Patent ID: 7874835

Claim:
A heating assembly for a radiant tube heater having a radiant heating burner tube with an upstream end, said heating assembly comprising: a mixing cup assembly adapted for mounting centrally within said burner tube and adapted for mixing primary air and combustible gas and for delivering the resulting mixture into the burner tube, said cup assembly having an inlet portion and a substantially cylindrical outlet portion located at a downstream end of the inlet portion and having a diameter greater than a corresponding dimension of said inlet portion, a series of air inlet holes being formed in an upstream end wall of said outlet portion for introduction of said primary air directly into said outlet portion, ports being formed in and around a peripheral surface of said inlet portion for introduction of said primary air into said inlet portion for an initial mixing with said combustible gas; a gas line for introducing said combustion gas into said mixing cup assembly, said gas line having one end connected to said mixing cup assembly and an opposite upstream end; a gas valve system including a gas valve unit having an outlet connected to said upstream end of the gas line, said gas valve system regulating flow of said combustible gas to said mixing cup assembly during use of the heating assembly; a blower for providing air for combustion to the radiant tube heater, said blower including a blower outlet section adapted for connection to said upstream end of the burner tube; an annular airflow restricting plate mounted on said mixing cup assembly and extending circumferentially around said mixing cup assembly, said restricting plate having an array of holes distributed over the plate and being arranged at a downstream end of said inlet portion and adjacent to said upstream end wall of the outlet portion; and an air diverter mounted at or near an upstream end of said mixing cup assembly, said air diverter having a plurality of diverter blades distributed circumferentially around said upstream end of the mixing cup assembly at least a section of each diverter blade sloping at an angle ranging between 30 and 60 degrees relative to a radial plane extending perpendicular to an axial centerline of the outlet portion, wherein during use of said heating assembly, said restricting plate substantially spans an annular passage for said secondary air formed between said outlet portion and the burner tube, said diverter blades direct a portion of the combustion air from said blower through said ports to provide primary air and impart a swirling motion to the combustion air from said blower, a further portion of the combustion air enters said outlet portion of the mixing cup assembly through said air inlet holes to provide a further amount of primary air for mixing with the combustible gas, and a remaining amount of the combustion air flows between said outlet portion and said burner tube to provide said secondary air for combustion.