Radiant tube heating system

A radiant tube heating system comprising:

• (1) a tubular catalytic combustion chamber having first and second orifices defining a combustion flow path therethrough;
• (2) fuel inlet means for injecting fuel into the combustion flow path;
• (3) first and second combined inlet and exhaust units each of which comprises a conduit, said conduit of the first unit communicating with said first orifice and said conduit of the second unit communicating with said second orifice, each of said conduits further comprising heat regenerator means, inlet means for selectively opening and closing fluid communication between a source of gas under pressure and said combustion chamber and outlet means for selectively opening and closing an exhaust path for discharge of products of combustion from the combustion chamber;
• (4) means for igniting the fuel with the gas in the combustion chamber;
• and (5) control means for operating the inlet and outlet means in a cycle which includes a first phase with the first unit having its inlet means open and its outlet means closed while concurrently the second unit has its inlet means closed and its outlet means open, and a second phase in which the first unit has its inlet means closed and its outlet means open while concurrently the second unit has its inlet means open and its outlet means closed, said control means in the first phase directing the flow in a direction from the inlet of the first unit to the outlet of the second unit and in the second phase directing the flow in a direction from the inlet of the second unit to the outlet of the first unit.