Full-Length Sleeving for Process Heat Exchanger Tubes

摘要

As heat exchangers age, their tube thickness decreases because of erosion, corrosion or a combination of both. Installing thin sleeves in tubes in which the tube walls have become so thin that failure is imminent is a maintenance technique useful for extending heat exchanger life. Sleeving introduces an additional resistance to heat flow called contact resistance. For most applications, sleeve material and tube material have the same specification. Therefore, the increase from the ambient temperature at which the sleeves are installed does not cause substantially different radial-expansion rates in the sleeve and parent tube. Only the creep properties of the sleeve and tube limit the temperature at which the sleeved exchanger can function with the sleeve-tube interface intact. However, it may be desirable to use a sleeve material that is more resistant to corrosion and erosion than the parent sleeve material.