Heat exchanging apparatus for industrial furnaces

Claim 1

A heat exchanger, for use in an industrial furnace, which utilizes the heat of combustion in a radiant tube of the furnace for preheating the combustion air for the furnace and which includes therein at least one silencing means for diminishing the combustion noise from the radiant tube, said heat exchanger, which is substantially a cylindrical body composed of multiple cylinders, comprises: a fairly narrow cylindrically shaped upward air passage defined by double cylindrical walls disposed at the outermost portion thereof; a downward air passage, communicating with said cylindrically shaped upward air passage, disposed concentrically therewith and on the inner side thereof; a passage for high temperature exhaust gas formed inside said upward air passage and disposed concentrically therewith; at least one resonator disposed inside said upward air passage; an inlet for the air to be heated disposed at a lower portion of the outer periphery of said heat exchanger in communication with said upward air passage; an outlet for the preheated air disposed at a lower portion of the outer periphery of said heat exchanger in communication with the lower end of said downward air passage; an inlet for the high temperature exhaust gas disposed at the bottom of said heat exchanger in communication with the lower end of said high temperature exhaust gas passage; an outlet for the exhaust gas disposed at the top of said heat exchanger in communication with the upper end of said high temperature gas passage; whereby the upward stream of the high temperature exhaust gas is able to impart simultaneously the heat thereof to both the upward and downward stream of air, and the dispositon of the air passage at the outermost side and of the exhaust gas in the central portion increases the efficiency in both the heat exchanging and noise preventing.