GAS BOILER WITH EXCESS AIR

摘要

A gas boiler is supplied with at least sufficient air to operate at its maximum output, enough for stoichiometric combustion being delivered to a burner 8 and the excess being discharged from the boiler. The gas fired boiler comprises a casing 5, a burner assembly 8, vortex means 7 for supplying a gas/air mixture for combustion at the burner assembly in approximately stoichiometric proportions, a flue outlet 10, a heat exchanger 9 between the burner assembly 8 and the flue outlet 10 and a fan 6 operable to draw air at 6A into the casing 5 and to discharge combustion products to the flue outlet at 68, air flow passages being provided within the casing which enable air drawn into the casing by the fan 10 to flow both to the fuel supply means 7 and hence to the burner 8 (air A1, A2) or to bypass the burner and heat exchanger and pass directly to the flue outlet (air A3, Fig 1 not shown). The burner 8 comprises a series of water filled tubes 20 interconnected by spaced parallel plates 21 at the surface of which the fuel mixture burns. IMAGE