Pilot tube assembly and method for gas appliance ranges

Abstract

A pilot tube assembly comprises a gas inlet tube and a pilot tip with a central aperture. During delivery of gas, one or more apertures of the assembly aspirate ambient air to provide a combustible mixture. A central tapered bore of the assembly receives a gas inlet tube. The tapered bore of the pilot tip is swaged with a gas inlet tube by application of force. The taper angle of central tapered bore ranges from about 1 to 2 degrees, and is preferably 1.5 degrees, with respect to the center line of the pilot tip to enable swaging action at reasonable pressures and to enable a large thermal contact area between the pilot tip and gas inlet tube, thereby equilibrating their temperatures and preventing separation due to thermal expansion.

1 ) A pilot tube assembly for a gas appliance, comprising: 
 a) a pilot tip having a central aperture for gas flow, a centerline, one or more apertures for aspiration of combustion air, and a central tapered bore for receiving a gas inlet tube having an outer diameter;    b) said gas inlet tube being mechanically attached to said pilot tip's tapered bore by the application of force creating a swaged joint;    whereby said swaged joint between said gas inlet tube and said pilot tip is gas leak tight and sustains repeated heating and cooling thermal cycles, of at least 700 degrees F, typically experienced by said pilot tube during operation of said gas appliance.    
   
   
       2 ) A pilot tube assembly as recited by  claim 1 , wherein said central tapered bore has a taper inclined at an angle ranging from 1 to 2 degrees with respect to said centerline of said pilot tip.  
   
   
       3 ) A pilot tube assembly as recited by  claim 1 , wherein said central tapered bore has a taper inclined at an angle ranging from 1.25 to 1.75 degrees with respect to said centerline of said pilot tip.  
   
   
       4 ) A pilot tube assembly as recited by  claim 1 , wherein said central tapered bore has a taper inclined at an angle of 1.5 degrees with respect to said centerline of said pilot tip.  
   
   
       5 ) A pilot tube assembly as recited by  claim 1 , wherein said central tapered bore of said pilot tip has a diameter ranging from 1.005 to 1.05 times said outer diameter of said gas inlet tube.  
   
   
       6 ) A method of manufacturing pilot tube assembly, comprising the steps of: 
 a) preparing a pilot tip with a taper at one end for receiving a gas inlet tube, said gas inlet tube being straight or bent, and said pilot tip having a centerline;    b) loading said pilot tip with said taper in an assembly machine;    c) grabbing said straight or bent gas inlet tube by a pair of jaw grips to grab and position said gas inlet tube within said taper of said pilot tip;    d) applying pressure to swage a gas leak-tight joint between said taper of said pilot tip and said gas inlet tube;    whereby manufacture of said pilot tube assembly is automated.    
   
   
       7 ) A method of manufacturing a pilot tube assembly as recited in  claim 6 , wherein said taper ranges from about 1 to 2 degrees with respect to said centerline of said pilot tip.  
   
   
       8 ) A method of manufacturing a pilot tube assembly as recited in  claim 6 , wherein said taper ranges from about 1.25 to 1.75 degrees with respect to said centerline of said pilot tip.  
   
   
       9 ) A method of manufacturing a pilot tube assembly as recited in  claim 6 , wherein said taper is 1.5 degrees with respect to said centerline of said pilot tip.