device supporting the hydraulic chamber, according to its principle is divided into different automatic compensation and forced compensation two three valve device.

The three valve device with automatic compensation is widely used in the diaphragm metering pump, and this compensation device can only be used when the height of suction is required. The three valve device consists of three separate Fujian (safety valves, vent valves and oil filling valves).