Burner with integral mixer

Abstract

A burner for an appliance having a blower includes a tube extending from an inlet end to an outlet end with radially extending openings along its length. A cap closes the outlet end in a fluid-tight manner. A mixing system downstream from the blower extends into the inlet end for delivering a pre-mixed mixture of air and fuel to the interior of the tube for ignition by an igniter.

What is claimed is: 
     
         1 . A burner for an appliance having a blower, comprising:
 a tube extending from an inlet end to an outlet end and having radially extending openings along its length;   a cap closing the outlet end in a fluid-tight manner; and   a mixing system downstream from the blower and extending into the inlet end for delivering a pre-mixed mixture of air and fuel to the interior of the tube for ignition by an igniter.   
     
     
         2 . The burner of  claim 1 , wherein the mixing system comprises:
 a tubular venturi having an upstream end and a downstream end;   a gas supply tube extending into the upstream end and receiving fuel; and   a fuel nozzle including radially extending openings and positioned in the gas tube so as to be longitudinally aligned with the upstream end of the venturi, wherein air from the blower is received in a radial space between the venturi and the fuel nozzle such that the air is mixed with the fuel flowing through the radial openings in the fuel nozzle and delivered as a mixture of air and fuel to the central passage of the tube.   
     
     
         3 . The burner of  claim 2 , wherein an end of the gas supply tube receiving the fuel nozzle is flared. 
     
     
         4 . The burner of  claim 2 , wherein the upstream end of the venturi is converging and the downstream end of the venturi is diverging. 
     
     
         5 . The burner of  claim 2 , wherein the upstream end of the venturi is converging and the downstream end of the venturi is straight. 
     
     
         6 . The burner of  claim 2 , further comprising a mounting flange for connecting the inlet end of the tube to the venturi. 
     
     
         7 . The burner of  claim 6 , wherein the mounting flange includes:
 a planar base;   a stepped portion extending from the base into the inlet end of the tube; and   a curved portion extending over the upstream end of the venturi.   
     
     
         8 . The burner of  claim 1 , further comprising a flame arrester liner defining a central passage of the tube. 
     
     
         9 . The burner of  claim 1 , further comprising a fiber mesh provided over the tube. 
     
     
         10 . A burner for an appliance having a blower, comprising:
 an inner tube extending along a centerline from a first end to a second end and defining a central passage, wherein openings extend radially through the inner tube to the central passage;   an outer tube extending along a centerline from a first end to a second end and defining a central passage for receiving the inner tube, wherein openings extend radially through the outer tube to the central passage thereof;   an end cap closing the second ends in a fluid-tight manner;   a mixing system extending into the first end of the inner tube, comprising:
 a venturi having a central passage in fluid communication with the central passage of the tube; 
 a gas supply tube having a first end for receiving fuel and a second end extending into the venturi; and 
 a fuel nozzle extending into the second end of the gas supply tube and including radially extending openings for delivering the fuel to the central passage of the venturi, wherein air from the blower is received in a radial space between the venturi and the fuel nozzle such that the air is mixed with the fuel flowing through the radial openings in the fuel nozzle and delivered as a mixture of air and fuel to the central passage of the inner tube. 
   
     
     
         11 . The burner of  claim 10 , wherein the second end of the gas supply tube is flared. 
     
     
         12 . The burner of  claim 10 , further comprising a flame arrestor liner defining the central passage of the inner tube. 
     
     
         13 . The burner of  claim 10 , wherein the radial openings in the fuel nozzle are longitudinally aligned with a curved portion of the venturi. 
     
     
         14 . The burner of  claim 10 , wherein the venturi extends from a converging end longitudinally aligned with the radially extending openings to a diverging end for delivering the mixture of air and fuel to the central passage. 
     
     
         15 . The burner of  claim 14 , wherein the converging portion is upstream of the diverging portion. 
     
     
         16 . The burner of  claim 10 , wherein the venturi extends from a converging end longitudinally aligned with the radially extending openings to a straight end for delivering the mixture of air and fuel to the central passage. 
     
     
         17 . The burner of  claim 10 , further comprising a mounting flange for connecting the first ends of the inner and outer tubes to the venturi. 
     
     
         18 . The burner of  claim 17 , wherein the mounting flange includes:
 a planar base;   a stepped portion extending from the base into the first ends of the inner and outer tubes; and   a curved portion extending over and along a curved portion of the venturi.   
     
     
         19 . The burner of  claim 10 , further comprising a fiber mesh provided over the outer tube.