Where should the shell side gasket be installed when mounting a new tube bundle?

• A. On the hollow end cap
• B. Over the floating head end of the tube bundle, before the bundle is put back in the exchanger
• C. On the shell flange
• D. Inside the bundle

Answer: (B)

In a floating-head shell-and-tube exchanger, the shell-side seal is formed where the floating head meets the shell. So, when mounting a new tube bundle, the shell-side gasket should be placed on the floating head end of the bundle before you insert it back into the exchanger. This positions the gasket so that, once the floating head is bolted to the shell, the gasket sits correctly in the seal groove and is compressed to create a tight, leak-free interface.

Placing it elsewhere would not seal the shell side properly: on the hollow end cap, on the shell flange, or inside the bundle would either miss the actual sealing surface or misalign the gasket, leading to leaks or improper assembly.