Single Tubesheet Design

U-Tube Heat Exchangers For

Single Tubesheet Design
U-Tube Duty

One tubesheet instead of two is the U-tube's structural economy. It is also why the design tolerates unlimited thermal expansion, because nothing anchors the far end of the bundle.

In a straight-tube exchanger both ends of every tube must be held and sealed, which needs a tubesheet at each end. In a U-tube exchanger the tube turns around inside the shell, so both ends arrive at the same place.

The structural consequence. Half the tubesheets, no rear head, no rear pressure-boundary joint. On any exchanger those are significant components, and on a high-pressure or high-alloy unit they are a substantial fraction of the cost.

Where the Saving Actually Lands. On a small carbon steel exchanger the second tubesheet is a modest line item. On a large unit in Hastelloy or titanium it is enormous, and removing it changes the economics of the whole selection.

This is why U-tube construction dominates high-alloy service. The material cost of a thick alloy tubesheet is high enough that halving the count often outweighs the loss of tube-side cleaning access.