Basic pneumatic system

BASIC PNEUMATIC SYSTEM

We know that the pneumatic system uses mostly the compressed air as its fluid medium. Also, pneumatic system is always an open loop system.

1. Components of a Pneumatic System

The basic components required for any pneumatic system are presented in Table 10.1.

Table 10.1. Components of a pneumatic system

1. Compressor: 

• A compressor is a device used to compress the air that comes directly from the atmosphere.

• The compressor, considered as an air source, supplies the required quantity of air.

2. Air tank (or Receiver tank): The air tank stores a given volume of compressed air coming out from the compressor.

3. Prime mover: An electric motor or other prime mover is used to drive the compressor.

4. Fluid conditioners (or air processing equipment): The purpose of fluid conditioners is to make the compressed air more acceptable medium for the pneumatic system.

The important air processing equipment are as follows:

(i) Air filters: To remove contaminants from the air before it reaches pneumatic components such as valves and actuators.

(ii) Air pressure regulator: To reduce the air pressure to the desired level for the particular circuit application.

(iii) Air lubricator: To ensure proper lubrication of internal moving parts of pneumatic components.

(iv) Air dryers: To remove the moisture from the air leaving the compressor. 

(v) Pneumatic silencer (or muffler): To control the noise caused by a rapidly exhausting air stream flowing into the atmosphere.

5. Control valves: 

• Control valves are used to control air direction, pressure, and flow rate.

• The important control valves include check valve, shuttle valve, directional control valve, and flow control valve.

6. Pneumatic actuators: The actuator is used to convert the energy of the compressed air into mechanical force or torque to do useful work.

• Actuators can be cylinders to provide linear motion, or motors to provide rotary motion.

7. Piping: The pneumatic piping carries the air from one location to another.

2. Construction and Operation

Fig.10.2 illustrates a typical pneumatic system which uses compressed air to obtain the useful mechanical work through the pneumatic actuator. This self-explanatory circuit consists of compressor, receiver tank, air processing equipment (filter, regulator, and lubricator), control valves (4 way manual DC valve and two adjustable flow control valves), pneumatic actuator, and miscellaneous components such as piping, pressure gauges, and water drain.

Note 

For the comparison between hydraulic and pneumatic systems, please refer to Section 1.9, Chapter 1.