Actuator and accessory are mechanical or electro-mechanical devices that provide controlled and sometimes limited motion or Positioner to be operated by electricity, by hand, or by various fluids such as air, hydraulics , etc. The two basic motions are linear and rotational. Linear actuators convert power to linear motion, typical for Positioner applications, and often have a push and pull function.
Some linear actuators are not powered and hand operated by using a rotary knob or hand wheel. The rotary Actuator and accessory converts the power to provide rotational motion. A typical use is the control of different valves such as ball or butterfly. Each actuator has different versions for electrical configurations and has many designs and sizes depending on the application. Linear actuators provide push and pull motions with rigid lugs.
Actuator and accessory usually incorporate motors, cylinders, or other moving devices to produce linear rotation or translation. Assembled and pinion arrangements, ball screws, and other types of transmission components connect the motor, etc. to the load.
Actuators are separated by motion and power. Linear actuators produce push / pull action. Rotary Actuator and accessory produce rotary motion. In many cases, the linear actuator starts with a rotary motor – a typical motor – which rotates into linear motion via a screw or similar device. The reverse is also true: many rotary actuators can start with linear devices such as hydraulic cylinders that produce circular motions through arrangement of racks and gears.
Actuators are widely used to operate valves remotely. A valve equipped with so-called control valves. (See the Valve Buying Guide for a discussion of control valves.) A typical actuator for a global valve needs to be capable of rotating the valve through multiple turns between opening and closing.
Typically, a global valve actuator will consist of an electric motor that drives the gear. Which in turn rotates a nut with the threads of the valve body. Flip-flops such as ball valves usually use pneumatic actuators to push and pull the gearboxes through the gears to allow rotation of the ball, butterfly etc. In short, Valve actuators correspond to the design of the valve they are intended to operate.
Actuators are also used in many linear motion applications where air is not available to control cylinders. Or need more force from the compact design. An abnormal linear drive uses a line that when straight forms a rigid length but can bend around the rudder to get its motion. Other linear motion Actuator and accessory use a belt, a screw, or a rack and pinion to achieve push / pull operation. Linear and rotary actuators generally use coil motors directly.
Selecting actuators supported requires knowing the parameters such as load, stroke length, duration, etc. Many of these parameters have speed limits and force. And narrow the selection according to this way can bring appropriate technology. Other considerations include the types of services available. Hydraulic transmission provides great power at small sizes but requires a hydraulic pressure source.
The actuator uses the available air of the plant but there is a balance made due to the larger size for the equivalent force. Electric actuators have better control and less leakage advantages. Which are advantageous in clean room settings and more economical in the long run. Electric actuators tend to have higher initial cost. They also have the advantage of being installed outdoors, where air systems can freeze.
Pneumatic actuator control valves fall into two camps: dual operation and spring return. Dual action means that air pressure will move the valve in both directions. Spring back means that a spring is used once that the air pressure must pass to open (or close) the valve. It makes a difference how the valve will behave when air pressure is lost. Spring return valves will return the valve to the unused state when the air pressure is lost. Hydraulic valve drives can be fitted in similar fashion.
For motion control, actuators are selected based on speed and accuracy requirements. Some linear actuators are designed for micro Positioner and rely on piezoelectric crystals to produce very small resolution movements that are very useful in the nanometer world of optics, In general, belt drives and screws allow locating the Positioner stages and the like to achieve repeatability measured in milliseconds of an inch.
Some linear actuators are used with manual controls, such as those found in dental chairs and require no other Positioner feedback with limited switches. Some manufacturers even remove the limit switches by providing integrated free-form motion at the end of the stroke, such as the actuators shown on the right.
Note: What is Pneumatic actuator?
Pneumatic actuator is the compressed air energy converter is formed by vacuum or compressed air at high pressure into linear motion or spinning Compressed air power is desirable for main engine control because it can react quickly at start and stop because the power supply does not need to be stocked to reserve.
Pneumatic actuator drives allow large forces to be generated from relatively small pressure changes. These forces are often used with valves to move the film to affect the flow of liquid through the valve. It is responsible for transforming the pressure into reality.