twin screw air compressor used rotary air compressor remanufactured screw compressors TWIN SCREW AIR COMPRESSOR Very soon the twin screw air compressor acquired the reputation of a machine with reliable performance. However, the break-through did not occur until 1960, in conjunction with intensive tests to inject oil and other liquids into the compression spaces in order to be able to cope with the compression of impure and explosive gases. Heinrich Krigar resided in Hannover and his illustrations clearly show a two lobe rotor assembly, each rotor having the same profile as each other. In fact the rotor configuration resembles the Roots design, exhibited in Europe during 1867, with the exception that the rotors in the Krigar twin screw air compressor twist through an angle of 180 deg along their length.