Burner assembly with fuel pre-mix and combustion temperature controls

A burner assembly comprising:

• a combustion chamber including therein an elongate combustion tube having upstream and downstream ends, the combustion chamber having a flame region within a downstream end portion of the combustion tube and extending downstream beyond the downstream end;
• means for directing a high velocity stream of combustion air from the upstream end through the combustion tube;
• means for returning heated gases from the flame region to the upstream end of the combustion tube;
• means for mixing liquid fuel and returned, heated gases with the combustion air at the upstream end of the combustion tube, whereby energy from the heated gases is transferred to the liquid fuel to vaporize the liquid fuel prior to the liquid fuel being carried by the stream of combustion air to the flame region;
• and
• a cooling jacket disposed about the combustion tube, the cooling jacket bounding an annular space about the combustion tube and including means for receiving and centrifugally spiraling cooling gases through the annular space and along the flame region thereby cooling the combustion tube and heating the spiraling gases, and for transferring heated cooling gases to the means for returning heated gases from the flame region to the upstream end of the combustion tube.

A method of generating a stream of hot combustion gases comprising:

• directing a stream of combustion air into a combustion chamber and into an upstream end of a combustion tube disposed in the combustion chamber to move toward a flame region at a downstream end of the combustion tube within the combustion chamber;
• injecting liquid fuel adjacent the upstream end of the combustion tube into the combustion chamber, mixing the injected fuel into the stream of combustion air and burning the fuel with the combustion air in the flame region of the combustion chamber;
• moving oxygen deficient cooling gas peripherally in a spiralling motion about the combustion tube and peripherally along the flame region, thereby heating the cooling gas with heat energy from the combustion tube and from burning fuel in the flame region;
• returning heated cooling gas to the upstream end of the combustion tube, mixing the fuel with the heated returned cooling gas to vaporize the fuel while mixing the fuel with the cooling gas and the stream of combustion air within the combustion tube;
• mixing a controlled quantity of a buffer gas at the upstream end of the combustion tube with the returned heated cooling gas, the fuel and the stream of combustion air;
• monitoring the flame temperature of the burning mixture;
• and
• adjusting the quantity of the buffer gas to maintain the flame temperature within a range of desirable temperatures.