GB1357519A - Combustion boilers - Google Patents

Abstract

1357519 Liquid heaters; combustion air control H E BOULTER 23 April 1971 [29 April 1970] 20495/70 Headings F4A F4T and F4W A combustion boiler comprises a combustion chamber 75, Fig. 8, a fuel burner, a fan 71 arranged to impel air for combustion into chamber 75, a heat exchanger 76 in which a liquid (water) is arranged to be heated by the hot combustion gases, a substantially air-tight enclosure 70 surrounding the chamber 75, fuel burner, fan 71 and heat exchanger 76, and a balanced flue inlet/exhaust system comprising an air inlet duct 73 communicating with fan 71 (via the interior of enclosure 70) and an exhaust duct 74, the ducts 73 and 74 extending from the upper part of enclosure 70 to terminal openings lying closely adjacent to one another. The ducts 73 and 74 are parallel, with outlet duct 74 within inlet duct 73, and an automatic air controller is provided at 72. A similar controller for controlling the supply of combustion air to chamber 75 is shown in Fig. 1 and comprises a movable controller plate 18, pivoted at a horizontal pivot 16, controlling air flow through the inlet duet by varying the effective size of an aperture at the lower edges of side walls 14. The plate 18 is biased towards an open position, in this case by an adjustable weight 21, and is movable automatically in a direction to reduce air flow in response to an increased air flow or increased pressure drop across the aperture in the direction of air flow.