Rotary Screw Compressors

Rotary screw compressors are just one of a variety of air compressors. They employ a rotary type positive expulsion system, which conveys pressurized air to power drills, pumps and other types of machinery. Rotary screw compressors, also known as positive displacement compressors, deliver a determinate amount of highly pressurized air.

Rotary screw compressors contain the following components, all enclosed in a sealed case: the compressor unit, systems that maintain proper lubrication, proper temperature control, proper capacity control and the system that cleans the discharged air. Inside of the compressor unit itself there are two interlocking corkscrew-shaped augers or rotors. Each auger or screw has a wide end and a narrow end. The wide end of the screw is the inlet that allows free air to flow into the screw housing upon demand, helped along by the partial vacuum caused by the screws rotating inside the housing.

The air and oil combination flows downward from the wide ends to the narrow ends of the screw. This increases the vacuum, pulling more air into the housing. As the mixture is pulled downward through the grooves of the auger, the space where the air was narrows. At the narrow end of the screw, a valve tunnels the condensed air and oil into a separator, removing as much oil as possible from the condensed air. It is then released into the compressor receiver.

Rotary screw compressors are available in oil cooled and oil free. When comparing the oil cooled model to the oil free model, the procedure for compressing the air is basically the same, although the medium in which the procedure is carried out is different. One is performed in an oil filled chamber which provides coolant and sealant properties. The byproducts of the oil filled units are gas and oil instead of air and oil, which are the byproducts of the oil free systems. Oil free rotary screw compressors work the same except that in the absence of the oil the process does create higher temperatures and it is less energy efficient.

When choosing a rotary screw air compressor there are some important things to remember and take into consideration. What type of project are you working on? Does your compressor need to be transportable? Do you want oil cooled or oil free? Many consumers report that rotary screw compressors are easy to maintain and have a long life. They are known for their above average production abilities in a small package.