What is a Valve Actuator?

A valve actuator is the device that “actuates,” or moves, a valve open or closed. It attaches to and works in conjunction with two parts: the valve body and the valve pilot.

How Does an Actuator Work?

In a Kimray High Pressure Control Valve, the pneumatic actuator is comprised of several parts. These include a bonnet, adjusting screw, spring, and motor valve diaphragm, breather plug, yoke, upper stem, coupling block, and travel indicator. This assembly—sometimes referred to as a valve’s “Topworks”—is bolted directly on top of the valve body.

The diaphragm pressurizes when the actuator receives a pneumatic signal from a pressure pilot. As a result, it actuates, driving the valve open or closed, depending on its configuration. (Note: The action in this particular valve can be reversed.)

Valve Pilot and Actuator

The signal to perform actuation must come from an outside source. This is provided by one of the following:

Pneumatic Actuator and Electric Actuator

In the case of a pneumatic actuator on a High Pressure Control Valve installed on a separator to hold back pressure. This signal is provided by a pressure pilot. The pilot on this package senses upstream pressure. Then it sends an output signal (gas) through tubing into the actuator of the valve.

In the case of an electric actuator on a High Pressure Control Valve installed in the same application, the signal is provided by an electric pilot. The electric pilot receives an analog 4-20mA signal from a sensor, which represents a process condition. The pilot conditions this signal and sends a corresponding signal (4-20mA) to the electric actuator of the valve.

If you have further questions or would like help setting up your actuator or other control equipment, reach out to your local Kimray store or authorized distributor.