Fire grate with hot coal and ash

Abstract

A fire grate assembly for burning solid fuel is discussed in the present disclosure. In one exemplary embodiment, a metal frame has a grate for supporting solid fuel during combustion and, below the grate, a hot coal and ash filter having an undulating upper surface for separating hot coals of different sizes, filtering out ash, and allowing vertical airflow through the hot coals. The assembly may also have a cage extending generally upwards from the solid fuel supporting grate perimeter to help retain the solid fuel thereon and may also have projections extending from the frame to support the hot coal and ash filter above a surface.

What is claimed is: 
     
         1 . A hot coal managing and ash filtering fire grate assembly comprising:
 a metal frame defining an open horizontal cross sectional area; and,   a solid fuel supporting grate affixed to an upper portion of the metal frame and extending generally horizontal, the solid fuel supporting grate having a plurality of spaced cross members defining vertical through openings that in use allow vertical passage of hot coals; and,   a coal and ash filter affixed to a lower portion of the metal frame at a spaced distance below the solid fuel supporting grate of about 2 inches to about 8 inches, measured from the top surface of the grate to the top surface of the filter, for receiving on an upper surface thereof hot coals passed downward from the solid fuel supporting grate, the coal and ash filter having an undulating upper surface that defines progressively smaller horizontal passageways from the upper surface to a lower surface thereof so that received hot coals progress vertically downward on the coal and ash filter as they burn and reduce in size, thereby creating vertical spacing between smaller and larger hot coals and allowing ash to pass completely through the filter.   
     
     
         2 . The hot coal managing and ash filtering fire grate assembly of  claim 1 , wherein the undulating surface is formed by a plurality of adjacent support struts defining the progressively smaller horizontal passageways from the upper surface to the lower surface thereof. 
     
     
         3 . The hot coal managing and ash filtering fire grate assembly of  claim 1 , wherein the undulating surface is formed by sheet metal in a zig-zag arrangement creating peaks and valleys in at least one horizontal direction defining the progressively smaller horizontal passageways from the upper surface to the lower surface thereof. 
     
     
         4 . The hot coal managing and ash filtering grate assembly of  claim 1 , wherein the assembly further comprises vertically downward projections that support the coal and ash filter above a surface. 
     
     
         5 . The hot coal managing and ash filtering grate assembly of  claim 1 , wherein the assembly further comprises support members extending beyond the horizontal cross sectional area to engage an edge of a fire pit or fire ring and support the coal and ash filter above a surface. 
     
     
         6 . The hot coal managing and ash filtering grate assembly of  claim 1 , wherein the solid fuel supporting grate includes a plurality of spaced crossmembers defining vertical through openings with horizontal spacing of about 3 inches to about 6 inches that in use allow vertical passage of hot coals. 
     
     
         7 . The hot coal managing and ash filtering grate assembly of  claim 6 , wherein the solid fuel supporting grate includes a first plurality of spaced crossmembers with horizontal spacing of about 3 inches to about 6 inches and a second plurality of spaced crossmembers, generally perpendicular to the first plurality, with horizontal spacing of about 3 inches to about 6 inches defining a grid of vertical through openings that in use allow vertical passage of hot coals. 
     
     
         8 . The hot coal managing and ash filtering grate assembly of  claim 1 , wherein the coal and ash filter passageways at the lower surface allow passage of hot coals having horizontal dimensions of less than about 0.25 inches to less than about 0.75 inches. 
     
     
         9 . The hot coal managing and ash filtering grate assembly of  claim 1 , wherein the coal and ash filter is affixed to a lower portion of the metal frame at a spaced distance below the solid fuel supporting grate of about 3 inches to about 5 inches measured from the top surface of the grate to the top surface of the filter. 
     
     
         10 . The hot coal managing and ash filtering fire grate assembly of  claim 3 , wherein the valleys of the coal and ash filter are substantially open passageways to minimize the build-up of ash on the surfaces thereof. 
     
     
         11 . The hot coal managing and ash filtering fire grate assembly of  claim 10 , wherein the valleys of the coal and ash filter are greater than 90% open passageways to minimize the build-up of ash on the surfaces thereof. 
     
     
         12 . The hot coal managing and ash filtering fire grate assembly of  claim 3 , wherein the horizontal distance between adjacent peaks is between about 1 inch and about 4 inches and the vertical distance between peaks and valleys is between about 1.5 inches and about 6 inches. 
     
     
         13 . The hot coal managing and ash filtering fire grate assembly of  claim 12 , wherein the horizontal distance between adjacent peaks is between about 2 inches and about 3 inches and the vertical distance between peaks and valleys is between about 2.5 inches and about 4 inches. 
     
     
         14 . The hot coal managing and ash filtering fire grate assembly of  claim 3 , wherein the sheet metal is perforated, creating openings with a minor dimension between 0.25 and 0.75 inches and an open area between 10 and 70 percent. 
     
     
         15 . A hot coal managing and ash filtering fire grate assembly comprising:
 a metal frame defining an open horizontal cross sectional area; and,   a solid fuel supporting grate affixed to an upper portion of the metal frame and extending generally horizontal, the solid fuel supporting grate having a plurality of spaced cross members defining vertical through openings that in use allow vertical passage of hot coals; and,   a coal and ash filter affixed to a lower portion of the metal frame at a spaced distance below the solid fuel supporting grate of about 2 inches to about 8 inches measured from the top surface of the grate to the top surface of the filter for receiving on an upper surface thereof hot coals passed downward from the solid fuel supporting grate, the coal and ash filter having an undulating upper surface that defines progressively smaller horizontal passageways from the upper surface to a lower surface thereof so that received hot coals progress vertically downward on the coal and ash filter as they burn and reduce in size, thereby creating vertical spacing between smaller and larger hot coals and allowing ash to pass completely through the filter; and,   a cage extending generally upwards from the solid fuel supporting grate perimeter to help retain the solid fuel thereon.   
     
     
         16 . The hot coal managing and ash filtering fire grate assembly of  claim 15 , wherein the cage extends generally upwards and outwards from the solid fuel supporting grate perimeter in a funnel shape which guides solid fuel towards the center of the grate as the solid fuel below it breaks up into hot coals and passes through the grate. 
     
     
         17 . The hot coal managing and ash filtering fire grate assembly of  claim 15 , wherein the cage is made from a metal mesh or perforated sheet metal having an open area of more than about 50 percent. 
     
     
         18 . The hot coal managing and ash filtering fire grate assembly of  claim 15 , wherein the cage comprises an array of generally vertical metal members with a profile width of about 0.04 inches to about 0.50 inches on the side that faces the center of the grate to minimize blockage of radiant heat from the burning solid fuel and hot coals. 
     
     
         19 . A hot coal managing and ash filtering fire grate assembly comprising:
 a metal frame defining an open horizontal cross sectional area; and,   a solid fuel supporting grate affixed to an upper portion of the metal frame and extending generally horizontal, the solid fuel supporting grate having a plurality of spaced cross members defining vertical through openings that in use allow vertical passage of hot coals; and,   a coal and ash filter affixed to a lower portion of the metal frame at a spaced distance below the solid fuel supporting grate of about 2 inches to about 8 inches measured from the top surface of the grate to the top surface of the filter for receiving on an upper surface thereof hot coals passed downward from the solid fuel supporting grate; and,   support members extending beyond the horizontal cross sectional area to engage an edge of a fire pit or fire ring and support the coal and ash filter above a surface.   
     
     
         20 . The hot coal managing and ash filtering fire grate assembly of  claim 19 , further comprising a cage extending generally upwards from the solid fuel supporting grate perimeter to help retain the solid fuel thereon.