Abstract: A burner construction which comprises a woven metal fabric supported on and surrounding a cylindrical metal support member which has openings along its length and around its periphery. A gas supply tube extends from an entrance end axially into the support member and forms an annular space therebetween. The gas supply tube is provided with openings in its periphery at the entrance end and is impervious at its periphery at the opposite. Gas enters the burner through the supply tube and into the annular space through the openings in the gas supply tube. Gas thereafter flows through the support member openings and through the woven metal fabric and is combusted at the outer surface of the metal fabric.

Abstract: The invention relates to the conversion of a substantially conventional gas fired furnace utilizing two or more of the clam shell-type heat exchanger cells, which is modified by converting one cell to a final stage counterflow heat exchanger for the hot gases of combustion, which modification incorporates directing the gases of combustion from the fired cells in a counterflow path through the non-fired cell by utilizing a positive displacement fan and then exhausting the gases of combustion. The modification eliminates the need for positive venting, while substantially increasing the operational efficiency of the furnace unit. The normal flue gas temperature in this type of furnace will be about 450.degree. F., while with the modification, the temperature will be reduced to less than about 200.degree. F. and efficiency will be increased by greater than 10 percent.