Converging-diverging combustion zones for furnace heat exchanges

Abstract

A furnace unit comprising a mounting panel, a burner assembly and a heat exchanger. The burner assembly is mounted to one side of said mounting panel, the burner assembly having at least one burner located therein. The heat exchanger is mounted to an opposite side of said mounting panel. The heat exchanger has at least one continuous combustion tube, wherein said combustion tube includes at least a first pass and a second pass. The first and second passes are interconnected by a curved pass of the combustion tube. One end of the combustion tube has a first opening that is coupled to the burner assembly. The combustion tube has at least three zones.

What is claimed is: 
     
         1 . A heating furnace unit, comprising:
 a mounting panel;   a burner assembly mounted to one side of said mounting panel, said burner assembly having at least one burner located therein; and   a heat exchanger mounted to an opposite side of said mounting panel, said heat exchanger having at least one continuous combustion tube, wherein said combustion tube includes at least a first pass and a second pass, said first and second passes interconnected by a curved pass of said combustion tube, one end of said combustion tube having a first opening that is coupled to said burner assembly, wherein
 said combustion tube has at least three zones, 
 a converging first surface of said first zone said first surface extending an entire length of the first zone and converging towards a direction of a flame emitted by the one burner during an operation of the heating furnace and forming a first non-straight angle with a diverging second surface of said second zone 
 said second surface extending an entire length of the second zone and diverging away from said direction of said flame, 
 said second surface has a second non-straight angle with a third surface of said third zone, 
 said first zone is nearest of said three zones to said burner assembly and extends to said first opening and said second zone is in-between said first zone and said third zone, 
 said first, second and third zones are within a flame length configured to be emitted from said burner, 
 said first non-straight angle is located on said opposite side of said mounting panel, and 
 said first non-straight angle and said second non-straight angle are within said first pass and are nearer to said first opening upstream end than said curved pass. 
   
     
     
         2 . The unit of  claim 1 , wherein said first zone is a converging zone and said second zone is a diverging zone with said first non-straight angle between 0 and 180 degrees. 
     
     
         3 . The unit of  claim 1 , wherein said first zone is a converging zone and said second surface of said second zone linearly diverges from said first zone to said third zone. 
     
     
         4 . The unit of  claim 1 , wherein said first zone is a converging zone and said second surface of said second zone curvilinearly diverges from said first zone to said third zone. 
     
     
         5 . The unit of  claim 1 , wherein a portion one or more of said outer surfaces of one or more of said three zones forms a straight angle with another one of said outer surfaces of said three zones. 
     
     
         6 . The unit of  claim 1 , wherein said first, said second and said third surfaces include exterior surfaces of said first, said second and third zones, respectively, and, said first and second non-straight angles are exterior angles. 
     
     
         7 . The unit of  claim 1 , wherein said first pass and said second pass each have a long axis, said long axes disposed in a substantially parallel relationship. 
     
     
         8 . The unit of  claim 1 , wherein a second opening at an opposite end of said continuous combustion tube is coupled to a collector assembly of said unit. 
     
     
         9 . A method of manufacturing a heating furnace unit, comprising:
 providing a mounting panel;   providing a burner assembly having at least one burner located therein;   providing a combustion tube of a heat exchanger, wherein said combustion tube includes at least a first pass and a second pass, said first and second passes interconnected by a curved pass of said combustion tube;   mounting said burner assemble to one side of said mounting panel;   mounting said heat exchanger to an opposite side of said mounting panel; and   coupling one end of said combustion tube to said burner assembly such that said at least one burner can emit a flame into an opening in said one end, wherein:
 said combustion tube has at least three zones, 
 a converging first surface of said first zone 
 said first surface extends an entire length of the first zone and converges towards a direction of a flame emitted by the one burner during an operation of the heating furnace and forming a first non-straight angle with a diverging second surface of said second zone, 
 said second surface extends an entire length of the second zone and diverges away from said direction of said flame, 
 said second surface has a second non-straight angle with a third surface of said third zone, 
 said first zone is nearest of said three zones to said burner assembly and extends to said first opening and said second zone is in-between said first zone and said third zone, 
 said first, second and third zones are within a flame length configured to be emitted from said burner, 
 said first non-straight angle is located on said opposite side of said mounting panel, and 
 said first non-straight angle and said second non-straight angle are within said first pass and are nearer to said first opening upstream end than said curved pass. 
   
     
     
         10 . The method of  claim 9 , wherein providing said combustion tube includes forming said three zones including bending a portion of one or more metal sheets to form said first non-straight angle and said second non-straight angle. 
     
     
         11 . The method of  claim 9 , wherein providing said combustion tube includes forming said three zones, including coupling separate first, second and third metal sheets together to form said first non-straight angle and said second non-straight angle. 
     
     
         12 . The method of  claim 11 , wherein coupling said separate first, second and third tubes together includes bonding said first and said second pieces together and bonding said second and said third pieces together.