GB599215A - Improvements in steam generator unit - Google Patents

Abstract

599,215. Water-tube steam boilers. KENNEDY, J. E. Aug. 7, 1945, No. 20235. Convention date, March 3. [Classes 123 (ii) and 123 (iii)] In a steam boiler the hot gases from a radiant heat combustion chamber 17, provided with burners 18 arranged for down-draught firing, are adapted to flow to the flue duct 86 through convection passes housing successively a superheater 66, an economiser 74 which is mounted on a grating 80 supported by cross beams 82 extending through the right-hand or back wall 12 of the boiler to provide a platform 106 for said economiser, when removed and an air heater 84. The two side and left-hand or front walls 12 of the boiler setting are lined with closely-set water tubes 24, 24 and 36 respectively, and in the combustion chamber alone, disposed in front of and spaced from these rows of wall tubes, are further single rows of spaced water tubes 56, 56 and 58. At the right-hand end of the boiler proper there is a wall of closely-mounted water tubes 40, the upper ends of alternate tubes being bent in to afford a passage for the gases from the superheater pass to the economiser pass, and between the two end walls, separating the combustion chamber and the superheater pass, is a wall of tubes 52, closely-spaced at their upper ends but open at their lower ends 54 for the passage of the gases, with a spaced row of spaced tubes 60 on the combustion chamber side. All the water tubes extend from lower headers 26, 34, 42 to an upper steam and water drum 16, either direct or through upper headers 28, 32, the lower headers also being connected to the drum 16 by external downcomers 108. The bottom of the chamber 17 is formed with sloping walls 20 terminating in an ash pit 22; an ash-trap 96 is also provided below the economiser 74. The superheater 66 comprises a plurality of looped tubes connected to inlet and outlet headers 68, 70 and it preferably extends across the whole width of the pass but is spaced from the tube bank 40 to provide a by-pass passage fitted with three vertically spaced dampers 98 for controlling the degree of superheat. The economiser 74 is also provided with a by-pass having hinged doors 102, 104 at its two ends, the doors being normally in the position shown with the flue gases flowing in the direction of the arrows. When, however, the doors are moved to the dotted line position the gases flow direct from the superheater to the air-heater 84 and permit removal of the economiser for repair or renewal, the boiler wall adjacent the economiser being fitted with one or more removal panels 100 above the platform 106. Air is supplied to the heater 84 from a duct 88 and blower 90 and, after passage around the tubes thereof, is led through an insulated duct 92 and secondary air-ducts 94 to the burners 18. The Specification as open to inspection under Sect. 91 comprises also a modified boiler, not shown, provided with tertiary air-ducts opening through the three outside walls of the combustion chamber 17. This subject-matter does not appear in the Specification as accepted.