Patent GB-636663-A (GB)
Title: Improvements in hot air and gas power plant
IPC: F02G3/00
Filed: 1945-07-11
Abstract: 636,663. Hot air and gas power plant. NETTEL, F. and KREITNER, J. July 11, 1945, No. 17740. [Class 7 (i)] The invention relates to a process of producing power and a hot air or gas power plant for carrying out the process. The plant comprises one or several rotary air compressors, fuel burning heating means for heating the compressed air issuing from the compressot, a single or plural stage gas turbine, a reciprocating expansion engine, the gas turbine disposed to drive the compressor, the engine disposed to supply useful power and conduit means so arranged that the compressed air is heated before expansion by combustion of fuel in it or by surface heat transfer by gases of combustion from the fuel burning heating means, conduit means being provided for leading in two' separate streams one from an intermediate stage or from the last stage compressor through the gas turbine to atmosphere and the other from the last stage compressor through the expansion engine to atmosphere the conduit means being arranged so that no reservoir is interposed between the compressor (or compressors) and the turbine or expansion engine whereby any change in the quantity of air consumed by the engine causes a substantially instantaneous change of pressure at the inlet to the turbine. In Fig. 1 a low pressure compressor 2 and high pressure compressor 21 in series with an intercooler 4 between them supply compressed air through a heat exchanger 8 to combustion chambers 10, 19. The heat supplied to the heat exchanger is obtained from the exhaust gases from a turbine 12 which drives the compressors 2, 2<SP>1</SP>. Fuel is supplied to the combustion chambers past regulating valves 171, 201 respectively. The exhaust from the combustion chamber 10 drives the turbine 12 and exhaust from the combustion chamber 19 drives a reciprocating engine 22 which performs external work. A number of modifications are described. In one a single stage compressor is employed and the combustion chamber 19 is omitted the exhaust from the combustion chamber 10 driving the reciprocating engine and the turbine and a valve may be provided to allow air direct from the heat exchanger to pass to the reciprocating engine. In a second modification the intercooler is removed and somÞ of the air from the outlet of the first compressor is passed through the heat exchanger to the combustion chamber 10 and air from the second compressor passes through the heat-exchanger to the combustion chamber 19. Air from the outlet of the second compressor may be byepassed to atmosphere by means of a byepass valve. In a variation of this second modification the combustion chamber 19 is dispensed with and the air from the second compressor after it has passed through the heat exchanger passes through a heating coil located in the first combustion chamber and then goes to the reciprocating engine. A valve for byepassing the heat exchanger and coil may be provided and the valve may be operated by a thermally sensitive device. In another modification (Fig. 5) part of the air from a first stage compressor 31 passes through heat-exchanger 38 to a combustion chamber 33 and exhaust from the combustion chamber passes to an intermediate stage of a turbine 36 driving the compressor. The remainder of the air is cooled by water injection in a chamber 41 and further compressed by a compressor 42 and then passes to heating coils 44, 47 some of the air going to the reciprocating engine and the remainder to the turbine 36. In a further modification the chamber 41 is replaced by an intercooler and all the air is taken from the outlet of the second compressor. This passes through a heat-exchanger heated by the exhaust of one turbine driving the compressors and then passes to a combustion chamber which supplies its exhaust to a high pressure second turbine driving the compressors. Some of the air is branched off from the outlet of the heat exchanger and passes through a heating coil having a byepass valve and arranged in the combustion chamber to the reciprocating engine. Fuel is injected into the exhaust of the high pressure turbine and passed to the low pressure turbine. Fig. 8 shows a modification in which all the heat is supplied to the air indirectly by means of heat exchangers. A compressor 81 supplies air partly through a heat exchanger 87 and a heating coil 83 to an intermediate stage of a turbine 85. The remainder of the air from this compressor, after being cooled by water injection at 90 is compressed in a compressor 91 and passed to heating coils 93, 96 some of the air passing from the coil 96 to the turbine 85 and the remainder passing to the reciprocating engine 95. The coils are heated by flue gases from a grate 100 which is supplied with air exhausted from the heat exchanger 87 and controlled by a valve 881 which regulates the exhaust of the air away to the atmosphere. The turbine and compressor may be started by a motor 103. Different fuels may be used in different combustion chambers of the same plant. The fuel supplies may be varied in accordance with load and/or speed of the reciprocating engine so that the admission temperatures at the turbine and reciprocating engine inlets are substantially constant.