GB707885A - Improvements in or relating to dampers for use in gas heated apparatus - Google Patents

Abstract

707,885. Furnace dampers. MAIN WATER HEATERS, Ltd. Jan. 11, 1952 [Jan. 12, 1951], No. 989/51. Class 51 (1). [Also in Group XI] A gas heated apparatus has associated with a flue outlet or with an air inlet an adjustable damper interconnected through a lost motion device with a valve controlling the gas supply, so that on opening the valve the damper commences to open when the valve reaches an intermediate position, and when the fully open valve is closed the damper is fully closed when said intermediate position of the gas valve is reached. In the construction shown the spindle 20 of a cock controlling the gas supply to a burner has a diametrical slot 21 through which passes an end portion 22 of a manipulating member 23, the part 22 passing also through arcuate slots 24 in an annular member 19. The latter is formed integrally with a forked lever 17 engaged between abutments 18 on the upwardly bent lower end 15 of a push rod 14 carrying a damper plate 12 adapted to abut against an internal conical surface 11 in the flue 10. A spring 25 connected between the members 19, 23 tends to hold the part 22 against one end of each arcuate slot 24. In the closed position of the gas cock the spring 25 is extended and holds the damper plate 12 against the surface 11, and on turning the member 23 to lessen the tension of the spring 25 the damper 12 is maintained closed until an intermediate position, that shown in Fig. 1, is reached. In this position a small flow of gas is allowed to the burner and products of combustion may pass through apertures 13 in the plate 12. On further movement of the member 23 the part 22 rotates the sleeve 19 and the lever 16 to actuate the push rod 14 to move the damper plate 12 away from the surface 11. In an alternative construction the lost motion device comprises a damper actuating member provided with slotted portions one on each side of a transverse slot, which slotted portions are engaged respectively by a fixed pin and a pin connected to the damper, and the transverse slot is engaged by a pin on an arm rotating with the gas cock. An auxiliary thermostat controlled gas valve may be provided.