Views:0 Author:Site Editor Publish Time: 2021-04-05 Origin:Site
1. Shell and tube heat exchanger
Shell-and-tube heat exchangers are also called shell-and-tube heat exchangers. It is a partitioned spiral plate heat exchanger with the wall surface of the tube bundle enclosed in the shell as the heat transfer surface. This kind of heat exchanger has a relatively simple structure and reliable operation. It can be made of various structural materials (mainly metal materials) and can be used under high temperature and high pressure. It is a widely used type at present.
2. Fixed tube plate heat exchanger
The fixed tube-sheet heat exchanger is a kind of shell-and-tube heat exchanger. The tube plates at both ends of the fixed tube sheet spiral plate heat exchanger are connected to the shell by welding, and are mainly composed of shell, tube sheet, tube bundle, top cover (head) and other components. The advantages of the fixed tube-sheet heat exchanger are: simple structure, in the same shell diameter, many rows of tubes, few bypasses, each heat exchange tube can be replaced, and the inside of the tube is easy to clean.
The disadvantages of the fixed tube-sheet heat exchanger are: the shell side cannot be mechanically cleaned, it is only suitable for fluid cleaning and not easy to scale, and the temperature difference between the two fluids is not large or the temperature difference is large but the shell side pressure is not high.
3. Floating head heat exchanger
Floating head heat exchanger is a kind of shell-and-tube spiral plate heat exchanger. It has one end of the tube sheet that is not connected to the shell and can float freely along the axial direction. It is also called a floating head. The floating head is composed of a floating tube plate, a hook ring and a floating head end cover, and is detachable connection, and the tube bundle can be drawn out of the shell. ￼The advantage of floating head heat exchanger is: if there is a temperature difference between the heat exchange tube and the shell, that is, when the shell or heat exchange tube expands, there will be no temperature difference stress, and the tube bundle can be drawn out of the shell, which is convenient for the tube and the tube. Clean.
The disadvantages of the floating head heat exchanger are: the structure is more complicated, the amount of materials used is large, and the cost is high. If the sealing between the floating head cover and the floating tube plate is not tight, internal leakage will occur, resulting in the mixing of the two media.
4. U-shaped tube heat exchanger
U-shaped tube heat exchanger is a kind of shell and tube heat exchanger, which is composed of tube sheet, shell, tube bundle and other parts. Each tube of the U-tube spiral plate heat exchanger is bent into a U-shape, and the inlet and outlet are respectively installed on both sides of the same tube plate. The head is divided into two chambers with a partition plate, so that each tube can be used. It is free to expand and contract, and has nothing to do with other tubes and shells.
The advantages of the U-tube heat exchanger are: the tube bundle can float freely without considering the temperature difference stress, and can be used in large temperature differences. It has only one tube plate, fewer flanges, fewer leaks, and simple structure. The U-tube heat exchanger The heater is reliable in operation and low in cost.
The disadvantages of U-tube heat exchangers are: it is difficult to clean the inside of the tube, because the tubes need to have a certain bending radius, the utilization rate of the tube sheet is low, the tube spacing in the inner layer of the tube bundle is large, and the shell side is easy to short circuit. When the flow velocity in the pipe is too high, it will cause serious erosion to the U-shaped elbow section and affect its service life. If the inner pipe is damaged, it cannot be replaced, so the scrap rate is high.