Welding type floating tube box heat exchanger

Abstract

The utility model discloses a welding type floating tube box heat exchanger, belongs to the technical field of heat exchange devices, and aims to solve the problems that an existing compressed air energy storage system needs to be started and stopped everyday, a heat exchanger belongs to a fatigue container, and the safety is poor. The heat exchanger comprises a front end socket, a front tube box, a fixed tube plate, a shell, a heat exchange tube bundle, a floating tube plate, a floating tube box, a floating end socket and a rear end socket, the front end socket is arranged at one end of the front tube box, the fixed tube plate is arranged at the other end of the front tube box, the shell is arranged at the other end of the fixed tube plate, and the rear end socket is arranged at the other end of the shell. The heat exchange tube bundle, the floating tube plate, the floating tube box and the floating end socket are all arranged in the shell, the floating tube box is arranged on the side, away from the fixed tube plate, of the floating tube plate, the floating end socket is arranged at the other end of the floating tube box, and the heat exchange tube bundle is arranged between the fixed tube plate and the floating tube plate. One end of the heat exchange tube bundle penetrates through the fixed tube plate and communicates with the front tube box, and the other end of the heat exchange tube bundle penetrates through the floating tube plate and communicates with the floating tube box. The heat exchange structure is mainly used in the compressed air energy storage low-pressure cooler.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat exchange devices, and in particular relates to a welded floating tube box heat exchanger. Background Art

[0002] Non-supplementary compressed air energy storage technology (abbreviated as NF-CAES) is one of the key technologies suitable for large-scale power energy storage. This technology can break the bottleneck problem of connecting renewable energy to the power grid. In the non-supplementary compressed air energy storage system, the heat exchanger is an important device that affects the performance of the system. Improving the efficiency of the heat exchanger will significantly improve the performance of the heat recovery system, which in turn is conducive to improving the power storage efficiency of the compressed air energy storage system. Furthermore, in order to maintain the normal operation of the unit, it is necessary to ensure the safety of the startup process and operation process of the heat exchanger.

[0003] At present, the medium used for compressed air energy storage is molten salt, thermal oil, water, and air is compressed to a high-pressure state by a compressor. The heat exchanger absorbs and stores the compression heat. The high-pressure air is cooled and stored in the gas storage reservoir. During the cooling process, straight tube, U-tube, and hairpin structures are generally used to meet the thermal requirements of different pressures and different flows. Considering that the compressed air energy storage system needs to be started and stopped daily, the heat exchanger is a fatigue container. From the perspective of safety, it is necessary to develop a straight tube floating tube box heat exchanger to improve the temperature difference adaptability, and the structure is simple and easy to maintain. Utility Model Content

[0004] In order to solve the problem that the existing compressed air energy storage system needs to be started and stopped every day, and the heat exchanger therein is a fatigue container, which has a weak safety, the utility model provides a welded floating tube box heat exchanger;

[0005] A welded floating tube box heat exchanger, the heat exchanger comprises a front head, a front tube box, a fixed tube sheet, a shell, a heat exchange tube bundle, a floating tube sheet, a floating tube box, a floating head and a rear head, the front head is arranged on one end of the front tube box, and the front head is welded and fixed to the front tube box, the fixed tube sheet is arranged on the other end of the front tube box, and one end of the fixed tube sheet is welded and fixed to the front tube box, the shell is arranged on the other end of the fixed tube sheet, and the shell is welded and fixed to the fixed tube sheet, the rear head is arranged on the other end of the shell, and the rear head is welded and fixed to the shell, the heat exchange The tube bundle, floating tube sheet, floating tube box and floating head are all arranged in the shell, and the floating tube sheet is arranged opposite to the fixed tube sheet, the floating tube box is arranged on the side of the floating tube sheet away from the fixed tube sheet, and the floating tube box is welded and fixed to the floating tube sheet, the floating head is arranged on the other end of the floating tube box, and the floating head is welded and fixed to the floating tube box, the heat exchange tube bundle is arranged between the fixed tube sheet and the floating tube sheet, and one end of the heat exchange tube bundle passes through the fixed tube sheet and is connected to the front tube box, and the other end of the heat exchange tube bundle passes through the floating tube sheet and is connected to the floating tube box;

[0006] Furthermore, an air inlet pipe is inserted at the top of the shell, and the air inlet pipe is connected to the shell, an air outlet pipe is inserted at the bottom of the shell, and the air outlet pipe is connected to the shell, the air inlet pipe is arranged close to the floating tube sheet, and the air outlet pipe is arranged close to the fixed tube sheet;

[0007] Furthermore, a fixed support and a rolling support are provided at the bottom of the shell, and the fixed support and the rolling support are arranged relative to each other along the center line of the length direction of the shell, and the fixed support is arranged close to the front head, and the top of the fixed support is fixedly connected to the shell, and the rolling support is arranged close to the rear head, and the top of the rolling support is fixedly connected to the shell;

[0008] Furthermore, a No. 1 manhole is provided on the front head, the No. 1 manhole is connected to the front head, a No. 1 manhole baffle is provided at the inlet end of the No. 1 manhole, and the No. 1 manhole baffle is detachably connected to the No. 1 manhole;

[0009] Furthermore, a liquid collecting baffle is provided at the bottom of the rear head, the liquid collecting baffle is fixedly connected to the rear head, a leakage detection tube is provided on the side of the liquid collecting baffle away from the floating head, the leakage detection tube is inserted at the bottom of the rear head, and the leakage detection tube is connected to the rear head;

[0010] Further, the heat exchange tube bundle is an odd tube bundle, a feed pipe is inserted at the top of the front tube box, and the feed pipe is connected to the front tube box, a floating discharge pipe is inserted at the end of the floating head, the floating discharge pipe is connected to the floating head, and the axis of the floating discharge pipe is collinear with the axis of the shell, a discharge connecting pipe is inserted at the end of the rear head, the discharge connecting pipe is connected to the rear head, and the axis of the discharge connecting pipe is collinear with the axis of the shell, a retaining ring is provided on the inner wall of the discharge connecting pipe, the retaining ring and the inner wall of the discharge connecting pipe are integrally formed, the discharge end of the floating discharge pipe is inserted in the discharge connecting pipe, and the floating discharge pipe is limited by the retaining ring, and a stuffing box is filled between the floating discharge pipe and the retaining ring;

[0011] Further, the heat exchange tube bundle is an even-numbered tube bundle, a feed pipe is inserted at the top of the front tube box, and the feed pipe is connected to the front tube box, a discharge pipe is inserted at the bottom of the front tube box, and the discharge pipe is connected to the front tube box, a No. 2 manhole is provided at the end of the floating head, a No. 3 manhole is provided at the end of the rear head, and the axis of the No. 2 manhole is arranged in a colinear manner with the axis of the No. 3 manhole, a No. 2 manhole baffle is provided at the inlet end of the No. 2 manhole, and the No. 2 manhole baffle is detachably connected to the No. 2 manhole, and a No. 3 manhole baffle is provided at the inlet end of the No. 3 manhole, and the No. 3 manhole baffle is detachably connected to the No. 3 manhole:

[0012] Furthermore, a flange baffle is provided on the discharge end of the discharge connecting pipe, and the flange baffle is detachably connected to the discharge connecting pipe;

[0013] The beneficial effects of this application compared to the prior art are as follows:

[0014] The compressed air energy storage low-pressure cooler served by a welded floating tube box heat exchanger proposed in this application has a cooling temperature difference of about 100°C. Traditional heat exchangers generally use a fixed tube sheet type plus an expansion joint type. However, the compressed air energy storage system is started and stopped daily, with a design life of more than 30 years and more than 20,000 starts and stops. The heat exchanger is a fatigue device, and the service life of the expansion joint is about 6 years, which does not meet the requirements of the compressed air energy storage system. Frequent replacement of the expansion joint also increases the cost of the equipment. The utility content of this new type provides a welded floating tube box heat exchanger, with liquid inside the tube and compressed air outside the tube. It can be effectively used in occasions with large temperature differences in the heat exchange zone. When the temperature difference between the tube bundle and the shell is large, the tube bundle will cause thermal expansion. Under the action of the expansion force, the tube bundle will push the floating tube sheet to move axially, absorbing the axial thermal expansion during the movement without affecting the safety and reliability of the heat exchanger, thereby improving the service life of the heat exchanger.

[0015] The floating tube box heat exchanger provided in the present application is a welded floating tube box heat exchanger structure. Compared with the floating head structure widely used in the petrochemical industry, it has no flange or hook ring, is simple to manufacture and easy to operate, has low cost, and is more popular. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the internal structure diagram of the welded floating tube box heat exchanger described in this application (single process);

[0017] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0018] Figure 3 for Figure 1 A partial enlarged view of point B in the middle;

[0019] Figure 4 This is the internal structure diagram of the welded floating tube box heat exchanger described in this application (even-numbered process);

[0020] In the figure, 1 is a front head, 2 is a front tube box, 21 is a feed pipe, 22 is a discharge pipe, 3 is a fixed tube sheet, 4 is a shell, 41 is an air inlet pipe, 42 is an air outlet pipe, 43 is a fixed support, 44 is a rolling support, 5 is a heat exchange tube bundle, 6 is a floating tube sheet, 7 is a floating tube box, 8 is a floating head, 9 is a rear head, 10 is a liquid collecting baffle, 11 is a leakage detection tube, 12 is a floating discharge pipe, 13 is a discharge connecting pipe, 14 is a flange baffle, 15 is a retaining ring, 16 is a stuffing box, 17 is a No. 1 manhole, 18 is a No. 3 manhole and 19 is a No. 2 manhole. DETAILED DESCRIPTION

[0021] Specific implementation method 1: Combination Figures 1 to 4The present embodiment is described. In the present embodiment, a welded floating tube box heat exchanger is provided. The heat exchanger comprises a front head 1, a front tube box 2, a fixed tube sheet 3, a shell 4, a heat exchange tube bundle 5, a floating tube sheet 6, a floating tube box 7, a floating head 8 and a rear head 9. The front head 1 is arranged on one end of the front tube box 2, and the front head 1 is welded and fixed to the front tube box 2. The fixed tube sheet 3 is arranged on the other end of the front tube box 2, and one end of the fixed tube sheet 3 is welded and fixed to the front tube box 2. The shell 4 is arranged on the other end of the fixed tube sheet 3, and the shell 4 is welded and fixed to the fixed tube sheet 3. The rear head 9 is arranged on the other end of the shell 4, and the rear head 9 is welded and fixed to the shell 4. The shell body 4 is welded and fixed, the heat exchange tube bundle 5, the floating tube sheet 6, the floating tube box 7 and the floating head 8 are all arranged in the shell body 4, and the floating tube sheet 6 is arranged opposite to the fixed tube sheet 3, the floating tube box 7 is arranged on the side of the floating tube sheet 6 away from the fixed tube sheet 3, and the floating tube box 7 is welded and fixed to the floating tube sheet 6, the floating head 8 is arranged on the other end of the floating tube box 7, and the floating head 8 is welded and fixed to the floating tube box 7, the heat exchange tube bundle 5 is arranged between the fixed tube sheet 3 and the floating tube sheet 6, and one end of the heat exchange tube bundle 5 passes through the fixed tube sheet 3 and is connected to the front tube box 2, and the other end of the heat exchange tube bundle 5 passes through the floating tube sheet 6 and is connected to the floating tube box 7.

[0022] In the present embodiment, the floating structure formed by the floating tube sheet 6, the floating tube box 7 and the floating head 8 can cause thermal expansion of the heat exchange tube bundle 5 when the temperature difference between the heat exchange tube bundle 5 and the shell 4 is large. Under the action of the expansion force, the heat exchange tube bundle 5 will push the floating tube sheet 6 and then drive the entire floating structure to move axially. During the movement, the axial thermal expansion is absorbed without affecting the safety and reliability of the heat exchanger, thereby improving the service life of the heat exchanger. In order to ensure the stability of the axial movement in the present embodiment, an assembly gap is provided between the floating tube box 7 and the inner wall of the shell, and the assembly gap is 7 mm.

[0023] Specific implementation method 2: Combination Figures 1 to 4 This embodiment is described. The difference between this embodiment and the first embodiment is that an air inlet pipe 41 is inserted at the top of the shell 4, and the air inlet pipe 41 is connected to the shell 4, and an air outlet pipe 42 is inserted at the bottom of the shell 4, and the air outlet pipe 42 is connected to the shell 4, the air inlet pipe 41 is arranged close to the floating tube sheet 6, and the air outlet pipe 42 is arranged close to the fixed tube sheet 3. Other components and connection methods are the same as those of the first embodiment.

[0024] Specific implementation method three: Combination Figures 1 to 4This embodiment is described. The difference between this embodiment and the second embodiment is that a fixed support 43 and a rolling support 44 are provided at the bottom of the shell 4. The fixed support 43 and the rolling support 44 are arranged relatively along the center line of the length direction of the shell 4. The fixed support 43 is arranged close to the front head 1, and the top of the fixed support 43 is fixedly connected to the shell 4. The rolling support 44 is arranged close to the rear head 9, and the top of the rolling support 44 is fixedly connected to the shell 4. Other components and connection methods are the same as those of the second embodiment.

[0025] In this embodiment, the stability and safety of the structure are well guaranteed by the fixed support 43, and the rolling support 44 allows the structure to slide in different directions, thereby alleviating deformation and avoiding stress concentration caused by factors such as temperature and earthquake. Therefore, it is more suitable for structures that are easily affected by external forces and deformation. At the same time, the friction between the foundation can also be continuously adjusted with the changes in the sliding surface, which can effectively reduce the vibration and damage of the structure.

[0026] Specific implementation method four: Combination Figures 1 to 4 This embodiment is described. The difference between this embodiment and the third embodiment is that the front head 1 is provided with a No. 1 manhole 17, the No. 1 manhole 17 is connected to the front head 1, the inlet end of the No. 1 manhole 17 is provided with a No. 1 manhole baffle, and the No. 1 manhole baffle is detachably connected to the No. 1 manhole 17. Other components and connection methods are the same as those of the third embodiment.

[0027] With such arrangement, maintenance personnel can enter the front end of the heat exchanger through the No. 1 manhole 17 and perform maintenance on the space formed by the front pipe box 2 and the front head 1 of the heat exchanger.

[0028] Specific implementation method five: Combination Figures 1 to 4 This embodiment is described. The difference between this embodiment and the fourth embodiment is that a liquid collecting baffle 10 is provided at the bottom of the rear head 9, the liquid collecting baffle 10 is fixed to the rear head 9, a leakage detection tube 11 is provided on the side of the liquid collecting baffle 10 away from the floating head 8, the leakage detection tube 11 is inserted at the bottom of the rear head 9, and the leakage detection tube 11 is connected to the rear head 9. Other components and connection methods are the same as those of the fourth embodiment.

[0029] With such arrangement, when the liquid in the tube leaks at the stuffing box, the liquid will remain at the bottom of the rear head. The liquid collecting baffle 10 can prevent the liquid from flowing back, and a leakage detection port 11 is provided for monitoring. If leakage is found, the stuffing box is replaced in time to ensure the sealing.

[0030] Specific implementation method six: Combination Figures 1 to 4To explain this embodiment, the difference between this embodiment and the specific embodiment five is that the heat exchange tube bundle 5 is an odd tube bundle, a feed pipe 21 is inserted at the top of the front tube box 2, and the feed pipe 21 is connected to the front tube box 2, a floating discharge pipe 12 is inserted at the end of the floating head 8, the floating discharge pipe 12 is connected to the floating head 8, and the axis of the floating discharge pipe 12 is colinear with the axis of the shell 4, a discharge connecting pipe 13 is inserted at the end of the rear head 9, the discharge connecting pipe 13 is connected to the rear head 9, and the axis of the discharge connecting pipe 13 is colinear with the axis of the shell 4, a retaining ring 15 is provided on the inner wall of the discharge connecting pipe 13, the retaining ring 15 and the inner wall of the discharge connecting pipe 13 are integrally formed, the discharge end of the floating discharge pipe 12 is inserted in the discharge connecting pipe 13, and the floating discharge pipe 12 is limited by the retaining ring 15, and a stuffing box 16 is filled between the floating discharge pipe 12 and the retaining ring 15. Other components and connection methods are the same as those of the fifth specific implementation method.

[0031] In the present embodiment, the setting of the stuffing box 16 can ensure the mobile seal between the floating discharge pipe 12 and the discharge connecting pipe 13. When the floating structure receives the expansion force and performs axial movement, the floating discharge pipe 12 will also perform axial movement relative to the discharge connecting pipe 13. Since the discharge connecting pipe 13 is fixed and the floating discharge pipe 12 is limited and guided by the retaining ring 15, the stuffing box 16 will be compressed under the extrusion of the floating discharge pipe 12, which can ensure the mobile seal while also absorbing thermal expansion.

[0032] Specific implementation method seven: Combination Figures 1 to 4 This embodiment is described. The difference between this embodiment and the sixth embodiment is that a flange baffle 14 is provided on the discharge end of the discharge connecting pipe 13, and the flange baffle 14 is detachably connected to the discharge connecting pipe 13. Other components and connection methods are the same as those of the sixth embodiment.

[0033] In this embodiment, the discharge connecting pipe 13 and the floating discharge pipe 12 can also serve as manholes when not in operation, and maintenance personnel can enter the interior of the floating pipe box through the discharge connecting pipe 13 and the floating discharge pipe 12 to perform maintenance work.

[0034] Specific implementation method eight: Combination Figures 1 to 4This embodiment is described. The difference between this embodiment and the fifth embodiment is that the heat exchange tube bundle 5 is an even-numbered tube bundle, a feed pipe 21 is inserted at the top of the front tube box 2, and the feed pipe 21 is connected to the front tube box 2, a discharge pipe 22 is inserted at the bottom of the front tube box 2, and the discharge pipe 22 is connected to the front tube box 2, a No. 2 manhole 19 is provided at the end of the floating head 8, a No. 3 manhole 18 is provided at the end of the rear head 9, and the axis of the No. 2 manhole 19 is arranged in line with the axis of the No. 3 manhole 18, a No. 2 manhole baffle is provided at the inlet end of the No. 2 manhole 19, and the No. 2 manhole baffle is detachably connected to the No. 2 manhole 19, and a No. 3 manhole baffle is provided at the inlet end of the No. 3 manhole 18, and the No. 3 manhole baffle is detachably connected to the No. 3 manhole 18. Other components and connection methods are the same as those of the seventh embodiment.

[0035] In this embodiment, maintenance personnel can enter the interior of the floating pipe box through the No. 2 manhole 19 and the No. 3 manhole 18 to perform maintenance work.

[0036] The present invention has been disclosed as above with preferred implementation cases, but it is not used to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above implementation cases based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

[0037] How it works

[0038] When the present application is working, compressed air circulates in the shell 4, and energy storage liquid is in the heat exchange tube bundle 5. When the compressed air stores energy, high-pressure and high-temperature air enters the shell 4 of the heat exchanger to exchange heat with the low-temperature energy storage liquid in the heat exchange tube bundle 5. The cooled air enters the next level of the compressed air energy storage system, and the heated energy storage liquid is stored in the storage tank. When the heat exchanger has an odd tube bundle structure, the energy storage liquid will enter the storage tank along the floating discharge pipe 12 and the discharge connecting pipe 13. If the heat exchanger has an even tube bundle structure, the energy storage liquid will enter the storage tank along the discharge pipe 22.

Claims

1. A welded floating tube box heat exchanger, characterized in that: The heat exchanger comprises a front head (1), a front tube box (2), a fixed tube sheet (3), a shell (4), a heat exchange tube bundle (5), a floating tube sheet (6), a floating tube box (7), a floating head (8) and a rear head (9), wherein the front head (1) is arranged on one end of the front tube box (2), and the front head (1) is fixedly welded to the front tube box (2), the fixed tube sheet (3) is arranged on the other end of the front tube box (2), and one end of the fixed tube sheet (3) is fixedly welded to the front tube box (2), the shell (4) is arranged on the other end of the fixed tube sheet (3), and the shell (4) is fixedly welded to the fixed tube sheet (3), the rear head (9) is arranged on the other end of the shell (4), and the rear head (9) is fixedly welded to the shell (4), the heat exchange tube bundle (5), The floating tube sheet (6), the floating tube box (7) and the floating head (8) are all arranged in the shell (4), and the floating tube sheet (6) is arranged opposite to the fixed tube sheet (3), the floating tube box (7) is arranged on the side of the floating tube sheet (6) away from the fixed tube sheet (3), and the floating tube box (7) and the floating tube sheet (6) are fixed by welding, the floating head (8) is arranged on the other end of the floating tube box (7), and the floating head (8) and the floating tube box (7) are fixed by welding, the heat exchange tube bundle (5) is arranged between the fixed tube sheet (3) and the floating tube sheet (6), and one end of the heat exchange tube bundle (5) passes through the fixed tube sheet (3) and is connected to the front tube box (2), and the other end of the heat exchange tube bundle (5) passes through the floating tube sheet (6) and is connected to the floating tube box (7).

2. A welded floating tube box heat exchanger according to claim 1, characterized in that: An air inlet pipe (41) is inserted at the top of the shell (4), and the air inlet pipe (41) is connected to the shell (4); an air outlet pipe (42) is inserted at the bottom of the shell (4), and the air outlet pipe (42) is connected to the shell (4); the air inlet pipe (41) is arranged close to the floating tube sheet (6), and the air outlet pipe (42) is arranged close to the fixed tube sheet (3).

3. A welded floating tube box heat exchanger according to claim 2, characterized in that: A fixed support (43) and a rolling support (44) are provided at the bottom of the shell (4); the fixed support (43) and the rolling support (44) are arranged relative to each other along the center line of the length direction of the shell (4); the fixed support (43) is arranged close to the front head (1); the top of the fixed support (43) is fixedly connected to the shell (4); the rolling support (44) is arranged close to the rear head (9); the top of the rolling support (44) is fixedly connected to the shell (4).

4. A welded floating tube box heat exchanger according to claim 3, characterized in that: The front sealing head (1) is provided with a No. 1 manhole (17), the No. 1 manhole (17) is connected to the front sealing head (1), a No. 1 manhole baffle is provided at the inlet end of the No. 1 manhole (17), and the No. 1 manhole baffle is detachably connected to the No. 1 manhole (17).

5. A welded floating tube box heat exchanger according to claim 4, characterized in that: A liquid collecting baffle (10) is provided at the bottom of the rear head (9), the liquid collecting baffle (10) is fixedly connected to the rear head (9), a leakage detection tube (11) is provided on the side of the liquid collecting baffle (10) away from the floating head (8), the leakage detection tube (11) is inserted into the bottom of the rear head (9), and the leakage detection tube (11) is connected to the rear head (9).

6. A welded floating tube box heat exchanger according to claim 5, characterized in that: The heat exchange tube bundle (5) is an odd-numbered tube bundle, a feed pipe (21) is inserted at the top of the front tube box (2), and the feed pipe (21) is connected to the front tube box (2), a floating discharge pipe (12) is inserted at the end of the floating head (8), the floating discharge pipe (12) is connected to the floating head (8), and the axis of the floating discharge pipe (12) is arranged in line with the axis of the shell (4), a discharge connecting pipe (13) is inserted at the end of the rear head (9), and the discharge connecting pipe (13) is connected to the rear head (9) is connected, and the axis of the discharge connecting pipe (13) is arranged in a colinear relationship with the axis of the shell (4), a retaining ring (15) is provided on the inner wall of the discharge connecting pipe (13), the retaining ring (15) and the inner wall of the discharge connecting pipe (13) are integrally formed, the discharge end of the floating discharge pipe (12) is inserted into the discharge connecting pipe (13), and the floating discharge pipe (12) is limited by the retaining ring (15), and a stuffing box (16) is filled between the floating discharge pipe (12) and the retaining ring (15).

7. A welded floating tube box heat exchanger according to claim 6, characterized in that: A flange baffle (14) is provided on the discharge end of the discharge connecting pipe (13), and the flange baffle (14) is detachably connected to the discharge connecting pipe (13).

8. A welded floating tube box heat exchanger according to claim 5, characterized in that: The heat exchange tube bundle (5) is an even-numbered tube bundle, a feed pipe (21) is inserted at the top of the front tube box (2), and the feed pipe (21) is connected to the front tube box (2), a discharge pipe (22) is inserted at the bottom of the front tube box (2), and the discharge pipe (22) is connected to the front tube box (2), a No. 2 manhole (19) is provided at the end of the floating head (8), a No. 3 manhole (18) is provided at the end of the rear head (9), and the axis of the No. 2 manhole (19) is arranged in a colinear manner with the axis of the No. 3 manhole (18), a No. 2 manhole baffle is provided at the inlet end of the No. 2 manhole (19), and the No. 2 manhole baffle is detachably connected to the No. 2 manhole (19), and a No. 3 manhole baffle is provided at the inlet end of the No. 3 manhole (18), and the No. 3 manhole baffle is detachably connected to the No. 3 manhole (18).

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