High-efficiency burner

Abstract

The invention relates generally to a fuel burner, and more particularly, but without limitation, to a high-efficiency gas burner with a gas pre-heat feature. Embodiments of the invention include a preheat tube that is coupled inline between a pressurized gas source and an orifice. The preheat tube may be formed into an elongated loop. An air/gas mixing tube extends inside the loop formed by the preheat tube from a proximal end near the orifice to a distal end away from the orifice. The distal end of the air/gas mixing tube is exposed to a portion of the preheat tube.

1 . A burner, comprising:
 an input port configured to receive pressurized gas;   a preheat tube, a first end of the preheat tube coupled to the input port;   an orifice coupled to a second end of the preheat tube; and   a mixer tube, a first end of the mixer tube disposed near the orifice, a second end of the mixer tube disposed near a first portion of the preheat tube, the preheat tube being disposed outside the mixer tube, the burner being configured such that, in operation, a flame produced in part by preheated gas escaping from the orifice is contained by the mixer tube except that the flame extends beyond the second end of the mixer tube to heat the first portion of the preheat tube.   
     
     
         2 . The burner of  claim 1 , wherein the pressurized gas includes propane. 
     
     
         3 . The burner of  claim 1 , wherein the pressurized gas includes natural gas. 
     
     
         4 . The burner of  claim 1 , wherein the preheat tube is stainless steel. 
     
     
         5 . The burner of  claim 1 , wherein the preheat tube has a circular cross-section. 
     
     
         6 . The burner of  claim 1 , wherein the first portion of the preheat tube is disposed in a middle portion of the preheat tube. 
     
     
         7 . The burner of  claim 1 , wherein the mixer tube is steel. 
     
     
         8 . The burner of  claim 1 , wherein the mixer tune has a circular cross-section. 
     
     
         9 . The burner of  claim 1  further comprising a common coupling, the common coupling configured to couple the pressurized gas to the first end of the preheat tube, the common coupling further configured to couple the second end of the preheat tube to the orifice. 
     
     
         10 . The burner of  claim 9 , wherein the common coupling is formed of brass. 
     
     
         11 . The burner of  claim 9 , wherein the pressurized gas is supplied via a gas line and the common coupling is threaded to facilitate coupling to the gas line. 
     
     
         12 . The burner of  claim 9 , wherein the mixer tube is affixed to the common coupling. 
     
     
         13 . The burner of  claim 1  further comprising:
 a first coupling configured to couple the pressurized gas to the first end of the preheat tube; and   a second coupling configured to couple the second end of the preheat tube to the orifice.   
     
     
         14 . The burner of  claim 13 , wherein the pressurized gas is supplied via a gas line and the first coupling is threaded to facilitate coupling to the gas line. 
     
     
         15 . The burner of  claim 1 , wherein a second portion of the preheat tube is formed in an elongated loop configuration, the second portion of the preheat tube including the first portion of the preheat tube. 
     
     
         16 . The burner of  claim 1 , wherein the preheat tube is affixed to a portion of an exterior surface of the mixer tube.