Heat activated air shutter for fireplace and related methods

Abstract

The present invention is directed to a heating unit, such as a fireplace, including an interior housing forming a combustion chamber. The housing includes a top wall, a rear wall and side walls defining an exterior housing about the combustion chamber. A burner assembly is positioned to provide combustion to the combustion chamber and a heat activated shutter is provided in communication with the burner assembly for controlling flow of air into the burner assembly so as to produce a yellow flame within the unit in a generally instantaneous time period.

1 . A gas heating unit, comprising: 
 a combustion chamber; and    a burner housing assembly positioned to provide combustion to said combustion chamber, wherein said burner housing assembly includes a burner housing and a gas and air mixing assembly in communication with said burner housing, said gas and air mixing assembly functioning to mix gas and air to provide a yellow appearing flame instantaneously after initiation of combustion.    
   
   
       2 . The gas heating unit of  claim 1 , wherein said gas and air mixing assembly is automatically responsive to changes in temperature to maintain said yellow appearing flame over time.  
   
   
       3 . A gas heating unit, comprising: 
 a combustion chamber; and    a burner housing assembly positioned to provide combustion to said combustion chamber, wherein said burner housing assembly includes a burner housing and a gas and air mixing assembly in communication with said burner housing;    said gas and air mixing assembly including a mixing tube assembly, said mixing tube assembly including a mixing tube having at least one air opening formed at an outer end thereof and a shutter collar assembly sized, shaped and positioned to seal with said at least one air opening of said mixing tube, said shutter collar assembly being attached to a bi-metal coil spring, said bi-metal coil spring being responsive to changes in temperature to withdraw said shutter collar assembly from said at least one air opening in response to an increase of temperature from an ambient temperature and permitting air to enter said at least one air opening.    
   
   
       4 . The gas heating unit of  claim 3 , wherein said burner housing includes a burner housing opening sized and shaped to receive said mixing tube.  
   
   
       5 . The gas heating unit of  claim 3 , wherein said at least one air opening includes an upper air opening and a lower air opening.  
   
   
       6 . The gas heating unit of  claim 5 , wherein said shutter collar assembly includes a first shutter collar having a first shutter collar inside surface and a first shutter gasket attached to said first shutter collar inside surface.  
   
   
       7 . The gas heating unit of  claim 6 , wherein said shutter collar assembly includes a second shutter collar having a second shutter collar inside surface and a second shutter gasket attached to said second shutter collar inside surface.  
   
   
       8 . The gas heating unit of  claim 7 , wherein said upper air opening includes a first shutter collar subassembly and said lower air opening includes a second shutter collar subassembly.  
   
   
       9 . The gas heating unit of  claim 8 , wherein said first shutter collar subassembly is attached to an upper bi-metal coil spring and said second shutter collar subassembly is attached to a lower bi-metal coil spring.  
   
   
       10 . A burner housing assembly for use in a heating unit, comprising: 
 a burner housing and a gas and air mixing assembly in communication with said burner housing;    said gas and air mixing assembly including a mixing tube assembly, said the mixing tube assembly including a mixing tube having at least one air opening formed at an outer end thereof and a shutter collar assembly sized, shaped and positioned to seal with said at least one air opening of said mixing tube, said shutter collar assembly being attached to a bi-metal coil spring, said bi-metal coil spring being responsive to changes in temperature to withdraw said shutter collar assembly from said at least one air opening in response to an increase of temperature from an ambient temperature and permitting air to enter said at least one air opening.    
   
   
       11 . The burner housing assembly of  claim 10 , wherein said burner housing includes a burner housing opening sized and shaped to receive said mixing tube.  
   
   
       12 . The burner housing assembly of  claim 10 , wherein said at least one air opening includes an upper air opening and a lower air opening.  
   
   
       13 . The burner housing assembly of  claim 12 , wherein said shutter collar assembly includes a first shutter collar having a first shutter collar inside surface and a first shutter gasket attached to said first shutter collar inside surface.  
   
   
       14 . The burner housing assembly of  claim 13 , wherein said shutter collar assembly includes a second shutter collar having a second shutter collar inside surface and a second shutter gasket attached to said second shutter collar inside surface.  
   
   
       15 . The burner housing assembly of  claim 14 , wherein said upper air opening includes a first shutter collar subassembly and said lower air opening includes a second shutter collar subassembly.  
   
   
       16 . The burner housing assembly of  claim 15 , wherein said first shutter collar subassembly is attached to an upper bi-metal coil spring and said second shutter collar subassembly is attached to a lower bi-metal coil spring.  
   
   
       17 . The burner housing assembly of  claim 16 , further including a spring plate connected to said mixing tube, said spring plate having a pair of spring tabs extending therefrom, each of said pair of spring tabs positioned adjacent a respective one of said upper air opening and said lower air opening.  
   
   
       18 . The burner housing assembly of  claim 17 , wherein said upper bi-metal coil spring is attached to an upper of said pair of spring tabs at a mounting portion thereof and said lower bi-metal coil spring is attached to a lower of said pair of spring tabs at a mounting portion thereof.  
   
   
       19 . The burner housing assembly of  claim 18 , when said upper bi-metal coil spring is attached to a first shutter collar subassembly at an attachment portion thereof and said lower bi-metal coil spring is attached to a lower shutter collar subassembly at an attachment portion thereof.  
   
   
       20 . A method of controlling the color of a flame in a heating unit, comprising; 
 supplying a burner housing of the heating unit with a flow of gaseous fuel;    sensing an initial start up condition of the heating unit;    limiting the amount of air flow into the burner housing of the heating unit in response to said sensing of the initial start up condition to generate an instantaneous yellow appearing flame upon combustion;    sensing an increase of temperature relative to the initial start up condition; and    increasing air flow into the burner housing in response to said sensing an increase in temperature to maintain the color of the flame.