A valve actuator is a mechanism for closing and opening a valve. The valve is generally regulating the flow of liquid, gas, or other materials traveling through a hose, line, or pipe. There are several kinds of valve actuators; these include: pneumatic and electric, the two most common actuators found on valves. Most actuators are rotary (ball valves and butterfly valves) but, may involve and/or incorporate an entire host of actuator movements, such as linear (plug valves),or diaphragm.
Pneumatic Valve Actuators
"Pneumatic" typically refers to air power, though other gasses are sometimes employed, and are specifically used on linear and quarter-turn valves. The air pressure moves a piston or a diaphragm bellows to create linear or rotary force on the valve stem. There are a variety of pneumatic valve actuators; some use springs to allow for a fail position (fail open, or fail close) and others are "double-acting" (air to open, air to close). The air supply for pneumatic valves needs to be clean and dry to assure the actuators will last for a long time. When engineering an actuated valve, one must know the amount of air pressure available for actuation to properly size the actuator.
Electric Valve Actuators
An electric valve actuator is normally a “fail-in-place” actuator (sometimes called "lock-ups"). That is, these actuators maintain the same percent of travel if they lose their supply of power. In other words, in the case of loss of power, the valve will stay in the same position it was in prior to loss of power. Fail-safe electric valve actuators are certainly available, although they are typically more expensive. The two options for fail-safe actuators are spring return or battery back-up. Typically, driven by three-phase, AC motors, (although 24VDC and other specifications are available) these actuators are smooth, quiet, and dependable.
Valve Actuators for Sale
Here at ValveMan.com, we do valves, and only valves. If you're shopping for a valve actuator that's a little more complicated than an ordinary manual ball-valve, particularly something more industrial, then you'll be glad to know that we've been in the business for over 50 years selling industrial valves. Unlike some of our competitors (the larger online retailers who tend to sell everything imaginable) we are experts in the valve field. If you need a valve, a valve part, a valve actuator, or anything to do with valves, discover ValveMan.com. ValveMan is your premier valve store. It's what we know, and we know them better than anybody else.