Tubular heat exchanger

Claim 1

A tubular heat exchanger comprising an inlet chamber including an apertured tube inlet plate, an outlet chamber including an apertured tube outlet plate, a nest of tubes extending between said tube inlet and outlet plates, each said tube having its ends mounted within apertures in respectively said tube inlet plate and said tube outlet plate, and sealing means mounted between each said tube end and the edges of its associated aperture to effect a seal between the tube and plate, and in which the sealing means comprises a sleeve constructed of elastically-deformable material and having three axiallydisplaced sealing zones, two of said sealing zones being external of said sleeve and having diameters such that when the sleeve is mounted in its associated aperture these external sealing zones each contact the plate around said aperture to effect a seal therewith, the other of said sealing zones being internal of said sleeve and having a diameter such that it tightly embraces the tube within the sleeve to effect a seal therewith, said internal sealing zone being intermediate and substantially equidistant from said external sealing zones and linked thereto by connecting zones, and in which each of the two external sealing zones includes a raised edge eXtending radially outwards normal to the axis of the sleeve, the axial distance separating these raised edges when the sleeve is unmounted being slightly less than the thickness of the associated tube plate, and in which the internal sealing zone is formed by a part of the inner surface of the sleeve which is cylindrical when the sleeve is unmounted but which deforms to become slightly concave when the sleeve is mounted in the associated plate, thus raising lips at each end of the deformed, slightly concave part of the inner surface to effect positive sealing between the sleeve and the associated tube.