Compressed Air - Air compressed to a pressure higher than atmospheric pressure, usually accomplished via mechanical means.
Types of Air Compressors
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Positive Displacement - Air is trapped in a compression chamber and the volume is mechanically reduced, causing a rise in pressure.
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Reciprocating - Seen in the image to the right, a piston reduces the volume of the cylinder compressing the air to a higher pressure.
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Rotary Screw - A male and female rotary screws mesh and compress the air as it moves along the screws. There are two types, Lubricant-Injected and Lubricant-Free.
Dynamic - Compresses air by imparting velocity energy and converting it to pressure energy.
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Centrifugal - An impeller rotates at speeds that may exceed 50,000rpm, the air is then reduced in a diffuser and volute.
Compressed Air Systems