Recuperative radiant tube

Claim 1

A radiant tube comprising a tubular radiator section directly communicating with an inflow section at one end thereof and with an outflow section at the other end thereof so as to provide a continuous inner cylindrical space through the tube so that high-temperture gases are allowed to enter the tube from said inflow section, increase the temperature of said radiator section in order for the same radiator section to radiate heat, and come out from said outflow section, which tube further includes: (a) a heat exchanger disposed to extend through said outflow section and project into said radiator section to define a cylindrical space thereby over both said outflow section and radiator section; (b) annular gas impermeable support means disposed at the interface of said radiator section and said outflow section; (c) a first tubular partition means formed of air-permeable solid matter which is located between said gas impermeable support means and the projecting end of said heat exchanger to enclose said projecting end of said heat exchanger on an upstream side of the gas flow relative to the location of said heat exchanger so that the high-temperature gases having heated said radiator section must pass through said first partition means and come thereinto in order to flow into said outflow section; (d) removable gas impermeable lid means at the downstream end of said outflow section; and (e) a second tubular partition means formed of air-permeable solid matter which is located between said lid means and said support means to enclose said portion of said heat exchanger on a downstream side of the gas flow relative to the location of said heat exchanger so that the gases having come into said first partition means must enter and pass through said second partition means in order to come out from the radiant tube.