Types of Pneumatic Compressors

Machines that compress atmospheric air, much like compressing a spring, to produce compressed air are called compressors. There are many types of compressors, depending on how they draw in atmospheric air and the construction of their components. Commonly used compressor types:

Piston (Reciprocating) Compressors

As the piston moving inside a cylinder cavity moves downward, a vacuum forms inside the cylinder and the intake valve opens. Air drawn from the atmosphere passes through a filter and fills the cylinder. The intake function continues throughout the piston’s travel to bottom dead center. When the piston starts moving upward, both the intake and exhaust valves are closed. The air trapped inside the cylinder begins to be compressed. Compression continues until the desired ratio is reached. Then the exhaust valve opens and sends the compressed air into the system.

Piston compressors aren’t a top preference due to their noisy operation and their tendency to develop problems frequently. Their most important selling point is their low price; for this reason, they’re preferred in small and medium-sized businesses.

Screw Compressors

Screw compressors use rotating components called the “screw set”. These rotating components are called “screw compressors” because they have helical grooves resembling a screw thread. As the screw set rotates, a vacuum forms at the intake port. Air is carried through the screw cavity all the way to the outlet port. Once the desired compression ratio is reached, the air is sent into the system.

See also, for the related topic and details: Piston Compressors and Their Working Principle

The components in the screw set rotate without touching each other. For this, gears are used at the ends of the screws. Since there’s no friction, there’s no wear. Screw compressors are a compressor type known for quiet operation and few maintenance problems. They’re used very heavily in large and medium-scale businesses.

See also, for the related topic and details: Screw Compressors: Construction, Types, Strengths, and Weaknesses

Rotary Compressors

The rotating components inside this type of compressor are called “rotors”. The rotors consist of components with different cross-sectional profiles.

While one rotor turns with the motion it receives from an electric motor, the other rotor turns freely. As the rotors turn, air is drawn in through the intake port and carried toward the outlet port. At the outlet port, the compressed air is sent into the system.

Turbo Compressors

Piston, screw, and rotary compressor types produce compressed air by compressing air at specific ratios. In dynamic compressors, on the other hand, kinetic energy is imparted to the air; then, as the air’s kinetic energy is reduced, that kinetic energy is converted into pressure energy. Turbo compressors are generally used in applications that require high flow rate and low pressure.

Air is compressed as it passes between the blades. This type of compressor can be built as a single stage or as multiple stages.

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