Question

How does pneumatics work with air compressors

Answer 1

The main components pneumatic system consist of air compressor, electric motor and motor control centre, pressure switch, check valve, storage tank, pressure gauge, auto drain, air dryer, filters, air lubricator, pipelines, and different types of valves.  

Air compressor is main component to run all pneumatic system effectively. Air compressor converts the mechanical energy of an electric or combustion motor into the potential energy of compressed air. There are several types of compressors which are used in the compressed air systems. Compressors used for generation of compressed air is selected on the basis of desired maximum delivery pressure and the required flow rate of the air The types of compressors in the compressed air systems are :

(i) piston or reciprocating compressors

(ii) rotary compressors

(iii) centrifugal compressors

The compressed air coming from the compressor is stored in the air receiver. The purpose of air receiver is to smooth the pulsating flow from the compressor.

For effective operation of the pneumatic system the compressed air needs to be cleaned and dried. Atmospheric air is contaminated with dust, smoke and is humid. These particles can cause wear of the system components and presence of moisture may cause corrosion. Hence it is essential to treat the air to get rid of these impurities. Further during compression operation, air temperature increases. Therefore cooler is used to reduce the temperature of the compressed air. The water vapour or moisture in the air is separated from the air by using a separator or air dryer.

The air treatment can be divided into three stages. In the first stage, the large sized particles are prevented from entering the air compressor by an intake filter. The air leaving the compressor may be humid and may be at high temperature. The compressed air from the compressor is treated in the second stage. In this stage temperature of the compressed air is lowered using a cooler and the air is dried using a dryer.

Control valves are used to regulate, control and monitor for control of direction flow, pressure etc. The main function of the control valve is to maintain constant downstream pressure in the air line, irrespective of variation of upstream pressure. Due to the high velocity of the compressed air flow, there is flow-dependent pressure drop between the receiver and load (application). Hence the pressure in the receiver is always kept higher than the system pressure.

Air cylinders and motors are the actuators which are used to obtain the required movements of mechanical elements of pneumatic system. Actuators are output devices which convert energy from compressed air into the required type of action or motion. In general, pneumatic systems are used for gripping and/or moving operations in various industries. These operations are carried out by using actuators.