Fire grate system for a low-emission outdoor fire ring

Abstract

The present invention is directed to several embodiments or variations of a fire grate system for a low-emission outdoor fire pit or fire ring. Several of these variations use the same fundamental fire grate framework within the system and are adapted burn liquefied petroleum gas (LPG), a common example of which is propane. A first embodiment of the invention may simulate a wood fire without burning wood by securely attaching artificial ceramic (or similarly constructed) fire logs to a LPG gas-burning fire grate framework. A second, alternative embodiment of the present invention is a gas/wood hybrid system and that uses LPG fuel to reduce emissions from a wood fire.

What is claimed is: 
     
         1 . A fire grate system for a low-emission outdoor fire ring, the fire grate system comprising:
 a grate structure;   a gas manifold attached to the grate structure and fluidly connectible to a gas supply, the gas manifold having a plurality of gas distribution apertures disposed therein and operative to distribute gas flowing therethrough into a primary combustion zone; and   an air outlet manifold cooperatively engaged to the gas manifold, the air outlet manifold having a plurality of air distribution apertures disposed therein and operative to distribute air flowing therethrough into a secondary combustion zone proximate the primary combustion zone.   
     
     
         2 . The fire grate system of  claim 1 , wherein the air outlet manifold is removably connected to the gas manifold. 
     
     
         3 . The fire grate system of  claim 1  wherein the gas manifold is rotatably connected to the grate structure, and selectively movable between extended and collapsed positions relative thereto. 
     
     
         4 . The fire grate system of  claim 1 , further in combination with an annular fire ring structure defining a cavity, the fire grate system at least partially residing with the cavity. 
     
     
         5 . The fire grate system of  claim 1 , further in combination with a fire pit structure defining an elevated cavity, the fire grate system at least partially residing with the cavity. 
     
     
         6 . The fire grate system of  claim 1 , wherein the gas manifold comprises:
 an upper manifold tube;   a lower manifold tube; and   a connection tube extending between and fluidly connecting the upper and lower manifold tubes to each other.   
     
     
         7 . The fire grate system of  claim 6  wherein the gas distribution apertures are disposed in only the upper and lower manifold tubes. 
     
     
         8 . The fire grate system of  claim 7  wherein the upper and lower manifold tubes and intervening connection tube are integrally connected to each other. 
     
     
         9 . The fire grate system of  claim 6  wherein the air outlet manifold comprises:
 an air outlet tube disposed proximate the upper manifold tube when the air outlet manifold is operatively coupled to the gas manifold; and 
 at least one air intake tube fluidly connected to and protruding from the air outlet tube, the air intake tube defining an air inlet opening which is disposed proximate one side of the primary combustion zone opposite another side thereof which is proximate the secondary combustion zone. 
 
     
     
         10 . The fire grate system of  claim 9  wherein the air distribution apertures are disposed in only the air outlet tube. 
     
     
         11 . The fire grate system of  claim 9  wherein three air outlet tubes are fluidly connected to and protrude from the air outlet tube in a common direction and in equidistantly spaced, generally parallel relation to each other. 
     
     
         12 . The fire grate system of  claim 9  wherein two air outlet tubes are fluidly connected to and protrude from the air outlet tube in a common direction and in spaced, generally parallel relation to each other. 
     
     
         13 . A fire grate system for a low-emission outdoor fire ring, the fire grate system comprising:
 a grate structure;   a gas manifold rotatably connected to the grate structure and fluidly connectible to a gas supply, the gas manifold having a plurality of gas distribution apertures disposed therein and operative to distribute gas flowing therethrough into a primary combustion zone; and   an air outlet manifold cooperatively engaged to the gas manifold and releasably engaged to the grate structure, the air outlet manifold having a plurality of air distribution apertures disposed therein;   the gas and air outlet manifolds being selectively movable between extended and collapsed positions relative to the grate structure, with the air outlet manifold being operative to distribute air flowing therethrough into a secondary combustion zone proximate the primary combustion zone when both the gas and air outlet manifolds are in the extended position.   
     
     
         14 . The fire grate system of  claim 13 , further in combination with an annular fire ring structure defining a cavity, the fire grate system at least partially residing with the cavity. 
     
     
         15 . The fire grate system of  claim 13 , further in combination with a fire pit structure defining an elevated cavity, the fire grate system at least partially residing with the cavity. 
     
     
         16 . The fire grate system of  claim 13 , wherein the gas manifold comprises:
 an upper manifold tube;   a lower manifold tube; and   a connection tube extending between and fluidly connecting the upper and lower manifold tubes to each other.   
     
     
         17 . The fire grate system of  claim 16  wherein the gas distribution apertures are disposed in only the upper and lower manifold tubes. 
     
     
         18 . The fire grate system of  claim 17  wherein the upper and lower manifold tubes and intervening connection tube are integrally connected to each other. 
     
     
         19 . The fire grate system of  claim 13  wherein the air outlet manifold comprises:
 an air outlet tube disposed proximate the upper manifold tube when the air outlet manifold is operatively coupled to the gas manifold; and 
 at least one air intake tube fluidly connected to and protruding from the air outlet tube, the air intake tube defining an air inlet opening which is disposed proximate one side of the primary combustion zone opposite another side thereof which is proximate the secondary combustion zone. 
 
     
     
         20 . A fire grate system for a low-emission outdoor fire ring, the fire grate system comprising:
 a ring-like, lower frame assembly fluidly connectible to a gas supply, the lower frame assembly having a plurality of gas distribution apertures disposed therein, the ;   a first upper frame assembly fluidly connected to and elevated above the lower frame assembly, the first upper frame assembly having a plurality of the gas distribution apertures disposed therein; and   a second upper frame assembly fluidly connected to and elevated above the lower frame assembly, the second upper frame assembly having a plurality of the gas distribution apertures disposed therein;   the first and second upper frame assemblies being shaped and oriented relative to each other to collectively define a ring-like configuration.