Axial flow water turbine water guide mechanism and using method

Abstract

The invention discloses an axial flow water turbine water guide mechanism and a using method, the axial flow water turbine water guide mechanism comprises an upper ring seat (1) and a lower ring seat (2), a plurality of guide vanes (3) are arranged between the upper ring seat (1) and the lower ring seat (2), rotating shafts (4) are arranged in the middles of the upper end and the lower end of each guide vane (3), a driving ring (5) is rotatably connected to the upper ring seat (1), and servomotors (6) are connected to the two sides of the driving ring (5). The upper ends of the rotating shafts (4) are connected with the driving ring (5) through a first connecting rod (7) and a second connecting rod (8), and a linkage mechanism connected with the lower ends of all the rotating shafts (4) is arranged at the bottom of the lower ring seat (2); the linkage mechanism comprises a plurality of adapter plates (9), the adapter plates (9) are fixed to the lower ends of the rotating shafts (4) respectively, third connecting rods (10) are arranged between the adjacent adapter plates (9), and the third connecting rods (10) are hinged to the adapter plates (9). The method has the advantage of being low in maintenance frequency.

Description

Technical Field

[0001] The present invention designs a wicket gate mechanism of an axial flow turbine and a usage method thereof. Background Art

[0002] An axial flow turbine has a spiral case. The diameter of the spiral case gradually decreases from the water inlet end to the water outlet end. Water flows in a circular motion in the spiral case. A wicket gate mechanism is provided on the inner side of the spiral case. In addition to flowing circularly in the spiral case, the water in the spiral case also flows radially inward through the wicket gate mechanism and then drives the water wheel to rotate. The water wheel drives the generator set to generate electricity.

[0003] The structure of the existing wicket gate mechanism includes an upper ring seat and a lower ring seat. A plurality of guide vanes evenly distributed circumferentially are provided between the upper and lower ring seats. Shafts are provided in the middle of the upper and lower ends of the guide vanes respectively. The upper and lower side shafts are rotatably connected to the upper and lower ring seats respectively. A driving ring is rotatably connected to the upper ring seat. Servomotors are provided on both sides of the driving ring. One end of the servomotor is hinged to the driving ring, and the other end of the servomotor is hinged to the installation position of the turbine. The driving ring is connected to the shaft at the upper end of the guide vane through a first connecting rod and a second connecting rod in sequence. When the servomotor expands and contracts, it pushes the driving ring to rotate. The driving ring drives the shaft to rotate through the first connecting rod and the second connecting rod, and further rotates the guide vane. By changing the rotation angle of the guide vane, the water inlet angle and flow rate of the water flow are changed. When all the guide vanes are connected end to end to form a ring, the water flow is cut off.

[0004] In the process of practice, it is found that the most prone problems of the existing wicket gate mechanism include the following:

[0005] First, the guide vane is under the huge impact of water flow for a long time, generating torsion on the shaft. The upper shaft is supported by the servomotor and is a fixed end, while the lower shaft has no external support and is a free end. As a result, the upper end of the guide vane is also a relatively fixed end, and the lower end of the guide vane is a relatively free end. Under the action of water flow impact, the guide vane twists around the axis of the shaft, forming a certain spiral angle. Due to the differences in the water flow impact conditions between the guide vanes, the torsion degrees of the guide vanes are inconsistent, making the sizes of the water flow channels between the guide vanes inconsistent, destroying the original carefully designed dynamic balance state, starting to vibrate and increasing the failure rate. And in the state where the wicket gate mechanism is closed, the adjacent guide vanes no longer fit tightly, and the water flow cutoff effect becomes poor.

[0006] Second, rich bubbles are generated during the rapid flow of water. These bubbles act on the root of the shaft at the root of the shaft, easily causing cavitation and strength reduction at the root of the shaft, increasing the maintenance frequency of the wicket gate mechanism.

[0007] Thirdly, the opening angle of the guide vane is determined by the extension length of the servomotor. After the guide vane adjusts to the required angle, the self-locking mechanism inside the servomotor acts to fix the extension length of the servomotor, keeping the guide vane at a fixed angle. The impact force of the water flow on the guide vane is transmitted to the servomotor, keeping the servomotor in a vibration condition for a long time. Since the servomotor is hydraulically driven, the wear rate of the internal sealing elements increases significantly under the vibration condition, making the servomotor prone to faults such as oil leakage, which also increases the maintenance frequency of the wicket gate mechanism. Summary of the Invention

[0008] The purpose of the present invention is to provide a wicket gate mechanism for an axial flow water turbine and a usage method. The present invention has the advantage of a relatively low maintenance frequency.

[0009] The technical solution of the present invention: A wicket gate mechanism for an axial flow water turbine includes an upper ring seat and a lower ring seat. A plurality of guide vanes are arranged between the upper ring seat and the lower ring seat. Shafts are arranged in the middle of the upper and lower ends of the guide vanes. A driving ring is rotatably connected to the upper ring seat. Servomotors are connected to both sides of the driving ring. The upper end of the shaft is connected to the driving ring through a first connecting rod and a second connecting rod. A linkage mechanism is arranged at the bottom of the lower ring seat, and all the shafts at the lower ends of the guide vanes are connected to the linkage mechanism.

[0010] In the aforementioned wicket gate mechanism for an axial flow water turbine, the linkage mechanism includes a plurality of adapter plates. The plurality of adapter plates are respectively fixed to the lower ends of the plurality of shafts. A third connecting rod is arranged between adjacent adapter plates, and the third connecting rod is hinged to the adapter plate.

[0011] In the aforementioned wicket gate mechanism for an axial flow water turbine, a flange edge extends radially outward from the root of the shaft, and the top surface of the flange edge is flush with the end surface of the guide vane.

[0012] In the aforementioned wicket gate mechanism for an axial flow water turbine, an annular groove coaxial with the shaft is arranged on the top surface of the flange edge.

[0013] In the aforementioned wicket gate mechanism for an axial flow water turbine, an exhaust hole is arranged on the bottom surface of the annular groove, and the lower end of the exhaust hole is located on the bottom surface of the flange edge.

[0014] In the aforementioned wicket gate mechanism for an axial flow water turbine, the flange edge is a square structure when viewed from above, and the bottom of the flange edge is a circular arc surface. The axis of the circular arc surface is perpendicular to the guide vane; there are two exhaust holes, and the two exhaust holes are respectively located on both sides of the shaft. The lower ends of the exhaust holes are located on the middle bisecting plane of the circular arc surface.

[0015] In the foregoing wicket gate mechanism of the axial flow turbine, an inner tube is formed by the upward extension of the inner edge of the upper ring seat. A driving ring is sleeved on the inner tube. The upper end of the driving ring extends radially outward to form an upper flange. The servomotor is hinged to the upper flange. The lower end of the driving ring extends radially outward to form a lower flange. A first connecting rod and a second connecting rod are arranged between the lower flange and the rotating shaft at the upper end of the guide vane. One end of the first connecting rod is hinged to the lower flange, the other end of the first connecting rod is hinged to the second connecting rod, and the second connecting rod is fixed to the rotating shaft.

[0016] In the foregoing wicket gate mechanism of the axial flow turbine, a friction ring is arranged on the upper side of the upper flange. A plurality of guide ears are arranged on the outer side of the friction ring. Guide holes are arranged on the guide ears, and guide columns fixed to the upper ring seat are arranged in the guide holes. A plurality of electromagnets are arranged at the bottom of the upper flange.

[0017] For the using method of the foregoing wicket gate mechanism of the axial flow turbine, when the servomotor drives the guide vane to rotate, the electromagnet remains open. When the guide vane stops rotating, the electromagnet remains closed.

[0018] Compared with the prior art, the following main improvements are made to the present invention on the basis of the existing wicket gate mechanism:

[0019] First, a linkage mechanism is arranged at the bottom of the lower ring seat. The linkage mechanism is connected to the lower ends of the guide vanes through corresponding rotating shafts, so that the lower ends of all the guide vanes form a linkage. When any one of the lower ends of the guide vanes twists, the lower ends of the remaining guide vanes are driven to twist accordingly. After the wicket gate mechanism is used for a long time, the twisting degrees of all the guide vanes tend to be consistent, the difference is reduced, so that the sizes of the water flow channels between the guide vanes are kept more consistent, the damage to the original dynamic balance state is small, the vibration is reduced and the failure rate is reduced, and the maintenance frequency is reduced. And when the wicket gate mechanism is in the closed state, the guide vanes can also fit closely to maintain a good water flow cutoff effect.

[0020] Second, a flange edge is arranged at the root of the rotating shaft, which prolongs the path length of the bubbles passing through the gap between the guide vane and the ring seat to reach the root of the rotating shaft, reduces the cavitation of the rotating shaft, makes the strength of the rotating shaft not easy to decline, and reduces the maintenance frequency. By arranging an annular groove on the flange edge, the bubbles are enriched in the annular groove. By arranging exhaust holes on the bottom surface of the annular groove, the bubbles in the annular groove are discharged through the exhaust holes. The bottom of the flange edge is an arc surface, which further increases the exhaust effect and further reduces the possibility of the bubbles contacting the root of the rotating shaft, further reducing the cavitation of the rotating shaft.

[0021] Third, a friction ring is arranged above the driving ring, and an electromagnet is arranged on the driving ring. When the guide vane does not need to adjust the angle, the friction ring is attracted by the magnetic force of the electromagnet, and a connection is established between the friction ring and the driving ring to keep the driving ring stationary. The impact force of the water flow on the guide vane is not easily transmitted to the servomotor, which alleviates the vibration condition of the servomotor, makes the servomotor not easy to fail, and reduces the maintenance frequency of the wicket gate mechanism.

[0022] In summary, the present invention has the advantage of a relatively low maintenance frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a top perspective view of the present invention.

[0024] Figure 2 is a bottom perspective view of the present invention.

[0025] Figure 3 is a schematic structural diagram of the drive ring.

[0026] Figure 4 is a top view schematic diagram of the guide vane.

[0027] Figure 5 is a front view schematic diagram of the guide vane.

[0028] Figure 6 is a schematic diagram of water flow when passing through the flange edge.

[0029] The reference signs in the drawings are: 1 - upper ring seat, 2 - lower ring seat, 3 - guide vane, 4 - rotating shaft, 5 - drive ring, 6 - servomotor, 7 - first connecting rod, 8 - second connecting rod, 9 - adapter plate, 10 - third connecting rod, 11 - flange edge, 12 - annular groove, 13 - exhaust hole, 14 - arc surface, 15 - inner pipe, 16 - upper flange, 17 - lower flange, 18 - friction ring, 19 - guide ear, 20 - guide post, 21 - electromagnet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention will be further described below with reference to the drawings and embodiments, but this is not intended to limit the present invention.

[0031] Embodiment: A wicket gate mechanism of an axial flow turbine, as Figure 1 shown, includes an upper ring seat 1 and a lower ring seat 2. A plurality of guide vanes 3 are provided between the upper ring seat 1 and the lower ring seat 2. Minute gaps (0.1 - 0.2 mm) are formed between the guide vanes 3 and the upper ring seat 1 and between the guide vanes 3 and the lower ring seat 2. Rotating shafts 4 are provided in the middle of the upper and lower ends of the guide vanes 3. The rotating shaft 4 at the upper end of the guide vane 3 passes through the upper ring seat 1, and the rotating shaft 4 at the lower end of the guide vane 3 passes through the lower ring seat 2. A drive ring 5 is rotatably connected to the upper ring seat 1. Servomotors 6 are connected to both sides of the drive ring 5. The upper end of the rotating shaft 4 is connected to the drive ring 5. The features are as follows:

[0032] A linkage mechanism is provided at the bottom of the lower ring seat 2. The linkage mechanism includes a plurality of triangular adapter plates 9. The plurality of adapter plates 9 are respectively fixed to the lower ends of the rotating shafts 4 located at the bottoms of the corresponding guide vanes 3. A third connecting rod 10 is provided between adjacent adapter plates 9. The third connecting rod 10 is hinged to the adapter plate 9.

[0033] A flange edge 11 extends radially outward from the root of the rotating shaft 4, and the top surface of the flange edge 11 is flush with the end surface of the guide vane 3. An annular groove 12 coaxial with the rotating shaft 4 is provided on the top surface of the flange edge 11. Two exhaust holes 13 are provided on the bottom surface of the annular groove 12, and the two exhaust holes 13 are respectively located on both sides of the guide vane 3 in the thickness direction. The flange edge 11 is a square structure when viewed from above looking up, and the bottom of the flange edge 11 is an arc surface 14, and the axis of the arc surface 14 is perpendicular to the guide vane 3; the lower end of the exhaust hole 13 is located on the middle bisecting plane of the arc surface 14.

[0034] An inner tube 15 extends upward from the inner edge of the upper ring seat 1. The driving ring 5 is sleeved on the inner tube 15. An upper flange 16 extends radially outward from the upper end of the driving ring 5. The servomotor 6 is hinged to the upper flange 16. A lower flange 17 extends radially outward from the lower end of the driving ring 5. A first connecting rod 7 and a second connecting rod 8 are provided between the lower flange 17 and the rotating shaft 4 at the upper end of the guide vane 3. One end of the first connecting rod 7 is hinged to the lower flange 17, the other end of the first connecting rod 7 is hinged to the second connecting rod 8, and the second connecting rod 8 is fixed to the rotating shaft 4.

[0035] A friction ring 18 is provided on the upper side of the upper flange 16. A plurality of guide ears 19 are provided on the outer side of the friction ring 18. Guide holes are provided on the guide ears 19, and guide posts 20 fixed to the upper ring seat 1 are provided in the guide holes; a plurality of electromagnets 21 are provided at the bottom of the upper flange 16

[0036] Usage method: The upper ring seat 1 and the lower ring seat 2 are fixed at the installation position of the water guide mechanism, and the servomotor is hinged at the installation position of the water guide mechanism.

[0037] When one servomotor 6 extends, the other servomotor 6 contracts, causing the driving ring 5 to rotate. The driving ring 5 drives the rotating shaft 4 to rotate through the first connecting rod 7 and the second connecting rod 8, and the guide vane 3 rotates accordingly, changing the magnitude and direction of the water flow. Since all the rotating shafts 4 are driven by the same driving ring 5, all the guide vanes 3 maintain synchronous movement.

[0038] When the servomotor 6 is working, the electromagnet 21 remains in an open circuit state, and the driving ring 5 can rotate freely. When the guide vane 3 is adjusted to an appropriate angle and the servomotor 6 stops working, the electromagnet 21 remains in a closed circuit state. The magnetic force of the electromagnet 21 attracts the friction ring 18, and the friction ring 18 presses the driving ring 5 against the upper ring seat 1. The driving ring 5 cannot rotate, and the impact force of the water flow acting on the guide vane 3 will not be transmitted to the servomotor. The servomotor is not prone to failure, reducing the maintenance frequency.

[0039] Since the root of the rotating shaft 4 has a flange edge 11, air bubbles in the water flow are not easily in contact with the root of the rotating shaft 4, reducing shaft cavitation, making the strength of the rotating shaft not easily decrease, and reducing the maintenance frequency.

[0040] By setting an annular groove 12 on the flange edge, air bubbles are enriched in the annular groove 12. By arranging exhaust holes on the bottom surface of the annular groove 12, the air bubbles in the annular groove 12 are discharged through the exhaust holes. Here, the Bernoulli principle is utilized. When water flows at high speed from the bottom of the flange edge 11, negative pressure is generated, and the water in the annular groove 12 will carry air bubbles through the exhaust holes. As Figure 6 shown, since the bottom of the flange edge 11 is an arc surface 14, the water flow passing through the guide vane is pressurized before reaching the exhaust hole, the flow velocity increases, and the suction force on the exhaust hole 13 increases.

Claims

1. Axial flow turbine guide vane mechanism, including an upper ring seat (1) and a lower ring seat (2), a plurality of guide vanes (3) are arranged between the upper ring seat (1) and the lower ring seat (2), the middle parts of the upper and lower ends of the guide vane (3) are respectively provided with a rotating shaft (4), a driving ring (5) is rotatably connected to the upper ring seat (1), a servomotor (6) is connected to both sides of the driving ring (5), the upper end of the rotating shaft (4) is connected to the driving ring (5) through a first connecting rod (7) and a second connecting rod (8), and it is characterized in that: A linkage mechanism is provided at the bottom of the lower ring base (2), and all the rotating shafts (4) located at the lower ends of the guide vanes (3) are connected to the linkage mechanism.

2. The guide vane mechanism of the axial flow water turbine according to claim 1, characterized in that: The linkage mechanism includes a plurality of adapter plates (9). The plurality of adapter plates (9) are respectively fixed to the lower ends of the plurality of rotating shafts (4). A third connecting rod (10) is provided between adjacent adapter plates (9), and the third connecting rod (10) is hinged to the adapter plate (9).

3. The guide vane mechanism of the axial flow water turbine according to claim 1, characterized in that: A flange edge (11) extends radially outward from the root of the rotating shaft (4), and the top surface of the flange edge (11) is flush with the end surface of the guide vane (3).

4. The guide vane mechanism of the axial flow water turbine according to claim 3, characterized in that: An annular groove (12) coaxial with the rotating shaft (4) is provided on the top surface of the flange edge (11).

5. The wicket gate mechanism of the axial flow water turbine according to claim 4, characterized in that: An exhaust hole (13) is provided on the bottom surface of the annular groove (12), and the lower end of the exhaust hole (13) is located on the bottom surface of the flange edge (11).

6. The guide vane mechanism of an axial flow water turbine according to claim 5, characterized in that: The flange edge (11) is a square structure when viewed from above, and the bottom of the flange edge (11) is an arc surface (14). The axis of the arc surface (14) is perpendicular to the guide vane (3); there are two exhaust holes (13), and the two exhaust holes (13) are respectively located on both sides of the rotating shaft (4). The lower ends of the exhaust holes (13) are located on the middle bisecting plane of the arc surface (14).

7. The wicket gate mechanism of the axial flow water turbine according to claim 1, characterized in that: The inner edge of the upper ring base (1) extends upward to form an inner tube (15). The driving ring (5) is sleeved on the inner tube (15). The upper end of the driving ring (5) extends radially outward to form an upper flange (16). The servomotor (6) is hinged to the upper flange (16). The lower end of the driving ring (5) extends radially outward to form a lower flange (17). A first connecting rod (7) and a second connecting rod (8) are provided between the lower flange (17) and the rotating shaft (4) at the upper end of the guide vane (3). One end of the first connecting rod (7) is hinged to the lower flange (17), the other end of the first connecting rod (7) is hinged to the second connecting rod (8), and the second connecting rod (8) is fixed to the rotating shaft (4).

8. The wicket gate mechanism of the axial flow turbine according to claim 7, characterized in that: A friction ring (18) is provided on the upper side of the upper flange (16). A plurality of guide ears (19) are provided on the outer side of the friction ring (18). A guide hole is provided on the guide ear (19), and a guide post (20) fixed to the upper ring base (1) is provided in the guide hole; a plurality of electromagnets (21) are provided at the bottom of the upper flange (16).

9. The method for using the guide vane mechanism of an axial flow water turbine according to claim 8, characterized in that: When the servomotor (6) drives the guide vane (3) to rotate, the electromagnet (21) remains open; when the guide vane (3) stops rotating, the electromagnet (21) remains closed.

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