ASME SA516 Gr.70N STATIONARY TUBESHEET
Fixed tube plate heat exchanger refers to a shell and tube heat exchanger in which the tube plates at both ends of the tube bundle are fixedly connected to the shell by welding. After the tube plate and the shell are welded, it can also serve as a flange and be connected to the pipe box flange with bolts. The advantage is that the structure is simple and the inner diameter of the shell required is the smallest while ensuring equal heat transfer surfaces.
Tube sheets are key components of various heat exchangers and shell-and-tube vessels. Its main purpose is to provide support and sealing to the tube bundle. Within cylindrical or rectangular tubes, there are different types of tubesheets, each type designed for a specific application. Here are some common segment types and their detailed descriptions:
1.Fixed tube sheet: Description: The fixed tube sheet is fixed in the shell of the heat exchanger and welded or welded into the hole of the fixed tube sheet. They will not move relative to the tube sheet and the expansion between the tubes and the shell is very small.
2. Floating tube sheet:
Description: The design of the floating tube sheet allows the tube bundles to expand and contract freely with temperature changes. The tube sheet is not connected to the shell by direct welding: however, it can be moved within certain limits. Use hs desien when stgticat temptre vanaton is present to help prevent damage to pipes and pipe-to-tubesheet joints.
3. U-shaped tube bundle:
Description: In a U-tube bundle heat exchanger, the tubes are bent into a "shape." The ends of the U-shaped tubes are fixed or welded to a single tube sheet. This configuration is typically used in applications where thermal expansion and contraction need to be accommodated, but the connector needs to be removed for maintenance.
4. Floating head tube plate:
Note: In some shell and tube heat exchangers, the other end is closed by a floating head tube heat exchanger, and one end of the shell is closed by a fixed tube sheet. The floating head can move axially to accommodate the thermal expansion and contraction of the tube. This design is common in Rappe heat exchangers.
5.Fixed tubesheet (with expansion joint description) If the temporary connection between the tube and shell is important and a floating tubesheet may not be practical, expansion joints may be incorporated into the design of the fixed tubesheet. These expansion joints allow a certain amount of movement while maintaining a strong connection between the tube and tubesheet. The choice of tubesheet type depends on a variety of factors, including the specific application, temperature and pressure requirements, and the need to accommodate thermal expansion and contraction. Proper selection and design of tubesheets is critical to ensuring efficient and safe operation of heat exchangers and pressure vessels
The characteristics of fixed tube plate heat exchanger are:
1. The bypass seepage is small;
2. Forgings are used less and cost is low;
3. No internal leakage;
4. The heat transfer area is 20% to 30% larger than that of the floating head heat exchanger.
The disadvantages of fixed tube plate heat exchangers are:
1. The temperature difference between the shell and the pipe wall is large. When t ≥ 50°C, an expansion joint must be installed on the shell;
2. Temperature difference force is easily generated, and temperature difference stress is easily generated between the tube plate and the tube head, causing damage;
3. The shell side cannot be cleaned mechanically;
4. After the pipes are corroded, they will be scrapped together with the casing, and the equipment life will be short.
