JP2007255316A - Francis turbine for hydraulic power generation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Francis turbine for hydraulic power generation for reducing manufacturing cost, by simplifying its structure, by reducing the number of part items for constituting a guide vane opening-closing means. <P>SOLUTION: This Francis turbine has the guide vane opening-closing means for adjusting water port opening of a plurality of guide vanes 17 introduced to a runner, by accelerating flowing water taken in from a casing. The guide vane opening-closing means is composed of an external gear 22 installed on the plurality of guide vanes 17, a guide ring 23 arranged so as to revolve around the plurality of guide vanes and an internal gear 24 meshing with the external gear installed on the inner periphery of the guide ring. The water port opening of the plurality of guide vanes can be varied by rotatably displacing the guide ring. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a Francis turbine for hydroelectric power generation, and more particularly, to a guide vane opening / closing means for adjusting the opening of a plurality of guide vanes provided in the Francis turbine.

  Conventionally, in a hydroelectric generator, a propeller turbine is used for a low head, while a Francis turbine is used for a medium to high head.

  Hereinafter, the reason why the propeller turbine cannot be applied to the medium to high drop hydroelectric generator will be described. The type of the turbine used for hydropower generation is determined by the specific speed Ns determined based on the rotation speed N of the turbine, the turbine output P, and the applied head H parameter (see Equation 1).

一般に、フランシス水車の適用範囲は、Ｎｓ＝６０〜３００であるのに対し、プロペラ水車の適用範囲は、Ｎｓ＝３００以上とされている。仮に、回転速度Ｎ＝１５００［ｍｉｎ^−１］の中高落差用のフランシス水車と同じ水車出力Ｐを、プロペラ水車で得られるようにするには、比速度Ｎｓが大きくなるように回転速度Ｎを大きくすればよいが、この回転速度Ｎは、一般的には１５００［ｍｉｎ^−１］までとされている。

In general, the application range of Francis turbines is Ns = 60 to 300, while the application range of propeller turbines is Ns = 300 or more. For example, in order to obtain the same turbine output P as that of the Francis turbine for medium and high heads in the rotational speed N = 1500 [min ⁻¹ ] with the propeller turbine, the rotational speed N is increased so that the specific speed Ns is increased. However, the rotational speed N is generally set to 1500 [min ⁻¹ ].

  Therefore, when a propeller turbine is applied to medium-high head hydropower generation, in order to divide the applicable head H, it is necessary to install a plurality of turbines on the water conduit and to provide a generator for each turbine. Therefore, there are problems that the installation space becomes large and the manufacturing cost increases. For this reason, Francis turbines that can generate power more efficiently than propeller turbines are suitable for medium- and high-head hydropower generation.

  In general, when both the runner vane and the guide vane of the propeller turbine are movable, the runner vane drive mechanism is installed inside the propeller turbine. Therefore, when the propeller water turbine is arranged at a small flow rate point, the size of the water turbine is small, so that it is difficult to store the runner vane drive mechanism.

  In addition, the efficiency characteristics of the propeller turbine have a flat efficiency characteristic in the entire flow region when the runner vane and the guide vane are movable, but when the runner vane is fixed, it becomes a sharp characteristic and follows the variable flow rate. It has the disadvantage of being difficult. On the other hand, the variable flow rate (particularly low flow rate) characteristics of Francis turbines are inferior to those of propeller turbines in which runner vanes and guide vanes are movable, but are superior to propeller turbines in which runner vanes are fixed. From this point of view, the Francis turbine is suitable as a turbine installed at a variable flow point in a medium to high drop hydroelectric power generation.

  Such a Francis turbine is disclosed in, for example, Patent Document 1, and FIG. 9 is a cross-sectional view of a main part showing a conventional Francis turbine. In the figure, a Francis turbine 101 includes a runner 103 fixed to one end (left side of FIG. 9) of a turbine main shaft 102, a guide vane 104 disposed on the outer periphery of the runner 103, and an outer periphery of the guide vane 104. And a generator (not shown) is connected to the other end (right side of FIG. 9) of the water turbine main shaft 102.

  The running water w guided to the water turbine inlet by the water guide pipe is accelerated by the guide vane 104 through the spiral casing 105 and flows into the runner 103 in a direction perpendicular to the water turbine main shaft 102. The inflowing water transmits water power to the runner 103 while filling and flowing between the blades of the runner 103. The water that has passed through the runner 103 and has flowed out in the axial direction of the turbine main shaft 102 is reduced in flow velocity by the draft pipe 106 and guided to the water outlet.

  The Francis turbine 101 includes a guide vane opening / closing device 107 that can simultaneously adjust the opening of the water ports of the plurality of guide vanes 104. FIG. 10 is a view of the guide vane opening / closing device 107 of FIG. 9 as seen from the direction of the white arrow. Hereinafter, the configuration of the conventional guide vane opening / closing device 107 will be described with reference to FIGS. 9 and 10.

  The guide vane opening / closing device 107 is provided with a guide ring 109 that transmits the movement of a servo mechanism that is driven based on a command such as a speed governor via a connecting rod 108 and that is rotationally displaced in the circumferential direction. In the circumferential direction of the guide ring 109, a link (glasses link) 111 is connected via a guide ring pin 110, and one end of an arm 113 is connected to the other end of the link 110 via an arm pin 112. Yes. A key 114 is formed at the other end of the arm 113, and the guide shaft 104 a of the guide vane 104 is fastened to the arm 113 by the key 114.

  In the conventional guide vane opening / closing device 107 having such a configuration, the guide ring 108 rotates in the circumferential direction as indicated by an arrow in FIG. 10, so that the rotational displacement is the guide ring pin 110, the link 111, and the arm pin. 112 is transmitted to the arm 113 via the arm 112, and the arm 113 swings clockwise or counterclockwise with respect to the axis. With this swing, the guide vane 104 swings so as to open and close the water port, and the flow rate of the running water w is adjusted.

JP 2003-021065 A

  However, in the conventional guide vane opening / closing device 107, the number of parts required for configuring the link mechanism that transmits the rotational displacement of the guide ring 108 to the guide vane 104 is large, and the structure of the link mechanism is also complicated. Therefore, since the assembly adjustment is not easy, there is a problem that the manufacturing cost increases, and it is difficult to reduce the cost of the water turbine provided with the guide vane opening / closing device 107.

  In addition, since the conventional guide vane opening / closing device 107 is provided with parts with aged wear such as the guide ring pin 110 and the arm pin 112, maintenance management such as replacement of parts is troublesome, and there is a problem in terms of the life of the apparatus. It was.

  The present invention has been made in view of the above points, and its purpose is to reduce the number of parts constituting the guide vane opening / closing means, simplify the structure, and reduce the manufacturing cost. It is to provide a Francis turbine for power generation.

  The above object of the present invention is to provide a hydroelectric power generation Francis turbine having guide vane opening / closing means for adjusting the opening degree of a plurality of guide vanes that accelerates flowing water introduced from a casing and introduces it into the runner. Means meshes with an external gear attached to the plurality of guide vanes, a guide ring arranged to surround the plurality of guide vanes, and the external gear attached to the inner periphery of the guide ring This is achieved by varying the opening of the plurality of guide vanes by rotating and displacing the guide ring.

  According to the guide vane opening and closing means of the Francis turbine for hydroelectric power generation according to the present invention configured as described above, the guide ring arranged to surround the plurality of guide vanes is rotationally displaced in the circumferential direction, The rotational displacement is transmitted to each guide vane via the internal gear and the external gear, so that the opening and closing operations of the guide vanes are performed simultaneously. As a result, the structure of the guide vane opening / closing means is simplified, and the manufacturing cost of the Francis turbine can be reduced.

  In addition, the structure that transmits the rotational displacement of the guide ring is a gear structure composed of an internal gear and an external gear, so there is no need to use an arm or pin that has been one of the factors that reduce the life of the device. The life of the apparatus can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing a main part of a Francis turbine for hydroelectric power generation according to an embodiment of the present invention, and FIGS. 2 and 3 are a side view and a top view, respectively. In FIG. 1, a Francis turbine 1 includes an annular water guide pipe 2 composed of an inner peripheral wall 2A and an outer peripheral wall 2B disposed on the outer side of the inner peripheral wall 2A, and one end side 2Aa of the inner peripheral wall 2A of the water guide pipe 2 ( The left side of FIG. 1 is an opening, while the other end side 2Ab (right side of FIG. 1) is closed.

  A turbine main shaft 4 is rotatably supported via bearings 5 and 6 in the internal space 3 formed by the inner peripheral wall 2A of the water guide pipe 2. One end of the water turbine main shaft 4 is provided with a runner 7 attached so as to rotate integrally with the water turbine main shaft 4. The runner 7 converts the energy of the running water w into rotational energy and transmits it to the water turbine main shaft 4. It is supposed to be. On the other hand, the other end of the water turbine main shaft 4 is provided with a power transmission mechanism 9 for transmitting the rotation of the water turbine main shaft 4 to the generator 8 disposed above the water guide pipe 2.

  The power transmission mechanism 9 is formed on the upper part of the water main shaft pulley 10 attached coaxially with the main shaft of the water turbine, the generator shaft pulley 11 attached coaxially with the shaft 8A of the generator 8, and the annular water conduit 2. It is composed of a transmission belt 13 wound between the turbine spindle pulley 10 and the generator spindle pulley 11 through the communication hole 12 (see FIG. 3), and is based on the flowing water w transmitted from the runner 7 to the turbine spindle 4. Rotational energy is transmitted to the generator 8. In the Francis turbine 1 for hydroelectric power generation according to the present embodiment, the generator 8 is disposed above the water conduit 2, but is not limited to this, and can be appropriately changed according to installation conditions and the like.

  Further, a casing 14 disposed on the outer periphery of the runner 7 is connected to one end side (left side in FIG. 1) of the annular conduit 2 in order to allow the running water w from the conduit 2 to flow into the runner 7. As shown in FIG. 4, an O-ring 15 is interposed at a joint portion (X region in FIG. 1) between the inner peripheral wall 14 </ b> A of the casing 14 and the inner peripheral wall 2 </ b> A of the water conduit 2. A gap S (about 0.5 mm) is provided between them. On the other hand, the joint portion (Y region in FIG. 1) between the outer peripheral wall 14B of the casing 14 and the outer peripheral wall 2B of the water conduit 2 is an inlay joint as shown in FIG. That is, in the Francis turbine 1 according to the present embodiment, the inner peripheral wall 2A of the water conduit 2 and the inner peripheral wall 14A of the casing 14 are joined via the O-ring 15 so that the joint surfaces of the inner peripheral walls 2A and 14A are joined. A gap S is provided in the inner wall, and the gap S enables the spigot connection between the outer peripheral wall 2B of the water conduit 2 and the outer peripheral wall 14B of the casing 14.

  Further, on the upstream side of the runner 7, a speed ring 16 that guides the running water w flowing from the casing 14 into the runner 7 in the radial direction of the runner 7, and the running water w that has passed through the speed ring 16 are efficiently accelerated to runners. A plurality of guide vanes 17 to be supplied to 7 are provided. On the other hand, a downstream side of the runner 7 is provided with a draft pipe 18 for decelerating the running water w that has passed through the runner 7 and discharged in the axial direction.

  A mounting portion between the runner 7 and the water turbine main shaft 4 is provided with a labyrinth seal 19 for maintaining water tightness, and a draining member 20 disposed between the labyrinth seal 19 and the water wheel main shaft 4. . The labyrinth seal 19 is attached to the water turbine main shaft 4 after the draining member 20 is attached to the water turbine main shaft 4. Here, the gap between the draining member 20 and the labyrinth seal 19 is adjusted, and then the runner 7 is fixed to one end of the water turbine main shaft 4. In the present embodiment, the labyrinth seal 19 is used to maintain water tightness, but the present invention is not limited to this. For example, a mechanical seal may be used instead of the labyrinth seal 19.

  FIG. 6 is a front view showing guide vane opening / closing means 21 for adjusting the water opening of the plurality of guide vanes 17. 1 and 6, an external gear 22 having external teeth on the outer periphery is attached to the shaft end (left side in FIG. 1) of each guide vane 17. Further, an internal gear 24 that meshes with each external gear 22 is integrally attached to the inner periphery of the guide ring 23 that is arranged so as to surround the external gear 22 of each guide vane 17. As shown in FIG. 1 and the like, the guide ring 23 is connected to a connecting rod 25 for transmitting movement from a servo mechanism (not shown). In the guide vane opening / closing means 21 having such a configuration, the guide ring 23 is rotationally displaced in the circumferential direction in accordance with the movement of the connecting rod 25, and the rotational displacement is transmitted through the internal gear 24 and the external gear 22. This is transmitted to the guide vanes 17 so that the opening and closing operations of the guide vanes 17 can be performed simultaneously.

  Further, as shown in FIGS. 2 and 3, the Francis turbine 1 according to the present embodiment is configured such that when the load of the generator 8 is disconnected due to a system fault or the like, that is, when the load is excessive, the flowing water w ′ is an annular conduit 2. A bypass mechanism 26 for discharging to the draft pipe 18 without passing through the runner 7 is provided. The bypass mechanism 26 includes a first bypass pipe 27 having one end connected to a part of the outer peripheral wall 2B of the annular water guide pipe 2, and a bypass valve portion having an introduction port 28A connected to the other end of the first bypass pipe. 28, and a second bypass pipe 29 having one end connected to the discharge port 28 </ b> B of the bypass valve portion 28 and the other end connected to a part of the draft pipe 18.

  FIG. 7 is a cross-sectional view of the main part showing the bypass valve portion 28 of the bypass mechanism 26, and FIG. 8 is a top view thereof. In addition, in the bypass valve part 28 of FIG. 7, for easy explanation, the water inlet 28A is virtually rotated 90 degrees and indicated by a two-dot chain line (reference numeral 28A ′). In FIG. 7, the bypass valve unit 28 includes a manual handle 31 attached to one end of the handle shaft 30, a suction plate 32 attached to the other end of the handle shaft 30, and an electromagnetic magnet that is attracted to the suction plate 32 by magnetic force. 33, a valve shaft 34 to which the electromagnetic magnet 33 is attached at one end, and a valve 36 attached to the other end of the valve shaft 34 for blocking the bypass valve 35.

  In the bypass valve portion 28 having such a configuration, when the load of the generator 8 is disconnected due to a system fault or the like, the power supplied to the electromagnetic magnet 33 is lost. Due to the demagnetization of the electromagnetic magnet 33, the electromagnetic magnet 33 is separated from the suction plate 32, and the electromagnetic magnet 33, the valve shaft 34, and the valve 36 move downward in FIG. 7 due to the weight of each member and the hydraulic load applied to the valve 36. To do. Thereby, the bypass valve 35 blocked by the valve 36 is opened, and the running water w ′ introduced from the water guide pipe 2 to the inlet 28A (28A ′) through the first bypass pipe 27 passes through the bypass valve 35. Then, it is discharged to the draft pipe 18 via the discharge port 28B and the second bypass pipe 29.

  On the other hand, when the opened bypass valve 35 is closed again, the attracting plate 32 is lowered to the upper surface of the electromagnetic magnet 33 by the rotation of the manual handle 31 after the electromagnetic magnet 33 is excited. When the attracting plate 32 and the electromagnetic magnet 33 are attracted, the manual handle 31 is rotated to raise the attracting plate 32, the electromagnetic magnet 33, the valve shaft 34, and the valve 36 upward. Closed by.

  As described above, according to the Francis turbine 1 for hydroelectric power generation according to this embodiment, the path of the flowing water w flowing into the runner 7 is connected to the annular conduit 2 and one end side of the annular conduit 2. And a casing 14. Thereby, space saving of radial direction can be achieved rather than the Francis turbine 1 provided with the conventional spiral type casing.

  Further, according to the Francis turbine 1 according to the present embodiment, the turbine main shaft 4 is provided in the internal space 3 of the annular water guide tube 2, and the rotational energy of the water turbine main shaft 4 is transferred to the outside of the water guide tube 2 via the power transmission mechanism 9. It was set as the structure transmitted to the generator 8 distribute | arranged to. With this configuration, space saving in the axial direction of the Francis turbine 1 can be achieved, and the generator 8 can be easily replaced when a size change or failure of the generator 8 occurs.

  Further, according to the Francis turbine 1 according to the present embodiment, the O-ring 15 is interposed between the inner peripheral wall 2A of the water conduit 2 and the inner peripheral wall 14A of the casing 14, and the gap S is provided therebetween. Thereby, the spigot joining of the outer peripheral wall 2B of the water conduit 2 and the outer peripheral wall 14B of the casing 14 becomes possible, and can be assembled easily.

  Further, according to the Francis turbine 1 according to the present embodiment, the structure of the attachment portion between the turbine main shaft 4 and the runner 7 is configured such that the labyrinth seal 19 is attached to the turbine main shaft 4 after the draining member 20 is attached to the turbine main shaft 23. It was to so. Thereby, a structure is simplified, the attachment process of the labyrinth seal 19 and the draining member 20 is facilitated, and manufacturing cost can be reduced.

  Further, according to the Francis turbine 1 according to the present embodiment, the guide vane opening / closing means 21 for adjusting the water opening of the plurality of guide vanes 17 moves the guide ring 23 in the circumferential direction according to the movement of the connecting rod 25. The structure is configured such that the rotational displacement is transmitted to each guide vane 17 via the internal gear 24 and the external gear 22. Thereby, the structure of the opening / closing means which performs the opening / closing operation | movement of each guide vane 17 simultaneously can be simplified, and the reduction of the manufacturing cost of the Francis turbine 1 can be aimed at. Further, since the member for connecting the guide ring 23 and the guide vane 17 is omitted, the number of assembling steps can be reduced, wear parts can be reduced, and the life of the apparatus can be extended.

  Further, the Francis turbine 1 according to the present embodiment discharges the running water w ′ from the annular conduit 2 to the draft tube 18 without passing through the runner 7 when the load of the generator 8 is disconnected due to a system fault or the like. A bypass mechanism 26 is provided. Thereby, even if the phenomenon that the flowing water w flowing into the runner 7 decreases with the rotation increase of the runner 7, the flowing water w ′ of the water guide pipe 2 can be released to the draft pipe 18 through the bypass mechanism 26. It is possible to prevent an increase in water pressure on the upstream side of the runner 7 and generation of water outage.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to this, In the range which does not deviate from the meaning, it can change suitably.

  The Francis turbine according to the present invention can be applied to hydroelectric power generation, and is particularly useful in the case of medium to high-head hydroelectric power generation.

It is sectional drawing which shows the Francis turbine for hydraulic power generation which concerns on embodiment of this invention. 1 is a side view showing a Francis turbine for hydroelectric power generation according to an embodiment of the present invention. 1 is a top view showing a Francis turbine for hydroelectric power generation according to an embodiment of the present invention. It is principal part sectional drawing which shows X area | region in FIG. It is principal part sectional drawing which shows the Y area | region in FIG. It is a front view which shows the guide vane opening / closing means of the Francis turbine for hydropower generation which concerns on embodiment of this invention. It is sectional drawing which shows the bypass valve part of the bypass mechanism of the Francis turbine for hydropower generation concerning the embodiment of the present invention. It is a top view which shows the bypass valve part of the bypass mechanism of the Francis turbine for hydropower generation concerning the embodiment of the present invention. It is principal part sectional drawing which shows the conventional Francis turbine. It is the arrow directional view which looked at the guide vane opening / closing apparatus 107 of FIG. 9 from the white arrow direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Francis turbine 2 Water guide pipe 2A Inner peripheral wall 2B Outer peripheral wall 3 Internal space 4 Turbine spindle 5 Bearing 6 Bearing 7 Runner 8 Generator 9 Power transmission mechanism 14 Casing 17 Guide vane 19 Labyrinth seal 20 Drain member 21 Guide vane opening / closing means 22 External gear 23 Guide ring 24 Internal gear 26 Bypass mechanism 27 First bypass pipe 28 Bypass valve section 29 Second bypass pipe

Claims (1)

A Francis turbine for hydroelectric power generation comprising guide vane opening and closing means for adjusting the opening of a plurality of guide vanes that accelerates flowing water introduced from a casing and introduces it into the runner,
The guide vane opening / closing means includes an external gear attached to the plurality of guide vanes, a guide ring arranged so as to surround the plurality of guide vanes, and the outer ring attached to the inner periphery of the guide ring. A Francis turbine for hydroelectric power generation comprising an internal gear meshing with a gear, wherein the opening of the plurality of guide vanes is varied by rotationally displacing the guide ring.

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