A shell-and-tube heat exchanger

Abstract

The application relates to a tube-shell heat exchanger, which is characterized in that a plurality of first flow tubes and second flow tubes are arranged in a ring shape at the end portions of the flow tubes on a flow tube plate, the radial outer side of each first flow tube is provided with a corresponding second flow tube, the end portions of the first flow tubes and the second flow tubes are connected through U-shaped tubes with the same shape and size, high-temperature first fluid flows out from the second inflow tubes, through the first flow tubes, the U-shaped tubes and the second flow tubes, and finally from the second outflow tubes, thereby completing heat exchange; second fluid which needs to be exchanged flows in from the first inflow tubes and flows out from the first outflow tubes; thus, heat exchange between the first fluid and the second fluid is realized; since the plurality of U-shaped tubes are arranged radially on the flow tube plate instead of being stacked in an inner-outer layer mode, when one U-shaped tube is blocked, the U-shaped tube and the corresponding first flow tube and second flow tube of the U-shaped tube can be axially drawn out, thereby facilitating the cleaning and maintenance of the U-shaped tube.

Description

Technical Field

[0001] This invention relates to heat exchangers, and more particularly to a shell-and-tube heat exchanger. Background Technology

[0002] Shell-and-tube heat exchangers, also known as tubular heat exchangers, are indirect heat exchangers that use the walls of tube bundles in a closed shell as the heat transfer surface. They are the most typical type of indirect heat exchanger.

[0003] Conventional shell-and-tube heat exchangers come in two main types:

[0004] 1. Straight tube heat exchanger, which is a type of heat exchanger in which multiple tube bundles are arranged in a straight line inside the shell. The fluid that needs to exchange heat enters from one side of the shell and exits from the other side. As a result, the fluid stays in the tube bundle for a short time, which cannot meet the requirements of sufficient heat exchange.

[0005] 2. U-tube heat exchangers consist of two tube bundles connected by U-shaped tubes. The size of the U-shaped tube is selected according to the distance between the two tube bundles, and the fluid flows in or out from the same side of the shell, exhibiting a U-shaped flow. Although this prolongs the residence time of the fluid in the tube bundle, since the U-shaped tubes are stacked from the inside out, when the inner U-shaped tube becomes blocked, the outer U-shaped tube needs to be disassembled to clean and repair that layer of U-shaped tubes. In addition, since the length of the outer U-shaped tube is greater than that of the inner U-shaped tube, the residence time of the fluid in the tube bundle is inconsistent, resulting in uneven heat exchange.

[0006] In summary, how to facilitate the cleaning and maintenance of U-shaped tubes and ensure uniform heat exchange of fluids have become urgent problems for researchers in this field. Summary of the Invention

[0007] The technical problem to be solved by this invention is: how to facilitate the cleaning and maintenance of U-shaped tubes and ensure uniform heat exchange of the fluid;

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0009] This invention relates to a shell-and-tube heat exchanger, comprising: a shell having a sealing plate and a flow plate respectively disposed on its inner sides, a first inlet pipe disposed on its top, and a first outlet pipe disposed on its bottom; a plurality of first flow pipes, each having two ends connected to the sealing plate and the flow plate respectively, the line connecting the centers of the plurality of first flow pipes forming a regular polygonal structure; a number of second flow pipes equal to the number of first flow pipes, each having two ends connected to the sealing plate and the flow plate respectively, each second flow pipe being located radially outward of a corresponding first flow pipe; a first end box disposed at one end of the shell near the sealing plate; a second end box disposed at one end of the shell near the flow plate; a number of U-shaped pipes equal to the number of first flow pipes disposed within the second end box, each having two ends connected to the ends of the first flow pipes and the ends of the corresponding second flow pipes respectively; a second inlet pipe, one end of which is located outside the first end box, and the other end of which is located inside the first end box and communicates with the inlet of the plurality of first flow pipes; and a second outlet pipe disposed at the bottom of the first end box.

[0010] Furthermore, the flow plate has flow holes to connect the housing to the second end box.

[0011] Furthermore, the axes of the first inflow pipe and the first outflow pipe are perpendicular to the axis of the housing, and the first inflow pipe and the first outflow pipe are located at different positions on the axis of the housing.

[0012] Furthermore, the shell has flange plates on both sides, as well as at the first and second end boxes; the two flange plates are provided with sealing plates or flow plates, and the three are connected by fasteners.

[0013] The beneficial effects of this invention are as follows: This invention is a shell-and-tube heat exchanger in which multiple first and second flow tubes are arranged in a ring on a flow plate. Second flow tubes are correspondingly arranged on the radial outer sides of each of the first flow tubes. The ends of the first and second flow tubes are connected by U-shaped tubes of the same shape and size. A high-temperature first fluid flows sequentially from the second inlet tube, through the first flow tube, the U-shaped tube, and the second flow tube, and finally flows out from the second outlet tube, completing the heat exchange. The second fluid requiring heat exchange flows in from the first inlet tube and flows out from the first outlet tube. This achieves heat exchange between the first and second fluids. Since the multiple U-shaped tubes are arranged radially on the flow plate, rather than being stacked inner and outer layers, when one U-shaped tube becomes blocked, the U-shaped tube and its corresponding first and second flow tubes can be axially pulled out, facilitating the cleaning and maintenance of the U-shaped tubes. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 This is a schematic diagram of the external structure of a shell-and-tube heat exchanger.

[0016] Figure 2 This is a cross-sectional view of a shell-and-tube heat exchanger;

[0017] Figure 3 This is a three-dimensional schematic diagram of a U-shaped tube. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0019] Figure 1 This is a schematic diagram of the external structure of a shell-and-tube heat exchanger. The shell 1 is located in the middle. The left side of the shell 1 is set as the first end box 2, and the right side of the shell 1 is the second end box 3. The first end box 2 is sealed to the shell 1 by a sealing plate 4, and the second end box 3 is connected to the shell 1 by a flow plate 5. The upper left of the shell 1 is set as the first inlet pipe 6, and the lower right of the shell 1 is set as the first outlet pipe 7. The second fluid that needs to be heat exchanged flows in from the first inlet pipe 6, completes the heat exchange in the shell 1, and finally flows out from the first outlet pipe 7.

[0020] The left side of the first end box 2 is provided with a second inlet pipe 8 for the first fluid to flow in, and the lower part of the first end box 2 is provided with a second outlet pipe 9 for the first fluid to flow out. The high-temperature first fluid flows sequentially from the second inlet pipe 8, through the first flow pipe 11, the U-shaped pipe 10, and the second flow pipe 12, and finally flows out from the second outlet pipe 9, completing the heat exchange with the first fluid.

[0021] The sealing plate 4 is disposed between the housing 1 and the first end box 2 and is connected to the housing 1 and the first end box 2 by means of a flange plate and fasteners. The flow plate 5 is disposed between the housing 1 and the second end box 3 and is connected to the housing 1 and the second end box 3 by means of a flange plate and fasteners.

[0022] Figure 2 This is a cross-sectional view of a shell-and-tube heat exchanger. Besides showing the positions of the first outflow pipe 7, the first inflow pipe 6, the second outflow pipe 9, and the second inflow pipe 8, the view also shows two first flow pipes 11 and two second flow pipes 12. The two first flow pipes 11 are located between the two second flow pipes 12, and all four are axially parallel. One U-shaped pipe 10 connects the upper first flow pipe 11 and the second flow pipe 12, and another U-shaped pipe 10 connects the lower first flow pipe 11 and the second flow pipe 12. A spacer 13 connects the second inflow pipe 8 to the end of each first flow pipe 11. The first fluid enters any one of the first flow pipes 11 from the second inflow pipe 8 through the spacer 13 to participate in heat exchange. After completing heat exchange, the first fluid exits from the second flow pipe 12 to the first end box 2, and finally exits through the second outflow pipe 9.

[0023] In the design, the total length of the heat exchange channel formed by the first flow pipe 11, the second flow pipe 12, and the U-shaped pipe 10 remains unchanged. Therefore, the first fluid flows a consistent distance within the tube bundle, achieving uniform heat exchange for the first fluid.

[0024] In addition, when any tube bundle becomes blocked, the second end box 3 and the shell 1 are separated, the cover tube bundle is pulled out to the right, and the U-shaped tube 10 is cleared and repaired.

[0025] Figure 3 This is a three-dimensional schematic diagram of a U-shaped tube. The flow plate 5 in the diagram has a flow hole 14, which allows the second fluid to enter the second end box 3 and exchange heat with the first fluid in the U-shaped tube 10.

[0026] exist Figure 3 The diagram only shows 6 first flow pipes 11 and 6 second flow pipes 12. This scheme is only applicable to small flow rates of the first fluid. Of course, this scheme can also be implemented by arranging annular first flow pipes 11 in the innermost first layer, annular second flow pipes 12 in the second layer, and connecting the two layers with corresponding U-shaped pipes; arranging annular first flow pipes 11 in the third layer, and annular second flow pipes 12 in the fourth layer, and connecting the two layers with U-shaped pipes; the inflow ends of the multiple first flow pipes 11 in the first layer are connected by a first spacer, and the inner and outer diameters of the first flow pipes 11 in the third layer are connected by a second spacer. The first spacer and the second spacer are connected by a connecting sleeve. The first fluid enters the first spacer from the second inflow pipe 8, and can enter any first flow pipe 11 in the first layer or enter the second spacer through the connecting sleeve, and then enter the first flow pipe 11 in the third layer to participate in heat exchange. This arrangement can perform heat exchange for large flow rates of the first fluid. The fluid after heat exchange flows into the second end box 3 from the second flow pipe 12 in the second layer or the second flow pipe 12 in the fourth layer.

[0027] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A shell-and-tube heat exchanger, characterized in that, include: The shell has a sealing plate and a flow plate on its inner sides, a first inflow pipe on its top, and a first outflow pipe on its bottom. Multiple first flow tubes are connected at both ends to the sealing plate and the flow plate, respectively, and the line connecting the centers of the multiple first flow tubes is a positive polygonal structure. The number of second flow tubes is the same as that of the first flow tubes, and their two ends are respectively connected to the sealing plate and the flow plate. Each second flow tube is located radially outside the corresponding first flow tube. A first end box is disposed at one end of the housing near the closing plate; The second end box is located at one end of the housing near the flow plate; The same number of U-shaped tubes as the first flow tubes are located in the second end box, with their two ends connected to the end of the first flow tube and the end of the corresponding second flow tube, respectively. The second inflow pipe has one end located outside the first end box and the other end located inside the first end box, and is connected to the inlet of multiple first flow pipes. The second outflow pipe is located at the bottom of the first end box; The innermost first layer of the shell is arranged with an annular first flow pipe, the second layer is arranged with an annular second flow pipe, and the two layers are connected by corresponding U-shaped pipes; the third layer is arranged with an annular first flow pipe, the fourth layer is arranged with an annular second flow pipe, and the two layers are connected by U-shaped pipes; the inflow ends of the multiple first flow pipes in the first layer are connected by a first spacer, and the inner and outer diameters of the first flow pipes in the third layer are connected by a second spacer. The first spacer and the second spacer are connected by a connecting sleeve. The first fluid enters the first spacer from the second inflow pipe, and can enter any first flow pipe in the first layer or enter the second spacer through the connecting sleeve, and then enter the first flow pipe in the third layer to participate in heat exchange.

2. A shell-and-tube heat exchanger according to claim 1, characterized in that, The flow plate has flow holes that connect the housing to the second end box.

3. A shell-and-tube heat exchanger according to claim 1, characterized in that, The axes of the first inlet pipe and the first outlet pipe are perpendicular to the axis of the housing, and the first inlet pipe and the first outlet pipe are located at different positions on the axis of the housing.

4. A shell-and-tube heat exchanger according to claim 1, characterized in that, Flange plates are provided on both sides of the shell and at the first and second end boxes; Both flanges are provided with a sealing plate or a flow plate, and the three are connected by fasteners.

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