Valve actuators are devices that attach to valves. The actuators, operated by an outside power source, adjust the valves to a desired position. Types of basic valve actuators include electric, pneumatic, electro-hydraulic, hydraulic and manual. The actuators are used for the automation of industrial valves found in manufacturing plants, wastewater treatment plants, refineries and power plants.
There are many types of valve actuators used in plants. Electric actuators operate by employing a single-phase, three-phase or direct current motor. When the motor receives a signal, it drives a gear set that positions the valve in the desired location. Pneumatic actuators, electro-hydraulic actuators and hydraulic actuators convert air pressure or fluids into linear or rotary motion. These types of actuators allow valve positioning from remote locations and are ideal for hazardous environments.
Manual valve actuators operate by using a hand wheel or lever to drive a series of gears to position the valve. Manual valve actuators do not require an outside power source. They operate by hand in non-hazardous environments.
Valve actuators incorporate emergency fail-safe methods. In the event of power failure or loss of control signal, the actuators will open or close. Valve actuators are designed to certain specifications for use in combustible or explosive atmospheres, such as in mining, oil and gas exploration, refineries and pipelines. For these types of atmospheres, the actuator is enclosed in a flameproof enclosure. This special housing prevents ignition sparks, which could ignite combustible mixtures from leaving the housing.
Automobile manufacturers incorporate valve actuators in the automobiles they produce. The actuators operate choke systems on carburetors to aid the engine when starting in cold conditions. Different types of actuators found in automobiles include solenoids, starter motors and vacuum valve actuators.
Valve actuators provide a valuable service in many aspects of everyday life. A common electronic actuator valve found in the home is the solenoid valve in an automatic dishwasher. Other examples of actuator valves found in the home are kitchen and bathroom faucets, toilets and water spigots, which are examples of manual actuator valves.