GB792747A - Improvements in or relating to water tube hot-water boilers or steam generators - Google Patents

Abstract

792,747. Forced-flow steam boilers; hotwater boilers; tubular heat exchange elements. VAPOR HEATING CORPORATION. Feb. 7, 1956 [Feb. 18, 1955], No. 3845/56. Classes 64(1), 64(3) and 123(2) A hot water boiler or forced-flow steam generator has a cylindrical outer casing 11 with a welded-on rear end plate 13 and a removable front plate 12 which supports a fire pot assembly 14 and burner (hot shown). The wall of the cylindrical combustion chamber 20 of the unit is formed by one tube group 26 of a helical coil assembly 21, the coil turns of the group 26 being disposed in contact with one another, the rear end of the chamber being closed by spiral turns 28 partly embedded in refractory material 31 held in a shell 32. The other group 23 of the coil assembly 21 surrounds the fire pot 14 and consists of a series of contacting turns each of which is of polygonal form the bends 36 of successive turns being staggered as shown in Fig. 3 to create a series of open spaces 37, Fig. 1, between the turns. A cylindrical sleeve 38 surrounds a rear portion of the tubes of the group 23 so that hot gases from the combustion chamber flow forwardly along the group and are then reversed adjacent the end plate 12 for rearward flow in the annular space between the casing 11 and the outer surfaces of the tube coil, the gases finally discharging through an exhaust conduit 19. Water enters the tube coil through a pipe 22 and flows successively through the tubes of groups 23, 26 and the spiral tubes 28, hot water or steam discharging through an outlet pipe 30. Adjacent coil turns may be welded together at intervals throughout the coil assembly. In modifications, the coil assembly may be enclosed within one or two further coils each of which has a portion consisting of turns of polygonal form which allow for the free passage of the combustion gases.