Heat exchanger

A heat exchanger, comprising:

• (a) a shell;
• (b) a head having an inner surface;
• (c) a tubesheet having a peripheral surface;
• (d) a tubesheet skirt;
• (e) a tube bundle connected to the tubesheet;
• (f) a channel cover;
• (g) vertical-sloped annular retaining keys;
• (h) a bolting ring having a plurality of holes therethrough for receiving a plurality of bolts, wherein:
• the head is welded to the shell;
• the tubesheet is positioned within the head to define a gap between the peripheral surface of the tubesheet and the inner surface of the head;
• the tubesheet skirt is welded to the head and the tubesheet:
• the head defines a channel with a recess;
• the tubesheet is positioned adjacent to the recess;
• the tubesheet skirt is cylindrical;
• the head defines a channel with a combined spherical-cylindrical geometry;
• the head has a distal end;
• the channel cover is removably disposed within the distal end of the head;
• the head defines vertical-sloped annular grooves in the distal end of the head;
• the vertical-sloped annular retaining keys are removably nested in the annular vertical-sloped grooves;
• the vertical-sloped annular retaining keys are made of stainless steel;
• the bolts and the bolting ring removably fasten the channel cover to the head;
• the holes in the bolting ring have a diameter sufficiently greater than the diameter of the bolts to allow for thermal expansion;
• the bolting ring is divided into a plurality of segments, and there is a thermal expansion gap between the ends of adjacent segments of the bolting ring when the bolting ring is installed on the head;
• the vertical-sloped annular retaining keys are smaller than the vertical-sloped annular grooves to allow room for thermal expansion of the vertical-sloped annular retaining keys;
• and
• the tubesheet has a ceramic coating.

A head assembly for a heat exchanger having a shell, a tubesheet, and a tube bundle connected to the tubesheet, comprising:

• (a) a head having an inner surface;
• and
• (b) a tubesheet skirt, wherein:
• the head is adapted to be attached to the shell;
• the head defines a channel with a recess adapted to receive the tubesheet within the head adjacent, to the recess so as to define a gap between the peripheral surface of the tubesheet and the inner surface of the head;
• and
• the tubesheet skirt is coupled to the head and is adapted to couple the tubesheet to the head such that the tubesheet is positioned adjacent to the recess so as to define a gap between the peripheral surface of the tubesheet and the inner surface of the head.

A head assembly for a heat exchanger having a shell, a tubesheet, and a tube bundle connected to the tubesheet, comprising:

• (a) a head having an inner surface;
• (b) a tubesheet skirt;
• (c) a channel cover;
• (d) vertical-sloped annular retaining keys;
• (e) a bolting ring having a plurality of holes therethrough for receiving a plurality of bolts, wherein:
• the head is adapted to be welded to the shell:
• the head defines a channel with a recess adapted to receive the tubesheet within the head adjacent to the recess so as to define a gap between the peripheral surface of the tubesheet and the inner surface of the head;
• the tubesheet skirt is welded to the head and is adapted to couple the tubesheet to the head such that the tubesheet is positioned adjacent to the recess so as to define a gap between the peripheral surface of the tubesheet and the inner surface of the head;
• the tubesheet skirt is cylindrical;
• the head defines a channel with a combined spherical-cylindrical geometry;
• the head has a distal end;
• the channel cover is removably disposed within the distal end of the head;
• the head defines vertical-sloped annular grooves in the distal end of the head;
• the vertical-sloped annular retaining keys are removably nested in the annular vertical-sloped grooves;
• the vertical-sloped annular retaining keys are made of stainless steel;
• the bolts and the bolting ring removably fasten the channel cover to the head;
• the spiral wound gasket provides a seal between the bolting ring and the channel cover;
• the holes in the bolting ring have a diameter sufficiently greater than the diameter of the bolts to allow for thermal expansion;
• the bolting ring is divided into a plurality of segments, and there is a gap between the ends of adjacent segments of the bolting ring when the bolting ring is installed on the head;
• the vertical-sloped annular retaining keys are smaller than the vertical-sloped annular grooves to allow room for thermal expansion of the vertical-sloped annular retaining keys;
• and
• the tubesheet has a ceramic coating.