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A pneumatic control valve refers to various pneumatic components that control the pressure, flow rate, and direction of the gas flow in a pneumatic system, ensuring the normal operation of pneumatic executing components or mechanisms. The structure of a pneumatic control valve can be decomposed into two parts, the valve body (including the valve seat and valve bore) and the valve core, and it can be classified into two types, normally closed and normally open, based on the relative position of the two parts. Valves can be further divided into three types, namely, globe valves, slide valves, and diaphragm valves, based on their structure.
A pneumatic control valve refers to various pneumatic components that control the pressure, flow rate, and direction of the gas flow in a pneumatic system, ensuring the normal operation of pneumatic executing components or mechanisms. The component that controls and regulates the compressed air pressure is called a pressure control valve.
Pneumatic components and devices can use the method of centralized air supply from an air compressor station to adjust the working pressure of their respective pressure relief valves according to usage requirements and control points. Hydraulic valves are equipped with oil return pipelines to facilitate the collection of used hydraulic oil in the oil tank. Pneumatic control valves can directly release compressed air into the atmosphere through an exhaust port.
The requirements for external leakage of hydraulic valves are strict, while the internal leakage of components is allowed to a small extent. In principle, internal leakage is not allowed in pneumatically control valves except for those with clearance seals. Internal air leakage in pneumatic valves can pose a safety hazard. For pneumatic pipelines, a small amount of leakage is allowed, while leakage in hydraulic pipelines causes a drop in system pressure and environmental pollution.
The working medium of hydraulic systems is hydraulic oil, and hydraulic valves do not have a lubrication requirement; the working medium of pneumatic systems is air, which has no lubricity. Therefore, many pneumatic valves require mist lubrication. The valve components should be made of materials that are not susceptible to water corrosion or take necessary anti-rust measures.
The working pressure range of pneumatic valves is lower than that of hydraulic valves. The working pressure of pneumatically control valves is usually within 10 bar, with a few reaching 40 bar. However, the working pressure of hydraulic valves is very high (usually within 50 MPa). If a pneumatically control valve is used beyond its maximum allowable pressure, serious accidents can occur.
Generally, pneumatic valve has a compact structure and is lightweight compared to hydraulic valve. It is easy to integrate and install, has a high working frequency, and has a long service life. Pneumatic valve is developing towards low power consumption and miniaturization, and low-power electromagnetic valves with a power of only 0.5 W have been developed. It can be directly connected to microcomputers and PLC programmable controllers. It can also be installed on printed circuit boards with electronic components, saving a lot of wiring. It is suitable for pneumatic industrial robots, complex production assembly lines, and other occasions.
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