What are the correct ways to choose a pneumatic actuator?

When we need pneumatic actuators, will choose relative suitable pneumatic actuators, cost-effective pneumatic actuators, so first of all to understand the type of actuator, the actuator can be divided into pneumatic actuators and electric actuators, these two kinds are commonly used  when we choose the pneumatic actuator.

And then we have to choose actuator according to the pressure of the air supply , the torque required to turn the valve, too small can't open the valve , too big valve life is not long. Generally add 30% safety factor is  OK.

Second, we have to assess the installation platform,there are standard for  choosing actuator in each environment, we have to find the corresponding standard according to the valve

Take electric actuator as an example, there are switch type for electric actuator. Passive contact type and adjustable type. We can only according to the valve flow size for sizing.