Air purity is critical for many applications where even the tiniest drop of oil, or air contaminated with oil can cause product spoilage, product recall, or damage production equipment. Various industries have developed stringent quality standards to ensure safety of both manufacturing processes and end customers. Oil Free compressors are guaranteed to meet ISO 8573-1 Class Zero.
Oil-free air compressors can be the perfect solution for the compressed air applications where meeting the highest air purity standards is key. A 100% dry oil-free air supply can be achieved with the use of a number of different oil-less compressor technologies such as scroll, water injected screw , 2 stage dry screw, depending on your requirements.
Rotary screw compressors are positive displacement compressors. The principle of compression in oil-less rotary screw compressors is similar to that of oil-injected models, but without oil being introduced into the compression chamber. Two distinct types are available – the dry type and the water-injected type.
In the dry type oil-free rotary screw compressors, the intermeshing rotors do not touch and their relative positions are maintained through lubricated timing gears outside the compression chamber. In the water injected type, similar timing gear construction is used, but water is injected into the compression chamber to act as a seal in internal clearances, and to remove the heat of compression.
Oil-free rotary screw compressors utilize oil for lubrication of bearings and gears, which are isolated from the compression chamber. The lubricating oil, therefore, does not cause compressed air contamination.
The cooling system in dry type oil-free rotary screw compressors normally consists of an air cooler after each stage and an oil cooler. These may be water-cooled or air-cooled radiator type. Water-injected oil-free rotary screw compressors use the injected water to remove the heat of compression. The injected water is then removed from the discharged compressed air by a conventional moisture separation device.