Vapor flame burner and method of operating same

Abstract

Apparatus and method for creating a vapor flame in a burner having an adjustable BTU output using a liquid diesel fuel and air mixture. A burner tube within which the fuel air mixture initially combusts to form a flame is heated from its outside circumference by a combustion flame within a counterflow chamber surrounding the burner tube. The temperature of the burner tube is maintained at a value where the fuel air mixture within the burner tube turns into vapor with a lack of combustion air which vapor fuels the flame within the counterflow chamber and which vapor also travels to a burner head where it combusts. The combustion air and compressor air are varied following establishment of the vapor flame to increase and decrease the heat output from the burner.

We claim: 
     
         1 . A liquid fueled burner comprising a burner head, a burner tube, a nozzle for ejecting fuel into said burner tube, a counterflow chamber surrounding a substantial portion of said burner tube, first and second sets of perforations extending through said burner tube into said counterflow chamber, said second set of perforations being located adjacent said nozzle and said first set of perforations being located distant of said nozzle, an adjustable combustion fan to provide combustion air to said burner tube and said counterflow chamber, said burner head being operably connected to said burner tube and means to increase and decrease the supply of said fuel and to increase and decrease said combustion air. 
     
     
         2 . A burner utilising a liquid fuel supply fuel line to supply liquid fuel to a nozzle, a variable speed compressor to introduce air under pressure to said nozzle and to draw said liquid fuel into said nozzle to produce an air-fuel mixture emanating from said nozzle into a burner tube, an adjustable combustion fan to supply combustion air to said burner tube, an igniter to ignite the air-fuel mixture emanating from said nozzle and to commence combustion of said air-fuel mixture within said burner tube, a burner head, a counterflow chamber surrounding said burner tube, a first set of perforations extending though said burner tube located at the distant end of said burner tube, said first set of perforations allowing the escape of at least a portion of said fuel vapor in said burner tube into said counterflow chamber, adding combustion air to said counterflow chamber to form a flame within said counterflow chamber, a second set of perforations extending through said burner tube located adjacent said nozzle, said second set of holes allowing the entry of fuel vapor from said counterflow chamber into said burner tube and controls to increase or decrease the supply of air to said nozzle and to said burner head. 
     
     
         3 . A burner as in  claim 2  and further comprising a ring member being concentric to said burner tube and surrounding at least a portion of said burner tube, said ring member being positioned generally over said first set of perforations in said burner tube. 
     
     
         4 . A burner as in  claim 3  and further comprising a flame suppressor surrounding said burner tube and being situated within said counterflow chamber between said first and second sets of perforations in said burner tube. 
     
     
         5 . A burner as in  claim 4  and further comprising a sealing member between said burner to seal said burner in an appliance within which said burner is positioned to prevent the ingress and egress of air to and from said burner. 
     
     
         6 . A burner as in  claim 5  and further comprising a first flame sensor outside said burner head to sense the presence or absence of a flame on said burner head. 
     
     
         7 . A burner as in  claim 6  wherein said burner head has a first outer flame surface with perforations extending through said flame surface from said outside of said flame surface to the inside of said flame surface and further comprising an inner baffle located within said burner head. 
     
     
         8 . A burner as in  claim 7  wherein said inner baffle has perforations extending through said baffle. 
     
     
         9 . A burner as in  claim 8  wherein said first burner head and said first flame surface are round and wherein said inner baffle is concentric to said flame surface. 
     
     
         10 . A burner as in  claim 9  and further comprising a second flame sensor positioned within said burner head to sense the presence of a flame within said burner head. 
     
     
         11 . A method of creating a combustible vapor from a liquid fuel within a burner comprising the steps of introducing a liquid air-fuel mixture into a burner tube from a nozzle, supplying combustion air to said burner tube, passing at least a portion of said air-liquid fuel mixture from said nozzle through an igniter to ignite said air-liquid fuel mixture into a flame within said burner tube, allowing said combustion flame to emanate from a burner head located downstream of said burner tube, allowing fuel vapor within said burner tube to escape to a counterflow chamber surrounding said burner tube via a first set of perforations in said burner tube located distant from said nozzle, supplying combustion air to said counterflow chamber to combust said fuel vapor within said counterflow chamber, heating at least a portion of the outside of said burner tube with said flame in said counterflow chamber, restricting the flame within said counterflow chamber by a flame suppressor and allowing byproducts of said combustion of said flame in said counterflow chamber to be reintroduced to said burner tube through a second set of perforations located in said burner tube at the end of said burner tube adjacent said nozzle, terminating the operation of said igniter after a predetermined time period wherein the temperature within said burner tube is high enough to maintain vaporization of said air-diesel fuel mixture emanating from said nozzle and allowing said flame within said burner tube to extinguish, said flame appearing on said burner head and inside said counterflow chamber. 
     
     
         12 . A method as in  claim 11  and further comprising locating a ring member over said first set of holes around said burner tube and within said counterflow chamber. 
     
     
         13 . A method as in  claim 12  and further comprising positioning a flame grid between said first and second set of holes within said counterflow chamber and around said burner tube. 
     
     
         14 . A counterflow chamber comprising a counterflow air chamber surrounding a burner tube, a first set of perforations extending from said burner tube into said counterflow chamber to allow passage of fuel vapor from said burner tube, a second set of perforations extending from said counterflow chamber into said burner tube to allow combustion by products into said burner tube and an inlet for combustion air to enter said counterflow chamber and combust said fuel vapor within said counterflow chamber thereby to heat the circumference of said burner tube. 
     
     
         15 . A burner head for a burner comprising an outer flame surface with perforations extending through said flame surface from the outside of said flame surface to the inside of said flame surface, an inner baffle located within said burner head, said inner baffle having perforations extending through said baffle, said first outer flame surface and said inner baffle being concentric, a first flame sensor outside said burner head adjacent said flame surface and a second flame sensor located within said burner head.