Selecting air compressors requires specifications and requirements

Selecting air compressors requires specifications and requirements such as air quality, temperature, power, size, and mobility. Some air compressors are equipped with motors (screw compressors) to remove condensation, which is created during the compression process. Others include chillers to reduce the temperature of the compressed air. Air compressors with paper or polyester filters to remove oil, dust, vapor, and other debris are also available. Oil-free air is particularly important in applications such as food processing and semiconductor manufacturing, where parts per billion (ppb) of oil are unacceptable. Smaller air compressors are usually powered by gasoline, diesel fuel, or single-phase electricity. In terms of mobility, they are available at 208V, 230V, or 460V. Larger, commercial and industrial units often use three-phase power. Portable air compressors feature wheels, casters, or self-contained trailers. Vertical air compressors are designed for fixed installations and require less floor space.

Air compressors that compress and direct air for industrial applications. Small-scale equipment designed for pneumatic tools such as grinders, drills, and nail guns. Production-scale products are used to drive stamping and punching equipment, power robot tools, and convey parts. Air compressors designed for direct use applications such as sandblasting and painting are also available. There are three basic types of air compressors: reciprocating compressors, rotary screw compressors, and centrifugal compressors. Reciprocating air compressors use a piston to compress the contents of a cylinder and force them into an air receiver. These piston-driven air compressors are designed for intermittent use. Rotary screw air compressors use twin-screw pistons to pressurize air. They are designed for continuous use and have a 100% duty cycle rating. Centrifugal air compressors are turbine engines that use rotating blades to generate high pressures. Typically, these air compressors are used in power generation and large-scale industrial applications.

Air compressor pressure, air flow, efficiency, and operating costs are important parameters. Air pressure is usually measured in pounds per square inch (psi). Air flow is usually measured in standard cubic feet per minute (SCFM). Reciprocating air compressors can achieve up to 100CFM of air flow. Rotary air compressors can reach 1500 CFM single stage and up to 2500 CFM two stage. Centrifugal air compressors operate at levels over 1000 CFM. Regarding air compressor efficiency, the Compressed Air and Gas Institute (CAGI) has developed a set of standard test criteria. Air compressor suppliers can provide CAGI data sheets with information on horsepower, efficiency and expected energy consumption.