Rack and Pinion Valve Actuators - A Look Inside | CTI Controltech Industrial Combustion and Process Control Blog

Here is an animation of the assembly components of a Flowserve Automax Supernova rack and pinion actuator with a transparent look inside to see its operation.

The critical components to take note of during the video are:

body
pinion gear
o-ring seals
piston "racks"
travel adjustments
end caps and seals
housing bolts

At the end, the video allows you to see the operation (in both directions) of the rack and pinion actuator as it is pressurized from either port. The pinion gear rotates 90 degrees, which in most applications, is used to open or close a valve or damper.