AU2014259522B2

AU2014259522B2 - Adjusting device for turbine rotor blades

Info

Publication number: AU2014259522B2
Application number: AU2014259522A
Authority: AU
Inventors: Johannes Geromiller; Stefan Winkler; Erich Wurm
Original assignee: Andritz Hydro GmbH Austria
Current assignee: Andritz Hydro GmbH Austria
Priority date: 2013-11-07
Filing date: 2014-11-06
Publication date: 2017-10-19
Anticipated expiration: 2034-11-06
Also published as: AT515497A1; KR102094985B1; AU2014259522A1; ES2625157T3; EP2871356B1; PT2871356T; EP2871356A1; PH12014000297A1; CN104632685A; KR20150053251A; AT515497B1; PH12014000297B1; NZ701717A

Abstract

ADJUSTING DEVICE FOR TURBINE ROTOR BLADES The invention relates to an adjusting device for turbine (1) rotor blades (2) mounted on a hub (3), where a hydraulic servo-cylinder (5) is provided as well as another servo-cylinder (6). It is largely characterized in that one end of the adjusting rods (7, 8) of the servo-cylinders (5, 6) is swivel mounted at the adjusting crank (9) rigidly connected to the axis (3) of the rotor blade (2). With this arrangement, adjustments, i.e. rotations, through 3600 are also possible. Here, the bearings (13, 14) of the adjusting rods (7, 8) can be arranged eccentrically, i.e. outside the rotating axis (17) of the hub (3). Alternatively, an auxiliary servo-cylinder (6) is provided in addition to the main servo-cylinder (5) and is arranged opposite the main servo-cylinder (5), while its adjusting rod (8) is disposed on the adjusting crank (9) opposite the adjusting rod (7) of the main servo-cylinder (5) and offset. Thus, adjustment beyond 180' is also possible and the dead center of the adjusting rod (7) of the main servo-cylinder (5), which lies between the two, can be overcome. In this way, the dead centers of the servo-cylinders (5, 6) can be overcome, while there is always at least one cylinder (5, 6) available to apply the necessary force. (Fig. 2) (9346207 1l dah

Description

ADJUSTING DEVICE FOR TURBINE ROTOR BLADES

[0001] The invention relates to an adjusting device for turbine rotor blades mounted on a hub, where a hydraulic servo-cylinder is provided as well as another servo-cylinder.

[0002] Rotor blade adjusting devices are used, in Kaplan turbines for example, in order to achieve the most advantageous efficiency at all times for all flow rates. The adjusting range of the rotor blades in axial turbines with unidirectional flow is in the region of 30° in this case. In reversible axial turbines, which have bi-directional flow, the adjusting range required to achieve the optimum rotor blade position increases to at least 200°. This cannot be achieved with a hydraulic servo-cylinder in the solution available so far because a dead center emerges here at one angle position where the moment arm of the servo-cylinder becomes zero and no further adjustment is thus possible.

[0003] There are alternative solutions in that a symmetrical blade profile with reduced efficiency is selected on the one hand, and the adjusting movement is effected by toothed racks, for example, on the other hand.

[0004] The aim of the invention is thus to provide an adjusting device for turbine rotor blades which substantially overcomes or at least ameliorates one or more of the disadvantages of the prior art. It would, for example, be useful to provide a means of adjusting the rotor blades for reversible axial turbines as well.

[0005] According to one aspect, the invention provides an adjusting device for turbine rotor blades mounted on a hub, where a hydraulic servo-cylinder is provided as well as another servo-cylinder, wherein one end of the adjusting rods of the servo-cylinders is swivel mounted at the adjusting crank rigidly connected to the axis of the rotor blade. With a design of this type, a rotor blade can also be rotated through 360°.

[0006] An advantageous embodiment of the invention is characterized in that the bearings of the adjusting rods are arranged eccentrically, i.e. outside the rotating axis of the hub, where the servo-cylinders can be arranged concentrically. As a result, the servo-cylinders can be arranged concentrically on the one hand, which saves space. On the other hand, both servo-cylinders always have sufficient power to drive the crank in any crank position.

[0007] An alternative embodiment of the invention is characterized in that the servo-cylinders are designed as individual cylinders, where the servo-cylinders can have a shared piston rod.

[0008] An advantageous embodiment of the invention is characterized in that the adjusting rods are arranged on a shared pin, which is connected to the adjusting crank.

[0009] An alternative embodiment of the invention is characterized in that the adjusting rods are arranged on different levels at a distance from the rotation axis of the hub, where the adjusting rods can be arranged at different pins disposed at an angle to one another round the rotation axis of the rotor blade.

[0010] A favorable embodiment of the invention is characterized in that the bearings of the adjusting rods of all turbine rotor blades arranged on the hub are connected to the same servo-cylinders.

[0011] It has proved advantageous if a torque is generated on the adjusting crank of the rotor blade in each position of the crank of at least one adjusting rod of a turbine rotor blade.

[0012] Another embodiment according to the invention is characterized in that an auxiliary servo-cylinder is provided in addition to the main servo-cylinder and is arranged opposite the main servo-cylinder, and its adjusting rod is disposed on the adjusting crank opposite the adjusting rod of the main servo-cylinder and offset at an angle. Since the adjusting rods of the main and auxiliary servo-cylinders are offset, continuous movement is possible and, as a result, the rotor blades can be adjusted beyond 180° up to 360°.

[0013] An advantageous development of the invention is characterized in that the cylinders of the main servo-cylinder and the auxiliary servo-cylinder are arranged on a shared piston rod. This allows a compact construction.

[0014] A favorable embodiment of the invention is characterized in that the angle of offset between the points of application of the adjusting rods of the main servo-cylinder and the auxiliary servo-cylinder is between 60° and 120°. In this way, the force needed for adjustment can be optimized particularly well.

[0015] An advantageous embodiment of the invention is characterized in that the auxiliary servo-cylinder applies a force that is between 10 and 30%, preferably approximately 20%, of the force applied by the main servo-cylinder.

[0016] It has proved particularly favorable if the auxiliary servo-cylinder takes over blade adjustment in the region of the dead center of the adjusting rod of the main servo-cylinder, where the auxiliary servo-cylinder is preferably pressureless for the remainder of the stroke. In this way, adjustment is possible over the entire positioning range with a minimum energy requirement.

[0017] Embodiments of the invention are now described by way of examples with reference to the accompanying drawings, in which: [0018] Fig. 1 shows a view of a turbine in which the invention is used, [0019] Fig. 2 shows a schematic view of the adjusting device according to the invention, [0020] Fig. 3 shows an embodiment of the adjusting device according to the invention, [0021] Fig. 4 shows an alternative embodiment of the adjusting device according to the invention [0022] Figs. 5a to 5h show the blade adjusting sequence for a rotation through 360°, [0023] Fig. 6 shows another embodiment of the adjusting device according to the invention, [0024] Fig. 7 shows a sectional view along the line marked VII- VII in Fig. 6, [0025] Fig. 8 shows a sectional view through a turbine hub with an alternative arrangement according to the invention, and [0026] Figs. 9a to 9e show the blade adjusting sequence for the alternative arrangement.

[0027] Figure 1 shows a Kaplan runner 1, which has three rotor or runner blades 2 in this example, which are pivoted or swivel-mounted on the rotor hub 3. This adjustability guarantees that the rotor blades 2 are always in the optimum position for optimum efficiency. Thus, the position of the rotor blades 2 is always adapted to the water flow. A runner 1 of this kind can also be used as an axial rotor in pipes. In cases with flow reversal, there is a problem here because the runner 1 can generally only be designed to achieve optimum efficiency for one flow direction. In order to circumvent this problem, rotor geometries are often chosen that may not represent the optimum for the individual flow direction, but are adapted accordingly overall for both directions.

[0028] In Figure 2, a schematic diagram shows a device according to the invention. The diagram depicts a rotor blade 2 connected to a blade plate or adjusting crank 9. The two rods 7, 8 of the two servo-cylinders act upon the crank pin 15, where the rod bearings 13 (left-hand servo-cylinder) and 14 (right-hand cylinder) are arranged at a distance 16 from the axis of rotation 17 of the hub. Advantageously, the connecting line between the rod bearings 13, 14 is disposed parallel to the axis 17 of the hub 3.

[0029] Figure 3 shows a variant of an adjusting device according to the invention, where the two servo-cylinders are combined here and arranged in a shared cylinder housing. The rotor blade 2, which is swivel-mounted in the hub 3, is connected via rods (connecting rods) 7, 8 to the crank pin 15 of the adjusting crank 9 in a swivel mounting by means of two linear actuators 5 and 6 (normally hydraulic cylinders). Due to the eccentric arrangement of the rod bearings 13, 14, it is also guaranteed when a rod 7, 8 is in a dead center position that the other rod can drive the adjusting crank 9. The circumferential guides 18 transfer the rod reaction forces to the hub 3.

The two servo-cylinders 5, 6 are arranged here on a shared piston rod 4. This arrangement forms a very compact construction.

[0030] Figure 4 shows another variant of the invention, where two individual servo-cylinders 5, 6 are shown here. Here, too, the rod bearings 13, 14 of the two rods 7, 8 are disposed in an eccentric arrangement, i.e. the bearings 13, 14 are outside the axis 17 of the hub.

[0031] Figures 5a to 5h show the movement sequence for a 360° rotation by a rotor blade 2. The respective movement of the cylinders 5, 6 is illustrated by the arrows 5’ and 6’, respectively.

The movement by the crank pin 15 is indicated by the arrow 15’.

[0032] Figure 5a shows a movement by the servo-cylinder 5, 6 in the same direction 5’ and 6’ to the left. As a result, the crank pin 15 moves away from the summit counter-clockwise in direction 15’. In Figure 5b, the first dead center (left) of the cylinder 6 is reached (thus no arrow 6’). The left-hand cylinder 5 takes over the full tractive force for rotation of the crank pin 15. After overcoming the dead center of cylinder 6, the cylinder once again acts in the direction of the arrow 6’ towards the right, while cylinder 5 continues to act in direction 5’ to the left. (Fig. 5 c). This continues until the first dead center (on the left) of cylinder 5 is reached. (Fig. 5d). Here, cylinder 6 takes over the full tractive force for rotating the crank pin 15 in direction 15’.

[0033] Now the force of cylinder 5 acts in direction 5’, to the right, where the lower summit of the crank pin 15 is soon reached. Thus, the rotor blade 2 has also rotated through 180°. (Fig. 5e). The movement continues until the second dead center (on the right) for cylinder 6 is reached (see Fig. 5f). The crank pin 15 is now rotated further according to Fig. 5g until the second dead center (on the right) of cylinder 5 (according to Fig. 5h) is reached and cylinder 6 takes over the full force. The movement sequence is thus concluded in Fig. 5a, when the rotor blade has completed one full revolution through 360°.

[0034] Generally, there is no need for a full revolution and instead, the rotor blade 2 moves between two positions, where the blade moves in the opposite direction after reaching the “final position” and passes through a zone of approximately 220°.

[0035] Figure 6 shows an alternative embodiment of the invention, where the adjusting rods 7, 8 act on different crank pins 15, 15”. Here, the crank pins 15, 15” are disposed at an angle a to one another round the axis of rotation of the rotor blades. This angle is preferably 90°, but can also be larger, for example 120°.

[0036] Figure 7 shows a sectional view along the line marked VII - VII in Figure 6, i.e. along the axis of rotation of the hub. This illustration corresponds to Fig. 4, where the adjusting rods 7, 8 here are arranged at different distances from the axis of rotation and act on different crank pins 15, 15”. All other parts are the same as in Fig. 4 and are marked with the same reference numerals.

[0037] Figure 8 now shows an alternative embodiment of the adjusting device according to the invention, where only the runner hub 3 is shown without the corresponding rotor blades. This adjusting device is also only shown for one rotor blade, although it is designed at the same time for all rotor blades, in this case for three blades. In the rotation axis of the machine there is a piston rod 4 with a main servo-cylinder disposed upon it. An auxiliary servo-cylinder 6 is arranged on the side opposite the hub 3. The adjusting rod 7 of the main servo-cylinder 5 and the adjusting rod 8 of the auxiliary servo-cylinder 6 are disposed in an offset arrangement at the adjusting crank 9, where the adjusting crank 9 is connected directly to the rotor blade 2 (not shown here). The offset points of application of the adjusting rods 7 and 8 can enclose an angle a of 90° to 120° (approximately 90° shown here).

[0038] Figures 9a to 9e show the positions of the rotor blade 2 and of the servo-cylinders 5, 6 for different operating conditions. The hub 3, which is immersed in water under operating conditions, is arranged around the adjusting device.

[0039] Fig. 9a shows operation of the reversible axial turbine at minimum blade opening, where the water enters from the left as indicated by the arrow 10 and the turbine thus rotates in counter-clockwise direction. Here, the point of application of the adjusting rod 7 of the main servo-cylinder 5 encloses an angle of -110° (corresponding to 250°) towards the cylinder axis.

[0040] Figure 9b shows the operating condition of the axial turbine in turbine operation at maximum blade opening, where the water flow here also enters from the left according to the arrow 10 and the turbine rotates in counter-clockwise direction. The water thus flows from the head water to the tail water of the power station. The angle between the point of application of the adjusting rod 7 and the horizontal axis is -70° here (corresponding to 290°), where the axis of rotation of the machine is marked with the numeral 11.

[0041] Figure 9c now illustrates the critical situation where the adjusting rod 7 of the main servo-cylinder 5 has arrived at the dead center and thus cannot apply any force to further adjust the blade 2. As a result, the invention foresees that the main servo-cylinder is depressurized approximately 20° before and 20° after reaching this position, and the auxiliary cylinder 6 is activated. Due to the offset arrangement of the points of application of the adjusting rods 7 and 8, the dead center of the main servo-cylinder 5 together with adjusting rod 7 can thus be overcome. The auxiliary servo-cylinder 6 remains depressurized for the remaining time and simply follows the movement.

[0042] Figure 9d now shows pump or turbine operations in the second direction, where the water flow according to the arrow 12 enters from the right and the axial turbine rotates in clockwise direction here. At the minimum blade opening according to Fig. 9d, the angle of the adjusting rod 7 of the main servo-cylinder 5 to the horizontal axis is +70°.

[0043] If the axial turbine is run in pump or turbine operation in the second direction at the maximum blade opening, the resulting position is as shown in Fig. 9e, with an angle of 110° and a flow direction from the right according to the arrow 12, which results in a clockwise sense of rotation.

[0044] The angles of the adjusting rod 7 to the axis shown here are provided by way of example and may also vary slightly. The position of the adjusting rods at maximum and minimum blade opening depends here on the blade structure. The area around the dead center can also vary depending on the offset angle of the points of application of the adjusting rods 7 and 8 and on the force that can be applied by the auxiliary servo-cylinder 6. However, it is important that the main servo-cylinder 5 is de-pressurized here and that the auxiliary servo-cylinder 6 is depressurized outside this area.

[0045] The invention is not limited by the drawings. Thus, the rotor blades could also turn through one complete revolution in the opposite direction to that shown in Figs. 5a to 5h (i.e. in clockwise direction). The set-up of the servo-cylinders, for example, can also be different.

Claims

1. Adjusting device for turbine rotor blades mounted on a hub, where a hydraulic servo-cylinder is provided as well as another servo-cylinder, wherein one end of the adjusting rods of the servo-cylinders is swivel mounted at the adjusting crank rigidly connected to the axis of the rotor blade and permits the rotor blade to be rotated through 360°.

2. Adjusting device according to Claim 1, wherein the hydraulic cylinder is provided as the main servo-cylinder and the other servo-cylinder as an auxiliary servo-cylinder, which is arranged opposite the main servo-cylinder, while its adjusting rod is disposed on the adjusting crank opposite the adjusting rod of the main servo-cylinder and offset at an angle.

3. Adjusting device according to Claim 2, wherein the angle of offset between the points of application of the adjusting rods of the main servo-cylinder and the auxiliary servo-cylinder is between 60° and 120°.

4. Adjusting device according to Claim 2 or Claim 3, wherein the auxiliary servo-cylinder applies a force that is between 10 and 30%, preferably approximately 20%, of the force applied by the main servo-cylinder.

5. Adjusting device according to any one of Claims 2 to 4, wherein the auxiliary servo-cylinder takes over blade adjustment in the region of the dead center of the adjusting rod of the main servo-cylinder and the main servo-cylinder is depressurized, where the region can be approximately 20° before and 20° after the dead center position.

6. Adjusting device according to Claim 5, wherein the auxiliary servo-cylinder is pressure-free for the remainder of the stroke.

7. Adjusting device according to Claim 1, wherein the bearings of the adjusting rods are arranged eccentrically, i.e. outside the rotating axis of the hub.

8. Adjusting device according to any one of Claims 1 to 7, wherein the servo-cylinders are arranged concentrically.

9. Adjusting device according to any one of Claims 1 to 7, wherein the servo-cylinders are designed as individual cylinders.

10. Adjusting device according to any one of Claims 1 to 9, wherein the servo-cylinders have a shared piston rod.

11. Adjusting device according to any one of Claims 7 to 10, wherein the adjusting rods are arranged on a shared pin, which is connected to the adjusting crank.

12. Adjusting device according to any one of Claims 7 to 10, wherein the adjusting rods are arranged on different levels at a distance from the rotation axis of the hub.

13. Adjusting device according to Claim 12, wherein the adjusting rods are arranged at different pins disposed at an angle to one another round the rotation axis of the rotor blade.

14. Adjusting device according to any one of Claims 7 to 13, wherein the bearings of the adjusting rods of all turbine rotor blades arranged on the hub are connected to the same servo-cylinders.

15. Adjusting device according to any one of Claims 7 to 14, wherein a torque is generated on the adjusting crank of the rotor blade in each position of the crank of at least one adjusting rod of the turbine rotor blade.