Water sealing device for water pump water turbine ring water pressure test and installation method thereof

Abstract

This invention proposes a water-sealing device and its installation method for hydrostatic testing of pump-turbine mounting rings, belonging to the field of pump-turbines in pumped storage units. It solves the problem that the water-sealing tools for hydrostatic testing are not universally applicable and require repeated manufacturing due to the different structural dimensions of the pump-turbine mounting rings in different pump-turbine projects. The device includes an upper transition flange, a water-sealing ring, and a lower transition flange. The upper end face of the upper flange of the water-sealing ring is detachably connected to the upper transition flange, and a first sealing element is detachably provided between the upper end face of the upper flange of the water-sealing ring and the mating surface of the upper transition flange. The lower end face of the lower flange of the water-sealing ring is detachably connected to the lower transition flange, and a fifth sealing element is detachably provided between the lower end face of the lower flange of the water-sealing ring and the mating surface of the lower transition flange. A second sealing element is provided on the side of the lower end face of the upper transition flange away from the water-sealing ring, and a fourth sealing element is provided on the side of the lower end face of the lower transition flange away from the water-sealing ring.

Description

Technical Field

[0001] This invention belongs to the technical field of pump-turbine technology for pumped storage units, and in particular relates to a sealing device and its installation method for a water pressure test of the pump-turbine mounting ring. Background Technology

[0002] In the construction of pumped storage power stations, the spiral casing and seat ring of the pump-turbine require on-site hydrostatic testing during the installation phase, followed by the pouring of outer concrete under pressure. To complete this test, the equipment manufacturer needs to provide a specialized sealing tool. This tool, after connecting with the seat ring on-site, forms a sealed cavity to meet the process requirements of pressure testing and pressure-holding pouring. Currently, different pumped storage projects may have their main equipment supplied by different manufacturers. Due to differences in the technical approaches and designs of each company, even if the power station parameters are the same, the specific structural dimensions of the pump-turbine seat ring in different projects often vary in areas such as the height of the fixed guide vanes, the diameter of the tangent circle of the fixed guide vane outlet edge, and the inner diameter of the upper and lower ring plates. This means that the sealing tool for the hydrostatic test of the seat ring designed for a specific project usually cannot be directly applied to another seat ring with different structural dimensions. Therefore, for different projects or different manufacturers, the sealing tool is often not directly applicable. For commercial products, specialized testing tools need to be designed and manufactured, leading to problems such as the inability to share tools and equipment, redundant investment, material waste, increased warehousing and management costs, and extended on-site preparation cycles. Existing technologies include some improvements for the hydrostatic testing process. For example, Chinese patent CN219142495U discloses an intelligent monitoring device for hydrostatic testing of a volute seat ring, which focuses on monitoring the deformation of the seat ring body during pressurization using a digital dial indicator and other mechanisms. This is a technological improvement in the field of testing and monitoring, but does not address the universal design of the sealing tool structure itself. Chinese patent CN222070052U discloses a high-pressure hydrostatic testing system, whose core is controlling the opening and closing of the high-pressure vessel port through a drive component. This falls under the category of testing system control and similarly fails to solve the problem of adaptability and universality of sealing tools for large hydraulic structures across different projects. Summary of the Invention

[0003] In view of this, the present invention aims to provide a water sealing device and its installation method for water pressure testing of pump turbine seat rings, in order to solve the problem that the special water sealing tools for water pressure testing are not universal and need to be repeatedly manufactured due to the different structural dimensions of pump turbine seat rings in different pumped storage projects.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a sealing device for a water pump turbine seat ring hydrostatic test, comprising an upper transition flange, a sealing ring, and a lower transition flange. The upper end face of the upper flange of the sealing ring is detachably connected to the upper transition flange via a first connecting member, and a first sealing element is detachably provided between the upper end face of the upper flange of the sealing ring and the mating surface of the upper transition flange. The lower end face of the lower flange of the sealing ring is detachably connected to the lower transition flange via a second connecting member, and a fifth sealing element is detachably provided between the lower end face of the lower flange of the sealing ring and the mating surface of the lower transition flange. A second sealing element is provided on the side of the lower end face of the upper transition flange away from the sealing ring, and a fourth sealing element is provided on the side of the lower end face of the lower transition flange away from the sealing ring.

[0005] Furthermore, a third sealing element is provided on the lower end face of the upper flange of the water sealing ring.

[0006] Furthermore, the upper transition flange and the sealing ring are both provided with mutually matching stop structures between their connection surfaces and the lower transition flange and the sealing ring.

[0007] Furthermore, the fitting length of the stop structure along the axial direction of the sealing ring is greater than the thickness of the upper or lower transition flange.

[0008] Furthermore, the mating surfaces of the upper transition flange and the sealing ring, as well as the mating surfaces of the lower transition flange and the sealing ring, are widened contact surfaces.

[0009] Furthermore, the water sealing device also includes a connecting stud with an extended overall length.

[0010] Furthermore, the connecting stud has an extended threaded section, and a nut is provided on the connecting stud.

[0011] Furthermore, both the first and second connecting parts are bolts.

[0012] Furthermore, the first, second, third, fourth, and fifth seals are all sealing strips.

[0013] A method for installing a sealing device for a water pump turbine base ring hydrostatic test includes the following steps: When the sealing device is connected to the turbine mounting ring of the first water pump, the first assembly mode is executed: The first sealing element is installed on the upper end face of the upper flange of the water sealing ring, and the fifth sealing element is installed on the lower end face of the lower flange of the water sealing ring. The upper transition flange is connected to the upper end of the sealing ring with the first sealing element through the first connector, and the lower transition flange is connected to the lower end of the sealing ring with the fifth sealing element through the second connector. The second seal is installed on the lower end face of the upper transition flange away from the sealing ring, and the fourth seal is installed on the lower end face of the lower transition flange away from the sealing ring, to assemble a sealing unit. The sealing unit is connected to the turbine seat ring of the first water pump and fixed by fasteners to form the sealing structure for the first water pressure test. When the sealing ring structure is connected to the second water pump turbine mounting ring, the second assembly mode is executed: Install the third sealing element on the lower end face of the upper flange of the sealing ring, and install the fifth sealing element on the lower end face of the lower flange of the sealing ring. The sealing ring, equipped with a third and a fifth sealing element, is connected to the second water pump turbine base ring and fixed by connecting studs and nuts to form the second water pressure test sealing structure.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention adopts a detachable and split structure of upper transition flange, water sealing ring and lower transition flange, and designs the water sealing ring as a standard universal component. When applied to water pump turbine seat rings of different structural sizes, it is only necessary to replace the upper transition flange and lower transition flange that match the water sealing ring according to the structural size, without having to remanufacture the entire water sealing device. This fundamentally solves the problem of special tools not being universal due to project differences, avoids the repeated investment in tooling, and saves production costs and warehousing management costs. 2. Because the sealing ring of this invention is universal and the upper and lower transition flanges are detachably connected, it is convenient to assemble, replace and adapt on site. This structure allows the same set of sealing ring core components to be quickly combined with transition flanges customized for different projects to quickly form a sealing unit that meets the current test requirements, shortening the tooling preparation cycle of the hydrostatic test and improving work efficiency. 3. The present invention provides a first and a fifth sealing element between the water sealing ring and the connection surfaces of the upper and lower transition flanges to ensure the sealing at the split connection. A second and a fourth sealing element are respectively provided on the connection end faces of the upper and lower transition flanges and the external seat ring to ensure the sealing of the interface with different seat rings. By adding a third sealing element on the lower end face of the upper flange of the water sealing ring, a sealing defense line for specific installation modes is formed. This layered, multi-layered sealing structure design effectively prevents high-pressure water from leaking at each connection interface, and the test safety is high. 4. The invention features a mutually fitting stop structure between the upper and lower transition flanges and the sealing ring. The axial fitting length of the stop structure is greater than the flange thickness, which provides good positioning and guiding, ensuring assembly alignment accuracy and resisting the radial separation force generated by water pressure, thus improving connection rigidity. The widened mating surface increases the pressure-bearing area, making the seal more uniform and reliable. The use of connecting studs with extended overall length and threaded sections provides more ample preload length and connection strength, ensuring that the entire sealing structure remains stable under high pressure and preventing seal failure caused by bolt elongation or loosening of the connection. Attached Figure Description

[0015] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a first-view axial side structural diagram of a sealing device for a water pump turbine base ring water pressure test according to the present invention; Figure 2 This is a second-view axial side structural diagram of a sealing device for a water pump turbine mounting ring water pressure test according to the present invention; Figure 3 This is a side view of the sealing device for water pressure testing of a water pump turbine base ring according to the present invention; Figure 4 This is a cross-sectional structural schematic diagram of a sealing device for a water pump turbine base ring water pressure test according to the present invention; Figure 5 for Figure 4 Enlarged structural diagram at point A; Figure 6 for Figure 4 Enlarged structural diagram at point B; Figure 7 This is a schematic diagram of the shaft side structure of the water sealing device for water pump turbine seat ring hydrostatic test and the connection between the first water pump turbine seat ring according to the present invention. Figure 8 for Figure 7 Enlarged structural diagram at point C; Figure 9 for Figure 7 Enlarged structural diagram at point D; Figure 10 This is a schematic diagram of the shaft side structure of the connection between the sealing device for the water pressure test of the water pump turbine seat ring and the second water pump turbine seat ring according to the present invention. Figure 11 for Figure 10 Enlarged structural diagram at point E; Figure 12 for Figure 10 A magnified structural diagram at point F in the middle.

[0016] In the picture: 1. Upper transition flange; 2. Sealing ring; 3. Lower transition flange; 4. First connecting piece; 5. Second connecting piece; 6. First sealing element; 7. Second sealing element; 8. Third sealing element; 9. Fourth sealing element; 10. Fifth sealing element; 11. Connecting stud; 12. Nut; 13. First water pump turbine base ring; 14. Second water pump turbine base ring. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0018] Detailed implementation method: See Figure 1-12This embodiment describes a water sealing device for a water pump turbine seat ring hydrostatic test, comprising an upper transition flange 1, a water sealing ring 2, and a lower transition flange 3. The upper end face of the upper flange of the water sealing ring 2 is detachably connected to the upper transition flange 1 via a first connecting piece 4. The water sealing ring 2, the upper transition flange 1, and the lower transition flange 3 constitute a modular water sealing device adaptable to seat rings of different structures. The inner diameter of the water sealing ring 2 corresponds to the flow channel of the seat ring. The axial height of the water sealing ring 2 must ensure that it can be used in combination with the transition flange and can also be directly connected to the seat ring in a specific mode. The upper transition flange 1 is connected to the upper transition flange 2 via a first connecting piece 4. The connecting piece 4 is detachably connected to the sealing ring 2, allowing the upper transition flange 1 to be installed or removed as needed. A first sealing element 6 is detachably provided between the upper flange face of the sealing ring 2 and the mating surface of the upper transition flange 1. When the first connecting piece 4 is tightened to connect the upper transition flange 1 and the sealing ring 2, the first sealing element 6 is compressed, thereby sealing the gap between the upper transition flange 1 and the sealing ring 2, preventing pressurized water from leaking between the sealing ring 2 and the upper transition flange 1. The lower flange face of the sealing ring 2 is detachably connected to the lower transition flange 3 via a second connecting piece 5. The lower transition flange 3 is connected via... The second connecting piece 5 is detachably connected to the water sealing ring 2, allowing the lower transition flange 3 to be installed or removed as needed. A fifth sealing element 10 is detachably provided between the lower end face of the lower flange of the water sealing ring 2 and the mating surface of the lower transition flange 3. When the second connecting piece 5 is tightened to connect the lower transition flange 3 to the water sealing ring 2, the fifth sealing element 10 is compressed, thereby sealing the gap between the lower transition flange 3 and the water sealing ring 2, preventing pressurized water from leaking between the water sealing ring 2 and the lower transition flange 3. A second sealing element 7 is provided on the side of the lower end face of the upper transition flange 1 away from the water sealing ring 2, i.e., the upper transition flange 1 and the fifth sealing ring 2 are connected. A second sealing element 7 is pre-installed on the flange surface that fits against the first water pump turbine seat ring 13. A fourth sealing element 9 is provided on the lower end face of the lower transition flange 3 away from the sealing ring 2. That is, the fourth sealing element 9 is pre-installed on the flange surface that fits against the first water pump turbine seat ring 13. When the sealing device is pressed against the first water pump turbine seat ring 13, the interfaces between the upper transition flange 1 and the first water pump turbine seat ring 13, and between the lower transition flange 3 and the first water pump turbine seat ring 13 are sealed by the second sealing element 7 and the fourth sealing element 9, respectively, thereby finally forming a complete and closed pressure-resistant chamber.

[0019] This invention constructs a universal water sealing device module by detachably combining the water sealing ring 2 with the upper transition flange 1 and the lower transition flange 3, and by sealing the first sealing element 6, the second sealing element 7, the fourth sealing element 9 and the fifth sealing element 10. This device module can adapt to seat rings of different shapes and sizes by matching with transition flanges of different specifications or by directly connecting with the water sealing ring 2.

[0020] The lower end face of the upper flange of the sealing ring 2 is provided with a third sealing element 8. When the upper transition flange 1 is removed, and the sealing ring 2 needs to use the lower end face of the upper flange as an independent sealing interface to connect with external components, the third sealing element 8 can provide a seal for this connection surface, making the lower end face of the upper flange of the sealing ring 2 a complete and effective sealing end face. Thus, the sealing ring 2 does not need to rely on the upper transition flange 1 and the second sealing element 7, and has a direct sealing capability on its own, thereby providing another sealing configuration option for the water sealing device.

[0021] See Figure 4-6 In this embodiment, the connecting surfaces of the upper transition flange 1 and the sealing ring 2, as well as the connecting surfaces of the lower transition flange 3 and the sealing ring 2, are provided with mutually matching stop structures. A stepped structure is designed on the outer side of the upper and lower end faces of the sealing ring 2. A stepped structure matching the protrusion of the sealing ring 2 is machined on the inner side of the end faces of the upper transition flange 1 and the lower transition flange 3 that meet the sealing ring 2. During assembly, the stepped structure of the sealing ring 2 engages with the upper transition flange 1 and the lower transition flange 3. The mutually fitting stop structures enable automatic radial alignment and precise pre-positioning of the upper transition flange 1, the lower transition flange 3, and the sealing ring 2, avoiding assembly stress caused by flange hole misalignment during installation and ensuring that the module assembled from the three has extremely high coaxiality. This is the basis for ensuring smooth subsequent docking with the seat ring and forming a regular sealing cavity.

[0022] The fitting length of the stop structure along the axial direction of the sealing ring is greater than the thickness of the upper or lower transition flange. By increasing the axial fitting depth of the stop, the bending stiffness of the upper transition flange 1 and the lower transition flange 3 and the structural stability of the entire connection node are significantly enhanced.

[0023] The mating surfaces of the upper transition flange 1 and the sealing ring 2, as well as the mating surfaces of the lower transition flange 3 and the sealing ring 2, are all widened contact surfaces. The widened contact surfaces refer to the end faces of the upper transition flange 1, the lower transition flange 3 and the sealing ring 2 that are fitted together and pressed together by the first connecting piece 4 and the second connecting piece 5. By increasing the stress-bearing area, stress is reduced, and the section modulus is increased to enhance bending stiffness.

[0024] See Figure 1-12In this embodiment, the water sealing device further includes a connecting stud 11. The connecting stud 11 has an extended overall length. The extended overall length refers to the length of the connecting stud 11 being designed to simultaneously satisfy the following conditions: in the first assembly mode, after passing through the lower transition flange 3 and the water sealing ring 2, the other end can still be connected to the first water pump turbine seat ring 13; and in the second assembly mode, after one end is connected to the water sealing ring 2, the other end can still be connected to the second water pump turbine seat ring 14. This achieves versatility, that is, when the water sealing device is connected to the first water pump turbine seat ring 13, the top of the connecting stud 11 passes through the lower transition flange 3 and is connected to the bottom of the water sealing ring 2; when the water sealing device is connected to the second water pump turbine seat ring 14, the top of the connecting stud 11 is directly connected to the bottom of the water sealing ring 2.

[0025] The connecting stud 11 has an extended threaded section, and a nut 12 is provided on the connecting stud 11. The nut 12 is screwed onto the connecting stud 11. The extended threaded section means that the length of the threaded part of the connecting stud 11 is also extended accordingly. Based on the extended overall length of the connecting stud 11, it is ensured that in any assembly mode, after the connecting stud 11 passes through all the parts to be connected, there is still a sufficient length of thread exposed to allow for effective and reliable engagement with the nut 12. After the connecting stud 11 passes through the mounting holes corresponding to the seat ring and the water sealing device, the nut 12 is tightened to generate an axial preload on the connecting stud 11, thereby pressing the water sealing device and the first water pump turbine seat ring 13 or the second water pump turbine seat ring 14 into a whole.

[0026] Both the first connecting piece 4 and the second connecting piece 5 are bolts. The bolt connection can provide a strong, controllable and uniform axial preload, thereby achieving a firm, sealed and detachable connection between the upper transition flange 1, the lower transition flange 3 and the sealing ring 2.

[0027] The first sealing element 6, the second sealing element 7, the third sealing element 8, the fourth sealing element 9, and the fifth sealing element 10 are all sealing strips. The compression deformation of the elastic material of the sealing strips achieves reliable static surface sealing, while meeting the functional requirements of modularity and detachability of the device. Furthermore, the independent arrangement improves the overall sealing performance of the sealing system.

[0028] See Figure 7-12 This embodiment describes a method for installing a sealing device for a water pump turbine base ring hydrostatic test, comprising the following steps: When the sealing device is connected to the turbine mounting ring 13 of the first water pump, the first assembly mode is executed: The first sealing element 6 is installed in the sealing groove on the upper end face of the upper flange of the sealing ring 2, and the fifth sealing element 10 is installed in the sealing groove on the lower end face of the lower flange of the sealing ring 2. The upper transition flange 1 is detachably fastened to the upper end of the sealing ring 2 with the first sealing element 6 by means of the first connecting piece 4, and the lower transition flange 3 is detachably fastened to the lower end of the sealing ring 2 with the fifth sealing element 10 by means of the second connecting piece 5. During this process, the extended stop structure between the upper transition flange 1 and the lower transition flange 3 and the sealing ring 2 achieves radial automatic centering and precise positioning. The second sealing element 7 is installed in the sealing groove on the lower end face of the upper transition flange 1 away from the sealing ring 2, and the fourth sealing element 9 is installed in the sealing groove on the lower end face of the lower transition flange 3 away from the sealing ring 2, so as to assemble a water sealing unit. That is, the upper transition flange 1, the sealing ring 2, the lower transition flange 3, the first sealing element 6, the second sealing element 7, the fourth sealing element 9 and the fifth sealing element 10 are assembled together to form a complete and independent water sealing unit. The sealing unit is connected to the first water pump turbine seat ring 13, so that the second sealing element 7 and the fourth sealing element 9 are aligned and fitted to the corresponding upper and lower flange surfaces of the first water pump turbine seat ring 13, and are connected and fixed by connecting studs 11 and nuts 12 to form a first water pressure test sealing structure. That is, one end of the connecting stud 11 is passed through the bolt holes corresponding to the lower transition flange 3 and the sealing ring 2 in sequence, and the nut 12 is tightened at the other end of the connecting stud 11 to tighten it as required, thereby forming a sealed first water pressure test sealing structure that can withstand high pressure. When the sealing ring structure is connected to the second water pump turbine mounting ring 14, the second assembly mode is executed: The third seal 8 is installed in the sealing groove on the lower end face of the upper flange of the sealing ring 2, and the fifth seal 10 is installed in the sealing groove on the lower end face of the lower flange of the sealing ring 2. In this mode, the upper transition flange 1, the lower transition flange 3 and the corresponding first seal 6, second seal 7 and fourth seal 9 are not installed. The sealing ring 2, which is equipped with the third sealing element 8 and the fifth sealing element 10, is connected to the second water pump turbine base ring 14 and fixed by connecting studs 11 and nuts 12 to form the second water pressure test sealing structure. That is, one end of the connecting stud 11 passes through the corresponding bolt holes of the sealing ring 2 in sequence, and the other end is tightened by screwing the nut 12 to fasten the sealing ring 2 to the second water pump turbine base ring 14, thereby forming the second water pressure test sealing structure.

[0029] The specific embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A sealing device for a water pump turbine base ring water pressure test, characterized in that: The system includes an upper transition flange (1), a water sealing ring (2), and a lower transition flange (3). The upper end face of the upper flange of the water sealing ring (2) is detachably connected to the upper transition flange (1) via a first connector (4). A first sealing element (6) is detachably provided between the upper end face of the upper flange of the water sealing ring (2) and the mating surface of the upper transition flange (1). The lower end face of the lower flange of the water sealing ring (2) is detachably connected to the lower transition flange (3) via a second connector (5). A fifth sealing element (10) is detachably provided between the lower end face of the lower flange of the water sealing ring (2) and the mating surface of the lower transition flange (3). A second sealing element (7) is provided on the side of the lower end face of the upper transition flange (1) away from the water sealing ring (2), and a fourth sealing element (9) is provided on the side of the lower end face of the lower transition flange (3) away from the water sealing ring (2).

2. The sealing device for water pump turbine base ring water pressure test according to claim 1, characterized in that: The lower end face of the upper flange of the sealing ring (2) is provided with a third sealing element (8).

3. A sealing device for a water pump turbine base ring water pressure test according to claim 1, characterized in that: The upper transition flange (1) and the sealing ring (2) are provided with mutually matching stop structures, as are the lower transition flange (3) and the sealing ring (2).

4. A sealing device for a water pump turbine base ring hydrostatic test according to claim 3, characterized in that: The fitting length of the stop structure along the axial direction of the sealing ring is greater than the thickness of the upper or lower transition flange.

5. A sealing device for a water pump turbine mounting ring hydrostatic test according to claim 1, characterized in that: The mating surfaces of the upper transition flange (1) and the sealing ring (2) and the lower transition flange (3) and the sealing ring (2) are all widened contact surfaces.

6. A sealing device for a water pump turbine mounting ring hydrostatic test according to claim 1, characterized in that: The water sealing device also includes a connecting stud (11) having an extended overall length.

7. A sealing device for a water pump turbine base ring water pressure test according to claim 6, characterized in that: The connecting stud (11) has an extended threaded section and a nut (12) is provided on the connecting stud (11).

8. A sealing device for a water pump turbine mounting ring water pressure test according to claim 1, characterized in that: Both the first connector (4) and the second connector (5) are bolts.

9. A sealing device for a water pump turbine mounting ring hydrostatic test according to claim 1, characterized in that: The first seal (6), the second seal (7), the third seal (8), the fourth seal (9) and the fifth seal (10) are all sealing strips.

10. A method for installing a sealing device for a water pump turbine base ring hydrostatic test as described in claim 1, characterized in that, Includes the following steps: When the sealing device is connected to the first water pump turbine mounting ring (13), the first assembly mode is executed: Install the first sealing element (6) on the upper end face of the upper flange of the sealing ring (2), and install the fifth sealing element (10) on the lower end face of the lower flange of the sealing ring (2); The upper transition flange (1) is connected to the upper end of the sealing ring (2) with the first sealing element (6) by the first connecting piece (4), and the lower transition flange (3) is connected to the lower end of the sealing ring (2) with the fifth sealing element (10) by the second connecting piece (5). The second seal (7) is installed on the lower end face of the upper transition flange (1) away from the sealing ring (2), and the fourth seal (9) is installed on the lower end face of the lower transition flange (3) away from the sealing ring (2) to assemble a sealing unit. The sealing unit is connected to the first water pump turbine seat ring (13) and fixed by fasteners to form the first water pressure test sealing structure; When the sealing ring structure is connected to the second pump turbine mounting ring (14), the second assembly mode is executed: Install the third seal (8) on the lower end face of the upper flange of the sealing ring (2), and install the fifth seal (10) on the lower end face of the lower flange of the sealing ring (2); The sealing ring (2) with the third seal (8) and the fifth seal (10) is connected to the second water pump turbine seat ring (14) and fixed by connecting studs (11) and nuts (12) to form the second water pressure test sealing structure.

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