Graphite rotary tube furnace

A rotary tube furnace comprising:

• a generally horizontally extending rotatable graphite tube comprising two or more removable and replaceable tube sections, said graphite tube having a feed entrance zone, a heating zone, and a product discharge zone;
• a multiplicity of graphite radiation baffles attached to an inner surface of said graphite tube to inhibit a loss of radiant heat;
• a plurality of split ring graphite bearings slidably supporting said rotatable graphite tube, at least one split ring bearing being within said entrance zone and at least one split ring bearing being within said product discharge zone;
• each of said split ring graphite bearings within said entrance zone and said product discharge zone, being surrounded by a water-cooled jacket;
• a stainless steel drive plate attached to said graphite tube to transmit rotational torque thereto, said drive plate being attached to said graphite tube by a keyway or spline connection to allow for differences in thermal expansion or contraction;
• an enclosure around said graphite tube adapted to maintain a selected atmosphere around and within said graphite tube, said enclosure comprising two graphite rings, each pressed against an opposite side of said drive plate by a flexible atmospheric sealing assembly to maintain a slidable sealing relationship between said graphite rings and said drive plate, a first hood at an end of said entrance zone of said graphite tube, a second hood at an end of said product discharge zone of said graphite tube, at least two of said water-cooled jackets, an insulated heating chamber around said heating zone, said two graphite rings, and said drive plate, said components being maintained in a sealing relationship by a spring-like force from said flexible atmospheric sealing assembly;
• gas inlet and outlet means in said insulated heating chamber for the entry and exit of gas to provide a selected atmosphere within said heating chamber;
• a first gas port in said first hood and a second gas port in said second hood for the entry or exit of gas to provide a co-current or counter-current flow of gas through said graphite tube;
• a gas entryway within each of said graphite rings for the transmission and maintenance of a positive pressure of gas against said drive plate.