When to use Double-Wall tubing in a heat exchanger?
Double-Wall tubes are used in applications where mixing of the two fluids is not acceptable, e.g. E. Glycol & domestic water, transformer oil cooler & water, etc. Double-Wall tubing consists of 2 tubes. The inside tube has 5/8 in OD and the outside tube has 0.75 in OD. The outside tube is of a heavier gauge (tube wall thickness) and has internal longitudinal “flutes”. If a pinhole develops on either side of the Double-Wall tubing, the leaking fluid travels along the tube length and is channeled to the outside of the unit alerting the operator to the problem. Double-Wall tubing is available from stock in copper and 90/10 Cu-Ni. The Heat Exchanger model nomenclature uses an “X” to indicate that the unit is equipped with Double-Wall tubing, e.g. the model will be a “WX” or “WSX” etc.
