The application of Rack&Pinion pneumatic actuators in regulating valves

Rack&Pinion  pneumatic actuators  are used in many valves, such as pneumatic Control Valves. So, what is their function?

The thrust of the Pneumatic Actuator in the pneumatic control valve is selected based on the maximum allowable pressure difference when the valve is closed and the required maximum axial thrust calculated by the valve core area. For pneumatic valves, the initial force of the spring minus the initial pressure of the diaphragm is greater than the required thrust of the valve stem. For gas shut-off valves, the final pressure of the diaphragm minus the compressed spring pressure should be greater than the required thrust of the valve stem. Generally speaking, manufacturers produce a set of actuators according to the thrust level series, and then select the actuators that match the required thrust of the valve as needed.

The above is the application of Rack&Pinion  pneumatic actuators  in regulating valves.