Heat exchanger bundle

Claim 1

IN A HEAT EXCHANGER DEVICE OF THE CLASS DESCRIBED, WHICH INCLUDES WITHIN ITS USUAL ASSEMBLY OF PARTS: A SHELL; A TUBE BUNDLE COMPRISING TUBES, TUBE SHEETS, AND RETAINER PLATES, SAID TUBES HAVING ENDS EXTENDING THROUGH SAID TUBE SHEETS, AND SAID RETAINER PLATES APPLIED TO THE OUTER SURFACES OF SAID TUBE SHEETS; AND FLUID INLET AND OUTLET CONNECTIONS: THE IMPROVEMENT WHICH COMPRISES THE TUBE AND TUBE SHEET CONNECTION WHEREINTHE TUBE SHEET IS PROVIDED WITH A HOLE PASSING THERETHROUGH INTO WHICH AN END OF THE TUBE EXTENDS, A COUNTERBORE EXTENDING INTO SAID TUBE SHEET FROM THE SIDE OPPOSITE TO THAT INTO WHICH THE TUBE EXTENDS, SAID COUNTERBORE CONSTITUTING A COAXIAL ENLARGEMENT OF SAID HOLE AND HAVING A CYLINDRICAL WALL SURROUNDING SAID TUBE END; A RIGID CYLINDRICAL RING DISPOSED WITHIN SAID COUNTERBORE AND HAVING AN OUTSIDE DIAMETER PROVIDING A SNUG FIT OF SMALL TOLERANCE WITHIN THE WALL OF SAID COUNTERBORE AND AN INSIDE DIAMETER PROVIDING A SIMILARLY SNUG FIT ONTO THE TUBE END; AND AN ELASTIC DEFORMABLE O-RING DISPOSED WITHIN SAID COUNTERBORE ALONGSIDE OF SAID RIGID CYLINDRICAL RING AND OF A THICKNESS FOR CONTACT OF ITS OUTER AND INNER DIAMETRICAL BOUNDARIES RESPECTIVELY WITH THE CYLINDRICAL WALL OF THE COUNTERBORE AND THE OUTER SURFACE OF THE TUBE END IN NORMAL RELAXED CONDITION, SAID COUNTERBORE BEING OF GREATER AXIAL LENGTH THAN THAT OF SAID RIGID RING AND SAID DEFORMABLE O-RING, WHEREUPON UPON SUBJECTION OF THE BUNDLE TO A PREPONDERANCE OF FLUID PRESSURE UPON EITHER THE INSIDE OR THE OUTSIDE OF THE TUBES, THE O-RING WILL EFFECTIVELY SEAL THE JUNCTIONS OF THE SURFACES CONCERNED WHETHER OF THE TUBE, THE TUBE SHEET, OR THE RIGID CYLINDRICAL RING.