Detailed structural characteristics of shell and tube heat exchangers
Shell-and-tube heat exchangers are used to repair or replace plate deformation. If no spare board is available, the deformed board can be temporarily removed and reassembled. An important part of the device and its function, in which the consumable part is a gasket of a plate heat exchanger. Resistant to acids, alkalis and salts. Low heat transfer efficiency, small temperature difference, strong anti-fouling and anti-fouling ability, high heat transfer coefficient, suitable for places with high critical load.
Leaks are prone to occur during operation, and there are many reasons for leaks. According to different reasons, the treatment methods of plate heat exchanger leakage are also different. The shell and tube heat exchanger consists of a shell, a heat transfer tube bundle, a tube sheet, a baffle (baffle) and a tube box. The housing is generally cylindrical, and the tube bundle is arranged inside, and both ends of the tube bundle are fixed to the tube sheet. There are two kinds of hot and cold fluids for heat exchange, one is flowing in the tube, called tube flowing fluid, and the other is flowing outside the tube, called shell-side fluid.
In order to increase the heat transfer coefficient of the fluid outside the tube, multiple baffles are usually installed in the housing. The baffle increases the velocity of the shell-side fluid, forcing the fluid to pass through the tube bundle laterally multiple times on a prescribed path, thereby increasing the turbulence of the fluid. The heat exchange tubes can be arranged on the tube sheet in an equilateral triangle or a square. The equilateral triangles are compactly arranged, the fluid outside the tube is highly turbulent, and the heat transfer coefficient is large. The square arrangement facilitates cleaning outside the tube and is suitable for fluids that are prone to fouling.
To increase the velocity of the fluid in the tubes, spacers can be arranged at both ends of the tube box to divide the tubes into groups. In this way, the fluid can only pass through a part of the tube at a time, and therefore travels back and forth in the tube bundle multiple times, which is called multi-tube. Similarly, in order to increase the flow rate outside the pipe, a longitudinal baffle can also be installed in the casing to force the fluid to pass through the casing space multiple times, which is called a multiple casing process. Multiple tubes and multiple shells can be used together.