compressor

A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. By converting energy input into pressure energy, compressors enable gases to be stored, transported, or circulated at higher pressure. They are used in a wide range of industries and applications, from manufacturing to refrigeration.

Compressors are broadly categorized into positive-displacement and dynamic (rotodynamic) types. Positive-displacement machines trap a fixed amount of gas and then reduce the volume to raise the pressure. Common variants include reciprocating (piston) units, diaphragm compressors, rotary screw compressors, and vane machines. Dynamic compressors impart energy to the gas with rapidly moving impellers or blades; centrifugal and axial-flow compressors are typical for high-volume, high-speed applications.

Applications include powering pneumatic tools, spray painting, and manufacturing processes; gas compression for natural gas transmission, processing, and chemical plants; and refrigeration and air conditioning cycles in HVAC systems. In refrigeration, a compressor circulates refrigerant through the evaporator and condenser, enabling heat transfer.

Most compressors have an intake filter, a compression chamber or stages, and a discharge line. Multi-stage units use intercoolers and aftercoolers to remove heat between stages. Lubrication and cooling systems protect moving parts. The drive may be electrical, internal combustion, or hydraulic. A receiver stores compressed gas and stabilizes delivery, while relief valves, gauges, and controls protect against overpressure and operational hazards. Removal of moisture is often necessary to prevent corrosion and freezing downstream.

Performance is described by discharge pressure, flow rate, and energy efficiency. Efficiency depends on technology, stage configuration, and heat management. High-pressure systems require appropriate ventilation, sound attenuation, and regular maintenance of seals, bearings, and valves to prevent leaks and failures. Safety considerations include hot surfaces, stored energy, and potential hazards when compressing flammable or reactive gases.