GB706352A - Improvements in and relating to combustion chambers of the pulsatory column type andthermal power plants - Google Patents

Abstract

706,352. Gas and steam turbines. HALLOWELL, E. July 14, 1952 [July 28, 1951], No. 17939/51. Class 110 (3). [Also in Group XII] A power plant comprises a pulse-jet combustion chamber 10 with pre-heated fuel mixtures, an air turbine 17, a steam generator 22 and steam turbine 23 and a number of heat-exchangers 30, 27, 19, 21. The exhaust gases from the chamber 10 contain surplus air which is mixed with fuel and air supplied by a fan 31, to heat the generator 22. The turbine 23 exhausts to a condenser 25 and feed water is passed by a pump 26 through pre-heaters 27, economizer 28 to the steamgenerator. Air is supplied to the chamber 10 by a fan 29 through a pre-heater 30 and heatexchanger 19, an annular space 11, a high-temperature heat-exchanger 21 (or bye-pass 20) to the hot-air turbine 17 which drives an electrical generator or the like 18. The turbine 17 exhausts at below atmospheric pressure to the exchanger 19, losing some heat to the air from the fan 29, and is fed to an inlet 13 of the chamber 10. The duct 10 has one or more sparking plugs 32, for starting purposes, and is supplied with fuel mixture through a port 14 by a fan 15. A rotor has vanes 38, 39 on a spindle 37 which is driven by an electric motor. The rotor ends have ported discs 44, containing fuel-admission ports 45, 46, rotating with fine clearances relative to the casing ends which contain co-acting ports ; the ends may be angularly adjustable. The interior of the spindle 37 and the vanes may be cooled. In between the full-open position of the vanes 38, 39, as shown, and the fully-closed position one or other of the admission ports 45, 46 in the end discs comes into alignment with the fuel admission port to allow admission of the fuel into the air stream entering the inlet 13. As the rotor rotates successive charges of air and air fuel mixture enter the duct 35 and during the intervals when the vanes cut off the supplies of air and fuel, a succession of explosions occurs near the admission end of the duct due to the plug 32. High-velocity gas columns travel outwardly thus inducing fresh charges of air and air-fuel mixture during the periods when the vanes are open, and when a gas column reaches an intermediate point it rebounds to compress an incoming charge of air followed by an airfuel mixture. The intermediate " cushion " of air prevents pre-ignition of the fuel charge by hot exhaust products. When the chamber 10 is warmed up it operates on compression-ignition and the sparking plug is cut out. A reduction in the aspiration pressure at the inlet 13 causes increasing frequency of rebound compression of the gas columns in the chamber 10, the duct of which may be very long. A valve 33 regulates the amount of air passing through the heat exchanger 21. Figs. 4 and 5 show other designs of the rotor. In the former two combustion chambers 50, 51 are arranged back to back, the air inlets being shown at 57 and 58. Fuel admission points 60 ... 63 are provided in rotary end discs 59 and co-act with ports 65, 66 in the casing ends. The quantity of excess air admitted to a chamber 10 may vary between 20 per cent and 200 per cent. Firebricks or the like may be used in the high temperature heat exchanger 21. Heat exchanger 19 may be omitted.