Heat concentrating device and firing method

Abstract

A heat concentrating device particular useful for firing objects formed of metal clay includes a preferably frusto-conical body with a hollow interior surrounded by a continuous sidewall, a wide lower end or base, a relatively narrow upper end, a support screen disposed across the upper end for supporting objects to be fired, and an aperture adjacent the upper end for insertion of a temperature sensor connected to a pyrometer assembly for monitoring the temperature at the upper end of the body. The device is placed over a stove burner to capture the heat emitted by the burner in the interior of the body and concentrate the heat at the upper end of the body so as to heat objects placed on the support screen to a suitable firing temperature.

1 . A heat concentrating device for concentrating the heat emitted from a burner for heating objects, the burner having a support structure around the burner, comprising, 
 a body having a continuous sidewall surrounding a hollow interior, with an open first end and an open second end, the cross-sectional area of said open first end being less than the cross-sectional area of said open second end, said body formed of an insulating material of low thermal conductivity, said body to be placed over the burner with said second end upon the support structure around the burner, such that heat emitted from the burner is captured within said hollow interior of said body at said second end and channeled within said interior of said body to and through said open first end, thereby concentrating the heat at said open first end; and    supporting means disposed at said first end of said body for supporting objects placed on said supporting means to be heated.    
   
   
       2 . The heat concentrating device of  claim 1 , wherein said supporting means is a planar screen.  
   
   
       3 . The heat concentrating device of  claim 1 , wherein said supporting means has a peripheral edge, and wherein said sidewall includes an annular ledge at said first end of said body to receive said peripheral edge of said supporting means.  
   
   
       4 . The heat concentrating device of  claim 1 , wherein said sidewall is penetrated by an aperture adjacent to said first end of said body, to receive a temperature sensor inserted through said aperture from the exterior of said body to said interior of said body.  
   
   
       5 . The heat concentrating device of  claim 1 , wherein said material from which said body is formed comprises aluminosilicate.  
   
   
       6 . The heat concentrating device of  claim 1 , wherein said sidewall has an inner surface and an outer surface, and wherein the thickness of said sidewall between said inner surface and said outer surface is generally uniform between said first end of said body and said second end of said body.  
   
   
       7 . The heat concentrating device of  claim 1 , wherein said body has a longitudinal axis extending between said first end and said second end, wherein said first end of said body defines a first plane, wherein said second end of said body defines a second plane, and wherein said first plane and said second plane are parallel and mutually perpendicular to said longitudinal axis of said body.  
   
   
       8 . The heat concentrating device of  claim 2 , wherein said screen is formed of stainless steel.  
   
   
       9 . The heat concentrating device of  claim 7 , wherein the cross-sectional configuration of said body in a plane perpendicular to said longitudinal axis is circular.  
   
   
       10 . The heat concentrating device of  claim 7 , wherein the cross-sectional configuration of said body in a plane perpendicular to said longitudinal axis is polygonal.  
   
   
       11 . The heat concentrating device of  claim 7 , wherein the cross-sectional area of said open first end of said body is about 25 percent of the cross-sectional area of said open second end of said body.  
   
   
       12 . The heat concentrating device of  claim 7 , wherein the cross-sectional area of said open first end of said body is within the range of about 16 percent to about 36 percent of the cross-sectional area of said open second end of said body.  
   
   
       13 . The heat concentrating device of  claim 9 , wherein the diameter of said open first end of said body is within the range of about 40 percent to about 60 percent of the diameter of said open second end of said body, and wherein the height of said body between said open first end and said open second end is within the range of about 50 percent to about 70 percent of said diameter of said open second end of said body.  
   
   
       14 . A heat concentrating device for concentrating the heat emitted by a burner for the purpose of firing objects formed of metal clay, objects formed of a combination of metal clay and ceramic beads, and enameled objects, the burner surrounded by a support structure, comprising, 
 a frusto-conical body to be placed over and around the burner on the support structure surrounding the burner, said body formed of an insulating material of low thermal conductivity, said body having a hollow interior, an open first end, an open second end, and a continuous sidewall of generally uniform thickness extending between said first end and said second end surrounding said hollow interior, said first end defining a first plane and said second end defining a second plane parallel to said first plane, the inside diameter of said body at said first end being in the range of about 40 percent to about 60 percent of the diameter of said body at said second end and the height of said body between said first and second ends being in the range of about 50 percent to about 70 percent of said inside diameter of said second end of said body, said body to be placed over the burner with said second end of said body resting upon the support structure around the burner, such that heat emitted from the burner is captured within said hollow interior of said body and channeled within said interior of said body from said second end through said first end, thereby concentrating the heat at said first end; and    an object support means removably disposed at said first end of said body for supporting objects to be fired.    
   
   
       15 . The heat concentrating device of  claim 14 , wherein said sidewall is penetrated by an aperture adjacent to said first end of said body, to receive a temperature sensor inserted through said aperture from the exterior of said body to said interior of said body.  
   
   
       16 . The heat concentrating device of  claim 14 , wherein said object support means has a peripheral edge portion, wherein said sidewall has an inner surface and an outer surface, and wherein said sidewall includes an annular ledge at said first end of said body, extending from said inner surface of said sidewall toward said outer surface of said sidewall, to receive said peripheral edge portion of said object support means.  
   
   
       17 . The heat concentrating device of  claim 14 , wherein said object support means is an open mesh screen formed of a material that is non-reactive with the objects to be fired.  
   
   
       18 . The heat concentrating device of  claim 14 , wherein said insulating material of which said body is formed comprises aluminosilicate.  
   
   
       19 . The heat concentrating device of  claim 14 , wherein said inside diameter of said body at said first end is approximately 50 percent of said inside diameter of said body at said second end, and wherein said height of said body between said first end and said second end is approximately 60 percent of said inside diameter of said body at said second end.  
   
   
       20 . A method of firing objects formed of metal clay, objects formed of a combination of metal clay and ceramic beads, and enameled objects, utilizing an adjustable gas fueled burner having a support structure around the burner, comprising the steps of, 
 placing upon the support structure and generally centering above the burner a heat concentrating device having a frusto-conical body formed of an insulating material of low thermal conductivity, said body having a hollow interior, an open first end, an open second end, and a continuous sidewall penetrated by an aperture adjacent to said first end of said body to receive a temperature sensor therethrough, the diameter of said body at said first end being substantially less than the diameter of said body at said second end, and the diameter of said body at said second end being larger than the burner such that said second end of said body extends outwardly beyond the burner;    inserting a temperature sensor through said aperture in said sidewall and connecting said temperature sensor to a pyrometer;    placing an object support screen across said first end of said body of said heat concentrating device;    placing the object or objects to be fired on said object support screen above said hollow interior of said body of said heat concentrating device;    igniting the burner so as to produce heat from the combustion of fuel, whereupon the heat produced by the burner flows upward into said hollow interior of said body of said heat concentrating device through said second end thereof, through said interior, and through said first end, thereby concentrating the heat and exposing the objects placed at said first end of said body to the concentrated heat;    monitoring the temperature adjacent to said first end of said body of said heat concentrating device measured by said temperature sensor and said pyrometer;    adjusting the burner to achieve and maintain the temperature desired for firing the objects placed on said support screen;    continuing operation of the burner for the time appropriate for the firing of the objects placed upon said support screen; and    extinguishing the burner upon completion of the firing of the objects.