SHELL AND TUBE HEAT EXCHANGER TYPES AND STRUCTURE
Fixed tube plate type: fix both ends of the pipe on the fixed tube plate at both ends of the shell. The tube plate is fixed to the shell. Advantages: simple structure, low manufacturing cost, wide range of specifications, widely used in engineering. Disadvantages: shell side inconvenience cleaning, can only use chemical cleaning, maintenance is difficult, more dirty or corrosive media can not go through the shell. When the temperature difference between the shell and the heat exchanger is large,small temperature difference stress can be reduced by single or multi-wave expansion.
U-tube type: the heat exchange tube is bent into a u-shape, and the two ends of the tube are fixed in the same block. On the tube plate, the bending end is not fixed. Heat exchange tube can be freely telescopic, so the shell and heat exchange tube without thermal stress. There is only one tube plate, the structure is simple, the tube bundle can be taken out from the shell, the shell side is easy to clean, but the cleaning inside the tube is difficult, the medium inside the tube must be clean and not easy to scale. Shell side can be set up longitudinal partition, shell side is divided into two.
Floating head type: one end of the tube plate is fixed with the shell, and the other end of the tube plate can float freely in the shell. Advantages: 1. Free thermal deformation of shell and tube bundle, no thermal stress. 2. The tube bundle can be extracted from the shell, which is convenient for the maintenance and cleaning of the shell. Disadvantages: 1. The floating head cover is connected with the tube plate flange with a considerable area, making the shell diameter increase. 2. A ring channel with less resistance is formed between the floating head and the shell, through which some fluid will pass by without taking part in heat exchange. Application: the temperature difference between the shell and the tube is large, the medium in the shell is corrosive and easy to scale.
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