The valve that changes the direction of air flow by changing the spool by air pressure becomes a pneumatic control reversing valve, which is called air operated control valve. The valve works safely and reliably in flammable, explosive, humid, dusty, strong magnetic field, high temperature and other harsh working environments, as well as in environments that can not be controlled by solenoid valves. But the switching speed of the air operated control valve is slower than that of the solenoid valve.
