One of the most common types of compressor is the rotary screw compressor. Screw compressors were first patented in Germany in 1878, but their development was hampered because of the lack of manufacturing capabilities of the day. The principle is very simple. There is a close-fitting chamber that is fitted with either one screw or two contra-rotating screws. Air or gas is drawn into the chamber through a non-return valve and forced through the chamber by the rotation of the screw(s). The screws have to fit well in the chamber to ensure efficiency, though there is never any direct contact between the two screws and therefore no wear, total reliability and non-pulsating gas delivery. This sort of screw compressor can pump gas up to 1500 cubic feet per minute at up to 350 pounds per square inch.

Screw compressors are commonly used in refrigerators and are becoming very popular with users of air powered tools, and are commonly used in industrial applications. You can often see portable varieties of this type of compressor in use at construction sites, where is often based on a flatbed truck either being driven by the truck engine or by a separate diesel engine. Screw compressors can either be oil flooded or oil free, the former having a greater output than the latter. The horsepower of these compressors can vary between from 5 to 500 horsepower, and they are often used in superchargers for car engines. Please contact us if you would like any more information on these compressors.