Interestingly, control valves employed in this way tend to wear out very quickly or else they are slow and expensive so that they can be made more durable. Anyb

Interestingly, control valves employed in this way tend to wear out very quickly or else they are slow and expensive so that they can be made more durable. Anybody working on this needs to hit that "good, fast and cheap" triple point. This is why wax motors are commonly used as valve actuators since the only calibrations are the wax mixture, the mechanical force applicator, and the thermal resistance of various components in contact with each other