Heat exchanger capable of completely eliminating thermal stress

Abstract

The invention discloses a heat exchanger capable of completely eliminating thermal stress. The heat exchanger comprises two tube plates. Heat exchange tube holes are formed in each tube plate. Heat exchange tubes are arranged between the two tube plates. The two ends of each heat exchange tube correspondingly penetrate the heat exchange tube holes of the two tube plates. At least one end of each heat exchange tube is in sealing connection with the corresponding heat exchange tube hole through a sealing ring, and a stop sleeve is fixedly connected to the outer end of the end in sealing connection with the corresponding heat exchange tube hole of each heat exchange tube. By the adoption of the structure, the thermal stress between the heat exchange tubes and the tube plates can be completely eliminated, and the free expansion and contraction of all the heat exchange tubes at the tube plates are realized.

Description

technical field [0001] The patent of the present invention relates to the technical field of heat exchangers, in particular to a heat exchanger that can completely eliminate thermal stress. Background technique [0002] A heat exchanger is an energy-saving device that transfers heat between materials between two or more fluids at different temperatures, also known as a heat exchanger, which transfers heat from a fluid with a higher temperature to a fluid with a lower temperature. , so that the fluid temperature reaches the index specified in the process to meet the needs of process conditions, and it is also one of the main equipment to improve energy utilization. [0003] The heat exchange tube is one of the elements of the heat exchanger, which is placed inside the cylinder and used for the exchange of heat between the two media. Has high thermal conductivity and good isothermal properties. The tube plate is to drill a hole slightly larger than the outer diameter of the ...

AI Technical Summary

Problems solved by technology

[0005] The fixed tube-sheet heat exchanger used at the beginning is fixed and supported by tube sheets at both ends of the heat exchange tubes, and both tube sheets are fixedly connected to the shell, which makes the heat exchanger have greater thermal stress Existence, it is easy to cause the joint between the tube and the tube sheet to be pulled off and rupture, resulting in leakage or instability of the tube

The floating head heat exchanger that appeared later effectively solved the thermal stress and can work under high temperature and high pressure. This is because only one end of the tube sheets at both ends of the floating head heat exchanger is fixed to the shell, and the other end can be opposite to the shell. Free movement; the floating head is composed of floating tube plate, hook ring and floating head flange, which are detachable connections, and the tube bundle can be drawn out from the shell. When the tube is heated, the tube bundle and the floating head can freely expand and contract along the axial direction, completely eliminating the temperature difference stress; Although the floating head heat exchanger can eliminate thermal stress well, because of its super-static structure, each heat exchange tube and the tube sheet are fixedly connected, and the heat exchange tube and the tube sheet must be "floating" at the same time. Completely eliminate the stress of each heat exchange tube and tube sheet, even the heat exchange tube is damaged due to stretching

In addition, the structure of the floating head heat exchanger is complicated, the cost is high, the equipment is bulky, the material consumption is large, and the small cover of the floating head end cannot be inspected during operation and is prone to internal leakage, and the sealing requirements are relatively high during manufacture

Another U-shaped tube heat exchanger can also solve the thermal stress well. Since the U-shaped tube heat exchanger has only one tube plate, both ends of the tube are fixed on the same tube plate, and the tube can be stretched freely. Therefore, its thermal compensation performance is good and there is no thermal stress; however, due to the limitation of the radius of curvature of the bent tube, it requires a large space for tube layout and a large ineffective heat exchange area, resulting in fewer heat exchange tubes and a relatively small spacing between the innermost tubes of the tube bundle. Large, the utilization rate of the tube sheet is low, and the shell-side fluid is easy to form a short circuit, which is not good for heat transfer. When the tube leaks and is damaged, only the U-shaped tube at the periphery of the tube bundle is easy to replace. The inner heat exchange tube is broken and cannot be replaced. It can only be blocked, which will reduce the heat transfer area

Images