To realize this principle of 2 walls with an intermediate circuit, an inner and an outer tube are assembled into one physical tube. The outer tube is on the inside provided with longitudinal leak detection grooves. The inner tubes are mechanical bonded over the full length against the outer tube to ensure a perfect metallic contact. Also 2 tube sheets on each side are used instead of one.
The grooves are in open connection with the space between the two tube sheets.
In case of oil as primary fluid, an increased efficiency is obtained by using externally finned outer tubes, resulting in a compact design.
The materials of the tubes can be different. The outer tube is preferably made of copper. In case contact between copper and cooling medium is not allowed it will be possible to provide the tubes with a tin (Sn) layer. It is obvious that the thermal calculation is also based on the material-choice of the tubes.
The construction of the Double Tube cooler does not require specific measures for the cooling system, such as a minimum operating pressure.
Detection
To detect any fluid in the intermediate space, leak detection equipment is required. A special connection between the 2 tube plates is provided for mounting the leakage detector. The principle of the leakage detector is based on a change in capacity between 2 conductors. A switch, which is connected to the alarm system, is activated. This leakage detector is normally included in the supply.
