PNEUMATIC SOLENOID VALVE1

There are both rotary and linear pneumatic valve actuators. Linear designs use a sliding stem to adjust the degree of closure. They are commonly used with diaphragm, pinch, angle-style, and globe valves. By contrast, rotary-type actuators move valves a quarter-turn (90 degrees) to open or close them. Rotary motion actuators are often used in conjunction with butterfly, ball, and plug valves.

Pneumatic valve actuators employ a variety of actuation methods. Diaphragm-style actuators are most commonly used with linear designs, but they can also be used with rotary motion designs that include some form of linkage from linear to rotary motion.

Another approach is used in a rack-and-pinion design. These actuators typically transfer the linear motion of a piston cylinder to rotary motion. Oftentimes, Scotch yoke devices are employed to change the linear motion to rotary motion. These rack-and-pinion actuators can also be used to adjust manually-operated valves.

Vane actuators are used exclusively with rotary motion valves. Link and lever actuators make use of a slotted lever that is attached directly to the valve shaft. This lever transfers the linear motion of either piston cylinder or diaphragm actuators to rotary motion.

The CV3000 series of pneumatic check valves employs an innovative seat/seal concept that serves to extend the life of the soft seal. These check valves are suited for use in both hydraulic and pneumatic systems. These units are popular because of their ability to withstand the negative effects of pulsing, vibration, and shock.

Different types of seals can be used to properly handle either gases or liquids. This series of pneumatic valves feature a standard cracking pressure of 1 psi to keep pressure drops to a minimum. Sizes range from 1/4-inch to 2-inches.

Pneumatic solenoid valves convert electrical signals into pneumatically-powered linear action. These valves in both 3/2 and 5/2 designs. The 3/2 solenoid valve is used to control sprung or single-acting cylinders. When the electrical impulse occurs, pressure is applied to just one side of the cylinder and the spring's force causes movement.

By contrast, the 5/2 design results in pressure alternating between one side of the cylinder and the other. Such solenoid valves typically are used to control double-acting cylinders with electrical signals.

A manual pneumatic actuator moves a valve to a desired position without any outside power source. Instead, they make use of a variety of different mechanisms that all produce the same result. That is, they convert low input torque to higher output torque. Such valves may make use of chain wheel, hand wheel, or lever-type mechanisms. Such manual pneumatic valve actuators use worm gears to transmit motion between right-angle axes that do not intersect. Another type of manual pneumatic actuator cause rotary motion valves to move a quarter-turn to open and close. Such valves include ball, butterfly, and multi-turn designs.

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