Heat exchanger

Claim 1

A HEAT EXCHANGER COMPRISING WALL MEANS FORMING A VERTICALLY ELONGATED PRESSURE VESSEL OF CIRCULAR CROSS SECTION, A VERTICALLY ARRANGED TUBULAR SHAPED BAFFLE EXTENDING DOWNWARDLY FROM THE UPPER END OF SAID VESSEL TO A HORIZONTAL PLANE SPACED ABOVE AND ADJACENT TO THE LOWER END OF SAID VESSEL, SAID BAFFLE SPACED INWARDLY FROM THE WALL MEANS OF SAID PRESSURE VESSEL DIVIDING THE INTERIOR OF SAID VESSEL INTO A ANNULAR SHAPED OUTER CHAMBER AND A CENTRALLY DISPOSED INNER CHAMBER IN COMMUNICATION WITH SAID OUTER CHAMBER AT THE LOWER END OF SAID VESSEL, A PLURALITY OF HEAT EXCHANGE TUBES DISPOSED WITHIN SAID PRESSURE VESSEL FOR PARALLEL FLOW OF A FLUID TO BE HEATED THERETHROUGH, EACH OF SAID TUBES HAVING A FIRST DOWNCOMER PORTION POSITIONED IN SAID INNER CHAMBER AND A SECOND RISER PORTION POSITIONED IN SAID OUTER CHAMBER, THE SECOND PORTION OF SAID TUBES SUBSTANTIALLY FILLING SAID OUTER CHAMBER AND FORMING A NUMBER OF VERTICALLY EXTENDING CIRCUMFERENTIALLY SPACED TUBE BANKS, EACH OF SAID TUBE BANKS COMPRISING A PLURALITY OF UNIFORMLY HORIZONTALLY SPACED VERTICALLY EXTENDING TUBE PLATENS EACH ARRANGED IN A SINGLE CHORDALLY DISPOSED VERTICAL PLANE, EACH OF SAID TUBES WITHIN SAID PLATENS COMPRISING A PLURALITY OF HORIZONTALLY EXTENDING VERTICALLY SPACED TUBE SECTIONS JOINED BY REVERSE BENDS AND ARRANGED FOR COUNTER-FLOW HEAT TRANSFER, MEANS FOR SUPPLYING FLUID TO BE HEATED TO THE UPPER ENDS OF THE FIRST DOWNCOMER PORTIONS OF SAID TUBES, MEANS FOR COLLECTING THE FLUID TO BE HEATED AFTER ITS PASSAGE THROUGH THE RISER PORTIONS OF SAID TUBES, HEATING FLUID INLET MEANS LOCATED IN THE UPPER PART OF SAID OUTER CHAMBER, AND HEATING FLUID OUTLET MEANS LOCATED IN THE LOWER END OF SAID PRESSURE VESSEL WHEREBY THE HEATING FLUID TRANSFERS HEAT TO THE FLUID TO BE HEATED AS IT FLOWS DOWNWARDLY THROUGH THE OUTER CHAMBER PASSING OVER THE SECOND RISER PORTIONS OF SAID TUBES WITHIN WHICH THE FLUID TO BE HEATED FLOWS.