Gaskets and Sealing

U-Tube Heat Exchangers For

Gaskets and Sealing
U-Tube Duty

Sealing a removable bundle means gaskets, and gaskets are the components most often got wrong during maintenance. Material, thickness and torque all matter, and all three are easy to get casually wrong.

A U-tube exchanger seals in several places: between the shell flange and the tubesheet, between the tubesheet and the head, at the pass partition rib on multi-pass units, and at every bolted nozzle.

Bundle sealing. On many removable-bundle designs the tubesheet is sealed with an o-ring in a machined groove rather than a flat gasket. That arrangement seals well and is sensitive to o-ring size and material, which is why the correct part should come with the bundle.

Thickness Changes More Than You Expect. A gasket of correct material but different thickness alters the compressed stack height. That changes bolt load, and on a bundle it can change the axial position of the tubesheet relative to the shell.

Small position changes matter when nozzle-to-baffle alignment is tight. It is a genuine cause of performance loss and of leaks that no one can explain, and it is entirely avoidable by using the specified part.