In the actuator, there are two parts: electric actuator and pneumatic actuator. Choosing the scotch yoke pneumatic actuator of the fork is helpful for us to carry out our work better. Now let's talk about the correct selection of the pneumatic actuator of the fork.
Taking pneumatic as an example, pneumatic can be divided into single action (spring reset) and double action. The screw rod is driven to rotate by compressed air.
1. Select the actuator according to the size of the gas source (instrument gas)

2. The output torque of the pneumatic actuator depends on the required torque of the valve.

The torque required for valve opening and closing determines how much output torque the electric actuator chooses. Usually, it is proposed by the user or selected by the valve manufacturer. As the actuator manufacturer, it is only responsible for the output torque of the actuator. The torque required for valve opening and closing normally is determined by the valve caliber, working pressure and other factors, but because of the difference in processing accuracy and assembly technology of the valve manufacturer, so it is necessary for the actuator manufacturer to select the output torque. The same specifications of valves manufactured by different manufacturers also have different torsion. Even the same specifications of valves manufactured by the same valve manufacturer have different torsion. Torsion selection of actuators is too small when the type is selected, which will result in failure to open and close valves normally. Therefore, pneumatic actuators must choose a reasonable torsion range. (Shanghai Jinzexin Pneumatic Valve Co., Ltd.)
2. Torque required to turn the valve is too small to move and too large to last long. Typically, a 30% allowance for torque is OK.
The difference is that when the actuator is selected too small, the valve can not be opened and closed properly, so the pneumatic actuator must choose a reasonable range of torsion.
This paper introduces the difference between electric actuator and pneumatic actuator in detail, which is helpful for us to choose the scotch yoke pneumatic actuator.