Actuators can be classified into two types based on their motion. Two primary actuator types are
Example of a rotary actuator is an electric motor, which is an actuator used to converts an electrical signal into a rotating motion of its shaft, where as Linear actuators produce a non-rotary motion, such as a sliding motion, or piston motion in response to an input signal.
The distinction between a linear actuator vs rotary actuator is somewhat abstract. However, as a linear actuator can be built using a normal rotary motor as its basis, and vice verse. In each case, the initial motion produced is mechanically converted to the other motion-type. Linear actuators can be electrically operated or pneumatic. The pneumatic diaphragm actuator is more popular and used to actuate linear valves such as globe, three-way (diverting or mixing) and angle valves. Pneumatic linear actuators have the simplest construction and provide very precise control of flow. There are several factors that need yo be considered while choosing a linear actuator vs rotary actuator
The main power source of Pneumatic Actuator is Compressed Air or Gas. There are two types of pneumatic actuators, the diaphragm type and the piston cylinder type actuator is a linear actuator. They are used on linear or quarter-turn valves. Air pressure acts on a piston or bellows diaphragm creating linear force on a valve stem.
Rotary Actuator also known as quarter-turn actuator produces torque to provide rotary motion to operate a quarter-turn valve. While majority of the applications prefer pneumatic actuators due to their light weight and rugged structure the choice between linear vs rotary actuator depends on several factors. There are a few advantages and disadvantages when selecting a linear actuator vs rotary actuator. Moreover they are cost effective and highly reliable. Pneumatic actuators are used in a potentially explosive environment as well. Also the failsafe action of pneumatic actuators is system inherent. A pneumatic actuator may be designed to be spring-closed or spring-opened, with air pressure overcoming the spring to provide movement. A double acting actuator uses air applied to different inlets to move the valve in the open or close direction.