What is Pneumatic Actuators – Types Of Pneumatic Actuators
Pneumatic actuators are the devices used for converting pressure energy of compressed air into the mechanical energy to perform useful work. In other words, Actuators are used to perform the task of exerting the required force at the end of the stroke or used to create displacement by the movement of the piston. The pressurised air from the compressor is supplied to reservoir. The pressurised air from storage is supplied to pneumatic actuator to do work.
The air cylinder is a simple and efficient device for providing linear thrust or straight line motions with a rapid speed of response. Friction losses are low, seldom exceeds 5 % with a cylinder in good condition, and cylinders are particularly suitable for single purpose applications and /or where rapid movement is required. They are also suitable for use under conditions which preclude the employment of hydraulic cylinders that is at high ambient temperature of up to 200 deg cel. to 250 deg cel.
TYPES OF PNEUMATICS ACTUATORS :
Pneumatic cylinders can be used to get linear, rotary and oscillatory motion. There are three types of pneumatic actuator: they are
i) Linear Actuator or Pneumatic cylinders
ii) Rotary Actuator or Air motors
iii) Limited angle Actuators
Types of Pneumatic cylinders /Linear actuators
Pneumatic cylinders are devices for converting the air pressure into linear mechanical force and motion. The pneumatic cylinders are basically used for single purpose application such as clamping, stamping, transferring, branching, allocating, ejecting, metering, tilting, bending, turning and many other applications.
The different classification scheme of the pneumatic cylinders are given below
1. Based on application for which air cylinders are used
i) Light duty air cylinders
ii) Medium duty air cylinders
iii) Heavy duty air cylinders
2. Based on the cylinder action
i) Single acting cylinder
ii) Double acting cylinder
- Single rod type double acting cylinder
- Double rod type double acting cylinder
3. Based on cylinder’s movement
i) Rotating type air cylinder
ii) Non rotating type air cylinder
4. Based on the cylinder’s design
i) Telescopic cylinder
ii) Tandem cylinder
iii) Rod less cylinder
- Cable cylinder,
- Sealing band Cylinder with slotted cylinder barrel
- Cylinder with Magnetically Coupled Slide
- Impact cylinder
- Duplex cylinders
- Cylinders with sensors
5. Based on the cylinder action
Based on cylinder action we can classify the cylinders as single acting and double acting. Single acting cylinders have single air inlet line. Double acting cylinders have two air inlet lines. Advantages of double acting cylinders over single acting cylinders are
1. In single acting cylinder, compressed air is fed only on one side. Hence this cylinder can produce work only in one direction. But the compressed air moves the piston in two directions in double acting cylinder, so they work in both directions
2. In a single acting cylinder, the stroke length is limited by the compressed length of the spring. But in principle , the stroke length is unlimited in a double acting cylinder
3. While the piston moves forward in a single acting cylinder, air has to overcome the pressure of the spring and hence some power is lost before the actual stroke of the piston starts. But this problem is not present in a double acting cylinder.
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