Knowledge of electric and pneumatic valves
1. The essential difference between electric valves and pneumatic valves lies in the use of different driving devices, that is, actuators, while there is no difference between the regulating valve itself. Matching with different actuators is mainly required by working conditions, such as chemical and other explosion-proof occasions. Pneumatic valves are most used because of high safety requirements and low price. They can be connected to the bus with intelligent positioner, and the control mode is also simple.
2. The action force distance of the pneumatic valve is larger than that of the electric valve. The opening and closing speed of the pneumatic valve can be adjusted. The structure is simple and easy to maintain. During the action process, it is not easy to be damaged due to jamming due to the buffer characteristics of the gas itself, but there must be a gas source, and its control system is also more complex than that of the electric valve. Pneumatic valves are sensitive, safe and reliable. Many factories with high control requirements set compressed air stations for pneumatic instrument control elements. The power source of the pneumatic valve actuator is the air source, which comes from the air compressor. The positioner is used to convert the electric control signal into pneumatic control signal to drive the pneumatic actuator for valve position adjustment.
3. The power source of the electric valve actuator is the power supply. If the circuit board or motor fails, sparks are easy to occur, so it is generally used in occasions with low environmental requirements and no danger. Compared with the regulation performance of the pneumatic actuator and the electric actuator, the pneumatic actuator has faster response speed and can be more suitable for regulation conditions, Therefore, the manufacturers of regulating valves also produce pneumatic actuators to match them.
4. The adjustment response speed of the electric actuator is not fast enough, and the pneumatic actuator on the control valve is more applied than the electric actuator.