Tube design for terrace wall furnace

Claim 1

A PRIMARY REFORMER FOR USE IN THE PRODUCTION OF HYDROGEN AND CARBON MONOXIDE MIXTURES COMPRISING A HOUSING INCLUDING OPPOSITE VERTICALLY ORIENTED SIDE WALLS EACH SIDE WALL DEFINING AT LEAST TWO REFRACTORY FACED PLANAR SURFACES ONE ABOVE THE OTHER; INWARDLY ORIENTED STEP MEANS BETWEEN THE PLANAR SURFACES; OPPOSITE PLANAR SURFACES BEING SUBSTANTIALLY COEXTENSIVE WITH EACH OTHER IN A VERTICAL DIRECTION SO THAT THE SIDE WALLS AND STEP MEANS DEFINE AT LEAST TWO DISTINCT HEATING CHAMBERS ONE ABOVE THE OTHER; INDIVIDUALLY CONTROLLED HEATING MEANS FOR EACH OF SAID HEATING CHAMBERS; A PLURALITY OF CLOSELY SPACED PARALLEL UPRIGHT CATALYST FILLED REACTION TUBES WITHIN SAID HOUSING APPROXIMATELY MIDWAY BETWEEN SAID SIDE WALLS; EACH OF SAID TUBES HAVING A UNIFORM OUTSIDE DIAMETER LENGTHWISE THEREOF AND OPPOSED INLET AND OUTLET ENDS; SAID TUBES ALSO HAVING A CHANGE IN WALL THICKNESS ALONG THEIR LENGTHS OCCURRING SUBSTANTIALLY AT THE PLANE OF SAID STEP MEANS SO THAT EACH TUBE DEFINES AT LEAST TWO REACTION ZONES ONE ABOVE THE OTHER, EACH REACTION ZONE BEING SUBSTANTIALLY COEXTENSIVE WITH A HEATING CHAMABER; THE TUBE WALL THICKNESS BEING SUBSTANTIALLY UNIFORM IN EACH REACTION ZONE, AND GREATER IN A AREACTION ZONE AJACENT A TUBE OUTLET END THAN IN A REACTION ZONE ADJACENT A TUBE INLET END.