Multi-segmented tube sheet

A tube sheet construction that includes a tube sheet and a plurality of elongated tubular elements supported by the tube sheet, said tube sheet comprised of a plurality of separate planar tube sheet segments, multiple holes being provided in each planar tube sheet segment in a predetermined pattern, each hole for accommodating one of the plurality of elongated tubular elements, all of the tube sheet segments being aligning so that the hole pattern of each segment aligns with the hole pattern in all other segments, each said elongated tubular element having a flanged top end and a contiguous tubular shaft with the flanged top end having a diameter greater than a diameter of the tubular shaft, wherein the flanged top end of a first elongated tubular element is disposed between a first pair of adjacently disposed tube sheet segments, and the flanged top end of a second elongated tubular element is disposed between a second pair of adjacently disposed tube sheet segments that is different than the first pair of adjacently disposed tube sheet segments.