Double Wall Shell & Tube Heat Exchangers

Please contact us with your heat exchanger requirements. AF Pipes offer a wide range of designs and possibilities for double wall shell &  tube heat exchangers, and the final design depends on a combination of the process requirements and the design limitations.  Therefore it is recommended to contact AF Pipe Solutions at an early stage in the process to assess the suitabilty of the design. AF pipe solutions wil be happy to provide guidance at the planning stage. The shell and tube heat exchanger is available in a variety of configurations for double wall safety, as described below.

Shell & Double Tube

A Shell & Double tube heat exchanger is the safest and most robust unit.  The process and heating media are separated by using the specially developed AF Slim double tubes, and double tubesheets, and in some cases which are extra critical double shells. Whilst it is possible to design according to standard, there are specific design characteristics such as heat transfer and pipe stability that are unique to double tube designs, and not covered by standard calculations. They are available in a range of configurations depending on process requirements, including floating or fixed , straight or U tubes. Internally finned or corrugated tubes can also be applied to the process.

The leaking fluid is contained within the unit, through a series of leakage passages, where it is ultimately deteceted by means of a leakage detection system (see leakage secion for more details).

Double Tubesheet

Double tubesheet heat exchangers are used to prevent any leakages through the tube to tubesheet joints. This can be an issue on expanded only tube joints, which will frequently experience leakages over time due to vibrations and thermal fatigue. However there is no double wall safety in case of tube leakage, and the leakage i not contained in the heat exchanger itself. The double tubesheet can be used with U-tube type HEX to prevent leakage through tube to tubesheet connections.

When used with straight tubes (M-type) then a double sheel is also employed.