Main points of type selection of pneumatic control valve
Pneumatic control valve refers to the pneumatic system to control the flow of air pressure, flow and flow direction, and to ensure that pneumatic actuators or institutions work properly all kinds of pneumatic components. Pneumatic control valve structure can be broken down into the valve body (including the valve seat and valve hole, etc.) and valve heart two parts, according to the relative location of the two, there are normally closed and normally open two. Valve from the structure can be divided into: cut-off type, slide column and slide valve type three valves.
Comparison of pneumatic control valve and hydraulic valve(I) the energy used is differentPneumatic components and devices can use the air compressor station centralized gas supply method, according to the use requirements and control points to adjust the working pressure of each reducing valve. The hydraulic valve is provided with a return line to facilitate the collection of the hydraulic oil used by the tank. The pneumatic control valve can direct the compressed air to the atmosphere through the exhaust port.(two) the requirement of leakage is differentThe hydraulic valve is strict with the outward leakage, but a small leak inside the component is permissible. For pneumatic control valves, in addition to the clearance seal valve, in principle, does not allow internal leakage. The internal leakage of pneumatic valves causes the risk of accidents.
For pneumatic pipes, a little leakage is allowed, and the leakage of the hydraulic pipe will cause pressure drop and pollution to the environment.(three) the requirement of lubrication is differentHydraulic system of the working medium for hydraulic oil, hydraulic valve does not exist on the lubrication requirements; pneumatic system of the medium of work for the air, the air is no lubrication; therefore, many pneumatic valves need oil mist lubrication. The valve parts shall be made of materials which are not subject to water corrosion or take necessary rust preventive measures.(four) the pressure range is differentThe working range of the pneumatic valve is lower than that of the hydraulic valve. Pneumatic valve working pressure is usually less than 10bar, a few can reach less than 40bar. But the hydraulic valve has high working pressure (usually less than 50Mpa). If the pneumatic valve is used under the maximum allowable pressure. Accidents often happen.(five) the use of different characteristics;General pneumatic valve than hydraulic valve structure compact, light weight, easy to integrated installation, valve work frequency, long service life. Pneumatic valve is in the direction of low power and miniaturization. Low power solenoid valve with 0.5W power has appeared. With computer and PLC programmable controller connected directly, can also be installed on a printed circuit board with electronic devices connected through standard gas electric circuit board, save a lot of wiring, suitable for pneumatic manufacturing assembly line of industrial manipulator, complex etc..
