compressors

Compressors are machines that increase the pressure of a gas by reducing its volume. They are used to provide a supply of compressed air and other gases for industrial equipment, manufacturing processes, refrigeration cycles, and heating, ventilation, and air conditioning systems.

Classification and principles

Compressors are broadly divided into positive-displacement and dynamic (ram or kinetic) types. Positive-displacement compressors trap a fixed volume of gas and reduce its pressure through mechanical action, while dynamic compressors impart velocity to the gas and raise pressure through diffusion and energy transfer.

Positive-displacement types include:

- Reciprocating (piston) compressors, which use one or more pistons in cylinders to compress gas. They can be single- or multi-stage for higher pressures.

- Rotary screw compressors, which trap gas between intermeshing rotors for continuous compression.

- Rotary vane and scroll compressors, which use rotating components or interleaved spirals to achieve compression. Scrolls are common in air conditioning and heat pump systems.

Dynamic types include:

- Centrifugal (radial) compressors, which use an impeller to accelerate gas and a diffuser to convert velocity to pressure, suitable for large volumes.

- Axial compressors, with multiple stages of rotating blades, used in high-flow, high-speed applications such as gas turbines.

Applications and performance

Compressors support manufacturing, tooling, mining, oil and gas, automotive, and process industries. In refrigeration and HVAC, reciprocating, screw, or scroll compressors raise refrigerant pressure. Performance is described by capacity (CFM or m3/min), discharge pressure, power input, and efficiency.

Maintenance and safety

Lubricated and oil-free variants exist; maintenance covers seals, valves, filters, and cooling systems. High pressures, electrical hazards, and heat generation require proper safety practices and ventilation.