Patent GB-843808-A (GB)
Title: Steam generator
IPC: F22B7/04
Filed: 1958-08-18
Abstract: 843,808. Liquid fuel combustion apparatus. VAPOR HEATING CORPORATION. Aug. 18, 1958 [Sept. 24, 1957], No. 26552/58. Class 51 (1). [Also in Groups XIII and XXIX] In a steam generator of the kind in which the water 74 to be converted into steam is forced in a continuous stream through a heating unit 10 immersed in the water 74 in a drum 11, the water heated in the unit 10 is delivered into an upper space in the drum 11 above the water 74 at a pressure higher than that maintained therein so that a portion of the heated water flashes into steam. A motor 104, mounted in the base of a skid 14, drives a pump 47 which draws heated water through a pipe 54 from the drum 11 and delivers it through parallel pipes 48, 49 to concentric coiled water-pipes 39, 40 contained within the casing 10a of the unit 10. The motor 104 also drives a blower 88 which supplies air to a plenum chamber 87a around a firepot 58 and has its shaft connected to a pump 98 which delivers oil through a pressure relief valve 96, pipes 99, and a control valve 100 (see Group XXIX) to a fuel nozzle 93 which is bolted at 95 to a removable plate 92 to project, with ignition electrodes 95, through a hooded opening 89 into the interior of the firepot. The nozzle 93 is also supplied with compressed air from a pipe 132, fed from the blower 88 or a separate compressor, to atomize the fuel oil which, when ignited, provides hot combustion products, further air from the plenum 87a being introduced into the firepot 58 through radial holes 90. The combustion products pass via a fire stabilizing ring 83 into the heating chamber 57, defined by the contiguous turns of the coil 39, and into an annular space 59 between the coil 39 and the drum 11 through spaces 62, 63 provided respectively between spaced-apart turns 60, 61 at the rear end of the coil 39 and the latter and the rear end 13 of the drum 11. The combustion products then pass through a smoke-box chamber 66, removably attached to the front wall 12 of the drum, to a smoke stack 65. The turns 68 of the outer coil 40 are of larger diameter than the turns 69 so that the combustion gases, sweeping the inner and outer surfaces respectively of the drum 10a and the coil 39, follow a circuitous path through the coil 40 to heat the water in the latter and the coil 39 and to preheat the body of water 74. The end tails 41, 42 of the coils 39, 40, extending through bridge-pieces 36, 37 which are sealed by plugs 43, 44 and locate the rear end of the heating unit in the drum 11, are connected by pipes 70, 71, respectively to a spray head 23, a flow restrictor 82 being incorporated in the pipe 71. The temperature of the water supplied to the head 23 is controlled by a pair of temperature-responsive switches 137 which are inserted in the pipes 70, 71 so that, on the temperature of the water in the pipes 70, 71 exceeding a predetermined limit, they interrupt the circuit of the motor 104 and thus the operation of the water-circulating pump 47, the blower 88, and the fuel pump 98 to cut off the heat to the heating unit 10. The spray head 23, supported by strips 24 in a frame 25 which is welded to the drum 11 and carries the wire mesh 27 of a mist collector, has rows of openings 73 of a size which maintain the water pressure within the head considerably higher than that prevailing in the space above the water 74 in the drum 11. This ensures that a portion of the high-pressure hot water as it is discharged from the spray head 23 flashes into steam, the other portion falling into the water 74. The steam, rising through the wire mesh 27, which collects condensate and returns it to the body of water 74, passes out of the drum 11 through a pipe 28. The water 74 is delivered to the drum 11, through a pipe 78, by means of a pump 76 driven by an electric motor 77, the water level in5,7idcated in a sight-glass 79, being automatically maintained by a switch mechanism 147 in a housing 80 and actuated by a float 81 to control the operation of the pump 76. A flap valve 110, controlling the entrance of air into the blower 88, is regulated by a pressure motor 112 connected to a fuel return line 107 leading to a fuel tank 109 supplying oil, through a pipe 97, to the pump 98. The fuel valve 100 is controlled by a pressure-motor 115, Fig. 6, not shown, which responds to pressure variations within the drum 11. The heating unit shell 10a welded to the front wall of the drum 11 cooperates with stay-bolts 12a to reinforce the front end wall 12 of the drum 11. In a modification three heating units such as . 10 are enclosed within a single drum, each smoke box communicating with a single smoke stack. Manifolds, incorporating connectors and shutoff valves to facilitate respectively the rendering of each heating unit inoperative or the easy removal of the units, are associated with the water pump 47, the tail ends of the inner and outer water coils, and the fuel pump 102.