GB472488A - Improved rotary compressor for varying loads - Google Patents

Abstract

472,488. Meshing - screw compressors; gas turbines. AKTIEBOLAGET MILO. March 23, 1936, No. 8618. Convention date, March 28, 1935. [Classes 110 (ii) and 110 (iii)] One or more compressors supply air to a combustion turbine, each compressor having a byepass to atmosphere valve, the opening of which is controlled in accordance with the load on the plant. A double - rotation turbine 1 drives electric generators 4, 5, and screw compressors 6, 7. The latter have rotors 13, 14, preferably driven without making contact, which are geared together by gears 19, 20. A piston 24 is fitted to the shaft 21 for pressure-equalization purposes. A byepass valve 29 is normally kept in the position shown by an energized solenoid 33 overcoming the resistance of a spring 35. The solenoid is connected with the generator 4. Upon a fall in load on the latter, the spring tends to raise the valve 29 and a less quantity of air is compressed and fed to a combustion chamber 40. Fuel is supplied to the chamber by a gear pump 43, the quantity being controlled by a centrilugal governor 47 and double-piston slide 48. The compressed air is supplied partly for combustion purposes, to the nozzles 45, and partly to a jacket 42 for cooling purposes. If a supply of air at constant pressure is required at the combustion chamber, the outlet ports of each compressor may be arranged to be opened later as the valve 29 opens. Fig. 2 shows another arrangement in which an axial-flow turbine 59 drives a generator 60 and two compressors 61, 62, which are arranged in series to supply air to the combustion chamber 40. In this case the valve 29 is held closed against spring-pressure, by the pressure of air in the supply pipe 67. A hydraulic coupling 63 is supplied by a pump 85, but when the pressure in the pipe 67 talls, a piston valve 75 moves to the right and at a predetermined pressure cuts off the supply pipe from the pump and the liquid is byepassed back to a container 84 which, actually, is below the coupling so that liquid may flow under gravity from the coupling. If the load on the generator is reduced the fuel supply is throttled by the valve 48, and the valve 29 commences to open. When the compressor 62 is uncoupled, a non-return valve 91 opens automatically. Other means may be used to control the plant in accordance with the load, such as the temperature of the driving medium. The valve 29 may be actuated manually.