Single-ended recuperative radiant tube assembly and method

A single-ended recuperative radiant tube assembly, comprising:

• radiant tube means, a burner positioned within said radiant tube means, fuel means for feeding fuel to said burner, outer recuperator tube means positioned generally about said burner and defining an inner exhaust flow passageway for receiving exhaust gases from said burner, said outer recuperator tube means operatively positioned within and cooperating with said radiant tube means for defining an annular exhaust chamber communicating with said inner exhaust flow passageway, and inner recuperator tube means spaced inwardly of said outer recuperator tube means and defining therewith an annular air chamber for feeding air to said burner, said annular air chamber operatively positioned adjacent and cooperating with said annular exhaust chamber so that air passing through said annular air chamber is heated by the exhaust gases in said annular exhaust chamber before said air reaches said burner, said outer recuperator tube means including a non-converging, generally cylindrical swirling portion generally adjacent and spaced from said burner, said burner including a plurality of air swirling fins extending radially to said swirling portion for inducing swirling turbulence in air heated within said annular air chamber before the air is mixed with fuel, said burner further including at least one radially extending discharge opening through which fuel flows closely associated with said fins for enhancing progressive combustion within said inner exhaust flow passageway.

A single-ended recuperative radiant tube assembly, comprising:

• radiant tube means, a burner, fuel means for feeding fuel to said burner, outer recuperator tube means positioned generally about said burner and defining an inner exhaust flow passageway for receiving exhaust gases from said burner, said outer recuperator tube means operatively positioned within and cooperating with said radiant tube means for defining an annular exhaust chamber communicating with said inner exhaust flow passageway, an annular air chamber operatively positioned adjacent and cooperating with said annular exhaust chamber so that air passing through said annular air chamber is heated by the exhaust gases in said annular exhaust chamber before said air reaches said burner, said outer recuperator tube means including a generally converging portion positioned upstream of said burner for increasing the velocity of said heated air and directing said heated air towards said burner, and swirling turbulence inducing means positioned downstream of said converging portion within a non-converging portion defined by said outer recuperator tube means for creating swirling turbulence within said heated air prior to mixing of said heated air with said fuel, said burner including radially extending fuel discharge means closely associated with said turbulence inducing means for enhancing progressive combustion by said burner within said inner exhaust flow passageway.

A method of increasing the efficiency of a furnace combustion system, comprising the steps of:

• providing a single-ended recuperative radiant tube assembly, emitting exhaust gases into a flame tube from a burner within said single-ended recuperative radiant tube assembly,
• heating air with said emitted exhaust gases within said single-ended recuperative radiant tube assembly,
• directing said heated air to said burner, and shielding fuel fed to said burner from said heated air,
• swirling said heated air by passage through a non-converging swirling portion disposed about said burner by providing said burner with a plurality of radially extending fins which extend to said non-converging swirling portion, and
• mixing fuel with said swirling heated air by radial discharge of the fuel into the central portion of said swirling heated air through at least one discharge opening of said burner closely associated with said fins for enhancing progressive combustion of said burner within said flame tube.