U-Tube Bundle Titanium, Nickel, Stainless Steel, Fin Tube

U-Tube Bundle

Tubing that is generally used in TEMA sizes is made from low carbon steel, copper, Admiralty, Copper-Nickel, stainless steel, Hastalloy, Inconel, titanium and a few others. It is common to use tubing from 5/8" to 1-1/2" in these designs.
Tubes are either generally drawn and seamless or welded as well as finned tubes. High quality ERW (electro-resistance welded) tubes exhibit superior grain structure at the weld.

Tube holes of tubesheets can be drilled and reamed and can be machined with one or more grooves. This greatly increases the strength of the tube joint.      

                                                                                                      
Where the tube and tube sheet materials are joinable, weldable metals, the tube joint can be further strengthened by applying a seal weld or strength weld to the joint.

A strength weld has a tube slightly reccessed inside the tube hole or slightly extended beyond the tube sheet. The weld adds metal to the resulting lip.

A seal weld is specified to help prevent the shell and tube liquids from intermixing. In this treatment, the tube is flush with the tube sheet surface. The weld does not add metal, but rather fuses the two materials.

In cases where it is critical to avoid fluid intermixing, a double tube sheet can be provided. In this design, the outer tube sheet is outside the shell circuit, virtually eliminating the chance of fluid intermixing. The inner tube sheet is vented to atmosphere so any fluid leak is easily detected.