Dual outlet burner and method

Abstract

A burner includes a casing that encloses an outer plenum, the casing forming a fuel inlet and an outer nozzle at its end. An inner tube extends generally concentrically through the outer plenum and forms an inner plenum such that the casing encloses the outer plenum and the inner plenum. The inner tube forms an inner nozzle at its end. The inner nozzle is disposed generally concentrically with respect to the outer nozzle. A valve arrangement adjusts a fuel velocity separately through each of the outer nozzle and the inner nozzle to shape a flame created when the fuel is provided in an oxidant rich environment.

We claim: 
     
         1 . A burner, comprising:
 a casing that encloses an outer plenum formed in the casing;   a fuel inlet opening formed in the casing;   an outer nozzle opening formed at an end of the casing;   an inner tube extending generally concentrically through the outer plenum, the inner tube forming an inner plenum such that the casing encloses the outer plenum and the inner plenum, the inner plenum extending generally concentrically with respect to the outer plenum;   an inner nozzle opening formed at an end of the inner tube, the inner nozzle being disposed generally concentrically with respect to the outer nozzle; and   a valve arrangement configured and operating to adjust a fluid velocity separately through each of the outer nozzle and the inner nozzle.   
     
     
         2 . The burner of  claim 1 , further comprising a manual activation mechanism to adjust the fluid flow velocity through each of the outer and inner nozzles by use of the valve arrangement. 
     
     
         3 . The burner of  claim 1 , further comprising an automated activation mechanism to adjust the fluid flow velocity though each of the outer and inner nozzles by use of the valve arrangement. 
     
     
         4 . The burner of  claim 1 , further comprising a swirling device to impart swirl to fluids exiting through the outer nozzle. 
     
     
         5 . The burner of  claim 1 , wherein the valve arrangement comprises:
 an intermediate tube disposed around the inner tube;   a first sealed bushing extending generally radially between the casing and the intermediate tube such that it fluidly blocks a radial gap therebetween while also permitting sealable sliding displacement between the casing and the intermediate tube;   a second sealed bushing extending generally radially between the intermediate tube and the inner tube to fluid block a radial gap therebetween while also permitting sealable sliding displacement between the intermediate tube and the inner tube;   a series of axially aligned, fuel inlet slots formed along the inner tube;   a series of fuel passages formed along the intermediate tube;   a frusto-conical valve element connected at an end of the intermediate tube that is disposed within the casing and is arranged to move with the intermediate tube in unison as the intermediate tube slides relative to the inner tube; and   a valve seat formed on a collar that is integrated with the outer tube casing with which the frusto-conical valve element is slidably associated;   wherein, as the inner tube and the intermediate tube are moved relative to the casing and to one another, a variable alignment between the fuel inlet slots and the fuel passages determines a fluid flow rate through the inner tube, and thus the inner nozzle; and   wherein, as the intermediate tube and the frusto-conical valve element move with respect to the valve seat, a variable flow opening is created between the frusto-conical valve element and the valve seat, which determines a fluid flow rate through the outer plenum, and thus the outer nozzle.   
     
     
         6 . A burner, comprising:
 three concentric cylinders with tapered or thickened ends, the opposing end being blocked or otherwise plugged, wherein outer and inner concentric nozzles are formed in radial gaps between the three concentric cylinders, wherein each cylinder is sealably translatable in an axial direction relative to the remaining two concentric cylinders such that a cross-sectional area between the three concentric cylinders changes to control a proportion of gas flow to an outer nozzle formed between an outermost cylinder and an intermediate cylinder, and an inner nozzle formed in an innermost cylinder, wherein an intermediate plenum formed between the intermediate cylinder and the innermost cylinder is blocked or otherwise plugged at both ends; and   radial holes formed in each of the three cylinders, the radial holes providing the only gas conduits between an outer plenum, which is defined between the outermost cylinder and the intermediate cylinder, and an inner plenum, defined within the innermost cylinder;   wherein, during operation, gas flow originating from a gas inlet formed in the outermost cylinder is fluidly provided to the inner plenum through the radial holes, and wherein the gas inlet is in fluid communication with a fuel source.   
     
     
         7 . The burner of  claim 6 , wherein a manual activation mechanism is used to adjust an axial position of the intermediate cylinder and the innermost cylinder separately with respect to the outermost cylinder, thus selectively aligning the radial holes in the intermediate cylinder and the innermost cylinder to control a fluid flow area therebetween. 
     
     
         8 . The burner of  claim 7 , wherein the manual activation mechanism comprises a knob acting on a threaded rod that is threadably engaged with an activation arm that is connected to a sealed bushing, such that motion of the knob causes a relative motion of a respective tube with respect to the outermost cylinder. 
     
     
         9 . The burner of  claim 6 , wherein an automated activation mechanism is used to axially, separately move the intermediate cylinder and the innermost cylinder with respect to the outermost cylinder. 
     
     
         10 . The burner of  claim 6 , wherein the outer gas nozzle includes a swirling device adapted to impart swirl to an outer gas jet, creating a wide flame shape. 
     
     
         11 . The burner of  claim 6 , wherein an inner cylinder is open at both ends forming a passage adapted to provide cooling air when the burner is not operating, wherein the passage is blocked during operation of the burner. 
     
     
         12 . The burner of  claim 6 , wherein the radial holes in the intermediate cylinder and an inner cylinder are located such that they are fluidly blocked when the intermediate cylinder is disposed at a limit position, and wherein gas flow through the inner nozzle is blocked when the intermediate cylinder is at the limit position. 
     
     
         13 . A method for separately controlling flow rate and/or velocity of gas provided to concentric nozzle outlets for a burner, the method comprising:
 providing a casing that encloses an outer plenum formed in the casing;   providing fuel to the outer plenum through a fuel inlet opening formed in the casing;   providing an outer nozzle opening formed at an end of the casing, the outer nozzle providing the fuel to an oxidant rich environment;   providing an inner tube extending generally concentrically through the outer plenum, the inner tube forming an inner plenum such that the casing encloses the outer plenum and the inner plenum, the inner plenum extending generally concentrically with respect to the outer plenum;   providing an inner nozzle opening formed at an end of the inner tube, the inner nozzle being disposed generally concentrically with respect to the outer nozzle; and   adjusting a fuel velocity separately through each of the outer nozzle and the inner nozzle to shape a flame extending therefrom.   
     
     
         14 . The method of  claim 13 , further comprising activating manually the fluid flow velocity through each of the outer and inner nozzles by use of a valve mechanism. 
     
     
         15 . The method of  claim 13 , further comprising automatically activating a valve mechanism to adjust the fluid flow velocity though each of the outer and inner nozzles. 
     
     
         16 . The method of  claim 13 , further comprising imparting swirl to fuel exiting the outer nozzle. 
     
     
         17 . The method of  claim 13 , wherein adjusting the fuel velocity through each of the outer nozzle and the inner nozzle to shape the flame comprises:
 providing an intermediate tube disposed around the inner tube;   forming a series of axially aligned, fuel inlet slots along the inner tube;   forming a series of fuel passages along the intermediate tube;   providing a valve element on the intermediate tube; and   providing a valve seat connected to the casing and cooperating with the valve element to adjust a flow area through the outer plenum from the fuel inlet;   moving the inner tube relative to the casing to variably align the fuel inlet slots and the fuel passages and determines a fluid flow rate through the inner tube, and thus the inner nozzle; and   moving the intermediate tube with respect to the casing to create a variable flow opening between a frusto-conical valve element and the valve seat, which determines a fluid flow rate through the outer plenum, and thus the outer nozzle.