Selection of tube material
In order to transfer heat well, the pipe should have good thermal conductivity. Because heat is transferred from the hot side to the cold side through the tube, there is a temperature difference across the width of the tube. Thermal stress is generated during operation due to the tendency of the tube material to thermally expand at various temperatures. This is a supplement to any stress caused by the high pressure of the fluid itself. The tube material should also be compatible with the shell and tube side fluids for extended periods of time under operating conditions (temperature, pressure, pH, etc.) to minimize degradation such as corrosion. All of these requirements require careful selection of sturdy, thermally conductive, corrosion resistant, high quality tubing, typically metals, including aluminum, copper alloys, stainless steel, carbon steel, colored copper alloys, inconel, nickel, Hastelloy and titanium. Fluoropolymers such as perfluoroalkoxy alkane (PFA) and fluorinated ethylene propylene (FEP) are also used for the production of pipes due to their high resistance to extreme temperatures. Improper selection of tube material may result in leakage of the tube between the housing and the side of the tube, causing fluid cross-contamination and possibly pressure loss.
Applications and uses
The simple design of the shell and tube heat exchanger makes it an ideal cooling solution for a variety of applications. One of the most common applications is the cooling of hydraulic oil and oil in engines, transmissions and hydraulic power units. They can also be used to cool or heat other media, such as pool water or pressurized air, by choosing the right materials. One of the great advantages of using shell-and-tube heat exchangers is that they are usually easy to service, especially for models where a floating tube bundle can be used (the tubesheet is not welded to the casing).