Technology automation pneumatic valve principle of knowledge

in order to successfully implement process automation, the most important thing is to make sure that the pneumatic valve can meet the special requirements of process medium and the pipe. Production process and process medium usually decide the type of the pneumatic valve, pneumatic valve core type and the structure of the pneumatic valve internal parts and pneumatic valves and materials.

pneumatic valve selection after the next consider the requirements of the automation is the selection of the actuator. Can simply press the two basic consider actuator pneumatic valve operation type.

. Rotary pneumatic valves ( Single rotary pneumatic valves)

this kind of pneumatic valves including: cock pneumatic valves, pneumatic ball valve, butterfly valve and air door or flap. Need this kind of pneumatic valve has required torque for degrees of rotation operation actuator

. Many rotary pneumatic valve

this kind of pneumatic valve can be rotating lift stem or rotate the lift rod, or they need more turn operation to drive the pneumatic valve to open or close position. This kind of pneumatic valves including: through pneumatic valve ( The pneumatic valve) , brake, pneumatic valve, pneumatic valve breaker, etc. As a kind of choice, output linear pneumatic or hydraulic cylinder or thin film actuator also drive the pneumatic valve.

at present there are four types of actuators, they can use different driving energy, able to operate various types of pneumatic valves.

. More than electric rotary actuator

power driven rotary actuator is the most commonly used, one of the most reliable type of actuator. Using single phase or three phase motor drive gear or worm gear and worm drive pneumatic stem nut finally, pneumatic stem nut make pneumatic valve rod movement pneumatic valve opened or closed.

many rotary electric actuators can be fast to drive the large size of pneumatic valves. From being damaged in order to protect the pneumatic valve, pneumatic valve installed in the end of the trip will limit switch to cut off the motor power, when the safety moment is over at the same time, the torque sensor will also cut off the motor power, position switch is used to indicate the pneumatic valve switch state, install clutch device of the handwheel mechanism can be manual pneumatic valve when power failure.
the main advantage of this type of actuator is all parts are installed in a casing, in the waterproof, dustproof, explosion-proof enclosure integrated with all the basic and advanced function. Main drawback is that when the power failure, pneumatic valve can only stay in situ, pneumatic valve can be achieved only using standby power system, fail safe position ( Fault on or off)

. Electric single rotary actuators

this is similar to the electric actuator rotary actuators, the main difference is the executive body of the final output is/biographies of sport. A new generation of electric single rotary actuator is a combination of most complex function of rotary actuator, such as: the use of entering type user friendly operation interface to realize the parameter setting and the diagnosis function.

single rotary actuator compact structure can be installed to the small size of pneumatic valves, the output torque can reach kg of rice, usually also should be required to power is small, they can install the battery to achieve a fail-safe operation.

. Fluid drive rotary or linear output more actuators

this type often used for direct operation of pneumatic actuator valve ( The pneumatic valve) Pneumatic valve and gate, they use pneumatic or hydraulic operating mode. Simple structure, reliable operation, easy to realize fail-safe operation mode.

people normally use electric rotary actuator pneumatic valve, pneumatic valve to drive the gate and globe only in the absence of power supply are considering to use hydraulic or pneumatic actuators.

. Fluid drive single rotary actuator

pneumatic, hydraulic single rotary actuator is very general, they do not need power and simple structure, reliable in performance. Their application has a very wide range of areas. Often the output from a few kilograms meters to tens of thousands of kilograms of m. They use a cylinder and transmission device converts linear motion orthogonal output, transmission device usually has: fork, gear and rack, lever. Pinion and rack in the whole travel within the scope of the same output torque, they are very applicable to small sizes of pneumatic valves, fork has high efficiency in journey starting point with high torque output is very suitable for large caliber of pneumatic valve. General installation solenoid pneumatic valve pneumatic actuators, locator, or position switch accessories to achieve control of the pneumatic valve and monitoring.
this type of actuator is easy to implement a fail-safe operation mode.