Kaplan turbine runner oil isolation structure

Abstract

The invention discloses a rotating wheel oil isolation structure of a Kaplan turbine, and relates to the field of reaction hydraulic machinery, the rotating wheel oil isolation structure comprises a main shaft and a hub, the inner side of the main shaft is provided with an operation oil pipe, the center of the main shaft is provided with a piston rod extending into the hub, the hub is internally provided with a piston cavity and an oil-free cavity, and the piston cavity and the oil-free cavity are communicated with each other. Breathing channels are arranged in the main shaft and the hub, and the piston rod is sleeved with a flexible telescopic joint which is fixedly connected with the hub and the piston rod. One end of the flexible expansion joint is fixed to the hub, the other end of the flexible expansion joint is fixed to the piston rod, the flexible expansion joint does not generate contact friction when moving between the piston rod and the hub, the installation position belongs to static sealing, stability and reliability are higher, and leakage of hydraulic oil can be effectively prevented. The hub oil-free cavity is communicated with the atmosphere through the main shaft and a breathing channel in the hub, so that the pressure of the hub oil-free cavity is lower than that of a flow channel, and pollution caused by leakage of contents in the hub is further avoided.

Description

Technical Field

[0001] The present invention relates to a reaction hydraulic machine, and more particularly to an oil isolation structure for a runner of a Kaplan turbine. Background Art

[0002] The Kaplan turbine is a type of Kaplan turbine with adjustable blades. It was developed by Austrian professor Viktor Kaplan in 1913. He combined automatically adjustable blades and automatically adjustable guide vanes to achieve high energy indicators within a wide range of large flow rate variations and large water head variations. Kaplan turbines are widely used in current hydropower generation due to their wide operating range and high weighted efficiency.

[0003] However, the adjustment of the blades of the Kaplan turbine relies on the operation oil pipe in the main shaft to supply pressure oil to the relay actuator, driving the piston or piston cylinder to reciprocate, and driving the movement of the link mechanism connected to the blade to adjust the angle of the blade. Since hydraulic oil is used for pressurization and it cannot be ensured that the hydraulic oil will not leak from the piston rod, there is a phenomenon that the hydraulic oil of the existing Kaplan turbine leaks into the river from the blade, which pollutes the water environment.

[0004] Although the prior art has increased the area of the sealing ring at the position where the piston rod may leak oil, the sealing ring is still a dynamic seal and will still have sliding friction with the piston rod. There is still a risk of leaking oil into the external environmental water body after long-term use. For example, the "runner and water turbine" disclosed in publication number CN117905625A uses a plug rod seal to seal the piston rod and the piston cavity, but the up and down movement of the piston rod will inevitably cause friction with the plug rod seal, thereby accelerating the wear of the piston rod seal, resulting in hydraulic oil leakage, reducing the service life, and increasing the maintenance difficulty. Summary of the Invention

[0005] The object of the present invention is to provide an environmentally friendly runner oil isolation structure that can effectively prevent hydraulic oil from leaking from the piston chamber and the piston rod and thus entering the environmental water body to pollute the environmental water body. The present invention fixedly installs a flexible expansion joint on the hub and the piston rod as a sealing component. At the same time, the flexible expansion joint will not generate frictional contact with the piston rod during the up and down movement of the piston rod, and can completely collect the hydraulic oil in the flexible expansion joint without leakage and has a long service life. A further object of the present invention is to provide an oil return pipeline leading to the main shaft on the piston rod, and the hydraulic oil in the flexible expansion joint can also return to the main shaft through the oil return pipeline. Another object of the present invention is to connect the air pressure in the oil-free chamber with the atmospheric pressure by providing a breathing channel on the hub and the main shaft, reducing the air pressure in the oil-free chamber so that the pressure in the oil-free chamber is less than the pressure of the external water body. Even if the blade seal leaks, it will only extend from the external water body into the oil-free chamber, further avoiding the leakage of hydraulic oil into the external water body.

[0006] The present invention realizes the above technical objects through the following technical means.

[0007] An oil isolation structure for a Kaplan turbine runner, comprising a main shaft and a hub. An operating oil pipe is provided inside the main shaft. A piston rod extends into the hub at the center of the main shaft. There is a piston chamber and an oil-free chamber in the hub. A breathing channel is provided in the main shaft and the hub. A flexible expansion joint is sleeved on the piston rod and fixedly connected to the hub and the piston rod.

[0008] Furthermore, a breathing channel is provided in the shell walls of the hub and the main shaft. One end of the breathing channel is communicated with the oil-free chamber. A hub breathing device is provided on the main shaft. The other end of the breathing channel is communicated with the hub breathing device.

[0009] Preferably, a piston chamber is formed at the connection position between the hub and the main shaft. A piston cylinder head is installed at the opening position at the center of the main shaft. The piston rod passes through the piston cylinder head and is movably sealed with the piston cylinder head. A piston is fixedly installed on the piston rod. The piston is located in the piston chamber.

[0010] The piston chamber is above the oil-free chamber.

[0011] Furthermore, one end of the flexible expansion joint is fixedly connected to the position of the hub close to the oil-free chamber. The other end of the flexible expansion joint is fixedly connected to the piston rod. The middle part of the flexible expansion joint is sleeved outside the piston rod and does not contact the piston rod.

[0012] Preferably, an operating frame is fixedly installed in the oil-free chamber at the end of the piston rod. The operating frame does not contact the hub.

[0013] Preferably, an opening is provided at the outer wall of the hub, the outer end of the pivot is accommodated at the opening, the inner end of the pivot is accommodated at the contact section between the hub and the piston rod, and a blade is installed at one end of the pivot close to the opening.

[0014] The pivot is provided with a crank arm in the oil-free chamber, and the operating frame is provided with a connecting rod mechanism hinged to the crank arm.

[0015] Furthermore, a blade seal is provided between the blade and the opening of the hub, the blade seal is fixedly connected to the hub and contacts the blade seal, and the blade rotates with the pivot.

[0016] Preferably, the piston rod is fixedly connected to the wheel hub, the end of the piston rod is covered with a piston cylinder upper shell, a piston is installed on the piston rod in the piston cylinder upper shell, a piston cylinder lower cover is sealably installed below the piston cylinder upper shell, a piston cylinder moving part is installed below the piston cylinder lower cover, and the piston cylinder moving part is movably connected to the piston cylinder guide frame installed on the wheel hub.

[0017] Preferably, a rotary wheel cover is installed between the main shaft and the wheel hub, an operating frame is provided below the rotary wheel cover and fixedly connected to the piston rod, and a piston cylinder lower cover is covered at the lower opening position of the piston cavity.

[0018] Furthermore, an oil return pipeline is provided in the piston rod, one end of the oil return pipeline is opened on the side of the piston rod, and the other end opens to the main shaft. The opening of the oil return pipeline on the piston rod is covered in the flexible expansion joint, and the flexible expansion joint isolates the oil return pipeline from the oil-free chamber.

[0019] The present invention has the following gain effects: Compared with the comparative technology, the sealing effect is increased by increasing the contact area of the contact part, but the problem of the traditional paddle wheel is that the contact part is a dynamic seal, and the hydraulic oil is still easy to leak from the seal to the oil-free chamber, thereby polluting the water body. The present invention fixes one end of the flexible expansion joint to the wheel hub and the other end to the piston rod. The flexible expansion joint itself will not generate contact friction when moving between the piston rod and the wheel hub, and the sealed part does not move relative to the components at the fixed installation. The installation position is a static seal and is more stable. It is only necessary to ensure that the sealing surface quality is good and the compression of the seal is sufficient to make it difficult for the hydraulic oil to leak from the flexible expansion joint to the oil-free chamber and pollute the water body.

[0020] The air pressure in the hub is connected to the atmosphere through the breathing channel and the breathing device, so that the pressure in the hub is lower than the water pressure at the blades, further preventing the contents in the oil-free cavity from leaking into the ambient water body, thus avoiding the pollution of the external water body caused by the leakage of hydraulic oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the sectional structure diagram of the adjustable blade of the water turbine of the present invention.

[0022] Figure 2 It is Figure 1 The partial enlarged view of part A in

[0023] Figure 3 This is the sectional structure diagram of the adjustable blade of the water turbine with another configuration of the present invention.

[0024] Figure 4 This is different from the present invention Figure 1 and Figure 3 The sectional structure diagram of the adjustable blade of the water turbine with the configuration.

[0025] In the figure, 1 - main shaft, 2 - operating oil pipe, 3 - piston cylinder head, 4 - piston rod, 5 - hub, 6 - piston, 7 - flexible expansion joint, 8 - operating frame, 9 - linkage mechanism, 10 - crank arm, 11 - blade seal, 12 - pivot shaft, 13 - blade, 14 - hub breathing device, 15 - piston cavity, 16 - oil - free cavity, 17 - breathing channel, 18 - oil return pipeline, 19 - piston rod guiding column, 20 - outer wall of oil - free cavity, 21 - chamber partition wall, 22 - outer wall of piston cavity, 23 - drainage cone, 24 - oil return channel, 25 - upper shell of piston cylinder, 26 - lower cover of piston cylinder, 27 - moving part of piston cylinder, 28 - empty section of main shaft, 29 - runner cover, 30 - guiding frame of piston cylinder. Detailed implementation mode

[0026] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0027] Embodiment 1: As Figure 1 and Figure 2 shown, the present invention discloses an oil isolation structure for the runner of an adjustable - blade water turbine, including a main shaft 1 and a hub 5. An operating oil pipe 2 is arranged inside the main shaft 1. A piston rod 4 extends into the hub 5 at the center of the main shaft 1. There are a piston cavity 15 and an oil - free cavity 16 in the hub 5. A breathing channel 17 is arranged in the main shaft 1 and the hub 5. A flexible expansion joint 7 is sleeved on the piston rod 4 and fixedly connected to the hub 5 and the piston rod 4.

[0028] The hub 5 has a hollow structure. The cross-sectional structure of the upper part of the hub 5 is in an M shape. The bottom of the hub 5 is spliced with the drain cone 23 to form a complete housing. The hub 5 and the main shaft 1 are spliced to form the structure of the piston chamber 15. The middle part of the hub 5 is the chamber partition wall 21. The edge part of the chamber partition wall 21 extends upward to be provided with the piston chamber outer wall 22. The upper end surface of the piston chamber outer wall 22 is fixedly installed and sealed with the lower end surface of the main shaft 1.

[0029] The main shaft 1 has a hollow shaft structure. The central hole of the main shaft 1 is filled with hydraulic oil. The hydraulic oil in the central hole of the main shaft 1 is separated from the hub 5 by the piston cylinder head 3. The piston cylinder head 3 is embedded and sealed on the main shaft 1. The piston cylinder head, the end surface of the main shaft 1, the piston chamber outer wall 22 and the chamber partition wall 21 of the hub 5, and the piston rod guiding column 19 together form the piston chamber 15.

[0030] The piston rod 4 is arranged in the piston chamber 15. The piston rod 4 extends into the hollow part of the main shaft 1, passes through the piston cylinder head 3, and penetrates through the piston guiding column 19 to extend into the oil-free chamber 16. The contact part of the piston rod 4 and the piston cylinder head 3 is a dynamic seal, and the contact part of the piston rod 4 and the piston guiding column 19 is also a dynamic seal. The end of the piston rod 4 in the oil-free chamber 16 is fixedly connected with the operating frame 8.

[0031] The breathing channels 17 are arranged in the shell walls of the hub 5 and the main shaft 1. One end of the breathing channel 17 is communicated with the oil-free chamber 16. The hub breathing device 14 is arranged on the main shaft 1. The other end of the breathing channel 17 is communicated with the hub breathing device 14. The breathing channel 17 in the hub 5 is located in the piston chamber outer wall 22. The breathing channel 17 in the main shaft 1 is communicated with the breathing channel 17 in the piston chamber outer wall 22. The outlet of the breathing channel 17 in the main shaft 1 is connected with the hub breathing device 14. The ventilation opening of the hub breathing device 14 faces downward, ensuring that only the air pressure in the oil-free chamber 16 is the same as the outside world, and at the same time preventing foreign objects from entering through the hub breathing device 14 and blocking the breathing channel 17.

[0032] The piston chamber 15 is formed at the connection position of the hub 5 and the main shaft 1. The piston cylinder head 3 is installed at the opening position in the center of the main shaft 1. The piston rod 4 passes through the piston cylinder head 3 and is movably connected with the piston cylinder head 3 in a sealed manner. The piston 6 is fixedly installed on the piston rod 4. The piston 6 is located in the piston chamber 15. The piston 6 and the piston rod 4 are fixedly connected. The piston 6 drives the piston rod 4 to reciprocate in the piston chamber 15.

[0033] An operating oil pipe 2 is provided in the main shaft 1. The operating oil pipe 2 injects hydraulic oil into the piston rod 4. The hydraulic oil enters the piston chamber 15. The piston 6 is in sealed contact with the side wall of the piston chamber 15. The hydraulic oil can be injected from the operating oil pipe 2 and injected into the piston chamber 15 from below the piston 6 to lift the piston 6, thereby driving the piston rod 4 to move upward and also driving the operating frame 8 to move upward.

[0034] The piston chamber 15 is above the oil-free chamber 16. Compared with the formation method of the piston chamber 15, the oil-free chamber 16 is mainly formed by combining the oil-free chamber outer wall 20 of the hub 5, the chamber partition wall and the piston rod guide column 19 and the water discharge cone 23 to form a space that is hermetically isolated from the external water body. The piston rod guide column 19 extends into the oil-free chamber 16.

[0035] In the oil-free chamber 16, a flexible expansion joint 7 is provided between the piston rod 4 and the piston rod guide column 19. One end of the flexible expansion joint 7 is fixedly connected to the lower end surface of the piston rod guide column 19, and the other end of the flexible expansion joint 7 is fixedly connected to the piston rod 4 above the position where the operating frame 8 is installed on the piston rod 4. The flexible expansion joint 7 has good seals at the connection positions with the piston rod guide column 19 and the piston rod 4. The connection between the flexible expansion joint 7 and the piston rod guide column 19 remains relatively stationary with respect to the piston rod guide column 19, and the connection between the flexible expansion joint 7 and the piston rod 4 also remains relatively stationary with respect to the piston rod 4.

[0036] Therefore, the sealing method of the flexible expansion joint 7 between the piston rod guide column 19 and the piston rod 4 is a static seal. Compared with a dynamic seal, a static seal requires fewer factors to be considered and has fewer influencing factors, and the sealing life is longer and the seal is more reliable. Due to the presence of the flexible expansion joint 7, the hydraulic oil leaked from the piston chamber 15 will accumulate in the flexible expansion joint 7 and will not directly enter the oil-free chamber 16. And because the sealing method of the flexible expansion joint 7 is a static seal, the reliability of the seal is further improved, and the possibility of hydraulic oil leaking from the flexible expansion joint 7 into the oil-free chamber 16 is lower.

[0037] If the hydraulic oil only accumulates in the flexible expansion joint 7, it is easy to cause the pressure of the hydraulic oil in the flexible expansion joint 7 to increase, affecting the service life of the flexible expansion joint 7 and increasing the risk of hydraulic oil leakage. Therefore, a device for allowing the leaked hydraulic oil to flow back needs to be provided on the piston rod 4. At the same time, to allow the hydraulic oil to flow back, a certain pressure difference is required, that is, the pressure in the flexible expansion joint 7 should be greater than the pressure at the part where the hydraulic oil flows back.

[0038] In this embodiment, an oil return pipeline 18 is provided in the piston rod 4. The opening position of the oil return pipeline 18 in the piston rod 4 is located at the side position of the piston rod 4, and the opening position of the oil return pipeline 18 in the piston rod 4 is covered by the flexible expansion joint 7. Since the lower part of the piston 6 is the hydraulic oil injection position with high pressure, and the oil return pipeline 18 leads to the main shaft 1, the upper opening of the oil return pipeline 18 is located above the piston cylinder head 3 and leads to the oil return passage 24 in the main shaft 1.

[0039] The pressure in the oil return passage 24 of the main shaft 1 is relatively small. Therefore, under the action of the pressure difference, the hydraulic oil in the flexible expansion joint 7 will more easily enter the oil return passage 24 of the main shaft 1 from the oil return pipeline 18 and be collected and recycled. On the one hand, it avoids the risk of hydraulic oil leaking into the oil-free cavity 16 and polluting the environmental water body. On the other hand, it also reduces the waste of hydraulic oil, recycles the hydraulic oil, and saves costs.

[0040] The length of the flexible expansion joint 7 is telescopic. During the process of the piston rod 4 sliding up and down in the piston rod guiding column 19, the relative position and relative distance between the operating frame 8 and the piston rod guiding column 19 will change. Therefore, the flexible expansion joint 7 can effectively adapt to the change of the relative position between the piston rod guiding column 19 and the operating frame 8, and at the same time maintain the seal between the flexible expansion joint 7, the piston rod guiding column 19 and the piston rod 4 as a static seal. This ensures good sealing performance.

[0041] However, relying solely on the flexible expansion joint 7 for sealing also has the risk of seal failure. Therefore, in order to further enhance the sealing performance of the oil separation structure of the present invention, the role of the breathing passage 17 becomes more important. The breathing passage 17 connects the pressure in the oil-free cavity 16 with the atmospheric pressure, making the pressure in the oil-free cavity 16 less than the pressure outside the hub 5. In this way, even if hydraulic oil leaks into the oil-free cavity 16, because the pressure in the oil-free cavity 16 is less than the pressure outside the hub 5, only the outside water body may penetrate into the oil-free cavity 16, and the substances in the oil-free cavity 16 are not easily penetrated into the outside water body.

[0042] An operating frame 8 is fixedly installed at the end of the piston rod 4 in the oil-free cavity 16, and the operating frame 8 does not contact the hub 5. The operating frame 8 moves up and down in the hub 5 following the piston rod 4.

[0043] The outer wall 20 of the oil-free cavity of the hub 5 is provided with a plurality of openings for installing blades. The pivot 12 is installed at the opening position and at the contact section between the hub 5 and the piston rod 4, i.e., the opening position of the piston rod guide column 19. The end of the pivot 12 is installed with a blade 13 at the position of the oil-free cavity outer wall 20. A blade seal 11 is also installed between the blade 13 and the oil-free cavity outer wall 20 to prevent the contents of the hub from leaking into the ambient water.

[0044] The pivot 12 is T-shaped and can be divided into a rod portion and a disk portion. The side end surface of the disk portion of the pivot 12 is rotatably matched with the opening of the outer wall 20 of the oil-free chamber, and the pivot 12 can rotate on the piston rod guide column 19. The rod portion of the pivot 12 is fixedly connected to a crank arm 10 in the oil-free chamber 16, and the operating frame 8 is fixedly installed with a connecting rod mechanism 9 hinged to the crank arm 10.

[0045] A blade seal 11 is provided between the matching position of the blade 13 and the opening of the hub 5 . The blade seal 11 is fixedly connected to the hub 5 and is in sealing contact with the blade 13 . The blade 13 rotates with the pivot 12 .

[0046] A blade seal 11 is provided between the matching position of the blade 13 and the opening of the hub 5 . The blade seal 11 is fixedly connected to the hub 5 and is in sealing contact with the blade 13 . The blade 13 can rotate around the pivot 12 .

[0047] When the angle of the blade 13 needs to be adjusted, the operating oil pipe 2 injects high-pressure hydraulic oil into the lower side of the piston 6 of the piston chamber 15 to move the piston 6 upward. The upward movement of the piston 6 drives the piston rod 4 to move upward, thereby driving the operating frame 8 to move upward. Because the connecting rod mechanism 9 is fixedly installed with the operating frame 8 and the connecting rod mechanism 9 is incompressible, the connecting rod mechanism will drag the pivot 12 to rotate, thereby driving the rotation of the blade 13 to achieve the angle adjustment of the blade 13. When the piston 6 of the piston chamber 15 is pressed, the piston rod 4 is pressed upward, thereby driving the operating frame 8 to move upward. When high-pressure hydraulic oil is injected into the upper side, the piston 6 moves downward, and the blades 13 also rotate in the opposite direction accordingly.

[0048] When the piston 6 moves upward, the inner cavity volume of the flexible expansion joint 7 decreases, and the hydraulic oil therein enters the oil return channel 24 of the main shaft 1 through the oil return pipeline 18. When the piston 6 moves downward, the hydraulic oil in the oil return pipeline 18 flows from the oil return channel 24 of the main shaft 1 to the inner cavity of the flexible expansion joint 7. Thus, the pressure in the flexible expansion joint 7 is kept stable.

[0049] When the piston 6 moves upward, it drives the piston rod 4 to move upward, and the internal cavity volume of the oil-free chamber 16 of the runner increases. Under the action of atmospheric pressure, air is inhaled into the oil-free chamber 16 of the runner through the breathing channel 17 by the hub breathing device 14. When the piston 6 moves downward, it drives the piston rod 4 to move downward, and the internal cavity volume of the oil-free chamber 16 of the runner decreases. The oil-free chamber 16 of the runner exhales air through the breathing channel 17 by the hub breathing device 14. The oil-free chamber 16 of the runner maintains its pressure stability through the above breathing function.

[0050] Embodiment 2: The structure of this embodiment is different from that of Embodiment 1 in the middle piston structure and its working mode.

[0051] As Figure 3 As shown, the present invention discloses an oil isolation structure for a runner of a Kaplan turbine, including a main shaft 1 and a hub 5. An operating oil pipe 2 is provided inside the main shaft 1. A piston rod 4 extends into the hub 5 at the center of the main shaft 1. There is a piston chamber 15 and an oil-free chamber 16 in the hub 5. A breathing channel 17 is provided in the main shaft 1 and the hub 5. A flexible expansion joint 7 is sleeved on the piston rod 4 and fixedly connected to the hub 5.

[0052] The hub 5 is a hollow structure. The hub 5 is fixedly connected to the piston rod 4, and no relative movement occurs between the hub 5 and the piston rod 4. The piston rod 4 is hinged to the blade assembly.

[0053] The main shaft 1 is a hollow shaft structure. The central hole of the main shaft 1 is filled with hydraulic oil. The hydraulic oil in the central hole of the main shaft 1 enters the piston rod 4 through the hub 5 and then enters the piston chamber 15. Different from Embodiment 1, in this embodiment, the piston chamber 15 is located below the oil-free chamber 16. In this embodiment, the piston rod 4 does not move, but the piston chamber 15 moves up and down relative to the piston rod 4.

[0054] The piston rod 4 is below the hub 5. The piston rod 4 is fixedly connected to the hub 5. A piston cylinder upper shell 25 is sleeved at the end of the piston rod 4. A piston 6 is installed on the piston rod 4 inside the piston cylinder upper shell 25. A piston cylinder lower cover 26 is hermetically installed below the piston cylinder upper shell 25. A piston cylinder moving part 27 is installed below the piston cylinder lower cover 26. The piston cylinder moving part 27 is movably connected to a piston cylinder guide frame 30 installed on the hub 5. One end of the link mechanism 9 is hinged to the piston cylinder upper shell 25.

[0055] The other end of the link mechanism 9 is hinged to an elbow arm 10 in the blade assembly.

[0056] A breathing channel 17 is provided in the housing walls of the hub 5 and the main shaft 1. One end of the breathing channel 17 communicates with the oil-free chamber 16, and a hub breathing device 14 is provided on the main shaft 2. The other end of the breathing channel 17 communicates with the hub breathing device 14. The breathing channel 17 in the hub 5 and the breathing channel 17 in the main shaft 1 are in communication. The outlet of the breathing channel 17 in the main shaft 1 is connected to the hub breathing device 14. The exhaust opening at the hub breathing device 14 faces downward, ensuring that only the air pressure in the oil-free chamber 16 is the same as that of the outside world, and at the same time preventing foreign objects from entering through the hub breathing device 14 and blocking the breathing channel 17.

[0057] Inside the hub 5, except for the piston chamber 15 surrounded by the piston cylinder upper shell 25, the piston cylinder lower cover 26, and the piston cylinder moving part 27, the other space inside the hub 5 is the oil-free chamber 17.

[0058] An operating oil pipe 2 is provided in the main shaft 1. The operating oil pipe 2 injects hydraulic oil into the piston rod 4. The hydraulic oil enters the piston chamber 15. The piston 6 is in sealed contact with the side wall of the piston chamber 15. The hydraulic oil can be injected from the operating oil pipe 2 and injected into the piston chamber 15 from above the piston 6, jacking up the piston chamber 15 surrounded by the piston cylinder upper shell 25, the piston cylinder lower cover 26, and the piston cylinder moving part 27 and sliding in the direction defined by the piston cylinder guide frame 30.

[0059] In the oil-free chamber 16, a flexible expansion joint 7 is provided between the piston rod 4 and the piston cylinder upper shell 25. One end of the flexible expansion joint 7 is fixedly connected to the upper end face of the piston cylinder upper shell 25, and the other end of the flexible expansion joint 7 is fixedly connected to the end face at the stepped position of the piston rod 4. The flexible expansion joint 7 has good seals at its connection positions with the piston cylinder upper shell 25 and the piston rod 4. Because the connection between the flexible expansion joint 7 and the piston cylinder upper shell 25 remains relatively stationary with respect to the piston cylinder upper shell 25, and the connection between the flexible expansion joint 7 and the piston rod 4 also remains relatively stationary with respect to the piston rod 4.

[0060] Therefore, the sealing method of the flexible expansion joint 7 between the piston cylinder upper shell 25 and the piston rod 4 is static sealing. Compared with dynamic sealing, static sealing requires fewer factors to be considered, has fewer influencing factors, has a longer sealing life, and is more reliable. Due to the existence of the flexible expansion joint 7, the hydraulic oil leaked from the piston chamber 15 will accumulate in the flexible expansion joint 7 and will not directly enter the oil-free chamber 16. And because the sealing method of the flexible expansion joint 7 is static sealing, the reliability of the sealing is further improved, and the possibility of hydraulic oil leaking from the flexible expansion joint 7 into the oil-free chamber 16 is lower.

[0061] If the hydraulic oil only accumulates in the flexible expansion joint 7, it is easy to cause the flexible expansion joint 7 to be filled with hydraulic oil, which affects the service life of the flexible expansion joint 7 and increases the risk of hydraulic oil leakage. Therefore, a device for allowing the leaked hydraulic oil to flow back needs to be provided on the piston rod 4. At the same time, to allow the hydraulic oil to flow back, a certain pressure difference is required, that is, the pressure inside the flexible expansion joint 7 should be greater than the pressure at the part where the oil flows back.

[0062] In this embodiment, an oil return pipeline 18 is provided in the piston rod 4. The opening position of the oil return pipeline 18 on the piston rod 4 is located at the side position of the piston rod 4, and the opening position of the oil return pipeline 18 on the piston rod 4 is covered by the flexible expansion joint 7. Since the upper part of the piston 6 is the hydraulic oil injection position and the pressure is high, and the oil return pipeline 18 leads to the main shaft 1, the upper opening of the oil return pipeline 18 is located at the top end of the piston rod 4 and leads to the oil return channel 24 in the main shaft 1.

[0063] The pressure in the oil return channel 24 of the main shaft 1 is relatively small. Therefore, under the action of the pressure difference, the hydraulic oil in the flexible expansion joint 7 will more easily enter the oil return channel 24 of the main shaft 1 through the oil return pipeline 18 and be collected and recycled. On the one hand, it avoids the risk of hydraulic oil leaking into the oil-free chamber 16 and polluting the environmental water body. On the other hand, it also reduces the waste of hydraulic oil, recycles the hydraulic oil, and saves costs.

[0064] The length of the flexible expansion joint 7 is telescopic. During the process of the piston chamber 15 sliding up and down, the relative position and relative distance between the piston cylinder guide frame 30 and the piston cylinder upper shell 25 will change. Therefore, the flexible expansion joint 7 can effectively adapt to the change in the relative position between the piston cylinder upper shell 25 and the piston cylinder guide frame 30, and at the same time maintain the static sealing between the flexible expansion joint 7 and the piston cylinder upper shell 25 and the piston rod 4. Ensure good sealing performance.

[0065] However, relying solely on the flexible expansion joint 7 for sealing also poses a risk of sealing failure. Therefore, in order to further enhance the sealing performance of the oil separation structure of the present invention, the function of the breathing passage 17 becomes even more important. The breathing passage 17 connects the pressure inside the oil-free chamber 16 to the atmospheric pressure, making the pressure in the oil-free chamber 16 less than the pressure outside the hub 5. In this way, even if hydraulic oil leaks into the oil-free chamber 16, since the pressure in the oil-free chamber 16 is less than the pressure outside the hub 5, only the external water body will penetrate into the oil-free chamber 16, and the substances in the oil-free chamber 16 are not likely to penetrate into the external water body.

[0066] The end of the piston rod 4 is sleeved with the piston cylinder upper shell 25 in the oil-free chamber 16, and the piston cylinder upper shell 25 does not contact the hub 5. The piston cylinder upper shell 25 moves up and down within the hub 5.

[0067] Several openings for installing impellers are provided on the side wall of the hub 5. At the opening positions, an elbow arm 10 is installed on the piston rod 4, and a blade 13 is installed on the elbow arm 10. The blade 13 is installed at the opening position of the hub 5. The blade 13 is also sealed with the outer wall 20 of the oil-free chamber to prevent hydraulic oil from leaking into the environmental water body.

[0068] The elbow arm 10 is hinged to the link mechanism 9.

[0069] When it is necessary to adjust the angle of the blade 13, the operating oil pipe 2 injects high-pressure hydraulic oil into the upper side of the piston 6 in the piston chamber 15, causing the piston chamber 15 to move upward. The upward movement of the piston cylinder upper shell 25 drives the link mechanism 9. Since the link mechanism 9 is incompressible, the link mechanism will drag the elbow arm 10 to rotate, thereby driving the rotation of the blade 13 to achieve the adjustment of the angle of the blade 13.

[0070] When the piston cylinder upper shell 25 moves upward, the internal cavity volume of the flexible expansion joint 7 decreases, and the hydraulic oil therein enters the oil return passage 24 of the main shaft 1 through the oil return pipeline 18. When the piston cylinder upper shell 25 moves downward, the hydraulic oil in the oil return pipeline 18 flows from the oil return passage 24 of the main shaft 1 to the internal cavity of the flexible expansion joint 7. Thus, the pressure inside the flexible expansion joint 7 is kept stable.

[0071] When the upper housing 25 of the piston cylinder moves upward, the internal cavity volume of the oil-free cavity 16 of the runner increases. Under the action of atmospheric pressure, air is inhaled into the oil-free cavity 16 of the runner through the breathing channel 17 by the hub breathing device 14. When the upper housing 25 of the piston cylinder moves downward, the internal cavity volume of the oil-free cavity 16 of the runner decreases, and the oil-free cavity 16 of the runner exhales air through the breathing channel 17 by the hub breathing device 14. The oil-free cavity 16 of the runner maintains its pressure stability through the above breathing function.

[0072] Embodiment 3: The structure of this embodiment is different from that of Embodiment 1 in the middle piston structure and its working mode.

[0073] As Figure 4 shown, the present invention discloses an oil isolation structure for a runner of a Kaplan turbine, including a main shaft 1 and a hub 5. An operating oil pipe 2 is provided inside the main shaft 1. A piston rod 4 extends into the hub 5 at the center of the main shaft 1. There are a piston cavity 15 and an oil-free cavity 16 in the hub 5. A runner cover 29 is provided in the main shaft 1 and the hub 5. A breathing channel 17 is provided between the main shaft 1 and the runner cover 29. A flexible expansion joint 7 is sleeved on the piston rod 4 and fixedly connected to the hub 5 and the piston rod 4.

[0074] Compared with Embodiment 1, the distribution structure of the oil-free cavity 16 and the piston cavity 15 in the middle of Embodiment 3 is opposite to that of Embodiment 1. Therefore, the structure of this embodiment can be understood as the reverse structure of Embodiment 1. The difference is that the breathing channel 17 of this embodiment is provided on the runner cover 29, and a main shaft empty section 28 is provided in the main shaft 1. The breathing channel 17 on the runner cover 29 communicates with the main shaft empty section 28. The breathing channel 17 on the main shaft 1 also communicates with the main shaft empty section 28.

[0075] When the angle of the blade 13 needs to be adjusted, the operating oil pipe 2 injects high-pressure hydraulic oil to the upper side of the piston 6 in the piston cavity 15, causing the piston 6 to move downward. The downward movement of the piston 6 drives the piston rod 4 to move downward, thereby driving the operating frame 8 to move downward. Since the linkage mechanism 9 is fixedly installed with the operating frame 8 and the linkage mechanism 9 is incompressible, the linkage mechanism will drag the pivot 12 to rotate, thereby driving the rotation of the blade 13 to realize the angle adjustment of the blade 13. When high-pressure hydraulic oil is injected to the lower side of the piston 6 in the piston cavity 15, the piston 6 moves upward, and the blade 13 also rotates in the opposite direction accordingly.

[0076] When the piston 6 moves upward, the internal cavity volume of the flexible expansion joint 7 increases, and the hydraulic oil therein is supplemented into the flexible expansion joint 7 through the oil return passage 24 of the operating oil pipe by the oil return pipeline 18. When the piston 6 moves downward, the hydraulic oil in the oil return pipeline 18 flows from the internal cavity of the flexible expansion joint 7 to the oil return passage 24 of the operating oil pipe. Thus, the pressure inside the flexible expansion joint 7 is kept stable.

[0077] When the piston 6 moves upward, it drives the piston rod 4 to move upward, and the internal cavity volume of the oil-free cavity 16 of the runner decreases. The oil-free cavity 16 of the runner exhales air through the breathing passage 17 by the hub breathing device 14. When the piston 6 moves downward, it drives the piston rod 4 to move downward, and the internal cavity volume of the oil-free cavity 16 of the runner increases. The oil-free cavity 16 of the runner inhales air through the breathing passage 17 by the hub breathing device 14. The oil-free cavity 16 of the runner maintains its pressure stability through the above breathing function.

Claims

1. A runner oil isolation structure of a Kaplan turbine, characterized in that, It includes a main shaft (1) and a hub (5). An operating oil pipe (2) is provided inside the main shaft (1). A piston rod (4) extends into the hub (5) at the center of the main shaft (1). There is a piston chamber (15) and an oil-free chamber (16) in the hub (5). A breathing channel (17) is provided in the main shaft (1) and the hub (5). A flexible expansion joint (7) is sleeved on the piston rod (4) and fixedly connected to the hub (5) and the piston rod (4).

2. The oil isolation structure of a Kaplan turbine runner according to claim 1, characterized in that A breathing channel (17) is provided in the shell walls of the hub (5) and the main shaft (1). One end of the breathing channel (17) communicates with the oil-free chamber (16). A hub breathing device (14) is provided on the main shaft (2). The other end of the breathing channel (17) communicates with the hub breathing device (14).

3. A runner oil isolation structure of a Kaplan turbine according to claim 1, characterized in that, A piston chamber (15) is formed at the connection position between the hub (5) and the main shaft (1). A piston cylinder head (3) is installed at the opening position at the center of the main shaft (1). The piston rod (4) passes through the piston cylinder head (3) and is in sealed movable connection with the piston cylinder head (3). A piston (6) is fixedly installed on the piston rod (4). The piston (6) is located in the piston chamber (15). The piston chamber (15) is above the oil-free chamber (16).

4. A runner oil isolation structure of a Kaplan turbine according to claim 1 or 2 or 3, characterized in that One end of the flexible expansion joint (7) is fixedly connected to the hub (5) near the oil-free chamber (16). The other end of the flexible expansion joint (7) is fixedly connected to the piston rod (4). The middle part of the flexible expansion joint (7) is sleeved outside the piston rod (4) and does not contact the piston rod (4).

5. A runner oil isolation structure of a Kaplan turbine according to claim 1 or 2 or 3, characterized in that, An operating frame (8) is fixedly installed at the end of the piston rod (4) in the oil-free chamber (16). The operating frame (8) does not contact the hub (5).

6. A runner oil isolation structure of a Kaplan turbine according to claim 1 or 2 or 3, characterized in that There is an opening at the outer wall of the hub (5). The outer end of the pivot shaft (12) is accommodated at the opening position. The inner end of the pivot shaft (12) is accommodated at the contact section between the hub (5) and the piston rod (4). A blade (13) is installed at one end of the pivot shaft (12) near the opening position. A crank arm (10) is provided on the pivot shaft (12) in the oil-free chamber (16). A linkage mechanism (9) is provided on the operating frame (8) and is hinged to the crank arm (10).

7. A runner oil isolation structure of a Kaplan turbine according to claim 6, characterized in that, A blade seal (11) is provided between the blade (13) and the opening of the hub (5). The blade seal (11) is fixedly connected to the hub (5) and is in sealed contact with the blade (13). The blade (13) rotates with the pivot shaft (12).

8. A runner oil isolation structure of a Kaplan turbine according to claim 1, characterized in that, The piston rod (4) is fixedly connected to the hub (5). A piston cylinder upper shell (25) is sleeved at the end of the piston rod (4). A piston (6) is installed on the piston rod (4) inside the piston cylinder upper shell (25). A piston cylinder lower cover (26) is hermetically installed below the piston cylinder upper shell (25). A piston cylinder moving part (27) is installed below the piston cylinder lower cover (26). The piston cylinder moving part (27) is movably connected to a piston cylinder guide frame (30) installed on the hub (5).

9. A runner oil isolation structure of a Kaplan turbine according to claim 1, characterized in that, A runner cover (29) is installed between the main shaft (1) and the hub (5). An operation frame (8) is provided below the runner cover (29) and fixedly connected to the piston rod (4). A piston cylinder lower cover (26) covers the lower opening position of the piston chamber (15).

10. A runner oil isolation structure of a Kaplan turbine according to claim 1 or 2 or 3 or 7 or 8 or 9, characterized in that, An oil return pipeline (18) is provided in the piston rod (4). One end of the oil return pipeline (18) opens on the side surface of the piston rod (4), and the other end opens towards the main shaft (1). The opening of the oil return pipeline (18) on the piston rod (4) is covered in the flexible expansion joint (7), and the flexible expansion joint (7) isolates the oil return pipeline (18) from the oil-free chamber (16).

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