Design and selection personnel often face a specific problem: when the metal wall temperature difference between the tube side and shell side is large, how to judge the reliability of the connection between the tubesheet and the tube bundle? Before selection, the difference in linear expansion coefficients of the two materials should be verified. For example, when carbon steel and stainless steel are combined, the linear expansion coefficients differ, and under the action of temperature difference, an expansion difference will occur. Once it exceeds the compensation range, the expansion difference between the shell and the tube bundle will be converted into thermal stress at the connection between the tubesheet and the tube bundle, and long-term action can easily cause failure of welds or expanded joints.
During selection, it is recommended to check the design pressure, design temperature, heat exchange area, and medium inlet and outlet pipe diameters. The design pressure determines the wall thickness grade of the shell and tube bundle, the design temperature affects material selection and expansion calculation, the heat exchange area must match the heat load, and the inlet and outlet pipe diameters are related to flow velocity and pressure drop. When replacing the tube bundle on site, attention should be paid to the difference in linear expansion coefficients of the two materials to avoid concentration of thermal stress due to temperature difference.
Select the tube bundle and shell materials according to the corrosiveness of the medium and the temperature difference range. When the temperature difference is large, an expansion joint or floating head structure may be considered to absorb the expansion difference. The fixed tubesheet structure is suitable for working conditions with a small temperature difference and clean shell-side medium.
The GCH-260 shell and tube heat exchanger can be used in chemical cooling, HVAC, and waste heat recovery systems, and is suitable for occasions where the temperature difference between the tube-side and shell-side media is controllable.
