GB442580A - Improvements in or relating to boiler furnaces and stoves - Google Patents

Abstract

442,580. Regulating combustion in furnaces. SCOTT, C. L., Leicester Arms Hotel, Penshurst, Kent. Aug. 10, 1934, No. 21203/35. Divided out of 442,547. [Class 51 (i)] In a solid fuel fired furnace for domestic water heating purposes and the like, a supply of primary air for combustion and of secondary cooling air at a point within the combustion chamber above the surface of the fire is controlled by thermostatic means sensitive to the water temperature, the main object being to keep the water temperature within safe limits at a time of " no demand," e.g. at night. In one form, Fig. 1, air entering the furnace at A is directed by a single thermostatically operated damper 9 into a duct 6 leading to below the grate and into a duct 10 leading to an outlet above the fire. The flue 12 is provided with a check-draught damper 13 such as is described in Specification 440,796, [Group X], The construction of and the means for controlling the grate are as described in Specification 442,547. The furnace shown in Fig. 2 is fed from a hopper (not shown),and the fuel passes over an inclined portion 3a to a grate 4. Air is admitted at A and passes, under the control of a valve 15 into a chamber 6a having an outlet 6 to the ashpit 5 and, under the control of a valve 16 into a chamber 10a having an outlet 10 to the space above the fire. Both valves 15 and 16 are mounted on a common thermostatically controlled spindle 9a. The valve 15 may be perforated to ensure a minimum primary air supply. In a modification, Fig. 7, both valves are loosely mounted on the spindle 9a, the valve 15 resting on a collar 15a and the valve 16 being supported by a spring 16a resting on a collar 16b. On a downward movement of the spindle, the spring keeps the valve 16 against its seating until the valve 15 has been closed. This arrangement ensures that the primary air supply has been reduced to a minimum before cooling air is admitted above the fire.