Views: 1 Author: Site Editor Publish Time: 2022-03-09 Origin: Site
Facial paper machine Shell-and-tube plate heat exchangers are also called shell-and-tube heat exchangers, pressure controllers, and use the wall of the tube bundle enclosed in the shell as a heat transfer tool. The shell-and-tube heat exchanger has the advantages of simple structure, convenient operation, wide selection of manufacturing materials, and can work in high temperature and high pressure environment. The main components of plate heat exchangers include shells, heat transfer tube bundles, tube sheets, baffles (baffles) and tube boxes. The shell of the plate heat exchanger is mostly designed in a cylindrical shape, and the heat transfer tube bundle is installed in the shell and fixed by the tube sheet.
The plate heat exchanger is made into a multi-shell pass in the form of baffles to force the fluid to pass through the shell space for many times. Heat transfer energy efficiency of shell and tube heat exchangers. The multi-tube side and multi-shell side of the plate heat exchanger can be used together.
If the temperature difference between the shell and the heat transfer tube bundle of the shell and tube heat exchanger is too large during the heat conduction process, a large stress will be generated inside the heat exchanger, resulting in bending, breaking or pulling off of the heat transfer tube bundle. Therefore, when the temperature difference between the shell and the tube bundle of the shell and tube heat exchanger is too large, appropriate compensation measures should be taken to eliminate or reduce the stress.
Facial paper machine shell and tube heat exchangers can be divided into the following three types according to different stress compensation methods:
1 Fixed Tray Tube Sheet Heat Exchanger
The fixed tube plate heat exchanger is the shell and tube heat exchanger with the simplest structure. The tube plates at both ends of the heat transfer tube bundle are directly connected to the shell. A stress compensation ring is installed on the shell. When the temperature difference inside the device is large, the thermal stress is reduced. The thermal stress compensation of the fixed tube sheet heat exchanger is small, and it cannot adapt to the work with a large temperature difference.
2 Floating head heat exchanger
Floating head heat exchanger is the most widely used type of shell and tube heat exchanger. The principle of stress relief is to release the tube sheet of a section of the heat transfer tube bundle and let it float in a certain space to eliminate thermal stress. The heat transfer tube bundle of the floating head heat exchanger can be extracted from the shell, which is convenient for cleaning and maintenance, but due to the complex structure, the price of the floating head heat exchanger is relatively high.
3 u-tube heat exchanger
The tray heat transfer tube bundle of the u-tube heat exchanger in the facial paper machine is a u-shaped bending heat exchanger. The two ends of the tube bundle are fixed on the upper and lower parts of the same tube sheet, and are divided into Import and export two parts, and completely eliminate the influence of thermal stress on the tube bundle. The cooling tower U-tube heat exchanger has a simple structure and convenient application, but it is difficult to disassemble and clean.