CN111980850B

CN111980850B - Paddle operating mechanism for rotary-paddle type water turbine

Info

Publication number: CN111980850B
Application number: CN202010703447.0A
Authority: CN
Inventors: 杜芝鹏; 崔兴国; 杜金釜
Original assignee: Dongfang Electric Machinery Co Ltd DEC
Current assignee: Dongfang Electric Machinery Co Ltd DEC
Priority date: 2020-07-21
Filing date: 2020-07-21
Publication date: 2022-01-25
Anticipated expiration: 2040-07-21
Also published as: CN111980850A

Abstract

The invention discloses a paddle operating mechanism for a Kaplan turbine, wherein a rotating wheel of the turbine is provided with a rotating wheel body and a paddle connected with a rotating shaft; the runner hub is provided with a piston cavity in which a piston is arranged; two ends of the piston are respectively in threaded connection with the runner hub and the rotating shaft to form a primary thread pair and a secondary thread pair with different thread leads; the rotating shaft is axially limited and is rotatably connected with the rotating wheel body. The paddle operating mechanism for the rotary paddle type water turbine has the advantages of compact overall structure, safety, reliability, large output torque and stable transmission.

Description

Paddle operating mechanism for rotary-paddle type water turbine

Technical Field

The invention relates to the technical field of a Kaplan turbine, in particular to a paddle operating mechanism for the Kaplan turbine.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

The hydraulic turbine is a power machine for converting the energy of water flow into rotary mechanical energy, and belongs to the turbine machinery in fluid machinery. Modern water turbines are mostly installed in hydropower stations and are used for driving generators to generate electricity. In a hydropower station, water in an upstream reservoir is guided to a water turbine through a water guide pipe to push a water turbine runner to rotate so as to drive a generator to generate electricity; the water after doing work is discharged to the downstream through the tail water pipeline, the higher the water head is, the larger the flow rate is, and the larger the output power of the water turbine is.

The adjustable blade type water turbine is a main type of the water turbine generator set, when the adjustable blade type water turbine is in operation, blades of a rotating wheel can rotate and keep a certain linkage relation with rotation of a guide vane so as to adapt to changes of a water head and flow, and the water turbine can keep high efficiency under different working conditions. In order to realize the variable working angle of the blade, the inventor knows that one implementation mode is that a piston cylinder and a crank connecting rod mechanism are arranged in a water drainage cone below a runner, and a reciprocating piston drives the blade to rotate through a connecting rod. However, the inventor has recognized that such an operating mechanism has certain drawbacks, and such an operating mechanism is generally complex in structure, has a limited internal space of the face drain cone, is not easy to install and maintain, and is prone to problems such as movement interference.

In addition, the counter force of the connecting rod can drive the piston cylinder to rotate along the circumferential direction, and then the operating mechanism is blocked. One solution known to the inventors is: the piston cylinder does not rotate in the circumferential direction by arranging the limiting slide block, so that the blocking phenomenon can be effectively avoided; however, since the circumferential component force exists all the time, the limit sliding block is abraded after long-term operation, the limit effect is deteriorated or disappears, and then the blocking phenomenon is generated.

Disclosure of Invention

In order to solve the existing problems, the invention discloses a paddle operating mechanism for a Kaplan turbine, wherein a rotating wheel of the turbine is provided with a rotating wheel body and a paddle connected with a rotating shaft; the runner hub is provided with a piston cavity in which a piston is arranged; two ends of the piston are respectively in threaded connection with the runner hub and the rotating shaft to form a primary thread pair and a secondary thread pair with different thread leads; the rotating shaft is axially limited and is rotatably connected with the rotating wheel body.

Furthermore, both ends of the piston are respectively provided with a piston rod with threads and a threaded hole which are respectively used for forming a primary thread pair and a secondary thread pair with the runner hub and the rotating shaft.

Further, the runner body is provided with a blind hole type multi-step stepped hole with the hole diameter gradually increasing from inside to outside, and the blind hole type multi-step stepped hole comprises a primary hole used for forming a primary thread pair with the piston and a secondary hole used as a piston cavity or a part of the piston cavity.

Furthermore, the axis of rotation has both sides respectively by spacing baffle and the spacing shaft shoulder of cavity end cover axial, spacing baffle locates in the piston chamber, the cavity end cover is used for sealing the piston chamber, spacing baffle with the cavity end cover is established in the axis of rotation.

Furthermore, thrust bearings are respectively arranged between the shaft shoulder and the limiting baffle plate as well as between the shaft shoulder and the cavity end cover.

Furthermore, the rotating shaft is sleeved with a blade shaft connected with the blades, and is provided with a flat key for limiting circumferential rotation displacement between the rotating shaft and the blade shaft and a snap ring for preventing the blade shaft from coming off from the rotating shaft.

Furthermore, a bearing bush is arranged between the paddle shaft and the rotating wheel body.

Further, the piston cavity is filled with fluid and is divided into a first chamber and a second chamber by the piston, and the pressure difference in the first chamber and the second chamber can be controlled by an external power device.

Furthermore, a liquid level meter is connected with the first chamber and/or the second chamber and is used for calculating the rotation angle of the paddle by measuring the displacement generated by the piston.

Furthermore, a displacement sensor is arranged on a runner chamber of the water turbine, and a target point matched with the displacement sensor is arranged on the paddle and used for calculating the rotation angle of the paddle by measuring the distance between the displacement sensor and the target point.

By comprehensively adopting the technical scheme, the invention can obtain the following beneficial effects:

1. the whole structure is compact, safe and reliable, the output torque is large, and the transmission is stable;

2. under the same output torque, the operating mechanism adopting the thread transmission has small volume and light weight, and can effectively save the manufacturing cost of the unit;

3. the operating mechanism adopting the screw transmission has good mechanical property, does not generate harmful additional force and is beneficial to the long-term safe operation of the unit;

4. in the blade operating mechanism adopting the crank link mechanism in the background art, the ear holes of the piston cylinders and the shaft holes of the rotating wheels can meet the requirements only by synchronous processing, and the piston cylinders cannot be used interchangeably among different rotating wheels.

Drawings

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of the overall structure of a runner of a Kaplan turbine according to some embodiments;

FIG. 2 is a schematic view of the overall structure of a blade operating mechanism for a Kaplan turbine in some embodiments;

FIG. 3 is a schematic illustration of the measurement of a turn angle using a level gauge in some embodiments;

FIG. 4 is a first schematic view of some embodiments employing a displacement sensor to measure rotational angle, with the blade in a fully closed state;

FIG. 5 is a second schematic view of some embodiments using a displacement sensor to measure rotational angle with the blade in a fully open position.

Description of reference numerals:

1-runner body, 1-runner chamber, 2-blade operating mechanism, 21-piston, 22-rotating shaft, 23-limit baffle, 24-chamber end cover, 25-thrust bearing, 26-blade shaft, 27-snap ring, 28-flat key, 29-bearing bush, 211-oil pipe I, 212-oil pipe II and 3-blade.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.

In the description of the present invention, it is to be understood that the terms indicating an orientation or positional relationship are based on the orientation or positional relationship shown in the drawings only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the drawings of the present invention, it should be understood that different technical features which are not mutually substituted are shown in the same drawing only for the convenience of simplifying the drawing description and reducing the number of drawings, and the embodiment described with reference to the drawings does not indicate or imply that all the technical features in the drawings are included, and thus the present invention is not to be construed as being limited thereto.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Axial or flow turbines typically have a runner which is rotated by the flow of water in a runner chamber 11, which in turn drives a generator to generate electricity. The blades 3 are usually at an angle with the water flow direction, which can be called blade working angle, the water turbine with variable blade working angle is called a Kaplan turbine, and adjusting the blade working angle is essentially the process of driving the blades 3 to rotate around an axis, which can be called a rotating axis 22. The rotating shaft 22 may be a solid shaft or a shaft cylinder, or may be another type of support; it can be connected directly to the blade 3 or indirectly to the blade 3 with the aid of other components.

The invention relates to a paddle operating mechanism 2 for a rotary paddle type water turbine. Referring to fig. 1-2, the wheel body 1 has a piston chamber with a piston 21 disposed therein. Two ends of the piston 21 are respectively in threaded connection with the runner body 1 and the rotating shaft 22 to form a primary thread pair and a secondary thread pair with different thread leads. The rotating shaft 22 is axially limited and is rotatably connected with the rotating wheel body 1. When piston 21 moves in the piston cavity, piston 21 can generate a spiral, but because rotating shaft 22 is axially limited, and the thread leads of the first-stage thread pair and the second-stage thread pair are different, the linear displacement of piston 21 is converted into the rotary displacement of rotating shaft 22.

In the paired screw pairs, either one of them may serve as a screw while the other serves as a screw hole. In some embodiments, the piston 21 has a threaded piston rod and a threaded hole at both ends thereof for forming a primary thread pair and a secondary thread pair with the rotating wheel body 1 and the rotating shaft 22, respectively. In other embodiments, the two ends of the piston 21 are provided with piston rods with different lead threads respectively, and the piston can also be used for forming a primary thread pair and a secondary thread pair with the rotating wheel body 1 and the rotating shaft 22 respectively.

The main components of the paddle operating mechanism 2 are all arranged in the runner hub 1. In some embodiments, the rotating wheel body 1 has a multi-step hole with a gradually increasing diameter from inside to outside, which is sequentially referred to as a first-step hole, a second-step hole, and the like. The primary hole is a blind hole for forming a primary thread pair with the piston 21. The secondary bore then serves as the piston chamber, or at least is part of the piston chamber. The runner body 1 may be solid or hollow. When the runner body 1 is a hollow structure, the stepped hole is formed by the inward recess of the partial wall surface of the runner body 1.

The rotational axis 22 is axially restrained and may be achieved in a variety of ways. In some embodiments, the rotating shaft 22 has a shoulder, two sides of the shoulder are axially limited by the limiting baffle 23 and the chamber end cover 24, respectively, and both the limiting baffle 23 and the chamber end cover 24 are sleeved on the rotating shaft 22. In at least one embodiment, thrust bearings 25 are also provided between the shoulder and the retainer baffle 23 and chamber end cap 24, respectively, to reduce wear.

The chamber end cover 24 is used for sealing the piston cavity, and the limit baffle 23 can be arranged in the piston cavity or outside the piston cavity. In one embodiment, the chamber end cap 24 is located in the fourth-stage bore, the second-stage bore and the third-stage bore are integrally formed as a piston chamber, and the limit baffle 23 and the shoulder are located in the third-stage bore, with the limit baffle 23 located in the piston chamber. In another embodiment, the shaft shoulders of the end covers of the chamber are all positioned in the third-stage holes, the second-stage holes are used as piston cavities, and the limiting baffle is positioned in the fourth-stage holes and is positioned outside the piston cavities.

The rotation shaft 22 may be directly or indirectly connected to the blade 3. In some embodiments, the rotating shaft 22 is sleeved with a blade shaft 26 connected with the blade 3, and the rotating shaft 22 is further provided with a flat key 28 for limiting circumferential rotational displacement of the rotating shaft 22 and the blade shaft 26, and a snap ring 27 for preventing the blade shaft 26 from falling off the rotating shaft 22. Through the above-mentioned structural arrangement, it can be realized that the rotation axis 22 drives the paddle 3 to rotate smoothly.

For lubrication and/or sealing purposes, in some embodiments, a bearing bush 29 is provided between the paddle shaft 26 and the runner hub 1, a piston seal is provided between the piston 21 and a cavity wall of the piston cavity, and an end cover seal is provided between the cavity end cover 24 and the rotating shaft 22 and the runner hub 1; in other embodiments, a blade seal is also provided between the blade 3 and the runner hub 1.

The power for driving the rotation of the piston 21 may be various types. In some embodiments, the primary bore is not a blind bore, and an external power device is coupled to the piston rod within the primary bore to rotate the piston 21. In other embodiments, the primary bore is a blind bore, the piston cavity is filled with fluid, the piston cavity is divided into a first chamber and a second chamber by the piston 21, the pressure difference between the first chamber and the second chamber can be controlled by an external power device, and the piston is driven to rotate by the pressure difference.

In order to accurately control the angle of rotation of the blade 3, at least two schemes can be adopted.

The first scheme is as follows: is a scheme of indirect measurement. Since the two-step screw pair has a certain transmission ratio in design, there is a one-to-one correspondence between the linear displacement of the piston 21 and the rotational angle of the rotary shaft 22. In some embodiments, a liquid level meter 43 is connected to the first chamber or the second chamber for calculating the rotation angle of the blade by measuring the displacement of the piston. The measuring device comprises a float 41, a measuring rod 42 and a level gauge 43, as shown in fig. 3. In at least one embodiment, the liquid level meters 43 are connected to the first chamber and the second chamber, which has the advantages that the measurement results of the two liquid level meters 43 can be checked with each other, so that the measurement accuracy is improved, and the measurement results of the two liquid level meters 43 can be used for checking whether the sealing performance of the piston 21 is good or not, so that the measurement reliability is improved.

Scheme II: is a direct measurement scheme. In some embodiments, a displacement sensor is disposed on the runner chamber 11 of the water turbine, and a target point adapted to the displacement sensor is disposed on the blade 3, so as to calculate the rotation angle of the blade 3 by measuring the distance between the displacement sensor and the target point. In at least one embodiment, two sets of displacement sensors and targets are provided to improve the accuracy of the measurement.

The two schemes can both achieve the purpose of accurately controlling the rotating angle of the paddle 3. Each blade 3 can be provided with an independent control system, and the effect of synchronous rotation is achieved among a plurality of blades 3 according to an independent control and cooperative work method.

At least one exemplary embodiment is now provided in connection with the drawings, a detailed description of which is provided in the drawings not intended to limit the scope of the claimed invention, but is merely representative of exemplary embodiments provided in the invention.

Exemplary embodiment 1

Referring to fig. 1 to 2, the present exemplary embodiment relates to a paddle operating mechanism 2 for a Kaplan turbine, in which a runner body 1 is provided with a multistage stepped hole, and a rotating shaft 22 connected to a paddle 3 is provided in the multistage stepped hole. And a piston 21 is further arranged in the multistage stepped hole, and the runner hub 1 and the piston 21, and the piston 21 and the rotating shaft 22 are respectively in threaded connection to jointly form a screw pair with different two-stage thread leads.

Specifically, a secondary bore is provided as part of the piston chamber, the piston 21 is movable within the secondary bore, and a piston seal is provided between the piston 21 and the rotor body 1. One end of the piston 21 is provided with a threaded piston rod which forms a primary thread pair together with the threaded primary hole; the other end of the piston 21 is provided with a threaded hole, and forms a secondary thread pair with the threaded rotating shaft 22. The rotating shaft 22 is provided with a shaft shoulder, two sides of the shaft shoulder are limited by the limiting baffle 23 and the cavity end cover 24 respectively, and the limiting baffle 23 and the cavity end cover 24 are sleeved on the rotating shaft 22. Thrust bearings 25 are arranged between the shaft shoulder and the limiting baffle 23 and between the shaft shoulder and the chamber end cover 24. The limit baffle 23 and the shaft shoulder are both positioned in the three-level hole. The chamber end cover 24 is located in the four-stage hole, and end cover sealing elements are arranged between the chamber end cover 24 and the rotating shaft 22 as well as between the chamber end cover and the rotating wheel body 1, so that the three-stage hole is also part of the piston cavity.

Outside the piston chamber, a blade shaft 26 is fitted over the rotating shaft 22. The rotating shaft 22 is further provided with a flat key 28 for limiting circumferential rotational displacement of the rotating shaft with the blade shaft 26, and a snap ring 27 for preventing the blade shaft 26 from coming off the rotating shaft 22. The paddle shaft 26 is positioned in the five-stage hole, and the circumference of the paddle shaft is provided with a bearing bush 29; the blades 3 mounted on the blade shaft 26 are positioned in the six-stage holes, and blade sealing elements are arranged on the circumferences of the blades.

The piston cavity is divided into two parts by the piston 21 to form a first cavity and a second cavity, the two cavities are respectively connected with an oil pipe I and an oil pipe II, and the pressure difference of the two cavities is controlled by an external power device so as to drive the piston 21 to move. Namely, the pressure of the oil pipe I and the oil pipe II is changed, so that the blades 3 can be driven to rotate according to expected requirements, and different operation conditions of the power station can be met. In order to accurately control the angle of rotation of the blade 3, the following scheme is adopted:

due to the design of the thread pair with a certain transmission ratio, the linear displacement of the piston 21 has a one-to-one correspondence with the rotation angle of the rotating shaft 22. By monitoring the real time position of the piston 21, the real time rotational angle of the blade 3 can be calculated. As shown in fig. 3, the oil lines i and ii are connected to a device with a level gauge 43, respectively. The change in the volume of oil in the two chambers during the movement of the piston 21 is measured by the level gauge 43. Because the volume change values of the two chambers and the moving stroke of the piston 21 have a one-to-one correspondence relationship, the moving displacement of the piston 21 can be calculated through the reading of the liquid level meter 43, the position of the piston 21 is determined, and the rotation angle of the paddle 3 is further judged.

It should be noted that the angle of rotation of the blade 3 can be obtained by monitoring the level gauge reading of the oil pipe i or oil pipe ii separately, which is a two-way objective in the exemplary embodiment. Firstly, the measurement data can be checked by two independent measurements, so that the measurement accuracy is improved; and secondly, the sealing performance of the piston 21 can be checked by measuring twice, so that the reliability of the measured data is improved. In addition, the measurement accuracy and resolution of the liquid level meter 43 can be obtained by inverse calculation according to the position accuracy requirement of the rotation of the turbine blade 3 and the size of the components.

Exemplary embodiment 2

The present exemplary embodiment differs from the exemplary embodiment in that:

in the exemplary embodiment, in order to accurately control the rotation angle of the blade 3, a scheme of direct measurement is adopted, which specifically includes the following steps:

as shown in FIGS. 4-5, two measurement target points T1 and T2 are firstly placed on the outer circle of the blade 3, and then two eddy current displacement sensors D1 and D2 are placed at corresponding positions of the runner chamber 11. For example, by adopting a KD2306 high-precision eddy current displacement sensor produced by KAMAN, the material of the target point is selected according to the operating principle of the eddy current sensor. When the blade 3 rotates from full close to full open, the distances L1 and L2 between the two sets of eddy current displacement sensors and the target point change simultaneously, and the rotating angle value of the blade 3 can be obtained through the distance change values measured by the eddy current displacement sensors D1 and D2.

It should be noted that the rotation angle of the blade 3 can be measured by using a single set of eddy current displacement sensor and the target points D1, T1, D2, and T2, and the accuracy of the measured data can be improved by using two sets of eddy current displacement sensors D1 and D2 to measure simultaneously in the exemplary embodiment. In addition, the measuring range and the precision of the eddy current sensors D1 and D2 can be determined according to the position precision requirement of the rotation of the turbine blade 3.

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.

Claims

1. The utility model provides a paddle operating device for a rotating blade type water turbine which characterized in that:

the rotating wheel of the water turbine is provided with a rotating wheel body and a blade connected with a rotating shaft;

the runner hub is provided with a piston cavity in which a piston is arranged;

two ends of the piston are respectively in threaded connection with the runner hub and the rotating shaft to form a primary thread pair and a secondary thread pair with different thread leads;

the rotating shaft is axially limited and is rotatably connected with the rotating wheel body.

2. The blade operating mechanism of claim 1, wherein: and the two ends of the piston are respectively provided with a piston rod with threads and a threaded hole which are respectively used for forming a primary thread pair and a secondary thread pair with the runner hub and the rotating shaft.

3. A blade operating mechanism according to claim 1 or 2, wherein: the runner hub is provided with a blind hole type multistage stepped hole with the hole diameter gradually increased from inside to outside, and comprises a primary hole for forming a primary thread pair with the piston and a secondary hole used as a piston cavity or a part of the piston cavity; and a piston sealing element is arranged between the piston and the runner body.

4. A blade operating mechanism according to claim 1 or 2, wherein: the rotating shaft is provided with shaft shoulders, the two sides of the shaft shoulders are axially limited by a limiting baffle and a cavity end cover respectively, the limiting baffle is arranged in the piston cavity, the cavity end cover is used for sealing the piston cavity, and the limiting baffle and the cavity end cover are sleeved on the rotating shaft.

5. The blade operating mechanism of claim 4, wherein: thrust bearings are respectively arranged between the shaft shoulder and the limiting baffle and between the shaft shoulder and the cavity end cover.

6. A blade operating mechanism according to claim 1 or 2, wherein: the rotating shaft is sleeved with a blade shaft connected with the blades, and is provided with a flat key and a clamping ring, wherein the flat key is used for limiting the blade shaft and the blade shaft to generate circumferential rotary displacement, and the clamping ring is used for preventing the blade shaft from being separated from the rotating shaft.

7. The blade operating mechanism of claim 6, wherein: and a bearing bush is arranged between the paddle shaft and the rotating wheel body.

8. A blade operating mechanism according to claim 1 or 2, wherein: the piston cavity is filled with fluid and is divided into a first cavity and a second cavity by the piston, and the pressure difference between the first cavity and the second cavity can be controlled by an external power device.

9. The blade operating mechanism of claim 8, wherein: and the first chamber and/or the second chamber are/is connected with a liquid level meter and used for calculating the rotation angle of the paddle by measuring the displacement generated by the piston.

10. A blade operating mechanism according to claim 1 or 2, wherein: the hydraulic turbine is characterized in that a displacement sensor is arranged on a runner chamber of the hydraulic turbine, a target point matched with the displacement sensor is arranged on the blade, and the hydraulic turbine is used for calculating the rotating angle of the blade by measuring the distance between the displacement sensor and the target point.