Air Compressor and function

Air Compressor

An air compressor is a machine that converts power (using an electric motor, diesel or gasoline engine, etc.) into potential energy stored in pressurized air (i.e., compressed air). By one of several methods, an air compressor forces more and more air into a storage tank, increasing the pressure. When tank pressure reaches its upper limit the air compressor shuts off. The energy contained in the compressed air can be used for a variety of applications, utilizing the kinetic energy of the air as it is released and the tank depressurizes. When tank pressure reaches its lower limit, the air compressor turns on again and re-pressurizes the tank.There are many methods of air compression and can be divided into either positive-displacement or negative- displacement type compressors.

Positive Displacement

Positive-displacement compressors work by forcing air into a chamber whose volume is decreased to compress the air. Common types of positive displacement compressors are:

● Piston-type air compressors

● Rotary screw compressors

● Vane compressors

Piston-type air compressors type of air compressors uses the principle in which pumping of air into an air chamber takes place because of the use of constant motion of pistons. They use one way valves to guide air into a cylinder chamber, where the air is compressed.

Rotary screw compressors use positive-displacement compression by matching two helical screws that, when turned, guide air into a chamber, whose volume is decreased as the screws turn. Vane compressors use a slotted rotor with varied blade placement to guide air into a chamber and compress the volume. Vane compressors deliver a fixed volume of air at high pressures.

Negative Displacement

Negative-displacement air compressors include centrifugal compressors. These use centrifugal force generated by a spinning impeller to accelerate and then de-accelerate captured air, which pressurises it.Compressors can also be classified according to the type of pressure:

● Low-pressure air compressors , which have a discharge pressure of 150 psi or less.

● Medium-pressure compressors, which have a discharge pressure of 151 psi to 1,000 psi.

● High-pressure air compressors which have a discharge pressure above 1,000 psi.

Working principle of Air Compressor

Air compressors collect and store pressurized air in a tank, and use pistons and valves to achieve the appropriate pressure levels within an air storage tank that is attached to the motorized unit. There are a few different types of piston compressors that can deliver even air pressures to the user.

Automotive compressors are combustion engine compressors that use the up-and-down stroke of the piston to allow air in and pressurize the air within the storage tank.Other piston compressors utilize a diaphragm, oil-free piston. These pull air in, and pressurize it by not allowing air to escape during the collection period.

These are the most common types of air compressors that are used today by skilled workers and craftsmen. Before the day of motorized engines, air compressors were not what they are today. Unable to store pressurized air, a type of antique air compressor may be found in the blacksmith’s foundry bellows. Now the air compressor is capable of building extreme pressures in storage tanks capable of storing enormous amounts of pressurized gases for industrial use.

Applications of Air Compressor

● Portable air compressor for powering tools, such as jack-hammers.

● To supply high-pressure clean air to fill gas cylinders.

● To supply moderate-pressure clean air to a submerged surface supplied diver.

● To supply moderate-pressure clean air for driving. Some office and school building. pneumatic HVAC control system valves.

● To supply a large amount of moderate-pressure air to power pneumatic tools, such as jack-hammers

● For filling tyres

● To produce large volumes of moderate-pressure air for large-scale industrial processes (such as oxidation for petroleum coking or cement plant bag house purge systems). Most air compressors either are reciprocating piston type, rotary vane or rotary screw type. Centrifugal compressors are common in very large applications. The power of a compressor is measured in HP (Horsepower) and CFM (cubic feet of air per minute). The gallon size of the tank tells you how much compressed air “in reserve” is available. Gas/diesel powered compressors are widely used in remote areas with problematic access to electricity.They are noisy and require ventilation for exhaust gases. Common workshop/ garage compressors are 110-120 Volt or 230-240 Volt. Compressor tank shapes are: “pancake”, “twin tank”, “horizontal”, and “vertical”. Depending on a size and purpose compressors can be stationary or portable.