Aluminum-based skeleton composite rubber sealing ring for the main shaft of a cross-flow turbine

Abstract

This utility model discloses an aluminum-based skeleton composite rubber sealing ring for the main shaft of a axial-flow turbine, comprising a sealing ring body, which includes an aluminum-based skeleton layer and an elastic rubber layer fixed on the aluminum-based skeleton layer; an annular water supply groove is provided on the sealing end face of the elastic rubber layer, which divides the sealing end face into an inner sealing ring and an outer sealing ring; multiple self-lubricating wear-resistant pillars embedded inside the elastic rubber layer are respectively provided on the sealing end faces of the inner and outer sealing rings; a limiting guide pin hole is provided on the aluminum-based skeleton layer for cooperating with the anti-rotation guide positioning pin on the sealing seat; an inner sealing ring groove and an outer sealing ring groove are respectively provided on the inner and outer sides of the aluminum-based skeleton layer, and an inner sealing rubber circle and an outer sealing rubber circle are respectively provided in the inner and outer sealing ring grooves. This utility model has the advantages of moderate hardness, strong elastic deformation capacity, which is conducive to the formation of a normal end face fit relationship and friction and wear relationship between the sealing dynamic and static rings, and good sealing effect.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical turbine sealing technology, specifically relating to an aluminum-based skeleton composite rubber sealing ring for the main shaft of a cross-flow turbine. Background Technology

[0002] Cross-flow turbines now widely use a so-called "double insurance" composite sealing device to ensure the high reliability of the main shaft sealing system. This means that a face seal is first installed on the side of the turbine shaft near the runner, followed by a packing seal to form a "double insurance" seal.

[0003] Existing piston-type end face seals for axial-flow turbines widely employ high-hardness, high-strength, low-elasticity polyurethane rubber (PU) as the stationary (non-rotating) sealing ring, forming a face seal with a stainless steel rotating anti-wear ring. The high-hardness polyurethane rubber end face seals used in current axial-flow turbines achieve a hardness of extremely high levels, specifically Shore A 90A–95A. In contrast, the nitrile rubber end face seals commonly used in traditional vertical-shaft turbines have a hardness of only around Shore A 70A.

[0004] like Figure 1 As shown, the working seal of the piston-type rubber seal ring on the main shaft of a conventional turbine includes a sealing seat 1 with a pressure water tank annular groove 1.2, and anti-rotation guide positioning pins 1.1 distributed in the pressure water tank annular groove 1.2 of the sealing seat 1. The rubber seal ring 2 is a conventional annular piston-type rubber seal ring (ring), which is set in the sealing seat 1 and cooperates with the anti-rotation guide positioning pins 1.1. The rubber seal ring 2 has a pressure sealing water inlet hole 5 with an axial through section; the working end face of the rubber seal ring 2 has a pressure water storage tank 6. The lower end of the flange 4 on the main shaft of the axial flow turbine is provided with a sealing rotating ring 3; the lower end face of the sealing rotating ring 3 cooperates with the upper working end face of the rubber seal ring 2. Among them, the pressure cleaning water 7 used for working, cooling, lubrication, and axial movement of the pressure sealing ring enters the pressure water tank ring groove 1.2 and the pressure sealing water inlet 5 from the through hole at the bottom of the sealing seat 1, and then enters the pressure water storage tank 6 at the working end face of the rubber sealing ring 2, which is used to limit the water leakage 8 from the turbine outside the flange 4 from entering the moving gap between the sealing rotating ring 3 and the rubber sealing ring 2.

[0005] Because hydro-generator units are mainly horizontally arranged with horizontal shafts, and because the aforementioned seals use high-strength, high-hardness, and non-deformable polyurethane (PU) polymer rubber piston-type sealing rings for adjusting the fit, the existing bulb turbine main shaft piston-type polyurethane rubber end face seals have the following problems: 1. During operation, it is not easy to quickly achieve a good break-in period and adjust the fit to a normal sealing fit state; 2. High-hardness, high-strength polymeric material PU rubber, when used in sealing applications where contact friction is frequent at linear speeds exceeding 10 m / s, can cause significant damage to the mating stainless steel. As can be seen from relevant research papers, the mechanism of polymeric soft materials wearing down hard materials is an objective reality. (See Tsinghua University Journal, 2021, Issue 06 - Mechanism of Polymeric Soft Materials Wearing Down Hard Materials). 3. Due to the uncontrollable and ineffective sealing performance of the piston-type PU rubber end face seal on the main shaft of the axial-flow turbine, the aforementioned seal, operating under conditions of high sediment content during the summer flood season, will increase the safety pressure on the turbine's second, traditionally simple packing seal. Abnormal leakage from the first polyurethane seal to the packing seal, resulting in sediment and water flow, will exacerbate wear on the packing seal and increase the workload of adjustment and maintenance.

[0006] The above situation is neither conducive to the safe operation of the turbine nor to the achievement of the goal of maintenance-free and unattended operation of the unit. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing an aluminum-based composite rubber sealing ring for the main shaft of a axial-flow turbine. This ring has moderate hardness, strong elastic deformation capability, facilitates the formation of a normal end-face fit and frictional wear relationship between the sealing dynamic and static rings, and provides a good sealing effect.

[0008] The technical objective of this utility model is achieved through the following technical solution: A composite rubber sealing ring with an aluminum-based skeleton for the main shaft of a axial-flow turbine includes a sealing ring body, which comprises an aluminum-based skeleton layer and an elastic rubber layer fixed on the aluminum-based skeleton layer. An annular water supply groove is provided on the sealing end face of the elastic rubber layer, dividing the sealing end face into an inner sealing ring and an outer sealing ring. Multiple self-lubricating wear-resistant posts embedded within the elastic rubber layer are respectively provided on the sealing end faces of the inner and outer sealing rings. A limiting guide pin hole is provided on the aluminum-based skeleton layer for engaging with an anti-rotation guide positioning pin on a sealing seat. An inner sealing ring groove and an outer sealing ring groove are respectively provided on the inner and outer sides of the aluminum-based skeleton layer, and an inner sealing rubber circle and an outer sealing rubber circle are respectively provided in the inner and outer sealing ring grooves.

[0009] Preferably, the elastic rubber layer is made of nitrile rubber-based composite material.

[0010] Preferably, the aluminum-based skeleton layer is made of aerospace aluminum alloy 7075t6.

[0011] Preferably, the self-lubricating wear-resistant columns are arranged in a ring array on the inner and outer sealing rings, the spacing between adjacent self-lubricating wear-resistant columns is no more than 30 mm, and the depth of the self-lubricating wear-resistant columns embedded in the elastic rubber layer is no less than 20 mm.

[0012] Preferably, the limiting guide pin hole is formed in the aluminum-based skeleton layer and extends partially into the elastic rubber layer, but does not penetrate the elastic rubber layer.

[0013] Preferably, the sealing ring body is provided with an active pressure water supply hole that penetrates the aluminum-based skeleton layer and the elastic rubber layer, for supplying pressure water to the water supply tank.

[0014] Preferably, the sealing ring body is composed of at least two sector-shaped arc blocks, and the sector-shaped arc blocks are connected by an end connection structure to form a complete ring structure.

[0015] Compared with the prior art, the beneficial effects of this utility model are: 1. The aluminum-based skeleton layer of this utility model provides a high-strength and high-rigidity support platform for the highly elastic elastic rubber layer, which can "appropriately control the overall free deformation of the elastic rubber layer", prevent its excessive deformation, ensure the stability of the sealing end face shape, and thus quickly form a good running-in and maintain a long-term stable sealing state. By using the metal guide pin hole on the aluminum-based skeleton layer and the metal positioning pin on the sealing seat, a "metal-to-metal" guiding and moving mechanism is achieved. Compared with the traditional rubber sealing ring and pin combination, the friction coefficient and resistance are greatly reduced, making the axial movement of the sealing ring more sensitive and able to respond to water pressure changes in a timely manner and adjust the sealing state.

[0016] By setting sealing ring grooves on the inner and outer sides of the aluminum-based skeleton layer and equipping them with sealing rubber circles, a double sealing barrier is formed to prevent pressurized water from leaking from the gap between the skeleton layer and the sealing seat, which significantly enhances the reliability of the overall sealing structure.

[0017] The self-lubricating wear-resistant pillars set on the sealing end face (sealing working end face) of the elastic rubber layer can effectively reduce the wear and frictional heat generated when the sealing rotating ring rubs against the stainless steel rotating ring, prevent the sealing surface from burning and abnormal damage, thereby extending the service life of the sealing ring.

[0018] The water supply tank stores pressurized water, which lubricates and cools the sealing friction pairs and provides pressure balance, thus contributing to a good sealing fit. This technology offers advantages such as moderate hardness, strong elastic deformation capacity, and a good sealing effect that facilitates a proper end-face fit and frictional wear relationship between the sealing dynamic and static rings. Attached Figure Description

[0019] Figure 1It is a traditional structure hydraulic turbine main shaft piston-type rubber seal working seal; Figure 2 This is a schematic diagram of the structure of this utility model in conjunction with the main shaft of a axial-flow turbine; Figure 3 This is a schematic diagram of the structure of this utility model; Figure 4 yes Figure 3 Sectional view along line AA; Figure 5 yes Figure 3 Sectional view along the BB direction; Figure 6 yes Figure 3 C-axis sectional view; Figure 7 yes Figure 3 Sectional view along the DD direction; Figure 8 yes Figure 3 sectional view of QQ direction; Reference numerals in the attached drawings: 1—Sealing seat; 1.1—Anti-rotation guide positioning pin; 1.2—Pressure water tank annular groove; 2—Rubber sealing ring; 3—Sealing rotating ring; 4—Flange; 5—Pressure sealing water inlet hole; 6—Pressurized water storage tank; 7—Pressurized cleaning water; 8—Leaking water from the water turbine; 9—Sealing ring body; 9.1—Connecting screw; 9.2—Limiting guide pin hole; 9.3—Active pressure water supply hole; 9.4—Sealing inner ring; 9.5—Sealing outer ring; 9.6—First self-lubricating wear-resistant column; 9.7—Second self-lubricating wear-resistant column; 9.8—Water supply groove; 9.9—Elastic rubber layer; 9.10—Aluminum-based skeleton layer; 9.11—Outer ring sealing working end face; 9.12—Inner ring sealing working end face; 9.13—Upper layer of end connection structure; 9.14—Lower layer of end connection structure; 9.15—Inner sealing rubber circle; 9.16—Outer sealing rubber circle; 9.17—Inner sealing ring groove; 9.18—Outer sealing ring groove; 9.19—Joint sealant; 9.20—Mounting hole sealing glue column; 9.21—Adhesive. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] like Figure 2 — Figure 8 As shown, the aluminum-based skeleton composite rubber sealing ring for the main shaft of a cross-flow turbine includes a sealing ring body 9, which includes an aluminum-based skeleton layer 9.10 and an elastic rubber layer 9.9 fixed on the aluminum-based skeleton layer 9.10. An annular water supply groove 9.8 is provided on the sealing end face of the elastic rubber layer 9.9, which divides the sealing end face into an inner sealing ring 9.4 and an outer sealing ring 9.5. Multiple self-lubricating wear-resistant columns embedded inside the elastic rubber layer 9.9 are respectively provided on the sealing end faces of the inner sealing ring 9.4 and the outer sealing ring 9.5. The aluminum-based skeleton layer 9.10 is provided with a limiting guide pin hole 9.2 for cooperating with the anti-rotation guide positioning pin 1.1 on the sealing seat 1; the inner and outer sides of the aluminum-based skeleton layer 9.10 are respectively provided with an inner sealing ring groove 9.17 and an outer sealing ring groove 9.18, and an inner sealing rubber circle 9.15 and an outer sealing rubber circle 9.16 are respectively provided in the inner sealing ring groove 9.17 and the outer sealing ring groove 9.18.

[0024] The aluminum-based skeleton layer 9.10 provides a high-strength, high-rigidity support platform for the highly elastic rubber layer 9.9, which can "appropriately control the overall free deformation of the elastic rubber layer" to prevent excessive deformation, ensure the stability of the sealing end face shape, and thus quickly form a good running-in and maintain a long-term stable sealing state. By engaging the metal guide pin hole 9.2 on the aluminum-based skeleton layer 9.10 with the metal positioning pin 1.1 on the sealing seat 1, a "metal-to-metal" guiding and moving mechanism is achieved. Compared with the traditional rubber sealing ring and pin engagement, the friction coefficient and resistance are significantly reduced, making the axial movement of the sealing ring more sensitive and able to respond promptly to changes in water pressure and adjust the sealing state.

[0025] A sealing ring groove is set on the inner and outer sides of the aluminum-based skeleton layer 9.10 and equipped with a sealing rubber circle, forming a double sealing barrier to prevent pressurized water from leaking from the gap between the skeleton layer and the sealing seat, which significantly enhances the reliability of the overall sealing structure.

[0026] The self-lubricating wear-resistant pillars set on the sealing end face (sealing working end face) of the elastic rubber layer 9.9 can effectively reduce the wear and frictional heat generated when the sealing rotating ring 3 rubs against the stainless steel rotating ring, prevent the sealing surface from burning and abnormal damage, thereby extending the service life of the sealing ring.

[0027] The 9.8 water supply tank can store pressurized water, which serves to lubricate and cool the sealing friction pairs and provide pressure balance, thus helping to form a good sealing fit. This technology offers advantages such as moderate hardness, strong elastic deformation capacity, and a good sealing effect that facilitates the formation of a normal end-face fit and frictional wear relationship between the sealing dynamic and static rings.

[0028] like Figure 2 — Figure 8 As shown, the sealing ring body 9 includes an aluminum-based skeleton layer 9.10 and an elastic rubber layer 9.9 fixed to the aluminum-based skeleton layer 9.10. Specifically, the cross-section of the sealing ring body 9 consists of an upper elastic rubber layer 9.9 made of highly elastic and variable rubber material and a lower aluminum-based skeleton layer 9.10 made of high-strength aerospace aluminum alloy material. The elastic rubber layer 9.9 is bonded and fixed to the aluminum-based skeleton layer 9.10 using adhesive 9.21.

[0029] In practical applications, the elastic rubber layer 9.9 is a low-friction, heat-generating composite rubber material, specifically made of nitrile rubber-based composite material. Its main technical indicators are: tensile strength ≥ 25 MPa, elongation ≥ 500%, and hardness ≤ Shore 80A. This technical measure ensures rapid and healthy break-in of the sealing ring, close contact with the mating surfaces, and effectively reduces frictional heat generation, thereby minimizing damage to the metal mating surfaces and extending the seal life.

[0030] The aluminum-based skeleton layer 9.10 is made of aerospace-grade aluminum alloy 7075t6. Aerospace-grade aluminum alloy 7075t6 has extremely high strength and stability, providing a robust and dimensionally consistent support skeleton for the sealing ring, which can precisely control the deformation of the elastic rubber layer 9.9 and ensure the long-term operational accuracy of the sealing end face.

[0031] like Figure 3 — Figure 6As shown, an annular water supply groove 9.8 is provided on the sealing end face of the elastic rubber layer 9.9, which divides the sealing end face into an inner sealing ring 9.4 and an outer sealing ring 9.5. Multiple self-lubricating wear-resistant pillars embedded within the elastic rubber layer 9.9 are respectively provided on the sealing end faces of the inner sealing ring 9.4 and the outer sealing ring 9.5. In this embodiment, the self-lubricating wear-resistant pillars include a first self-lubricating wear-resistant pillar 9.6 and a second self-lubricating wear-resistant pillar 9.7. Multiple first self-lubricating wear-resistant pillars 9.6 embedded within the elastic rubber layer 9.9 are provided on the sealing end face of the inner sealing ring 9.4; multiple second self-lubricating wear-resistant pillars 9.7 embedded within the elastic rubber layer 9.9 are provided on the sealing end face of the outer sealing ring 9.5. This structure balances the pressure on the sealing surface and forms a lubricating water film through the water supply groove 9.8, while the self-lubricating wear-resistant pillars directly reduce contact friction. The two work synergistically to ensure rapid and healthy break-in of the sealing ring, low-wear operation, and long-term sealing stability.

[0032] The sealing end face of the elastic rubber layer 9.9 consists of a sealing outer ring 9.5 of equal radial width, a sealing inner ring 9.4, and a sealing active pressure water groove 9.8.

[0033] In practical implementation, the self-lubricating wear-resistant columns are arranged in a ring array on the inner sealing ring 9.4 and the outer sealing ring 9.5. The spacing between adjacent self-lubricating wear-resistant columns is no more than 30 mm, and the depth to which the self-lubricating wear-resistant columns are embedded in the elastic rubber layer 9.9 is no less than 20 mm. This technical measure ensures that the self-lubricating effect is uniform and complete on the sealing surface, and effectively prevents the wear-resistant columns from falling off due to friction and shear forces during long-term operation, thus ensuring a stable and long-lasting wear-reducing and wear-resistant effect.

[0034] like Figure 2 , Figure 5 As shown, the limiting guide pin hole 9.2 is formed in the aluminum-based skeleton layer 9.10 and partially extends into the elastic rubber layer 9.9, but does not penetrate the elastic rubber layer 9.9. In specific implementation, there are four limiting guide pin holes 9.2, which are evenly distributed along the circumferential direction on the sealing ring body 9. By forming a metal-to-metal mating interface, the frictional resistance and wear during axial movement of the sealing ring are significantly reduced, and the operational sensitivity is improved; at the same time, the non-penetrating structure effectively prevents pressurized water from leaking through the pin holes, ensuring the reliability of the sealing system.

[0035] like Figure 2 , Figure 4 — Figure 8As shown, the aluminum-based skeleton layer 9.10 has an inner sealing ring groove 9.17 and an outer sealing ring groove 9.18 on its inner and outer sides, respectively, and an inner sealing rubber circle 9.15 and an outer sealing rubber circle 9.16 are respectively provided in the inner sealing ring groove 9.17 and the outer sealing ring groove 9.18. By setting an independent sealing rubber circle at the mating interface between the aluminum-based skeleton layer 9.10 and the sealing seat 1, a reliable static sealing barrier is constructed, effectively blocking the path of pressurized water leakage along this gap, thereby enhancing the reliability of the entire sealing system.

[0036] The sealing ring body 9 is provided with an active pressure water supply hole 9.3 that penetrates the aluminum-based skeleton layer 9.10 and the elastic rubber layer 9.9, for supplying pressurized water to the water supply tank 9.8. In specific implementation, there are four active pressure water supply holes 9.3, which are evenly distributed on the sealing ring body 9 along the circumferential direction.

[0037] like Figure 7 , Figure 8 As shown, the sealing ring body 9 is composed of at least two sector-shaped arc blocks, which are connected by end-connecting structures to form a complete ring structure. In practice, the sealing ring body 9 is generally divided into two or four sector-shaped arc blocks. It is assembled into a single unit using connecting screws at the site and then put into operation. This modular structure allows the sealing ring to be installed or replaced without disassembling the turbine main shaft, greatly simplifying the maintenance process and shortening downtime, making it particularly suitable for the on-site maintenance needs of large axial-flow turbines.

[0038] The end connection structure is an overlapping type. The overlapping type connection structure combines mechanical fastening and chemical sealing to ensure the connection strength and structural integrity between each sector arc block, while achieving a permanent seal on the joint gaps, effectively preventing pressurized water from leaking out from here.

[0039] like Figure 3 , Figure 7 , Figure 8 As shown, in practical implementation, the sealing ring body is composed of two fan-shaped arc blocks, which are connected by an end connection structure to form a complete ring structure. The end connection structure is an overlapping connection structure. At the connection point of the two fan-shaped arc blocks, the aluminum-based skeleton layer 9.10 is divided into an upper end connection structure 9.13 on the upper side and a lower end connection structure 9.14 on the lower side.

[0040] Corresponding to the water supply tank 9.8, the upper layer 9.13 and lower layer 9.14 of the end connection structure are respectively provided with screw mounting holes. The upper end of the screw mounting hole also penetrates the elastic rubber layer 9.9. The upper end of the screw mounting hole of the upper layer 9.13 of the end connection structure is provided with a screw head receiving groove. A connecting screw 9.1 is set in the screw mounting hole, and the mounting hole sealing rubber post 9.20 passes through the elastic rubber layer 9.9 and is set on the upper side of the connecting screw 9.1 to seal the screw mounting hole on the elastic rubber layer 9.9. The mounting hole sealing rubber post 9.20 is provided with a water discharge groove that mates with the water supply tank 9.8. A joint sealant 9.19 is provided between the upper layer 9.13 and the lower layer 9.14 of the end connection structure. The sealing outer ring 9.5 includes an outer ring sealing working end face ring 9.11, and the sealing inner ring 9.4 includes an inner ring sealing working end face ring 9.12. The outer ring seal working end face 9.11 and the inner ring seal working end face 9.12 are on the same plane to achieve the end face sealing function.

[0041] The technical solutions provided by the embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of this utility model. The description of the above embodiments is only for helping to understand the principles of the embodiments of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. An aluminum-based composite rubber sealing ring for the main shaft of a axial-flow turbine, comprising a sealing ring body (9), characterized in that: The sealing ring body (9) includes an aluminum-based skeleton layer (9.10) and an elastic rubber layer (9.9) fixed on the aluminum-based skeleton layer (9.10); an annular water supply groove (9.8) is provided on the sealing end face of the elastic rubber layer (9.9), which divides the sealing end face into an inner sealing ring (9.4) and an outer sealing ring (9.5); multiple self-lubricating wear-resistant pillars embedded in the elastic rubber layer (9.9) are respectively provided on the sealing end faces of the inner sealing ring (9.4) and the outer sealing ring (9.5); a limiting guide pin hole (9.2) is provided on the aluminum-based skeleton layer (9.10) for cooperating with the anti-rotation guide positioning pin (1.1) on the sealing seat (1); The aluminum-based skeleton layer (9.10) is provided with an inner sealing ring groove (9.17) and an outer sealing ring groove (9.18) on its inner and outer sides, respectively, and an inner sealing rubber circle (9.15) and an outer sealing rubber circle (9.16) are provided in the inner sealing ring groove (9.17) and the outer sealing ring groove (9.18), respectively.

2. The aluminum-based skeleton composite rubber sealing ring for the main shaft of a axial-flow turbine according to claim 1, characterized in that: The elastic rubber layer (9.9) is made of nitrile rubber-based composite material.

3. The aluminum-based skeleton composite rubber sealing ring for the main shaft of a axial-flow turbine according to claim 1, characterized in that: The aluminum-based skeleton layer (9.10) is made of aerospace aluminum alloy 7075t6 material.

4. The aluminum-based skeleton composite rubber sealing ring for the main shaft of a axial-flow turbine according to claim 1, characterized in that: The self-lubricating wear-resistant columns are arranged in a ring array on the inner sealing ring (9.4) and the outer sealing ring (9.5), the distance between adjacent self-lubricating wear-resistant columns is not greater than 30mm, and the depth of the self-lubricating wear-resistant columns embedded in the elastic rubber layer (9.9) is not less than 20mm.

5. The aluminum-based skeleton composite rubber sealing ring for the main shaft of a axial-flow turbine according to claim 1, characterized in that: The limiting guide pin hole (9.2) is opened in the aluminum base skeleton layer (9.10) and extends partially into the elastic rubber layer (9.9), but does not penetrate the elastic rubber layer (9.9).

6. The aluminum-based skeleton composite rubber sealing ring for the main shaft of a axial-flow turbine according to claim 1, characterized in that: The sealing ring body (9) is provided with an active pressure water supply hole (9.3) that penetrates the aluminum base skeleton layer (9.10) and the elastic rubber layer (9.9) to supply pressure water to the water supply tank (9.8).

7. The aluminum-based skeleton composite rubber sealing ring for the main shaft of a axial-flow turbine according to claim 1, characterized in that: The sealing ring body (9) is composed of at least two fan-shaped arc blocks, and the fan-shaped arc blocks are connected by an end connection structure to form a complete ring structure.

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