An expansion joint for a shell-and-tube heat exchanger

Abstract

The present invention relates to the technical field of pipeline interfaces, and specifically relates to an expansion joint for a shell-and-tube heat exchanger, which includes a shell-and-tube heat exchanger body. A connecting flange is coaxially and fixedly installed on the shell-and-tube heat exchanger body. An annular limiting strip and an annular positioning strip are arranged along the circumferential direction on the inner wall of the connecting flange. An annular embedding strip is movably and snap-fitted on the inner wall of the annular positioning strip. A countersunk bolt is arranged on the annular embedding strip, and the annular embedding strip is fixedly installed on the annular positioning strip through the countersunk bolt. The liquid flowing in the inner expansion tube will enter the cavity formed by the inner expansion tube, the annular sliding strip, the second annular connecting strip and the outer expansion tube through the pressure relief holes. The pressure generated during the liquid flow will be shared by the cavity formed by the inner expansion tube, the annular sliding strip, the second annular connecting strip and the outer expansion tube, reducing the pressure generated by the liquid flow, effectively reducing the pressure borne by the expansion joint, avoiding damage or failure of the expansion joint caused by excessive stress, and prolonging its service life.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline interfaces, and specifically to an expansion joint for a shell and tube heat exchanger. Background Art

[0002] The working principle of a shell and tube heat exchanger is as follows: The hot fluid and the cold fluid flow through the inside and outside of the tube bundle of the heat exchanger respectively (or vice versa). The hot fluid transfers heat to the cold fluid through the tube wall. Specifically, when the hot fluid flows inside the tube, the heat is conducted through the metal tube wall to the outside of the tube. At the same time, due to the temperature difference between the fluids, heat convection occurs, which further promotes the transfer of heat. When the cold fluid flows outside the tube, it continuously absorbs the heat from the tube wall, thereby increasing its own temperature, while the temperature of the hot fluid gradually decreases. In this way, the exchange of heat between the two fluids is achieved, and the purpose of heat exchange is reached.

[0003] The expansion joint for a shell and tube heat exchanger mainly has the following functions: compensating displacement: compensating for the axial, lateral, and angular displacements of the pipeline caused by temperature changes, thermal expansion and contraction of the pipeline, etc., and preventing the pipeline from being damaged due to deformation; absorbing vibration: reducing the vibration transmission in the pipeline system, reducing the impact of vibration on equipment and pipelines, and extending the service life of the equipment; reducing stress: reducing the stress concentration at the pipeline connection through its own telescopic deformation, and avoiding problems such as cracks; ensuring pipeline safety: ensuring that the pipeline can operate safely and stably under various working conditions, and reducing safety hazards such as leakage.

[0004] When the expansion joint is used on a shell and tube heat exchanger, since the shell and tube heat exchanger contains cold and hot water, compared with ordinary pipelines, the temperature difference between the cold and hot in the shell and tube heat exchanger is larger. Therefore, the shell and tube heat exchanger requires an expansion joint with better compensation ability to relieve the deformation caused by temperature changes and thermal expansion and contraction of the pipeline. When the traditional expansion joint is used for a shell and tube heat exchanger, its service life is relatively low. To solve this problem, a new type of expansion joint for a shell and tube heat exchanger is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide an expansion joint for a shell and tube heat exchanger to solve the problems raised in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solution: An expansion joint for a shell-and-tube heat exchanger, including a shell-and-tube heat exchanger body, on which a connecting flange is coaxially and fixedly installed. An annular limiting strip and an annular positioning strip are arranged along the circumferential direction on the inner wall of the connecting flange. An annular embedding strip is movably engaged and installed on the inner wall of the annular positioning strip. A countersunk head bolt is arranged on the annular embedding strip, and the annular embedding strip is fixedly installed on the annular positioning strip through the countersunk head bolt. On one side of the two annular embedding strips close to each other, a first annular connecting strip is provided. A pressure relief hole is opened on the first annular connecting strip. The side walls of the first annular connecting strip and the annular positioning strip are in contact with each other. An inner expansion tube is arranged between the two first annular connecting strips. An annular sliding strip is movably engaged in the structure composed of the annular limiting strip and the annular positioning strip. On one side of the two annular sliding strips close to each other, a second annular connecting strip is provided. The circumferential inner side wall of the second annular connecting strip is in contact with the circumferential outer side wall of the first annular connecting strip. An outer expansion tube is arranged between the two second annular connecting strips, and the structure composed of the outer expansion tube is located outside the structure composed of the second annular connecting strip.

[0007] Preferably, the pressure relief holes on the first annular connecting strip are annularly arranged in an array with the central axis of the first annular connecting strip as the array center.

[0008] Preferably, the inner expansion tube and the outer expansion tube are coaxially arranged, and the corrugation intervals on the outer expansion tube and the inner expansion tube are the same.

[0009] Preferably, the first annular connecting strip, the inner expansion tube, the second annular connecting strip, and the outer expansion tube form a sealed cavity.

[0010] Preferably, a driving push rod is fixedly connected to the outer wall of the second annular connecting strip. A guiding bracket is arranged on the side wall of the connecting flange close to the second annular connecting strip. The guiding bracket is movably mounted outside the driving push rod. A U-shaped buckle is fixedly installed on the driving push rod. The U-shaped buckle is movably sleeved on the guiding bracket. A locking bolt that supports at the corresponding position of the guiding bracket is threadedly connected to the U-shaped buckle. An L-shaped shielding member is arranged at the position on the inner side wall of the second annular connecting strip corresponding to the pressure relief hole.

[0011] Preferably, the guiding bracket is arranged along the arc corresponding to the central axis of the second annular connecting strip, and the guiding bracket is located between two adjacent mounting holes on the connecting flange.

[0012] Preferably, the annular embedding strip and the first annular connecting strip are of an integrally formed structure, and the circumferential inner side walls of the annular embedding strip and the first annular connecting strip are flush.

[0013] Preferably, an internal and external thread sleeve is movably installed on the connecting flange, a hexagon bolt is threadedly connected to the internal and external thread sleeve, the hexagon bolts are located on both sides of the connecting flange, an adjusting screw rod is threadedly connected to the hexagon bolt, a positioning ring is fixedly installed at the end of the adjusting screw rod, the positioning ring is located inside another internal and external thread sleeve and is rotatably connected to the internal and external thread sleeve, and a driving handle is arranged at the end of the adjusting screw rod.

[0014] Preferably, the internal and external thread sleeves at other positions can also be connected by a telescopic rod.

[0015] Preferably, the inner side of the inner expansion tube is connected by an annular baffle strip, and the annular baffle strip is flush with the inner circumferential side wall of the annular positioning strip.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. When it is necessary to increase the bearing capacity of the expansion joint, by turning the locking bolt so that the locking bolt no longer presses on the side wall of the guiding bracket, ensuring that the U-shaped buckle can move on the guiding bracket. By applying pressure to the driving push rod, the driving push rod drives the U-shaped buckle to move on the guiding bracket. During the movement of the driving push rod, the driving push rod will drive the second annular connecting strip to move in the corresponding direction. During the movement of the second annular connecting strip, the annular sliding strip is driven by the second annular connecting strip to rotate inside the annular limiting strip and the annular positioning strip, realizing the rotation of the outer expansion tube on the surface of the inner expansion tube. At the same time, the rotation of the second annular connecting strip will also drive the movement of the L-shaped shielding member, and the L-shaped shielding member moves away from the pressure relief hole, so that the pressure relief hole is exposed. The liquid flowing inside the inner expansion tube will enter the cavity formed by the inner expansion tube, the annular sliding strip, the second annular connecting strip and the outer expansion tube through the pressure relief hole. The pressure generated during the flow of the liquid will be shared by the cavity formed by the inner expansion tube, the annular sliding strip, the second annular connecting strip and the outer expansion tube, reducing the pressure generated by the liquid flow, effectively reducing the pressure borne by the expansion joint, avoiding damage or failure of the expansion joint caused by excessive stress, extending its service life, providing a better buffering space, enabling the pressure change to be transmitted and dissipated more smoothly, and reducing the impact on the surrounding structures.

[0018] 2. Insert the ends of the internal and external threaded sleeves into the flange on the shell-and-tube heat exchanger body and the connecting flange plate, and fix them with hexagon bolts. Optionally, install an adjusting screw between the corresponding internal and external threaded sleeves, and set telescopic rods between other internal and external threaded sleeves. By rotating the driving handle, the positioning ring at the end of the driving handle rotates inside the internal and external threaded sleeves. During the rotation of the adjusting screw, the adjusting screw moves inside the internal and external threaded sleeves that are threadedly connected to it, thereby driving the two internal and external threaded sleeves to approach or move away from each other, so as to adjust the distance between the two parts of the shell-and-tube heat exchanger body. By the mutual approach of the two internal and external threaded sleeves at this position, other internal and external threaded sleeves are driven to approach each other. At the same time, by adjusting the distance between the internal and external threaded sleeves, the stress of the expansion joint is changed, and its service life is extended. It can flexibly adjust the state of the expansion joint according to specific working conditions, such as changes in temperature, pressure, flow rate, etc., so that it can better adapt to various complex working conditions.

[0019] 3. Through the double-layer structure composed of the inner expansion tube and the outer expansion tube, when the shell-and-tube heat exchanger body undergoes axial, lateral, and angular displacements of the pipeline caused by temperature changes, thermal expansion and contraction of the pipeline, etc., the structure composed of the inner expansion tube and the outer expansion tube can deform in a double layer to adapt to the axial, lateral, and angular displacements of the pipeline caused by temperature changes, thermal expansion and contraction of the pipeline, etc., improving the anti-stress ability. Compared with a single-layer expansion joint, the two-layer structure helps to improve the sealing effect, reduce the possibility of leakage, ensure the tightness of the system, can withstand higher pressures, and can also work stably under high-pressure environments to ensure the safety of the system.

[0020] 4. Due to the presence of the annular baffle belt, the flow of the liquid is guided to prevent the liquid from directly contacting the inner wall of the inner expansion tube, which affects the flow effect of the liquid and prevents the inner expansion tube from directly contacting the liquid. At the same time, the annular baffle belt has a certain deformation ability to adapt to the deformation of the inner expansion tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic installation structure diagram of the present invention.

[0022] Figure 2 It is a schematic front view structure diagram of the present invention.

[0023] Figure 3 It is a schematic top view structure diagram of the present invention.

[0024] Figure 4 It is a schematic side view structure diagram of the present invention.

[0025] Figure 5 It is a schematic structure diagram of the corresponding position of the hexagon bolt of the present invention.

[0026] Figure 6 It is a schematic structure diagram of the corresponding position of the rotatable lead screw of the present invention.

[0027] Figure 7 This is a schematic structural diagram of the corresponding position of the internal expansion tube of the present invention.

[0028] Figure 8 This is a schematic cross-sectional structural diagram of the internal expansion tube and the external expansion tube of the present invention.

[0029] Figure 9 This is a schematic structural diagram of the corresponding position of the driving push rod of the present invention.

[0030] Figure 10 This is a schematic structural diagram of the corresponding position of the connecting flange of the present invention.

[0031] Figure 11 This is a schematic structural diagram of the corresponding position of the cross-section of the internal expansion tube of the present invention.

[0032] Figure 12 This is a schematic structural diagram of the corresponding position of the annular connecting belt of the present invention.

[0033] Figure 13 This is a schematic structural diagram of the corresponding position of the drainage hole of the present invention.

[0034] Figure 14 This is a schematic structural diagram of the corresponding position of the annular baffle belt of the present invention.

[0035] In the figure: 1. Shell and tube heat exchanger body; 2. Connecting flange; 3. Annular limiting strip; 4. Annular positioning strip; 5. Annular embedding strip; 501. Countersunk head bolt; 6. First annular connecting strip; 601. Pressure relief hole; 7. Internal expansion tube; 8. Annular sliding strip; 9. Second annular connecting strip; 901. L-shaped shielding part; 10. External expansion tube; 11. Driving push rod; 12. Guide bracket; 13. U-shaped buckle; 14. Locking bolt; 15. Internal and external thread sleeve; 16. Hexagon bolt; 17. Adjusting screw; 18. Positioning ring; 19. Driving handle; 20. Telescopic rod; 21. Annular baffle belt. Detailed implementation manners

[0036] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] Please refer to Figures 1 to 14, the present invention provides a technical solution: an expansion joint for a shell-and-tube heat exchanger, including the shell-and-tube heat exchanger body 1. The shell-and-tube heat exchanger body 1 is the body of a shell-and-tube heat exchanger. The shell-and-tube heat exchanger body 1 is composed of two parts, and the two parts are connected through a connecting flange 2 and the structure on the connecting flange 2 to assist in the assembly of auxiliary equipment. The shell-and-tube heat exchanger body 1 mainly uses the principle of heat exchange between two fluids at different temperatures inside and outside the tube bundle for heat exchange. A connecting flange 2 is coaxially and fixedly installed on the shell-and-tube heat exchanger body 1. The connecting flange 2 corresponds to the flanges at the corresponding positions on the shell-and-tube heat exchanger body 1, and the two are fixedly connected by bolts. An annular limiting strip 3 and an annular positioning strip 4 are arranged along the circumferential direction on the inner wall of the connecting flange 2. The annular limiting strip 3 and the annular positioning strip 4 are installed on the circumferential inner wall of the connecting flange 2. The annular limiting strip 3 is an annular strip, and the annular positioning strip 4 is a strip with an L-shaped cross-section. An annular embedding strip 5 is movably clamped and installed on the inner wall of the annular positioning strip 4. A countersunk head bolt 501 is provided on the annular embedding strip 5, and the annular embedding strip 5 is fixedly installed on the annular positioning strip 4 through the countersunk head bolt 501. The annular embedding strip 5 is an annular strip. A relief groove corresponding to the shape of the annular embedding strip 5 is opened on the annular positioning strip 4. The annular embedding strip 5 is movably clamped in the groove body on the annular positioning strip 4, and the two are movably connected. A threaded installation hole corresponding to the countersunk head bolt 501 is also opened on the annular positioning strip 4 to assist in the installation of the countersunk head bolt 501 on the annular positioning strip 4, thereby ensuring the connection and fixation between the annular positioning strip 4 and the annular embedding strip 5 and ensuring the fixing effect of the annular embedding strip 5 on the annular positioning strip 4. A first annular connecting strip 6 is provided on one side of the two annular embedding strips 5 close to each other. The annular embedding strip 5 and the first annular connecting strip 6 are of an integrally formed structure. The annular embedding strip 5 and the first annular connecting strip 6 are integrally formed. Through the integrally formed injection molding process, the manufacturing convenience of the structure composed of the annular embedding strip 5 and the first annular connecting strip 6 is improved. And the circumferential inner side walls of the annular embedding strip 5 and the first annular connecting strip 6 are flush, ensuring that when the fluid passes through the positions of the annular embedding strip 5 and the first annular connecting strip 6, it will not be affected by angular resistance and ensuring the normal flow of the liquid at the positions of the annular embedding strip 5 and the first annular connecting strip 6. A pressure relief hole 601 is opened on the first annular connecting strip 6. The pressure relief hole 601 is a groove penetrating the first annular connecting strip 6, and part of the liquid in the pressure relief hole 601 is introduced into the sealed cavity composed of the first annular connecting strip 6, the inner expansion tube 7, the second annular connecting strip 9, and the outer expansion tube 10. A sealed cavity is formed by the first annular connecting strip 6, the inner expansion tube 7, the second annular connecting strip 9, and the outer expansion tube 10. By allowing the liquid to enter the sealed cavity formed by the first annular connecting strip 6, the inner expansion tube 7, the second annular connecting strip 9, and the outer expansion tube 10, the pressure of the liquid in the shell-and-tube heat exchanger body 1 is buffered to prevent the excessive pressure on the inner expansion tube 7 and the outer expansion tube 10 from exceeding the maximum value of the pressure borne by the structure composed of the inner expansion tube 7 and the outer expansion tube 10.The buffer pressure is increased through the cooperation of the first annular connecting strip 6, the inner expansion tube 7, the second annular connecting strip 9 and the outer expansion tube 10. The pressure relief holes 601 on the first annular connecting strip 6 are annularly arrayed with the central axis of the first annular connecting strip 6 as the array center. The positions of the pressure relief holes 601 are reasonably distributed, so as to better discharge the liquid in the first annular connecting strip 6 and the inner expansion tube 7. The liquid enters the sealed cavity formed by the first annular connecting strip 6, the inner expansion tube 7, the second annular connecting strip 9 and the outer expansion tube 10, and the liquid flow is more reasonable.

[0038] The side walls of the first annular connecting strip 6 and the annular positioning strip 4 are in contact with each other to ensure that the gap between the first annular connecting strip 6 and the annular positioning strip 4 is blocked, preventing the liquid from leaving through the gap between the annular positioning strip 4 and the first annular connecting strip 6 and affecting the sealing effect. An inner expansion tube 7 is arranged between two first annular connecting strips 6. The inner expansion tube 7 is an expansion structure composed of multiple arc-shaped plates. The annular limiting strip 3 and the annular positioning strip 4 form a structure in which an annular sliding strip 8 is movably engaged. The structure formed by the annular limiting strip 3 and the annular positioning strip 4 forms an L-shaped space. The annular sliding strip 8 is movably engaged in this L-shaped space. Through the sliding of the annular sliding strip 8 in the structure formed by the annular limiting strip 3 and the annular positioning strip 4, the sliding of the structure composed of the annular sliding strip 8, the second annular connecting strip 9 and the outer expansion tube 10 is realized. Second annular connecting strips 9 are arranged on the sides of two annular sliding strips 8 close to each other. The second annular connecting strip 9 is an L-shaped structure, and the first annular connecting strip 6 is also an L-shaped structure. Through the cooperation of the first annular connecting strip 6 and the second annular connecting strip 9, a U-shaped structure is formed, and the structures composed of the first annular connecting strip 6 and the second annular connecting strip 9 are respectively used to fix the inner expansion tube 7 and the outer expansion tube 10. The circumferential inner side wall of the second annular connecting strip 9 is in contact with the circumferential outer side wall of the first annular connecting strip 6 to ensure the sealing at the connection position of the first annular connecting strip 6 and the second annular connecting strip 9, preventing the liquid from leaking out from the connection position of the first annular connecting strip 6 and the second annular connecting strip 9. An outer expansion tube 10 is arranged between two second annular connecting strips 9, and the structure composed of the outer expansion tube 10 is located outside the structure composed of the second annular connecting strip 9. The outer expansion tube 10 and the second annular connecting strip 9 form two sets of expansion structures on the outside and inside to buffer the expansion stress. Through the design of the inner expansion tube 7 and the outer expansion tube 10, the stress is better relieved. The inner expansion tube 7 and the outer expansion tube 10 are coaxially arranged, and the corrugation intervals on the outer expansion tube 10 and the inner expansion tube 7 are the same.

[0039] A drive push rod 11 is fixedly connected to the outer wall of the second annular connecting strip 9. The position of the drive push rod 11 does not correspond to the position of the mounting holes on the connecting flange 2, providing sufficient moving space for the drive push rod 11 to ensure the moving amplitude of the drive push rod 11. A guiding bracket 12 is provided on the side wall of the connecting flange 2 close to the second annular connecting strip 9. The guiding bracket 12 is a U-shaped bracket, which limits the moving track of the drive push rod 11 and at the same time ensures the moving amplitude of the drive push rod 11. The guiding bracket 12 is movably mounted outside the drive push rod 11. A U-shaped buckle 13 is fixedly installed on the drive push rod 11. The U-shaped buckle 13 is movably sleeved on the guiding bracket 12. The shapes of the U-shaped buckle 13 and the guiding bracket 12 are adapted to each other. Through the sliding of the U-shaped buckle 13 on the guiding bracket 12, the guiding and positioning during the movement of the drive push rod 11 are realized, ensuring the moving stability of the drive push rod 11. When the drive push rod 11 moves, it drives the rotation of the second annular connecting strip 9, the annular sliding strip 8 and the outer expansion tube 10. A locking bolt 14 that supports at the corresponding position of the guiding bracket 12 is threadedly connected to the U-shaped buckle 13. Through the threaded movement of the locking bolt 14 on the guiding bracket 12, the end of the locking bolt 14 presses on the side wall of the guiding bracket 12, realizing the fixation after the position adjustment of the drive push rod 11 and the U-shaped buckle 13. An L-shaped shielding member 901 is provided at the position of the inner side wall of the second annular connecting strip 9 corresponding to the pressure relief hole 601. The position of the L-shaped shielding member 901 corresponds to that of the pressure relief hole 601, realizing the control or cancellation of the shielding of the pressure relief hole 601 by the L-shaped shielding member 901.

[0040] The guiding bracket 12 is arranged along the arc corresponding to the central axis of the second annular connecting strip 9, and the guiding bracket 12 is located between two adjacent mounting holes on the connecting flange 2, ensuring the guiding effect of the guiding bracket 12 on the U-shaped buckle 13, restricting the moving track of the drive push rod 11, and ensuring the stable movement of the drive push rod 11.

[0041] An internal and external thread sleeve 15 is movably installed on the connecting flange 2. The internal and external thread sleeve 15 consists of a threaded part and a non-threaded part. A hexagonal bolt 16 is threadedly installed on the threaded part of the device. Due to the existence of the hexagonal bolt 16, the flange on the shell-and-tube heat exchanger body 1 and the connecting flange 2 are fixed together. A hexagonal bolt 16 is threadedly connected to the internal and external thread sleeve 15. The hexagonal bolt 16 is located on both sides of the connecting flange 2. An adjusting screw 17 is internally threadedly connected to the hexagonal bolt 16. A positioning ring 18 is fixedly installed at the end of the adjusting screw 17. A groove corresponding to the positioning ring 18 is provided on the internal and external thread sleeve 15, realizing the rotational connection and cooperation between the adjusting screw 17 and the internal and external thread sleeve 15. The positioning ring 18 is located inside another internal and external thread sleeve 15 and is rotationally connected to the internal and external thread sleeve 15. A drive handle 19 is provided at the end of the adjusting screw 17. The existence of the drive handle 19 is used to assist the rotation of the adjusting screw 17.

[0042] The internal and external threaded sleeves 15 at other positions can also be connected by a telescopic rod 20. According to different positions, either the telescopic rod 20 or the adjusting screw 17 can be selected for installation. Only one adjusting screw 17 is needed to adjust all the internal and external threaded sleeves 15.

[0043] The inner side of the inner expansion tube 7 is connected by an annular baffle strip 21, and the annular baffle strip 21 is flush with the inner circumferential wall of the annular positioning strip 4. Due to the presence of the annular baffle strip 21, the flow of the liquid is guided to prevent the liquid from directly contacting the inner wall of the inner expansion tube 7, which affects the flow effect of the liquid. At the same time, the annular baffle strip 21 has a certain deformation ability to adapt to the deformation of the inner expansion tube 7.

[0044] Working principle:

[0045] First step: Insert the ends of the internal and external threaded sleeves 15 into the flange on the shell-and-tube heat exchanger body 1 and the connecting flange plate 2, and fix them with hexagon bolts 16. By selection, an adjusting screw 17 is installed between the corresponding internal and external threaded sleeves 15, and a telescopic rod 20 is arranged between the other internal and external threaded sleeves 15. Drive the positioning ring 18 at the end of the driving handle 19 to rotate within the internal and external threaded sleeves 15 by rotating the driving handle 19. During the rotation of the adjusting screw 17, the adjusting screw 17 will move within the internal and external threaded sleeves 15 that are threadedly connected to the adjusting screw 17, thereby driving the two internal and external threaded sleeves 15 to approach or move away from each other, so as to adjust the distance between the two parts of the shell-and-tube heat exchanger body 1. By the approach of the two internal and external threaded sleeves 15 at this position, drive the other internal and external threaded sleeves 15 to approach each other. At the same time, adjust the distance between the internal and external threaded sleeves 15, thereby changing the stress magnitude of the expansion joint.

[0046] Step 2: When it is necessary to increase the bearing capacity of the expansion joint, turn the locking bolt 14 so that the locking bolt 14 no longer presses against the side wall of the guiding support 12, ensuring that the U-shaped buckle 13 can move on the guiding support 12. By applying pressure to the driving push rod 11, the driving push rod 11 drives the U-shaped buckle 13 to move on the guiding support 12. During the movement of the driving push rod 11, the driving push rod 11 drives the second annular connecting strip 9 to move in the corresponding direction. During the movement of the second annular connecting strip 9, the annular sliding strip 8 is driven by the second annular connecting strip 9 to rotate within the annular limiting strip 3 and the annular positioning strip 4, realizing the rotation of the outer expansion tube 10 on the surface of the inner expansion tube 7. At the same time, the rotation of the second annular connecting strip 9 also drives the movement of the L-shaped shielding member 901, and the L-shaped shielding member 901 moves away from the pressure relief hole 601, so that the pressure relief hole 601 is exposed. The liquid flowing in the inner expansion tube 7 will enter the cavity formed by the inner expansion tube 7, the annular sliding strip 8, the second annular connecting strip 9 and the outer expansion tube 10 through the pressure relief hole 601. The pressure generated during the liquid flow will be shared by the cavity formed by the inner expansion tube 7, the annular sliding strip 8, the second annular connecting strip 9 and the outer expansion tube 10, reducing the pressure generated by the liquid flow.

[0047] Step 3: Through the double-layer structure inside and outside composed of the inner expansion tube 7 and the outer expansion tube 10, when the shell-and-tube heat exchanger body 1 undergoes axial, lateral and angular displacements of the pipeline caused by temperature changes, pipeline thermal expansion and contraction, etc., the structure composed of the inner expansion tube 7 and the outer expansion tube 10 can deform in a double layer to adapt to the axial, lateral and angular displacements of the pipeline caused by temperature changes, pipeline thermal expansion and contraction, etc., improving the stress resistance ability.

[0048] Step 4: Due to the presence of the annular flow guiding belt 21, the flow of the liquid is guided to prevent the liquid from directly contacting the inner wall of the inner expansion tube 7, affecting the liquid flow effect, and preventing the inner expansion tube 7 from directly contacting the liquid. At the same time, the annular flow guiding belt 21 has a certain deformation ability to adapt to the deformation of the inner expansion tube 7.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An expansion joint for a shell-and-tube heat exchanger, comprising a shell-and-tube heat exchanger body (1), a connecting flange (2) being coaxially fixedly mounted on the shell-and-tube heat exchanger body (1), characterized in that: The inner wall of the connecting flange (2) is provided with an annular limiting strip (3) and an annular positioning strip (4) along the circumferential direction; the inner wall of the annular positioning strip (4) is movably engaged with an annular embedding strip (5); the annular embedding strip (5) is provided with a countersunk bolt (501), and the annular embedding strip (5) is fixedly installed on the annular positioning strip (4) by means of the countersunk bolt (501); a first annular connecting strip (6) is provided on one side of the two annular embedding strips (5) that are close to each other; a pressure relief hole (601) is provided on the first annular connecting strip (6); the side walls of the first annular connecting strip (6) and the annular positioning strip (4) are in contact with each other; an inner expansion tube (7) is provided between the two first annular connecting strips (6); the annular limiting strip (3) and the annular positioning strip (4) are in contact with each other; An annular sliding bar (8) is movably engaged in the structure of the positioning bar (4), and a second annular connecting bar (9) is provided on the side where the two annular sliding bars (8) are close to each other. The circumferential inner wall of the second annular connecting bar (9) is in contact with the circumferential outer wall of the first annular connecting bar (6), and an outer expansion tube (10) is provided between the two second annular connecting bars (9), and the structure of the outer expansion tube (10) is located outside the structure of the second annular connecting bar (9). An L-shaped shielding member (901) is provided at the position of the inner wall of the second annular connecting bar (9) corresponding to the pressure relief hole (601), and the rotation of the second annular connecting bar (9) will also drive the movement of the L-shaped shielding member (901), so that the L-shaped shielding member (901) leaves the pressure relief hole (601).

2. An expansion joint for a shell-and-tube heat exchanger according to claim 1, characterized in that: The pressure relief holes (601) on the first annular connecting strip (6) are distributed in an annular array with the central axis of the first annular connecting strip (6) as the center of the array.

3. The expansion joint for a shell-and-tube heat exchanger according to claim 1, characterized in that: The inner expansion tube (7) and the outer expansion tube (10) are coaxially arranged, and the corrugations on the outer expansion tube (10) and the inner expansion tube (7) have the same interval.

4. The expansion joint for a shell-and-tube heat exchanger according to claim 1, characterized in that: The first annular connecting strip (6), the inner expansion tube (7), the second annular connecting strip (9) and the outer expansion tube (10) form a sealed cavity.

5. An expansion joint for a shell-and-tube heat exchanger according to claim 4, characterized in that: The outer wall of the second annular connecting strip (9) is fixedly connected to a driving push rod (11); a guide bracket (12) is arranged on the side wall of the connecting flange (2) close to the second annular connecting strip (9); the guide bracket (12) is movably mounted outside the driving push rod (11); a U-shaped buckle (13) is fixedly mounted on the driving push rod (11); the U-shaped buckle (13) is movably sleeved on the guide bracket (12); a locking bolt (14) supported at a corresponding position of the guide bracket (12) is threadedly connected to the U-shaped buckle (13).

6. An expansion joint for a shell-and-tube heat exchanger according to claim 5, characterized in that: The guide bracket (12) is arranged along an arc corresponding to the central axis of the second annular connecting strip (9), and the guide bracket (12) is located between two adjacent mounting holes on the connecting flange (2).

7. An expansion joint for a shell-and-tube heat exchanger according to claim 6, characterized in that: The annular embedding strip (5) and the first annular connecting strip (6) are an integrally formed structure, and the circumferential inner side walls of the annular embedding strip (5) and the first annular connecting strip (6) are flush.

8. An expansion joint for a shell-and-tube heat exchanger according to claim 7, characterized in that: An internal and external threaded sleeve (15) is movably mounted on the connecting flange (2), and a hexagonal bolt (16) is threadedly connected to the internal and external threaded sleeve (15). The hexagonal bolt (16) is located on both sides of the connecting flange (2). An adjusting screw (17) is internally threadedly connected to the hexagonal bolt (16), and a positioning ring (18) is fixedly mounted on the end of the adjusting screw (17). The positioning ring (18) is located in another internal and external threaded sleeve (15) and is rotatably connected to the internal and external threaded sleeve (15). A driving handle (19) is provided on the end of the adjusting screw (17).

9. An expansion joint for a shell-and-tube heat exchanger according to claim 8, characterized in that: The internal and external threaded sleeves (15) at other positions are connected via a telescopic rod (20).

10. An expansion joint for a shell-and-tube heat exchanger according to claim 9, characterized in that: The inner side of the inner expansion tube (7) is connected via an annular flow blocking strip (21), and the annular flow blocking strip (21) is flush with the inner circumferential wall of the annular positioning strip (4).

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