Patent GB-759606-A (GB)
Title: Improvements in or relating to gas turbine propulsion power plants
Inventor: HOOKER STANLEY GEORGE
IPC: F02C7/32
Filed: 1953-07-22
Abstract: 759,606. Gas turbine plant. BRISTOL AEROPLANE CO., Ltd. July 21, 1954 [July 22, 1953], No. 20393/53. Class 110(3) [Also inGroup XXXV] A gas turbine propulsion power plant comprises at least two rotationally independent turbines at least one of which drives a compressor, the working fluid flowing in succession through the compressor or compressors and then after being heated, through the turbines. The plant is combined with an auxiliary machine i.e. an auxiliary rotary power-conversion machine such as an electrical generator or alternator which when driven produces a power output, or combination of such machines comprising two elements rotatable relatively to one another, means being provided for imparting relative rotation to the elements which is dependent upon the difference between the speeds of two members driven each by a positive drive from a different one.of the rotationally independent turbines. In Fig. 1 the two independent turbine systems T<SP>1</SP>, T<SP>2</SP> drive two parts of a threepart differential device D, the third part of which drives a rotatable element 10 of an auxiliary machine A, the second element 11 of the machine being stationary. In Fig. 2 the two elements 12, 13 of the auxiliary machine are each rotatable, each being driven by one of the turbine systems T<SP>1</SP>, T<SP>2</SP>. If the turbines T', T<SP>2</SP> do not rotate in the same direction, suitable gearing must be inserted in one of the drives so that the two elements 12, 13 rotate in the same direction whereby the output of the machine A is proportional to the difference between their speeds. In Fig. 3, the turbine systems T<SP>1</SP>, T<SP>2</SP> are connected to elements 14, 15 respectively of two auxiliary machines, the other elements 16 17 of the machines being stationary. The machines A<SP>1</SP>, A<SP>2</SP> are connected at 18. The machine A' is an alternator which is excited by a smaller alternator A<SP>2</SP>, the output frequency of A' being determined by the difference between the driving speeds of the two machines. The invention is shown applied in the case of a gas turbine jet propulsion engine in Fig. 4, the engine including an auxiliary drive power output shaft 29 driven by a differential gear constituted by the internally toothed gear ring 35 as the first part, the sun gear 34 driven by the low pressure rotary system as the second part, and the planet carrier 30 as the third part, the third part driving the auxiliary shaft 29 through the bevel gears 31, 32. The two turbinecompressor systems 20, 21 and 23, 24 rotate in the same direction and the layshaft gears 38, 39 meshing respectively with the annulus 36 and the sun gear 40 constitute a reversing device having a transmission ratiodifferent from unity arranged between the high pressure rotary system and the differential gear. In Fig. 5 a second differential gear D<SP>2</SP> is provided, a first part thereof being driven by the third part of the first differential D' and a second part being connected to drive the rotatable element 10 of the machine A. A dynamo-electric machine 50 is connected to the third part of the differential D<SP>2</SP>. A centrifugal governor 55 is driven from the second part of the differential D<SP>2</SP> and controls a potentiometer 53 the machine 50 acting either as a motor driving the third part of the differential or as a dynamo driven thereby. In a further embodiment, a power correcting machine is applied to the engine shown in Fig. 4. A second differential gear is driven from the shaft 29 and also bv an air turbine supplied with air tapped from the compressor discharge. The third part of the differential drives an auxiliary machine, also a centrifugal governor which operates a valve controlling air supply to the air turbine. Specification 181,914 [Class 79(iv)] is referred to.