Compressors

Air compression is used in some way by almost every industrial sector. Industrial compressors are used to provide compressed air for use in machine tool, instrument air, engine starting and process applications.

There are three main types of compressors: rotary screw compressors, centrifugal compressors, and reciprocating compressors. A rotary screw compressor uses two helical rotors to force the medium into a chamber with a steadily decreasing volume. This raises the pressure of the medium. Rotary screw compressors release low- pressure air at high rates of speed and may be oil-lubricated or non-lubricated. A centrifugal compressor uses a bladed rotor to accelerate and pressurize air or gas. As the rotor spins, it forces the medium to the outer part of the chamber by centrifugal force. A reciprocating compressor uses one or more pistons that move within a sealed cylinder to raise the pressure of the medium. As the piston moves up and down, the pressure of the medium rises, creating significant amounts of heat. Because of the heat, the cylinder will often use an air-cooled or water-cooled jacket. Some compressors have multiple stages and work by compressing the medium and cooling it with one piston, and then further compressing it with a second piston. With this process, higher compression can be produced without causing stress on the single compressing piston.

There are some safety concerns with regard to the compressor that users should be made aware of. First, it is important that trained maintenance people regularly inspect the compressor and all of its components. Second, the compressor should never be operated beyond the specified and recommended working pressures of the system.

References
www.jfiboomlifts.com/usedfor.htm
http://en.wikipedia.org
www.manufacturing.net
http://dmoz.org
www.aboutconstruction.org