A rotary screw compressor is a form of air compressor. It is larger, more complex and more expensive than the models kept by most private workshops. In most cases, it is a non-portable unit used to supply compressed air for many industrial purposes. Rather than run off electricity, the rotary screw compressor is powered by an internal combustion engine, either using regular gasoline or diesel.
Oil Flooded Rotary Screw Compressor
The oil flooded rotary screw compressor begins with the engine, which passes mechanical energy to the compressor housing by means of a fan belt. The compressor contains two rotating screws which mesh together, producing suction through the air intake while forcing the air through progressively smaller cavities, compressing it. This is done in an internal cavity within the compressor which is flooded with oil. The oil acts as a coolant and a sealant, preventing air from escaping as the screws turn. Both gas and oil are pulled into a separation chamber, where the gas rises to the top and the oil drains to the bottom. The gas is siphoned out of the chamber and sent to a storage tank, while the oil drains out of the chamber into a radiator, where it cools before flowing back into the compressor.
Oil-free Rotary Screw Compressor
An oil-free rotary screw compressor works much in the same fashion as its counterparts. Air is sucked into the compressor, both the suction and the compression created by two interlocking screws, which is then sent to a storage tank. This process creates more heat and is less energy-efficient as the oil is not present to act as a sealant, though it still is more efficient than many electrically powered gas compressors. The oil-free rotary screw compressor is used in industries where the possibility of oil contamination is not acceptable. Medical research and the manufacture of delicate computer components are two examples.