Axial sealing assembly of main shaft of water turbine and water turbine

Abstract

The utility model discloses a water turbine main shaft axial sealing assembly and a water turbine, and relates to the technical field of water turbines, the water turbine main shaft axial sealing assembly comprises a movable ring seat and a static ring seat, and a fluid leakage channel is arranged between the movable ring seat and the static ring seat. A second sealing element, a third sealing element and a fourth sealing element are arranged between the movable ring seat and the static ring seat, and the fluid leakage channel comprises an annular cavity defined by the movable ring seat and the static ring seat; a first fluid pipe is further included, and the first fluid pipe is communicated with the annular cavity. The second sealing piece and the third sealing piece are both comb tooth sealing assemblies. The fourth sealing piece is located on the downstream portion of the third sealing piece, and the fourth sealing piece is a packing sealing assembly. The sealing assembly is applied to the water turbine, and the structural design of the sealing assembly not only has a sealing assembly protection function, but also is convenient to control the axial leakage rate.

Description

Technical Field

[0001] The utility model relates to the technical field of water turbines, in particular to an axial sealing component of a water turbine main shaft and a water turbine. Background Art

[0002] There is always a gap in the radial direction between the main shaft of the turbine and its matching top cover (or front cover). When the turbine is running, a part of the water flows through the gap into the cavity between the upper crown and the top cover (or front cover). This part of the water flow is sealed by the main shaft sealing assembly of the turbine. If the water flow rate is too large, it will cause excessive overflow in the factory or affect the water guide bearing, etc. If the water flow rate is controlled too small, it will aggravate the wear of the corresponding sealing assembly, resulting in a higher failure rate and longer failure time of the sealing assembly and even the turbine.

[0003] In the prior art, in view of the fact that most turbines work in power stations with small storage capacity, the applicant disclosed a turbine blade pump type main shaft seal in the patent application document with patent application number CN201720534533.7. The main shaft seal is suitable for situations where the sediment content in the water flow is unstable. Specific technical means include adopting a multi-stage sealing component along the leakage channel, and the specific sealing component adopts a comb tooth sealing component.

[0004] However, the silt in the water flow is still an important reason for the failure of the main shaft axial seal: when the reservoir capacity is small, the silt in the water body cannot be fully settled before entering the turbine, or when there is a large amount of silt in the water body during the flood season, the silt cannot be completely discharged by the discharge pipe between the runner crown and the top cover. After entering the friction pair formed between the moving ring seat and the stationary ring seat, the silt causes serious damage to the corresponding sealing surface.

[0005] Further improving the performance of the main shaft axial sealing assembly is of great significance to ensuring the long-term reliable operation of the unit. Utility Model Content

[0006] In response to the above-mentioned technical problem of optimizing the performance of the main shaft axial sealing assembly, the utility model provides a turbine main shaft axial sealing assembly and a turbine. The sealing assembly is applied to the turbine, and the structural design of the sealing assembly not only has the sealing assembly protection function, but also facilitates the control of axial leakage.

[0007] In view of the above problems, the utility model provides a turbine main shaft axial seal assembly and a turbine to solve the problems through the following technical points: the turbine main shaft axial seal assembly comprises a dynamic ring seat and a static ring seat, a fluid leakage channel is provided between the dynamic ring seat and the static ring seat, a second seal, a third seal and a fourth seal are provided between the dynamic ring seat and the static ring seat and are arranged in sequence along the fluid leakage channel, the fluid leakage channel comprises an annular cavity surrounded by the dynamic ring seat and the static ring seat, the second seal is arranged on the inner side of the annular cavity and serves as a seal on the inlet side of the annular cavity, and the third seal is arranged on the outer side of the annular cavity and serves as a seal on the outlet side of the annular cavity;

[0008] It also includes a first fluid pipe connected to the stationary ring seat, wherein the first fluid pipe is in communication with the annular cavity;

[0009] The second seal and the third seal are both comb seal components;

[0010] In the fluid leakage channel, the fourth seal is located downstream of the third seal. The fourth seal is a packing seal assembly. A packing pressure ring for applying pressure to the packing in the fourth seal is connected to the stationary ring seat through a clamping bolt.

[0011] When the present solution is in use, the moving ring seat is fixed on the main shaft and rotates with the main shaft when the turbine is working, the stationary ring seat is fixed on the top cover and is in a stationary state when the turbine is working, the second seal, the third seal, and the fourth seal are formed between the moving ring seat and the stationary ring seat and are arranged in sequence along the fluid leakage channel of the sealing assembly, and the arrangement of the three seals can adopt the technical solution provided by application number CN201720534533.7. In the technical solution provided by application number CN201720534533.7, the specific implementation form of the labyrinth sealing surface is specifically realized by a comb tooth sealing assembly, that is, the inner ring and the outer ring, the annular ridges on the inner ring and the outer ring are the annular teeth in the prior art solution. The dynamic ring seat and the static ring seat can be an integral structure or a split structure that is convenient for assembly of parts. For example, the dynamic ring seat and the static ring seat are both arranged as an annular structure with a hole in the center, and the annular structure has a groove body coaxial with the hole. The inner and outer sides of the groove bodies on the dynamic ring seat and the static ring seat are both cylindrical structures. The dynamic ring seat and the static ring seat are assembled to be inverted with each other and surround the annular cavity. A second seal is arranged in the gap between the outer surface of the inner cylindrical structure of the groove body on the dynamic ring seat and the inner surface of the inner cylindrical body of the groove body structure on the static ring seat. A third seal is arranged in the gap between the inner surface of the cylindrical structure outside the groove body on the dynamic ring seat and the outer surface of the cylindrical body outside the groove body structure on the static ring seat. There is also an external cylindrical structure arranged on the static ring seat on the outer side of the outer cylinder of the groove body on the dynamic ring seat, and a fourth seal is arranged in the gap between the outer surface of the outer cylinder of the groove body on the dynamic ring seat and the inner surface of the external cylindrical structure.

[0012] In the above prior art solutions, a comb-tooth sealing assembly is used to form the labyrinth sealing surface. The characteristics of such a sealing form when the turbine is working include that if mud and sand enter the fluid leakage channel, the mud and sand will scratch and damage the sealing assembly on the comb teeth of the comb-tooth sealing assembly, so that such damage will not endanger the fixed structure of the turbine body. At the same time, the comb-tooth sealing assembly can adopt a flexible sealing structure and a non-contact sealing structure. The above damage will not cause a sharp decline in the performance of the sealing assembly. Therefore, the comb-tooth sealing assembly is suitable for use in occasions where there is a lot of mud and sand in the water body.

[0013] The difference between the present solution and the prior art is that the annular cavity is provided with a first fluid pipe, which can inject sealing water into the annular cavity. Different from the impeller provided in the annular cavity, under the action of the sealing water, the liquid pressure in the annular cavity is not affected by the main shaft speed. In this way, since the pressure in the annular cavity can be dynamically adjusted, the resistance of the fluid passing through the annular cavity can also be dynamically adjusted. For example, when the sediment content in the water body is large, the annular cavity is provided with a greater internal pressure through the first fluid pipe, thereby reducing the possibility of sediment entering the second seal to avoid the damage of the sediment to the main shaft axial seal assembly. Under such working conditions, the sealing performance of the fourth seal can be further squeezed by the packing pressure ring to further squeeze the corresponding packing to strengthen the sealing performance of the fourth seal, and the leakage amount can be controlled by sacrificing the wear rate of the packing; on the contrary, if the water body is relatively clear, the annular cavity is provided with a smaller internal pressure through the first fluid pipe. Under such working conditions, since there is a smaller pressure difference on both sides of the fourth seal, the leakage amount can be better controlled by the packing pressure ring appropriately squeezing the corresponding packing, so that the fourth seal can have a smaller packing wear rate.

[0014] At the same time, the second seal and the third seal, both of which are comb-tooth seal assemblies, are a sealing solution with low sensitivity to particles in the sealing fluid in terms of damage speed; the fourth seal, which is a packing seal assembly, is a sealing solution with a simple structure and convenient control of the sealing preload force.

[0015] In summary, this solution is a technical solution that has a structural design of a sealing component and has a sealing component protection function and is convenient for controlling axial leakage.

[0016] As a further technical solution of the turbine main shaft axial seal assembly:

[0017] When the above scheme is implemented, in order to control the internal pressure in the annular cavity to control the resistance of the leaking fluid through the fluid leakage channel, the method that can be used includes controlling the water supply pressure of the first fluid pipe, for example, controlling the pressure at the output end of the pressure reducing valve at the front end of the first fluid pipe or the pressure after pressurization by the pressurizing device at the front end of the first fluid pipe. As a preferred scheme for adjusting the internal pressure of the annular cavity, the number of the first fluid pipes is 2, and a control valve is connected in series on one of the first fluid pipes, and the control valve is used to adjust the fluid flow through the first fluid pipe. When the present solution is used in practice, one of the first fluid pipes is used as an inlet pipe for injecting sealing water into the annular cavity, and the other first fluid pipe is used as an outlet pipe for discharging fluid from the annular cavity to the outside. In this way, a pressure reducing valve with a constant pressure reducing value or a pump group with a constant head can be set at the front end of the water inlet pipe, and the flow rate of the water body discharged from the annular cavity can be controlled by controlling the control valve on the water outlet pipe. In this way, the fluid equipment structure and control at the front end of the water inlet pipe are simple, and at the same time, it has the ability to adjust the internal pressure of the annular cavity. Further, the condition of the water body discharged by the water outlet pipe can reflect the condition of the sediment entering the annular cavity through the second sealing member. When the first fluid pipe connected in series with the control valve is also equipped with a fluid cup for containing the fluid from the first fluid pipe, the sediment condition in the annular cavity can be determined by observing the turbidity of the liquid contained in the fluid cup. For example, the opening size of the control valve can be adjusted according to the determination result: when the turbidity is large, the opening of the control valve should be reduced to increase the resistance of the fluid passing through the second sealing member and entering the annular cavity by increasing the internal pressure of the annular cavity. On the contrary, the opening of the control valve can be appropriately increased to reduce the normal wear and tear of the axial sealing component.

[0018] As described above, since the comb seal assembly can be prepared as a non-contact seal structure and a flexible seal structure, but its ability to resist mud and sand from entering the seal surface is poor, preferably, in order to make the front end of the second seal have a mud and sand blocking function, it also includes a first seal, and the first seal is arranged upstream of the second seal on the fluid leakage channel;

[0019] The first seal comprises a moving ring fixed on a moving ring seat and a stationary ring installed on a stationary ring seat, wherein an annular groove is arranged on the stationary ring seat, the opening side of the annular groove faces the moving ring, the stationary ring is installed in the annular groove, and further comprises a second fluid pipe communicating with the bottom of the annular groove, when the pressure medium is introduced into the bottom of the annular groove through the second fluid pipe, the fluid introduced into the bottom of the annular groove through the second fluid pipe plays the role of pushing the stationary ring toward the side where the moving ring is located, and the stationary ring moves toward the moving ring under the pressure of the pressure medium. When this scheme is used in practice, the water supply pressure of the second fluid pipe can be adjusted according to the turbidity of the water body of the power station, when the water body is relatively clear, the water supply pressure of the second fluid pipe is reduced, so that there is a small positive pressure between the stationary ring and the moving ring to protect the first seal, when the water body is relatively turbid, the water supply pressure of the second fluid pipe is increased to increase the positive pressure, thereby increasing the difficulty of mud and sand entering between the moving ring and the stationary ring, so as to achieve the purpose of reducing the harm of mud and sand to the first seal. The preferred application is: the first seal is installed to be located at the lower side of the second seal, the first seal is installed on the top cover through a shroud coaxial with the main shaft on the top cover, the shroud divides the space inside the top cover into an inner space and an outer space, the first seal is located in the inner space, the inner space and the outer space are connected through a channel at the upper end of the shroud, and the fluid inlet side of the second seal is located in the outer space and above the shroud, so that the sediment passing through the first seal will settle in the outer space, thereby further reducing the possibility of sediment entering the second seal. A further application is: a drainage hole for discharging the fluid in the outer space is arranged on the top cover, the above drainage hole is a normally closed hole, and is opened when necessary to discharge the sediment deposited therein; a further application is: in a normal operating cycle of the turbine, there is a small pressure in the annular cavity in the early stage to protect the fourth seal, and as the sealing performance of the first seal is gradually lost, the internal pressure of the annular cavity and the compression of the seal ring on the packing are synchronously increased, so that the overall life of the axial seal assembly is longer.

[0020] As a specific implementation of the first sealing member, the dynamic ring is a wear-resistant alloy ring, and the static ring is a rubber ring;

[0021] The stationary ring is provided with a plurality of through holes, and the through holes are arranged at intervals along the circumferential direction of the stationary ring;

[0022] Each through hole has one opening located on the side of the stationary ring facing the bottom of the annular groove, and the other opening located on the side of the stationary ring facing the dynamic ring. In this solution, the outer side of the stationary ring, which is a rubber ring, has good sealing performance with the inner side of the annular groove. When the pressure of the pressure medium in the second fluid pipe is changed, the pressure between the stationary ring and the dynamic ring can be sensitively changed with the pressure of the medium. At the same time, the stationary ring can play the role of embedding the dynamic ring to remove the mud between the stationary rings, thereby reducing the wear on the first seal. The wear-resistant alloy ring is used to make the dynamic ring itself have good wear resistance. The through hole allows the sealing water from the second fluid pipe to enter the mating surface of the dynamic ring and the stationary ring, and form a liquid film on the mating surface to protect the first seal.

[0023] In order to protect the dynamic ring seat and make the first sealing element maintainable, the wear-resistant alloy ring is embedded in an annular mounting seat, and the mounting seat is connected to the dynamic ring seat by connecting bolts.

[0024] As a specific implementation of the comb teeth seal assembly, the comb teeth seal assembly includes a coaxial inner ring and an outer ring;

[0025] The outer side of the inner ring is provided with a plurality of annular ridges coaxial with the inner ring, and the inner side of the outer ring is provided with a plurality of annular ridges coaxial with the outer ring, the annular ridges on the inner ring are arranged at intervals along the axis of the inner ring, and the annular ridges on the outer ring are arranged at intervals along the axis of the outer ring, and the annular ridges on the inner ring are stacked with the annular ridges on the outer ring, and the specific stacking method is: in the axial direction of the inner ring and the outer ring, of any two adjacent annular ridges, one of the annular ridges is the annular ridge on the inner ring, and the other annular ridge is the annular ridge on the outer ring;

[0026] In the second sealing member, the inner ring is mounted on the dynamic ring seat, and the outer ring is mounted on the static ring seat;

[0027] In the third seal, the inner ring is installed on the stationary ring seat, and the outer ring is installed on the dynamic ring seat. In this solution, for the second seal and the third seal, the annular ridges on the inner ring and the annular ridges on the outer ring are arranged in a cross relationship to form a comb-tooth sealing structure. The inner ring and the outer ring are the bearing structures of the corresponding annular ridges, and further on the basis of the structure of the annular cavity, the dynamic ring seat is installed on the main shaft with the shaft sleeve as the installation basis. A corresponding installation method for the inner ring and the outer ring is provided, so that the second seal is located on the inner side of the third seal. In the specific application of this solution to the turbine, all the inner rings and the outer rings are coaxial with the main shaft of the turbine, and the annular ridges on all the inner rings and the outer rings are arranged at intervals along the axial direction of the main shaft.

[0028] The present solution also relates to a water turbine, comprising a main shaft and a top cover, and also comprising a water turbine main shaft axial seal assembly as described in any one of the above items, wherein:

[0029] The dynamic ring seat is bolted to the main shaft, and the stationary ring seat is bolted to the top cover;

[0030] The second seal, the third seal, and the fourth seal are arranged in sequence from inside to outside in the radial direction of the main shaft;

[0031] The first fluid pipe passes through the top cover, and the outlet end of the first fluid pipe is fixedly connected to the stationary ring seat. This solution provides a specific application of a main shaft axial sealing assembly on a water turbine.

[0032] As a further technical solution of the turbine:

[0033] It also includes a sealing ring disposed between the moving ring seat and the main shaft, and the sealing ring is used to achieve axial sealing of the gap between the inner side of the moving ring seat and the outer side of the main shaft. In this solution, the axial seal is used to solve the axial static sealing problem between the moving ring seat and the main shaft, and specifically adopts a step provided on the main shaft for axial positioning of the moving ring seat, and the axial seal is provided on the step and obtains an axial static sealing effect under the axial extrusion of the main shaft and the moving ring seat.

[0034] The spindle axial seal assembly is a spindle axial seal assembly with two first fluid pipes, and the first fluid pipe connected in series with the control valve is also equipped with a fluid cup for containing the fluid from the first fluid pipe. As described above, the fluid condition in the fluid cup can be used to determine the condition of mud and sand entering the annular cavity, thereby controlling the opening size of the control valve.

[0035] The utility model has the following beneficial effects:

[0036] In this solution, a first fluid pipe is provided for the annular cavity, and the above first fluid pipe can inject sealing water into the annular cavity. Different from setting an impeller in the annular cavity, under the action of the sealing water, the liquid pressure in the annular cavity can be not affected by the main shaft speed. In this way, since the pressure in the annular cavity can be dynamically adjusted, the resistance of the fluid passing through the annular cavity can also be dynamically adjusted. At the same time, the second seal and the third seal of the comb tooth sealing assembly are a sealing solution with low sensitivity to particulate matter in the sealing fluid in terms of damage speed; the fourth seal of the packing sealing assembly is a sealing solution with a simple structure and convenient sealing preload force control. In summary, the structural design of the axial sealing assembly not only has the sealing assembly protection function, but also facilitates the control of axial leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A cross-sectional view of a specific application embodiment of the turbine main shaft axial seal assembly described in this scheme;

[0038] Figure 2 for Figure 1A partial enlarged view of part A in the middle.

[0039] The reference numerals in the figure are: 1. main shaft, 2. packing pressure ring, 3. stationary ring seat, 4. fourth seal, 5. third seal, 6. second seal, 7. dynamic ring seat, 8. first seal, 9. top cover, 10. annular cavity, 11. first fluid pipe, 12. second fluid pipe, 13. sealing ring. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the embodiments, but the present invention is not limited to the following embodiments:

[0041] Embodiment 1:

[0042] like Figure 1 and Figure 2 As shown, the turbine main shaft axial sealing assembly includes a dynamic ring seat 7 and a static ring seat 3, a fluid leakage channel is provided between the dynamic ring seat 7 and the static ring seat 3, a second sealing member 6, a third sealing member 5 and a fourth sealing member 4 are provided between the dynamic ring seat 7 and the static ring seat 3, and the fluid leakage channel includes an annular cavity 10 surrounded by the dynamic ring seat 7 and the static ring seat 3, the second sealing member 6 is provided on the inner side of the annular cavity 10 and serves as a sealing member on the inlet side of the annular cavity 10, and the third sealing member 5 is provided on the outer side of the annular cavity 10 and serves as a sealing member on the outlet side of the annular cavity 10;

[0043] It also includes a first fluid pipe 11 connected to the stationary ring seat 3, wherein the first fluid pipe 11 is communicated with the annular cavity 10;

[0044] The second seal 6 and the third seal 5 are both comb seal components;

[0045] In the fluid leakage channel, the fourth seal 4 is located downstream of the third seal 5. The fourth seal 4 is a packing seal assembly. A packing pressure ring 2 for applying pressure to the packing in the fourth seal 4 is connected to the stationary ring seat 3 through a clamping bolt.

[0046] When the present solution is in use, the dynamic ring seat 7 is fixed on the main shaft 1 and rotates with the main shaft 1 when the turbine is working. The static ring seat 3 is fixed on the top cover 9 and is in a stationary state when the turbine is working. The second seal 6, the third seal 5, and the fourth seal 4 are formed between the dynamic ring seat 7 and the static ring seat 3 and are arranged in sequence along the fluid leakage channel of the sealing assembly. The arrangement of the three seals can adopt the technical solution provided by application number CN201720534533.7. In the technical solution provided by application number CN201720534533.7, the specific implementation form of the labyrinth sealing surface is specifically realized by a comb tooth sealing assembly, that is, the following includes an inner ring and an outer ring, and the annular ridges on the inner ring and the outer ring are the annular teeth in the prior art solution. The dynamic ring seat 7 and the static ring seat 3 can be an integral structure or a split structure that is convenient for assembling parts. For example, the dynamic ring seat 7 and the static ring seat 3 are both set as an annular structure with a hole in the center, and the annular structure has a groove body coaxial with the hole. The inner and outer sides of the groove bodies on the dynamic ring seat 7 and the static ring seat 3 are both cylindrical structures. The dynamic ring seat 7 and the static ring seat 3 are assembled to be inverted with each other and surround the annular cavity 10. A second sealing member 6 is set in the gap between the outer surface of the inner cylindrical structure of the groove body on the dynamic ring seat 7 and the inner surface of the inner cylindrical body of the groove body structure on the static ring seat 3. A third sealing member 5 is set in the gap between the inner surface of the cylindrical structure outside the groove body on the dynamic ring seat 7 and the outer surface of the cylindrical body outside the groove body structure on the static ring seat 3. There is also an external cylindrical structure set on the static ring seat 3 on the outer side of the outer cylindrical body of the groove body on the dynamic ring seat 7. A fourth sealing member 4 is set in the gap between the outer surface of the outer cylindrical body of the groove body on the dynamic ring seat 7 and the inner surface of the external cylindrical structure.

[0047] In the above prior art solutions, a comb-tooth sealing assembly is used to form the labyrinth sealing surface. The characteristics of such a sealing form when the turbine is working include that if mud and sand enter the fluid leakage channel, the mud and sand will scratch and damage the sealing assembly on the comb teeth of the comb-tooth sealing assembly, so that such damage will not endanger the fixed structure of the turbine body. At the same time, the comb-tooth sealing assembly can adopt a flexible sealing structure and a non-contact sealing structure. The above damage will not cause a sharp decline in the performance of the sealing assembly. Therefore, the comb-tooth sealing assembly is suitable for use in occasions where there is a lot of mud and sand in the water body.

[0048] The difference between this solution and the prior art is that the annular cavity 10 is provided with a first fluid pipe 11, and the first fluid pipe 11 can inject sealing water into the annular cavity 10. Different from the impeller provided in the annular cavity 10, under the action of the sealing water, the liquid pressure in the annular cavity 10 is not affected by the rotation speed of the main shaft 1. In this way, since the pressure in the annular cavity 10 can be dynamically adjusted, the resistance of the fluid passing through the annular cavity 10 can also be dynamically adjusted. For example, when the sediment content in the water body is large, the annular cavity 10 has a greater internal pressure through the first fluid pipe 11, thereby reducing the sediment entering the annular cavity 10. The possibility of the second seal 6 is to avoid damage to the axial sealing assembly of the main shaft 1 by mud and sand. Under such working conditions, the sealing performance of the fourth seal 4 can be strengthened by further squeezing the corresponding filler through the packing pressure ring 2, so as to control the leakage at the expense of the wear rate of the filler; on the contrary, if the water body is relatively clear, the annular cavity 10 has a smaller internal pressure through the first fluid pipe 11. Under such working conditions, since there is a small pressure difference on both sides of the fourth seal 4, the packing pressure ring 2 can better control the leakage by appropriately squeezing the corresponding filler, so that the fourth seal 4 can have a smaller filler wear rate.

[0049] At the same time, the second seal 6 and the third seal 5, both of which are comb-tooth seal assemblies, are a sealing solution with low sensitivity to particulate matter in the sealing fluid in terms of damage speed; the fourth seal 4, which is a packing seal assembly, is a sealing solution with a simple structure and convenient control of the sealing preload force.

[0050] In summary, this solution is a technical solution that has a structural design of a sealing component and has a sealing component protection function and is convenient for controlling axial leakage.

[0051] Embodiment 2:

[0052] This embodiment is further refined on the basis of embodiment 1:

[0053] When the above scheme is implemented, in order to control the internal pressure in the annular cavity 10 to control the resistance of the leaking fluid through the fluid leakage channel, the method that can be used includes controlling the water supply pressure of the first fluid pipe 11, for example, controlling the pressure at the output end of the pressure reducing valve at the front end of the first fluid pipe 11 or the pressure after the pressure is pressurized by the pressure-adding device at the front end of the first fluid pipe 11. As a preferred scheme for adjusting the internal pressure of the annular cavity 10, the number of the first fluid pipes 11 is 2, and a control valve is connected in series to one of the first fluid pipes 11, and the control valve is used to adjust the fluid flow through the first fluid pipe 11. When the present solution is used in practice, one of the first fluid pipes 11 is used as an inlet pipe for injecting sealing water into the annular cavity 10, and the other first fluid pipe 11 is used as an outlet pipe for discharging fluid from the annular cavity 10 to the outside. In this way, a pressure reducing valve with a constant pressure reducing value or a pump group with a constant head can be set at the front end of the water inlet pipe, and the flow rate of water discharged from the annular cavity 10 can be controlled by controlling the control valve on the water outlet pipe. In this way, the fluid equipment structure and control at the front end of the water inlet pipe are simple, and at the same time, it has the ability to adjust the internal pressure of the annular cavity 10. Furthermore, the condition of the water discharged from the water outlet pipe can reflect the sediment passing through the second sealing member. 6 enters the annular cavity 10. When the first fluid pipe 11 connected in series with the control valve is also equipped with a fluid cup for containing the fluid from the first fluid pipe 11, the turbidity of the liquid contained in the fluid cup can be observed to determine the silt situation in the annular cavity 10. For example, the opening of the control valve can be adjusted according to the determination result: when the turbidity is large, the opening of the control valve should be reduced to increase the resistance of the fluid passing through the second sealing member 6 and entering the annular cavity 10 by increasing the internal pressure of the annular cavity 10. On the contrary, the opening of the control valve can be appropriately increased to reduce the normal wear and tear of the axial sealing component.

[0054] Embodiment 3:

[0055] This embodiment is further refined on the basis of embodiment 1:

[0056] As described above, since the comb seal assembly can be prepared as a non-contact seal structure and a flexible seal structure, but its ability to resist mud and sand from entering the seal surface is poor, preferably, in order to make the front end of the second seal 6 have a mud and sand blocking function, it also includes a first seal 8, and the first seal 8 is arranged upstream of the second seal 6 on the fluid leakage channel;

[0057] The first seal 8 includes a dynamic ring fixed on the dynamic ring seat 7 and a static ring installed on the static ring seat 3. The static ring seat 3 is provided with an annular groove, the opening side of the annular groove faces the dynamic ring, and the static ring is installed in the annular groove. It also includes a second fluid pipe 12 communicated with the bottom of the annular groove. When the pressure medium is introduced into the bottom of the annular groove through the second fluid pipe 12, the fluid introduced into the bottom of the annular groove through the second fluid pipe 12 pushes the static ring toward the side where the dynamic ring is located, and the static ring moves toward the dynamic ring under the pressure of the pressure medium. When this scheme is used in practice, the water supply pressure of the second fluid pipe 12 can be adjusted according to the turbidity of the water body of the power station. When the water body is relatively clear, the water supply pressure of the second fluid pipe 12 is reduced, so that there is a small positive pressure between the static ring and the dynamic ring to protect the first seal 8. When the water body is relatively turbid, the water supply pressure of the second fluid pipe 12 is increased to increase the positive pressure, thereby increasing the difficulty of mud and sand entering between the dynamic ring and the static ring, thereby reducing the harm of mud and sand to the first seal 8. A better application is: the first seal 8 is installed to be located at the lower side of the second seal 6, and the first seal 8 is installed on the top cover 9 through a shroud coaxial with the main shaft 1 on the top cover 9, and the shroud divides the space inside the top cover 9 into an inner space and an outer space. The first seal 8 is located in the inner space, and the inner space and the outer space are connected through a channel at the upper end of the shroud, and the fluid inlet side of the second seal 6 is located in the outer space and above the shroud, so that the mud and sand passing through the first seal 8 will settle in the outer space, thereby further reducing the possibility of mud and sand entering the second seal 6. Further application is: a drain hole for draining the fluid in the outer space is arranged on the top cover 9, and the above drain hole is a normally closed hole, which is opened when necessary to discharge the sediment deposited therein; further application is: in a normal operating cycle of the turbine, there is a small pressure in the annular cavity 10 at the early stage to protect the fourth seal 4. As the sealing performance of the first seal 8 is gradually lost, the internal pressure of the annular cavity 10 and the squeezing of the packing by the sealing ring 13 are simultaneously increased, so that the overall service life of the axial sealing assembly is longer.

[0058] Embodiment 4:

[0059] This embodiment is further refined on the basis of Embodiment 3:

[0060] As a specific implementation of the first sealing member 8, the dynamic ring is a wear-resistant alloy ring, and the static ring is a rubber ring;

[0061] The stationary ring is provided with a plurality of through holes, and the through holes are arranged at intervals along the circumferential direction of the stationary ring;

[0062] Each through hole has one opening located on the side of the static ring facing the bottom of the annular groove, and the other opening located on the side of the static ring facing the dynamic ring. In this solution, the outer side of the static ring, which is a rubber ring, has good sealing performance with the inner side of the annular groove. When the pressure of the pressure medium in the second fluid pipe 12 is changed, the pressure between the static ring and the dynamic ring can be sensitively changed with the pressure of the medium. At the same time, the static ring can play the role of embedding the dynamic ring to reduce the wear on the first seal 8. The wear-resistant alloy ring is used to make the dynamic ring itself have good wear resistance. The through hole allows the sealing water from the second fluid pipe 12 to enter the mating surface of the dynamic ring and the static ring, and form a liquid film on the mating surface to protect the first seal 8.

[0063] Embodiment 5:

[0064] This embodiment is further refined on the basis of Embodiment 4:

[0065] In order to protect the dynamic ring seat 7 and make the first sealing member 8 maintainable, the wear-resistant alloy ring is embedded in an annular mounting seat, and the mounting seat is connected to the dynamic ring seat 7 via connecting bolts.

[0066] Embodiment 6:

[0067] This embodiment is further refined on the basis of embodiment 1:

[0068] As a specific implementation of the comb teeth seal assembly, the comb teeth seal assembly includes a coaxial inner ring and an outer ring;

[0069] The outer side of the inner ring is provided with a plurality of annular ridges coaxial with the inner ring, and the inner side of the outer ring is provided with a plurality of annular ridges coaxial with the outer ring, the annular ridges on the inner ring are arranged at intervals along the axis of the inner ring, and the annular ridges on the outer ring are arranged at intervals along the axis of the outer ring, and the annular ridges on the inner ring are stacked with the annular ridges on the outer ring, and the specific stacking method is: in the axial direction of the inner ring and the outer ring, of any two adjacent annular ridges, one of the annular ridges is the annular ridge on the inner ring, and the other annular ridge is the annular ridge on the outer ring;

[0070] In the second sealing member 6, the inner ring is mounted on the dynamic ring seat 7, and the outer ring is mounted on the static ring seat 3;

[0071] In the third seal 5, the inner ring is installed on the stationary ring seat 3, and the outer ring is installed on the dynamic ring seat 7. In this solution, for the second seal 6 and the third seal 5, the annular ridges on the inner ring and the annular ridges on the outer ring are arranged in a cross relationship to form a comb seal structure, and the inner ring and the outer ring are the bearing structures of the corresponding annular ridges, and further on the basis of the structure of the annular cavity 10, the dynamic ring seat 7 is installed on the main shaft 1 with the shaft sleeve as the installation basis, and a corresponding installation method of the inner ring and the outer ring is provided, so that the second seal 6 is located on the inner side of the third seal 5. In the specific application of this solution to the turbine, all the inner rings and the outer rings are coaxial with the main shaft 1 of the turbine, and the annular ridges on all the inner rings and the outer rings are arranged at intervals along the axial direction of the main shaft 1.

[0072] Embodiment 7:

[0073] This embodiment provides a water turbine, comprising a main shaft 1 and a top cover 9, and also comprising an axial sealing assembly of the water turbine main shaft 1 as described in the above embodiment 1, wherein:

[0074] The dynamic ring seat 7 is bolted to the main shaft 1, and the stationary ring seat 3 is bolted to the top cover 9;

[0075] The second seal 6, the third seal 5, and the fourth seal 4 are arranged in sequence from inside to outside in the radial direction of the main shaft 1;

[0076] The first fluid pipe 11 passes through the top cover 9, and the outlet end of the first fluid pipe 11 is fixedly connected to the stationary ring seat 3. This solution provides a specific application of the main shaft 1 axial sealing assembly on a water turbine.

[0077] Embodiment 8:

[0078] This embodiment is further refined on the basis of Embodiment 7:

[0079] It also includes a sealing ring 13 disposed between the moving ring seat 7 and the main shaft 1, and the sealing ring 13 is used to achieve axial sealing of the gap between the inner side of the moving ring seat 7 and the outer side of the main shaft 1. In this solution, the axial seal is used to solve the axial static sealing problem between the moving ring seat 7 and the main shaft 1, and specifically adopts a step provided on the main shaft 1 for axial positioning of the moving ring seat 7, and the axial seal is provided on the step and obtains an axial static sealing effect under the axial extrusion of the main shaft 1 and the moving ring seat 7.

[0080] Embodiment 9:

[0081] This embodiment is further refined on the basis of Embodiment 7 and Embodiment 2:

[0082] The main shaft 1 axial sealing assembly is a main shaft 1 axial sealing assembly with two first fluid pipes 11, and the first fluid pipe 11 connected in series with the control valve is also equipped with a fluid cup for containing the fluid from the first fluid pipe 11. As described above, the fluid condition in the fluid cup can be used to determine the condition of mud and sand entering the annular cavity 10, thereby controlling the valve opening size.

[0083] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and the specific embodiments of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, other embodiments derived without departing from the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A turbine main shaft axial seal assembly, comprising a moving ring seat (7) and a stationary ring seat (3), wherein a fluid leakage channel is provided between the moving ring seat (7) and the stationary ring seat (3), and a second seal (6), a third seal (5) and a fourth seal (4) are provided between the moving ring seat (7) and the stationary ring seat (3) and are arranged in sequence along the fluid leakage channel, wherein: The fluid leakage channel comprises an annular cavity (10) surrounded by a dynamic ring seat (7) and a stationary ring seat (3); the second sealing member (6) is arranged on the inner side of the annular cavity (10) and serves as a sealing member on the inlet side of the annular cavity (10); and the third sealing member (5) is arranged on the outer side of the annular cavity (10) and serves as a sealing member on the outlet side of the annular cavity (10); It also includes a first fluid pipe (11) connected to the stationary ring seat (3), wherein the first fluid pipe (11) is in communication with the annular cavity (10); The second sealing member (6) and the third sealing member (5) are both comb-teeth sealing components; In the fluid leakage channel, the fourth seal (4) is located downstream of the third seal (5), and the fourth seal (4) is a packing seal assembly. A packing pressure ring (2) for applying pressure to the packing in the fourth seal (4) is connected to the stationary ring seat (3) through a clamping bolt.

2. The turbine main shaft axial seal assembly according to claim 1, characterized in that: The number of the first fluid pipes (11) is 2, and a control valve is connected in series to one of the first fluid pipes (11), and the control valve is used to adjust the fluid flow rate passing through the first fluid pipe (11).

3. The turbine main shaft axial seal assembly according to claim 1, characterized in that: It also includes a first seal (8), which is arranged upstream of the second seal (6) on the fluid leakage channel; The first sealing member (8) comprises a dynamic ring fixed on a dynamic ring seat (7) and a static ring installed on a static ring seat (3), wherein an annular groove is arranged on the static ring seat (3), and the opening side of the annular groove faces the dynamic ring, the static ring is installed in the annular groove, and further comprises a second fluid pipe (12) connected to the bottom of the annular groove, when a pressure medium is introduced into the bottom of the annular groove through the second fluid pipe (12), the static ring moves toward the dynamic ring under the pressure of the pressure medium.

4. The turbine main shaft axial seal assembly according to claim 3, characterized in that: The dynamic ring is a wear-resistant alloy ring, and the static ring is a rubber ring; The stationary ring is provided with a plurality of through holes, and the through holes are arranged at intervals along the circumferential direction of the stationary ring; Each through hole has: one opening is located on the side of the stationary ring facing the bottom side of the annular groove, and the other opening is located on the side of the stationary ring facing the dynamic ring.

5. The turbine main shaft axial seal assembly according to claim 4, characterized in that: The wear-resistant alloy ring is embedded in an annular mounting seat, and the mounting seat is connected to the dynamic ring seat (7) via connecting bolts.

6. The turbine main shaft axial seal assembly according to any one of claims 1 to 5, characterized in that: The comb seal assembly comprises a coaxial inner ring and an outer ring; The outer side of the inner ring is provided with a plurality of annular ridges coaxial with the inner ring, and the inner side of the outer ring is provided with a plurality of annular ridges coaxial with the outer ring, the annular ridges on the inner ring are arranged at intervals along the axis of the inner ring, and the annular ridges on the outer ring are arranged at intervals along the axis of the outer ring, and the annular ridges on the inner ring are stacked with the annular ridges on the outer ring, and the specific stacking method is: in the axial direction of the inner ring and the outer ring, of any two adjacent annular ridges, one of the annular ridges is the annular ridge on the inner ring, and the other annular ridge is the annular ridge on the outer ring; In the second sealing member (6), the inner ring is mounted on the dynamic ring seat (7), and the outer ring is mounted on the static ring seat (3); In the third sealing member (5), the inner ring is mounted on the stationary ring seat (3), and the outer ring is mounted on the dynamic ring seat (7).

7. A water turbine, comprising a main shaft (1) and a top cover (9), characterized in that: It also includes the turbine main shaft axial seal assembly according to any one of claims 1 to 6, wherein: The dynamic ring seat (7) is bolted to the main shaft (1), and the stationary ring seat (3) is bolted to the top cover (9); The second sealing member (6), the third sealing member (5), and the fourth sealing member (4) are arranged in sequence from inside to outside in the radial direction of the main shaft (1); The first fluid pipe (11) passes through the top cover (9), and the outlet end of the first fluid pipe (11) is fixedly connected to the stationary ring seat (3).

8. The water turbine according to claim 7, characterized in that: It also includes a sealing ring (13) arranged between the dynamic ring seat (7) and the main shaft (1), wherein the sealing ring (13) is used to achieve axial sealing of the gap between the inner side of the dynamic ring seat (7) and the outer side of the main shaft (1).

9. The water turbine according to claim 7, characterized in that: The spindle axial sealing assembly is the spindle axial sealing assembly as claimed in claim 2, and the first fluid pipe (11) connected in series with the control valve is also provided with a fluid cup for containing the fluid from the first fluid pipe (11).

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