Air Compressors

The most common commercial compressors fall into two categories, according to the mechanism that powers them:

• Piston-driven (reciprocating) compressors - these are the most affordable (and oldest) models, and are best for small scale operations. Since the design involves a lot of mechanical movement, they need periods of down time during use to prevent them overheating. Reciprocating air compressors are usually portable and are available in single or 3-phase electric or petrol/diesel varieties.
• Rotary screw compressors - these use interlocking helical screws, or rotors, to increase air pressure. Without the furious movement of pistons they produce much less heat, and so are generally used for heavy duty, industrial work. They are designed to be used in a single, fixed location and are often housed in a special purpose cabinet.

Air compressors can be compact, portable affairs or (especially in the case of variable speed rotary compressors) large-scale, permanent pieces of apparatus that need to be installed by professional engineers. The size of a compressor will obviously be in proportion to its power, which is measured in terms of the maximum airflow (in cubic feet per minute) and the pressure (in pounds per square inch) required by your appliances.