SCREW COMPRESSORS
In an oil-flooded screw compressor, oil is injected into the compression cavities to aid sealing and provide cooling sink for the gas charge. The oil is separated from the discharge stream, then cooled, filtered and recycled. It is usual for some entrained compressor oil to carry over into the compressed gas stream. In some applications, this is rectified by coalescer/filter vessels. Within the compressor body there are two screws with matting profile: a female and a male screw, female having concave inlets and the male with convex helical inlets. The screws rotate in opposite directions with the female screw receiving the driving power and transmitting this power to the male screw through a set of synchronization gears of the screw compressor.
The principle of the screw compressor was first patented by Heinrich Krigar in Germany on 24th March 1878. He modified and improved his designs later that year and lodged a second patent on 16th August 1878. Both of these patents are amongst the earliest on record, as the German Patent Office had only been formed just one year earlier. By this time the original patent rights had expired. Lysholm developed the profile of the screw compressor and tested various configurations and rotor lobe combinations. Not only was the shape of the rotors important, he solved the problem and patented the method for accurately machining the rotors.
The screw compressor is a rotary, positive displacement compressor which incorporates a main screw compressor. Compression of the gas is accomplished by the engagement of the two gaterotors with the helical grooves in the main screw. The drive shaft imparts rotary motion to the main screw which in turn drives the intermeshed gaterotors. Standard screw compressors are capable of achieving output pressures over 200 psig, and output volumes of over 1500 cubic feet per minute (measured at 60 °C and atmospheric pressure).
|screw compressors|screw compressors|twin-screw compressor manufacturer|rotary screw compressors|
|
