Performance comparison of pneumatic control valve and hydraulic valve

(I) different energy sources

Pneumatic components and devices can adopt the method of centralized air supply from air pressure station to adjust the working pressure of their respective pressure reducing valves according to different requirements and control points. Hydraulic valves are equipped with oil return pipeline, easy to collect used hydraulic oil tank. Pneumatic control valve can be directly through the exhaust port to the compressed air into the atmosphere.



(ii) different requirements for leakage



Hydraulic valves are critical for outward leakage, but allow a small amount of leakage within components. For pneumatic control valves, except the gap seal valve, in principle, do not allow internal leakage. The internal leakage of Pneumatic Valve may lead to accident.



For pneumatic pipes, a little leakage is allowed; And the leakage of hydraulic pipeline will cause the system pressure drop and environmental pollution.







(3) different requirements for lubrication



The working medium of the hydraulic system is hydraulic oil, and there is no requirement for lubrication of the hydraulic valve. Pneumatic system medium for the air, the air is not lubricity, so many pneumatic valves need oil mist lubrication. Valve parts should be selected not prone to water corrosion of the material, or take necessary anti-rust measures.







(iv) different pressure ranges



Pneumatic valve operating pressure range is lower than the hydraulic valve. Pneumatic valve working pressure is usually less than 10bar, a few up to 40bar. But the working pressure of hydraulic valve is very high (usually within 50Mpa). If the pneumatic valve in excess of the maximum allowable pressure to use. Serious accidents tend to happen.







(v) different features of use

General pneumatic valve than hydraulic valve structure compact, light weight, easy to integrate installation, valve working frequency, long service life. Pneumatic valve is developing towards the direction of low power and miniaturization. Low-power Solenoid Valve with only 0.5w power has appeared. Can be directly connected with the microcomputer and PLC programmable controller, also can be installed with electronic devices on the printed circuit board, through the standard board connected with ventilation circuit, save a lot of wiring, suitable for pneumatic industrial manipulator, complex manufacturing assembly line and other occasions.

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