Rotary actuators produce rotary motion, which is circular rotation around an axis. A pneumatic rotary actuator employs compressed air as a power source rather than electricity or compressed fluid to produce that motion. These actuators are available in a wide range of sizes and can be used for many different applications. Manufacturers usually construct their pneumatic rotary actuators out of durable, high-quality materials such as hardened aluminum or steel.
Pneumatic systems are widely used in several industries, in part because of the flexibility of compressed air and gases as energy sources. The pressurized air or gas in a pneumatic system offers great mechanical motion potential, lending them to applications in the construction and operation of various motors and valves. Pneumatic rotary actuators are among a class of pneumatic systems that rely on single compressed air sources.
Most low-profile pneumatic rotary actuators are designed for operating under payloads between one pound (0.44 kilograms) and 30 pounds (13.6 kilograms). The average one-pound (0.44-kilogram) pneumatic rotary actuator offers approximately five inch-pounds (0.56 Newton-meters) of torque. Thirty-pound (13.6-kilogram) models can offer around 250 inch-pounds (29 Newton-meters) of torque. Their small, compact design of low-profile models allows them to fit into tighter spaces.
While they do not offer compact design, heavy-duty pneumatic rotary actuators offer other significant benefits. They produce much higher torque output than smaller models do, and can accommodate much heavier loads. A high-output model can produce well over 15,000 inch-pounds (just under 1,800 Newton-meters) torque output.
Operating temperature range refers to the range of temperatures under which a pneumatic rotary actuator can effectively operate. Most pneumatic rotary actuator models can operate at temperatures between -35 degrees Fahrenheit (-30 degrees Celsius) and 180 degrees Fahrenheit (80 degrees Celsius). Standard rotations on most models are usually 45, 90 or 180 degree rotations.
Pneumatic rotary actuators can be designed with many different features. Proximity switches monitor end of rotation and adjustable flow control systems, allowing for smoother deceleration and maximum cycle times. Many pneumatic rotary actuators offer zero backlash systems for precision rotary positioning; certain models also include shock absorbers to ensure smooth deceleration.
Several manufacturers produce hybrid rotary actuators that employ pneumatics and hydraulics. Combining the simplicity of pneumatics with the smooth control offered by hydraulic systems, tandem rotary actuators are ideal for many applications. One end of a these actuators features closed-loop hydraulic controls while the other end provides pneumatic power.