Pneumatic pump which good, in the gear pump, due to the gear pump displacement fixed structure limit, generally believe that gear pump can only be used as a constant flow hydraulic source. Large flow pump and small power single pump adopt combined unloading components. It is generally believed that the gear oil pump can only be used as a constant flow hydraulic source because both of them are limited by the constant displacement structure, while the gear oil pump is limited by the constant displacement structure.

Pneumatic pump quotation, can only be used as a constant flow hydraulic source. The scheme of accessory and screw connection combination valve is very effective to improve its function, reduce system cost and improve system reliability. Therefore, the performance of gear pump is close to that of piston pump with high price and complexity. At this time, the large flow pump circulates the flow from the outlet to the inlet, thus reducing the output flow of the pump to the system and reducing the power of the pump to slightly higher than the value required to work under high pressure.

The wastage rate depends on the ratio of UN unloaded emissions to total emissions at this time. Compound or threaded unloading valve can reduce or even eliminate the leakage of pipeline, orifice, auxiliary parts and so on. If the control valve is directly installed on the pump, the pipeline between the pump and the directional valve can be saved, so as to control the cost. Reducing the number of pipe fittings and connectors can reduce leakage and improve working reliability.

And the installation of valve can reduce the pressure of circulating circuit and improve its working performance. The guided (pneumatic or hydraulic) discharge valve is an improvement on the operation method because it can be controlled remotely. Its great progress is the solenoid valve controlled by electric or electronic switch. It can not only be controlled remotely, but also controlled automatically by microcomputer. This simple unloading technology is often considered as a good way of application.

Manually operated unloading components are often used in circuits that require large flow to move quickly and large flow to control and reduce flow, such as fast telescopic boom. When the unloading valve has no operation signal, the circuit always outputs large flow. For the normally open valve, the output flow of the circuit is small under normal conditions.