An inner packing box sliding tube plate type heat exchanger

Abstract

The application discloses an inner stuffing box sliding tube plate type heat exchanger, which comprises an upper tube box, a shell side cylinder, a lower tube box, a fixed tube plate, a plurality of heat exchange tubes, a plurality of baffle plates and a sliding tube plate, a split sealing mechanism is arranged between the shell side of the sliding tube plate and the inner wall of the shell side cylinder, a stuffing box sealing mechanism and a flow guide cylinder are arranged between the tube side of the sliding tube plate and the inner wall of the shell side cylinder, the split sealing mechanism comprises an annular elastic sealing sheet, the stuffing box sealing mechanism comprises an annular stuffing box, a stuffing gland and a sliding tube plate skirt and stuffing. The inner stuffing box sliding tube plate type heat exchanger has the advantages of simple structure, convenient manufacturing, low cost, etc., the split sealing mechanism is arranged on the shell side of the sliding tube plate, the stuffing box sealing mechanism is arranged on the tube side of the sliding tube plate, the double sealing effect of the shell side medium can be achieved, the shell side medium can be effectively prevented from leaking out of the heat exchanger, the heat exchanger is safe and reliable to use, and is suitable for flammable, explosive and toxic medium occasions.

Description

Technical Field

[0001] This invention relates to stuffed gland heat exchangers in the fields of petrochemical, coal chemical, and fine chemical equipment, specifically an internal stuffed gland sliding tube sheet heat exchanger suitable for flammable, explosive, and toxic media environments. Background Technology

[0002] For media with large temperature differences, suitable heat exchangers include floating head heat exchangers, U-tube heat exchangers, and stuffing box heat exchangers. Floating head heat exchangers have a complex floating head structure, affecting the number of tubes per row. When leakage occurs at the floating head sealing surface, it is difficult to take corrective measures, and the pressure testing fixtures are complex. U-tube heat exchangers, due to the limitation of the minimum bending radius of the U-tubes, have a wide spacing between tubes and fewer tubes per row. High flow velocities inside the tubes can severely erode the U-shaped bends, making internal cleaning difficult. Stuffing box heat exchangers can be used in applications with severe scaling and tube-side corrosion, with lower metal consumption. However, their packing seals are prone to leakage, making them unsuitable for applications where the shell-side medium is flammable, explosive, or toxic.

[0003] Specifically, stuffing box heat exchangers come in three structural forms: external stuffing box floating head type, single stuffing box sliding tube sheet type, and double stuffing box sliding tube sheet type. The shell-side design pressure of an external stuffing box floating head type heat exchanger should not exceed 2.5 MPa, as the tube / shell side medium is prone to leakage from the external stuffing box seal, posing a hazard. Single stuffing box sliding tube sheet type heat exchangers are further divided into two types based on the strict prohibition of mixing the tube and shell side media; however, leakage from the single stuffing box seal is also prone to hazard. Double stuffing box sliding tube sheet type heat exchangers have double packing: the inner packing seals both the tube and shell sides, while the outer packing primarily serves a protective function, collecting leaked media and leading it out through a leakage pipe. This structure has stricter requirements for the application environment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an internally packed sliding tube sheet heat exchanger suitable for flammable, explosive and toxic media applications, in order to address the shortcomings of the prior art.

[0005] The technical solution adopted by this invention to solve the above-mentioned technical problems is as follows: an internally packed gland sliding tube sheet heat exchanger, comprising an upper tube box, a shell-side cylinder, a lower tube box, a fixed tube sheet, multiple heat exchange tubes, multiple baffles, and a sliding tube sheet. The upper tube box and the lower tube box are respectively fixed to the upper and lower ends of the shell-side cylinder. The shell-side cylinder is provided with a shell-side inlet and a shell-side outlet. The fixed tube sheet is fixed to the upper tube box and the shell-side cylinder respectively. The sliding tube sheet is disposed at the bottom of the shell-side cylinder. The upper and lower ends of each heat exchange tube are respectively fixed to the fixed tube sheet and the sliding tube sheet. The multiple baffles are disposed inside the shell-side cylinder and are used to fix the multiple heat exchange tubes. A partitioned sealing mechanism is provided between the shell-side side of the sliding tube sheet and the inner wall of the shell-side cylinder. A stuffing gland sealing mechanism and a flow guide cylinder are provided between the tube-side side of the sliding tube sheet and the inner wall of the shell-side cylinder. The partitioned sealing mechanism includes an annular elastic sealing sheet. The radial inner end of the elastic sealing sheet is fixed to the upper edge of the sliding tube sheet, and the radial outer end of the elastic sealing sheet is bent upward and close to the inner wall of the shell-side cylinder. The stuffing box sealing mechanism includes an annular stuffing box, a stuffing gland, a sliding tube sheet skirt, and stuffing. The sliding tube sheet skirt includes a variable diameter section and a cylindrical section that are arranged vertically and communicate with each other. The wide diameter end of the variable diameter section is fixed to the lower edge of the sliding tube sheet, and the narrow diameter end of the variable diameter section is connected to the upper end of the cylindrical section. The stuffing surrounds and adheres to the outer wall of the cylindrical section. The stuffing is pressed and fixed by the upper and lower stuffing box and the stuffing gland. The radial outer surface of the stuffing box is close to the inner wall of the shell-side cylinder. The guide tube is trumpet-shaped with a small upper opening and a large lower opening. The upper end of the guide tube is fixed to the outer wall of the variable diameter section, and the lower end of the guide tube is suspended above the stuffing box. The side wall of the lower tube box is provided with a drain port, and the bottom surface of the drain port is flush with the upper surface of the stuffing box.

[0006] The working principle of the internal stuffing gland sliding tube sheet heat exchanger of this invention is as follows: During operation, flammable, explosive, and toxic tube-side and shell-side media exchange heat through the heat exchange tubes. When the temperature difference between the tube-side and shell-side is large, the sliding tube sheet slides up and down due to the deformation caused by the temperature difference under the sealing of the split sealing mechanism on the shell-side side of the sliding tube sheet and the stuffing gland sealing mechanism on the tube-side side.

[0007] Under normal circumstances, flammable, explosive, and toxic media in the shell side of multiple heat exchange tubes are sealed by the split-pass sealing mechanism, and the shell-side media is discharged from the shell-side outlet. When the split-pass sealing mechanism is damaged, most of the shell-side media still discharges from the shell-side outlet, while a small amount passes through the elastic sealing plate, is guided by the flow guide tube, flows to the drain port, and is led out through the drain port. When the stuffing box sealing mechanism on the tube side is damaged, a very small amount of shell-side media passes through the seal of the stuffing box sealing mechanism and enters the tube side, preventing flammable, explosive, and toxic media from leaking out of the heat exchanger.

[0008] Preferably, the fixed tube sheet is welded to both the upper tube box and the shell-side cylinder. The upper end of each heat exchange tube is connected to the fixed tube sheet via an internal bore weld, and the lower end of each heat exchange tube is connected to the sliding tube sheet via a strength weld and expansion joint. Since the weld temperature of the internal bore weld is close to the operating temperature of the shell-side medium, this invention uses an internal bore weld to connect the upper end of each heat exchange tube to the fixed tube sheet. During heat exchanger operation, there are no gaps between the heat exchange tube and the bore, and the welded joint is a butt joint, providing high load-bearing capacity and completely eliminating crevice corrosion. Furthermore, this invention uses a strength weld and expansion joint to connect the lower end of each heat exchange tube to the sliding tube sheet to meet the medium sealing requirements in applications involving flammable, explosive, toxic shell-side media and media with large temperature differences.

[0009] Preferably, a ring of bosses is fixed to the lower edge of the sliding tube sheet, and the wide-diameter end of the variable-diameter section is welded to the bosses. The bosses facilitate the butt welding of the variable-diameter section of the sliding tube sheet skirt to the sliding tube sheet, preventing damage to the sliding tube sheet.

[0010] Preferably, the wide-diameter end of the variable-diameter section adopts an outwardly convex bending structure, and the narrow-diameter end of the variable-diameter section adopts an inwardly convex bending structure. The use of bending structures at both ends of the variable-diameter section serves to control the concentricity of the section and the ellipticity of its end faces, prevent the weld from coinciding with discontinuities in the structure, and significantly reduce the deformation coordination stress between the variable-diameter section and the cylinder section.

[0011] Preferably, the radial inner end of the elastic sealing sheet is fixed to the upper edge of the sliding tube plate by a plurality of bolts and pressure strips. The plurality of bolts are evenly distributed along the circumference of the sliding tube plate, and each bolt passes through the pressure strip and the elastic sealing sheet and is threadedly connected to the sliding tube plate.

[0012] Preferably, the sliding tube sheet has n wedge-shaped bars, larger at the top and smaller at the bottom, fixed to its radial outer surface, where n is a multiple of 4. These n wedge-shaped bars are evenly distributed along the circumference of the sliding tube sheet. During heat exchanger manufacturing and operation, the multiple evenly distributed wedge-shaped bars facilitate the vertical movement of the sliding tube sheet within the shell-side cylinder. When the heat exchanger is placed horizontally for hydrostatic testing or transportation, the multiple evenly distributed wedge-shaped bars can support the sliding tube sheet, reducing pressure loss on the packing from the heat exchange tube bundle.

[0013] Preferably, the stuffing box includes a stuffing box body. A first vertical portion is integrally formed on the upper side of the radially inner end of the stuffing box body. A horizontal portion extending vertically towards the cylindrical section is integrally formed at the top of the first vertical portion. A second vertical portion is integrally formed on the lower side of the radially inner end of the stuffing box body. The stuffing gland includes a stuffing gland body, located below the stuffing box body and fixedly connected by fasteners. A third vertical portion is integrally formed on the upper side of the radially inner end of the stuffing gland body. The upper end of the third vertical portion is located radially inner to the second vertical portion. The stuffing is compressed by the horizontal portion, the first vertical portion, and the third vertical portion. The minimum radial distance between each wedge-shaped bar and the inner wall of the shell-side cylinder is denoted as L1, and the maximum radial distance between the radially inner surface of the horizontal portion and the radially outer surface of the cylindrical section is denoted as L2. Then, L1 > L2. The above design of the stuffing box and stuffing gland ensures the sealing performance of the stuffing box sealing mechanism and has a simple structure and convenient assembly.

[0014] Preferably, the maximum radial distance between the radial inner surface of the second vertical part and the radial outer surface of the third vertical part is denoted as L3, and the maximum radial distance between the radial inner surface of the third vertical part and the radial outer surface of the cylindrical section is denoted as L4, so that L2 = L3 = L4, in order to further optimize the overall sealing effect.

[0015] Compared with the prior art, the present invention has the following advantages: The internal stuffing gland sliding tube sheet heat exchanger of the present invention has a simple structure, is easy to manufacture, and has a low cost. By setting a split-pass sealing mechanism on the shell side of the sliding tube sheet and a stuffing gland sealing mechanism on the tube side of the sliding tube sheet, a double sealing effect on the shell side medium can be achieved, effectively preventing the shell side medium from leaking out of the heat exchanger. It is safe and reliable to use and is suitable for flammable, explosive, and toxic media. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the internal stuffing gland sliding tube sheet heat exchanger in the embodiment;

[0017] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0018] Figure 3 for Figure 1 Enlarged view at point B in the middle;

[0019] In the diagram: 1-Upper tube box, 11-Baffle plate, 2-Fixed tube sheet, 3-Shell side shell, 31-Shell side inlet, 32-Shell side outlet, 4-Multiple heat exchange tubes, 5-Sliding tube sheet, 51-Boss, 6-Lower tube box, 61-Drain port, 7-Elastic sealing sheet, 71-Bolt, 72-Pressure strip, 8-Wedge rod, 91-Stuffing gland, 911-Stuffing gland body, 912-First vertical section, 913-Second vertical section, 92-Stuffing gland, 921-Stuffing gland body, 922-Third vertical section, 93-Sliding tube sheet skirt, 94-Stuffing, 95-Variable diameter section, 951-Bending structure, 952-Bending structure, 96-Cylinder section, 97-Fastener, 98-Guide tube. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] The internally packed gland sliding tube sheet heat exchanger of this embodiment, as shown in the figure, includes an upper tube box 1, a shell-side cylinder 3, a lower tube box 6, a fixed tube sheet 2, multiple heat exchange tubes 4, multiple baffles 11, and a sliding tube sheet 5. The upper tube box 1 and the lower tube box 6 are respectively fixed to the upper and lower ends of the shell-side cylinder 3. The shell-side cylinder 3 is provided with a shell-side inlet 31 and a shell-side outlet 32. The fixed tube sheet 2 is welded and fixed to the upper tube box 1 and the shell-side cylinder 3 respectively. The sliding tube sheet 5 is located at the bottom of the shell-side cylinder 3. The upper end of each heat exchange tube 4 is connected to the fixed tube sheet 2 by means of... The heat exchange tubes 4 are connected by internal welding. The lower end of each heat exchange tube 4 is connected to the sliding tube sheet 5 by strength welding and expansion bonding. Multiple baffles 11 are set inside the shell-side cylinder 3. The multiple baffles 11 are used to fix multiple heat exchange tubes 4. The baffles 11 can be arc-shaped, disc-shaped, annular, spiral-shaped, etc. A split-pass sealing mechanism is provided between the shell-side side of the sliding tube sheet 5 and the inner wall of the shell-side cylinder 3. A stuffing box 91 sealing mechanism and a guide tube 98 are provided between the tube-side side of the sliding tube sheet 5 and the inner wall of the shell-side cylinder 3. The split-pass sealing mechanism includes an annular spring. The inner radial end of the elastic sealing plate 7 is fixed to the upper edge of the sliding tube sheet 5, and the outer radial end of the elastic sealing plate 7 is bent upward and pressed against the inner wall of the shell-side cylinder 3. The sealing mechanism of the stuffing box 91 includes an annular stuffing box 91, a stuffing gland 92, a sliding tube sheet skirt 93, and packing 94. The sliding tube sheet skirt 93 includes a variable diameter section 95 and a cylindrical section 96 that are arranged vertically and communicate with each other. A boss 51 is fixed to the lower edge of the sliding tube sheet 5. The wide diameter end of the variable diameter section 95 is welded to the boss 51, and the narrow diameter end of the variable diameter section 95 is... The diameter end is connected to the upper end of the cylindrical section 96. The packing 94 surrounds and adheres tightly to the outer wall of the cylindrical section 96. The packing 94 is pressed and fixed by the upper and lower packing glands 91 and packing caps 92. The radial outer surface of the packing gland 91 is in close contact with the inner wall of the shell-side cylinder 3. The guide tube 98 is a trumpet shape with a small upper opening and a large lower opening. The upper end of the guide tube 98 is fixed to the outer wall of the variable diameter section 95, and the lower end of the guide tube 98 is suspended above the packing gland 91. The side wall of the lower tube box 6 is provided with a drain port 61. The bottom surface of the drain port 61 is flush with the upper surface of the packing gland 91.

[0022] In this embodiment, the wide diameter end of the variable diameter section 95 adopts an outwardly convex bending structure 951, and the narrow diameter end of the variable diameter section 95 adopts an inwardly convex bending structure 952.

[0023] In this embodiment, the radial inner end of the elastic sealing sheet 7 is fixed to the upper edge of the sliding tube plate 5 by a plurality of bolts 71 and pressure strips 72. The plurality of bolts 71 are evenly distributed along the circumference of the sliding tube plate 5, and each bolt 71 passes through the pressure strips 72 and the elastic sealing sheet 7 and is threadedly connected to the sliding tube plate 5.

[0024] In this embodiment, n wedge-shaped bars 8, which are larger at the top and smaller at the bottom, are fixed on the radial outer surface of the sliding tube plate 5. n is a multiple of 4, and the n wedge-shaped bars 8 are evenly distributed along the circumference of the sliding tube plate 5.

[0025] In this embodiment, the stuffing box 91 includes a stuffing box body 911. A first vertical portion 912 is integrally provided on the upper side of the radially inner end of the stuffing box body 911. A horizontal portion 912 extending toward the cylinder section 96 is integrally and vertically provided at the top of the first vertical portion 912. A second vertical portion 913 is integrally provided on the lower side of the radially inner end of the stuffing box body 911. The stuffing cap 92 includes a stuffing cap body 921. The stuffing cap body 921 is located below the stuffing box body 911 and the two are fixedly connected by fasteners 97. A third vertical portion 922 is integrally provided on the upper side of the radially inner end of the stuffing cap body 921. The upper end of the third vertical portion 922 is located at the first vertical portion 913. On the radial inner side of the second vertical section 913, the packing 94 is pressed by the horizontal section 912, the first vertical section 912 and the third vertical section 922. The minimum radial distance between each wedge rod 8 and the inner wall of the shell-side cylinder 3 is denoted as L1, and the maximum radial distance between the radial inner surface of the horizontal section 912 and the radial outer surface of the cylinder section 96 is denoted as L2. Then L1 > L2. The maximum radial distance between the radial inner surface of the second vertical section 913 and the radial outer surface of the third vertical section 922 is denoted as L3, and the maximum radial distance between the radial inner surface of the third vertical section 922 and the radial outer surface of the cylinder section 96 is denoted as L4. Then L2 = L3 = L4.

Claims

1. A stuffed box sliding tube sheet heat exchanger, comprising an upper tube box, a shell-side cylinder, a lower tube box, a fixed tube sheet, multiple heat exchange tubes, multiple baffles, and a sliding tube sheet, wherein the upper tube box and the lower tube box are respectively fixed to the upper and lower ends of the shell-side cylinder, the shell-side cylinder has a shell-side inlet and a shell-side outlet, the fixed tube sheet is fixed to the upper tube box and the shell-side cylinder respectively, the sliding tube sheet is disposed at the bottom of the shell-side cylinder, the upper and lower ends of each heat exchange tube are respectively fixed to the fixed tube sheet and the sliding tube sheet, and the multiple baffles are disposed within the shell-side cylinder for fixing the multiple heat exchange tubes, characterized in that... A split-pass sealing mechanism is provided between the shell-side of the sliding tube sheet and the inner wall of the shell-side cylinder. A stuffing box sealing mechanism and a guide tube are provided between the tube-side of the sliding tube sheet and the inner wall of the shell-side cylinder. The split-pass sealing mechanism includes an annular elastic sealing plate. The radially inner end of the elastic sealing plate is fixed to the upper edge of the sliding tube sheet, and the radially outer end of the elastic sealing plate is bent upward and pressed against the inner wall of the shell-side cylinder. The stuffing box sealing mechanism includes an annular stuffing box, a stuffing gland, a sliding tube sheet skirt, and packing. The sliding tube sheet skirt includes a variable diameter section and a cylindrical section that are arranged vertically and communicate with each other. The wide-diameter end is fixed to the lower edge of the sliding tube sheet, the narrow-diameter end of the variable-diameter section is connected to the upper end of the cylindrical section, the packing surrounds and adheres tightly to the outer wall of the cylindrical section, the packing is pressed and fixed by the upper and lower packing glands, the radial outer surface of the packing gland is in close contact with the inner wall of the shell-side cylinder, the guide tube is trumpet-shaped with a small upper opening and a large lower opening, the upper end of the guide tube is fixed to the outer wall of the variable-diameter section, the lower end of the guide tube is suspended above the packing gland, the side wall of the lower tube box is provided with a drain port, the bottom surface of the drain port is flush with the upper surface of the packing gland.

2. The internally packed gland sliding tube sheet heat exchanger according to claim 1, characterized in that, The fixed tube sheet is welded and fixed to the upper tube box and the shell-side cylinder respectively. The upper end of each heat exchange tube is connected to the fixed tube sheet by internal hole welding, and the lower end of each heat exchange tube is connected to the sliding tube sheet by strength welding and expansion bonding.

3. A sliding tube sheet heat exchanger with internal stuffing gland according to claim 1, characterized in that, A boss is fixed to the lower edge of the sliding tube plate, and the wide diameter end of the variable diameter section is welded to the boss.

4. A sliding tube sheet heat exchanger with internal stuffing gland according to claim 3, characterized in that, The wide-diameter end of the variable-diameter section adopts an outwardly convex bending structure, and the narrow-diameter end of the variable-diameter section adopts an inwardly convex bending structure.

5. A sliding tube sheet heat exchanger with internal stuffing gland according to claim 1, characterized in that, The radial inner end of the elastic sealing sheet is fixed to the upper edge of the sliding tube plate by multiple bolts and pressure strips. The multiple bolts are evenly distributed along the circumference of the sliding tube plate, and each bolt passes through the pressure strip and the elastic sealing sheet and is threadedly connected to the sliding tube plate.

6. A sliding tube sheet heat exchanger with internal stuffing gland according to any one of claims 1-5, characterized in that, The sliding tube plate has n wedge-shaped bars that are larger at the top and smaller at the bottom fixed on its radial outer surface, where n is a multiple of 4, and the n wedge-shaped bars are evenly distributed along the circumference of the sliding tube plate.

7. A sliding tube sheet heat exchanger with internal stuffing gland according to claim 6, characterized in that, The stuffing box includes a stuffing box body. A first vertical portion is integrally provided on the upper side of the radially inner end of the stuffing box body. A horizontal portion extending toward the cylindrical section is integrally and vertically provided at the top of the first vertical portion. A second vertical portion is integrally provided on the lower side of the radially inner end of the stuffing box body. The stuffing gland includes a stuffing gland body. The stuffing gland body is located below the stuffing box body and the two are fixedly connected by fasteners. A third vertical portion is integrally provided on the upper side of the radially inner end of the stuffing gland body. The upper end of the third vertical portion is located radially inner to the second vertical portion. The stuffing is pressed together by the horizontal portion, the first vertical portion, and the third vertical portion. The minimum radial distance between each wedge bar and the inner wall of the shell-side cylinder is denoted as L1, and the maximum radial distance between the radially inner surface of the horizontal portion and the radially outer surface of the cylindrical section is denoted as L2. Then L1 > L2.

8. A sliding tube sheet heat exchanger with internal stuffing gland according to claim 7, characterized in that, Let L3 be the maximum radial distance between the inner radial surface of the second vertical part and the outer radial surface of the third vertical part, and let L4 be the maximum radial distance between the inner radial surface of the third vertical part and the outer radial surface of the cylindrical section. Then L2 = L3 = L4.

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