Patent ID: 7762807

Claim:
A radiant tube system comprising: an inner tubular member having an exhaust gas inlet end forming an exhaust gas inlet opening and having an exhaust gas outlet end forming an exhaust gas outlet opening; an outwardly extending circumferential flange connected with said exhaust gas inlet end of said inner tubular member; an inner intermediate tubular member concentrically disposed around said inner tubular member having a preheated first gaseous fluid outlet end forming a preheated first gaseous fluid outlet opening proximate said outwardly extending circumferential flange, a first gaseous fluid inlet end proximate said exhaust gas outlet end of said inner tubular member, and forming an inner annular region between said inner tubular member and said inner intermediate tubular member; an outer intermediate tubular member concentrically disposed around said inner intermediate tubular member forming an outer intermediate annular region between said outer intermediate tubular member and said inner intermediate tubular member and having a first end connected with said outwardly extending circumferential flange and having an opposite second end proximate said first gaseous fluid inlet end of said inner intermediate tubular member; an outer tubular member concentrically disposed around said outer intermediate tubular member having a closed-offend proximate said exhaust gas inlet end of said inner tubular member, an opposite end proximate said exhaust gas outlet end of said inner tubular member forming an opening through which each of said inner tubular member, inner intermediate tubular member and outer intermediate tubular member extends, and forming an outer annular region between said outer tubular member and said outer intermediate tubular member; fluid communication means for providing fluid communication between said outer intermediate annular region and said outer annular region; seal means for sealing between said outer tubular member and said outer intermediate tubular member proximate said exhaust gas outlet end of said inner tubular member proximate said exhaust gas outlet end of said inner tubular member, between said outer intermediate tubular member and said inner intermediate tubular member proximate said exhaust gas outlet end of said inner tubular member, and between said inner intermediate tubular member and said inner tubular member proximate said exhaust gas outlet end of said inner tubular member; a first gaseous fluid conduit connected with said opposite end of said outer tubular member proximate said exhaust gas outlet end of said inner tubular member and in fluid communication with said outer annular region; and a second gaseous conduit connected with said inner intermediate tubular member proximate said first gaseous fluid inlet end and in fluid communication with said inner annular region.