Comparison of pneumatic control valve and hydraulic valve

(1) Different energy used

Pneumatic components and devices can adopt the method of centralized air supply from the air compressor station, and adjust the working pressure of the respective pressure reducing valve according to the different use requirements and control points. The hydraulic valves are equipped with oil return lines to facilitate the collection of used hydraulic oil in the oil tank. The pneumatic control valve can directly discharge the compressed air to the atmosphere through the exhaust port.

(2) Different requirements for leakage

The hydraulic valve has strict requirements for external leakage, but a small amount of leakage inside the component is allowed. For pneumatic control valves, except for gap-sealed valves, internal leakage is not allowed in principle. The internal leakage of the pneumatic valve may cause an accident.

For pneumatic pipes, a small amount of leakage is allowed; while the leakage of hydraulic pipes will cause 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 hydraulic valves; the working medium of the pneumatic system is air, which has no lubricity, so many pneumatic valves require oil mist lubrication. The valve parts should be made of materials that are not easily corroded by water, or necessary anti-rust measures should be taken.

(4) Different pressure ranges

The working pressure range of pneumatic valves is lower than that of hydraulic valves. The working pressure of pneumatic valve is usually within 10bar, and a few can reach within 40bar. But the working pressure of hydraulic valve is very high (usually within 50Mpa). If the pneumatic valve is used at a pressure exceeding the maximum allowable pressure. Serious accidents often occur.

(5) Different usage characteristics

Generally, pneumatic valves are more compact and lighter than hydraulic valves, and are easy to integrate and install. The valve has a high working frequency and a long service life. Pneumatic valves are developing towards low-power and miniaturization, and low-power solenoid valves with a power of only 0.5W have appeared. It can be directly connected with a microcomputer and PLC programmable controller, or it can be installed on a printed circuit board together with electronic devices. The gas-electric circuit is connected through the standard board, which saves a lot of wiring. It is suitable for pneumatic industrial manipulators and complex manufacturing. Occasions such as assembly line.

Post time: Dec-29-2021