Please see Fig.5, that is floating head type heat exchanger. Only one end of channel is connected with shell by flange, called stationary end. The other end of tube sheet is not connected with shell but slid relative to shell, called floating head end. Therefore, thermal explosion of pipe bundle is not restrained by shell in this kind of heat exchanger. Thermal effect doesn’t appear because of differential expansion between shell and tube bundles.

Advantages: The tube bundle can be withdrawn in order to clean pipe and shell pass conveniently. Temperature difference among the medium can’t be limited. It can work under high temperature and high pressure. Generally, temperature and pressure are separately no more than 450℃ and 6.4MPa. It can be used in the situation that the dirt is very heavy and the tube side is easy to be corrosive.

Disadvantages: The flange connecting area between floating head cover and tube sheet is quite large, so that the diameter of shell increase, and the annual channel with small resistance between tube bundle and shell is formed. Part of fluid will pass here and don’t take part in the heat exchange process. The disadvantage includes complex structure; high metal consumption, high cost.

Above advantages and disadvantages indicate that the floating head type heat exchanger can suit the condition of large temperature difference between pipe and shell , high causticity of shell side medium and scale formation easily . It can be applied widely although it has complex structure, high metal consumption and high cost.