The fixed tube sheet heat exchanger has a simple structure and low manufacturing cost. The tube side is easy to clean and can be divided into multiple passes, while the shell side can also be divided into double passes. It offers a wide range of specifications and is therefore widely used in engineering. However, the shell side is difficult to clean, making it unsuitable for dirty or corrosive media. When there is a significant difference in expansion, an expansion joint can be installed on the shell to reduce thermal stress caused by the temperature difference between the tube and shell sides....