The reliability of the cut-off valve?

Cut-off valve is one of the automation system of actuators, pneumatic diaphragm actuator by a more spring or floating piston actuators and pneumatic control valve, the reception of the regulating instrument signal, fluid control technology of the pipe on the cut, or switch. It has a simple structure, sensitive reaction, reliable operation, etc. Can be widely used in petroleum, chemical, metallurgical and other industrial production. Pneumatic cut-off valve of air required by the compressed air filter, flowing through the valve body is supposed to be free of impurities and particles of the medium of liquid and gas. According to allow the pressure differential, medium characteristics and process piping requirements, can choose single seat, sleeve, tee cut-off valve. The reliability of the cut-off valve 1, sealing, cutting effect is good, but is not suitable for particle medium, once cut, leakage will increase sharply. Therefore, as far as possible when conditions permit choose hard seal. O hard sealing ball valves can reach 10 - 5, triple eccentric butterfly valve up to null leak. 2, considering the seal wear resistance: in addition to choose hard seal, 10 - to leakage requirement More than 4 cut type pneumatic control valve, must wear resistant alloy surfacing in order to improve the wear resistance, erosion resistance, tear on the seal ability, improve the life of the valve. 3, cutting of high temperature medium pneumatic regulator assembly at room temperature, working under high temperature, the temperature changes a few baidu. Thermal expansion will change when assembling sealing pressure ratio is established. Card, too tight, the sealing surface movement when they grazed and seriously, strain; Too loose, sealing pressure is not enough, two kinds of conditions can leak has increased dramatically. The best solution is to use resilient seated to absorb the difference caused by the change. Usually there are three kinds of elastic solution: (1) spring loaded; (2) wafer type flexible metal ring; (3) and flexibility of resilient seated. As well as the latter is best, flexible thermal expansion, overcome another stiffness and surfacing wear resistant alloy to improve the reliability.