JP4758797B2 - Francis turbine for hydropower - Google Patents

Description

  The present invention relates to a Francis turbine for hydroelectric power generation, and more specifically, to save space and improve the behavior so that it does not propagate to the outside when it is excessive, so that it can be applied to medium-to-high drop hydropower generation. Concerning water wheel.

  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 at 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.

  Hereinafter, a conventional Francis turbine will be described with reference to FIGS.

  FIG. 9 is a schematic view of a conventional Francis turbine, and FIGS. 10 and 11 are a top view and a cross-sectional view of a main part thereof. In FIG. 9, a Francis turbine 101 surrounds a runner 103 fixed to one end (right 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 106 coupled to the other end (left side of FIG. 9) of the turbine main shaft 102.

  Flowing water guided to the turbine inlet by the water conduit 105 a (see FIG. 10) is accelerated by the guide vane 104 through the spiral casing 105 and flows into the runner 103 in a direction perpendicular to the 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 in the axial direction of the turbine main shaft 102 has its flow velocity reduced by the draft pipe 107 and is discharged from the water discharge port via the suction pipe 108.

  However, in the conventional Francis turbine 101 having such a configuration, the diameter D1 of the spiral casing 105 is significantly larger than the diameter of the water guide pipe 105a and the diameter D2 of the draft pipe 107, and as shown in FIG. Since the water guide pipe 105a and the draft pipe 107 are arranged so as to open at a right angle, there is a case where space is restricted and it is difficult to secure the installation space.

  Further, in the conventional Francis turbine 101, since the generator 106 and the turbine main shaft 102 are arranged outside the water guide pipe 105a and the draft pipe 107, a space for installing the generator 106 and the turbine main shaft 102 is secured. In addition, it is necessary to secure a space not only in the radial direction but also in the axial direction.

  From the above points, the conventional hydroelectric generator 101 has a problem that it cannot be applied when the installation space is limited or when the arrangement of the conduit pipe and the draft pipe 107 is limited. .

  In the conventional Francis turbine 101, the device that opens and closes the guide vane 104 is a complicated link mechanism in which a plurality of arms and pins are connected. For this reason, there are problems that assembly adjustment is difficult, the manufacturing cost is increased, parts are replaced due to aging of the pins, and maintenance management is not easy.

  Further, in the conventional Francis turbine 101, when the load of the generator 106 is disconnected, that is, when it is excessive, the rotation of the runner 103 rises and the water flowing to the runner 103 decreases. As the water pressure on the upstream side rose, there was a risk of water breakage.

  Furthermore, in the conventional Francis turbine 101, the draining member 109 disposed in the attachment portion of the runner 103 and the turbine main shaft 102 has a structure that is attached after the gap adjustment of the labyrinth seal 110 also disposed in the attachment portion. There is a problem in that it takes time to install and the manufacturing cost cannot be reduced.

  The present invention has been made in view of the above points, and the object thereof is to reduce the space of the apparatus and prevent the excessive behavior from spreading to the outside so that it can be applied to medium- and high-head hydropower generation. An object of the present invention is to provide a Francis turbine that is improved as described above and that simplifies the guide vane opening and closing means to reduce the manufacturing cost.

The above object of the present invention is to provide an annular water conduit comprising an inner peripheral wall having an open end on one end and a closed end on the other end, and an outer peripheral wall disposed outside the inner peripheral wall, and the annular guide pipe. A turbine main shaft rotatably supported via a bearing in an internal space formed by an inner peripheral wall of the water pipe, a runner attached to one end of the turbine main shaft so as to rotate integrally with the turbine main shaft, A generator connected to the water wheel main shaft, a casing connected to one end of the annular conduit, and a casing disposed on an outer periphery of the runner to allow the flowing water from the annular conduit to flow into the runner; to accelerate the flowing water incorporating from casing and a plurality of guide vanes to be introduced into the runner, and an outer gear attached to said plurality of guide vanes, arranged a plurality of guide vanes such that encircled A guide vane opening / closing means comprising an idling and an internal gear meshing with the external gear attached to the inner periphery of the guide ring, and opening the water ports of the plurality of guide vanes by rotationally displacing the guide ring. Accomplished by Francis turbine, which varies degrees .

  Further, the object is effectively provided with a bypass mechanism for discharging the flowing water from the annular conduit without going through the runner when the load of the generator is disconnected. Achieved.

  Moreover, the said objective is effectively achieved by connecting the said generator to the said turbine shaft via the power transmission mechanism provided in the other end side of the said turbine main shaft.

  Further, the object is that the mounting portion between the runner and the water turbine main shaft is a labyrinth seal or mechanical seal for maintaining water tightness, and a draining member disposed between the water wheel main shaft and the labyrinth seal or mechanical seal. The labyrinth seal or the mechanical seal is effectively achieved by attaching the water draining member to the turbine main shaft after the water draining member is attached to the turbine main shaft.

  According to the Francis turbine for hydroelectric power generation according to the present invention configured as described above, the path of flowing water flowing into the runner includes an annular water conduit and a casing connected to one end of the annular water conduit. The turbine main shaft is arranged in the internal space formed by the inner peripheral wall of the annular water conduit. Thereby, the space saving of the radial direction and axial direction of a Francis turbine can be achieved. As a result, the Francis turbine, which has conventionally been difficult to apply to hydropower generation in terms of installation space, can be used for hydropower generation.

  Further, the guide ring arranged so as to surround the plurality of guide vanes is rotationally displaced in the circumferential direction, and the rotational displacement is transmitted to each guide vane via the internal gear and the external gear, The guide vanes are opened and closed at the same time. Thereby, the structure of the opening / closing means of the guide vane can be simplified, and the manufacturing cost of the Francis turbine can be reduced.

  In addition, when the load on the generator is disconnected due to a system fault, etc., a bypass mechanism is provided to discharge the running water from the water conduit without going through the runner, so that the behavior during excessive times is not propagated to the outside. . Thereby, when rotation of a water turbine runner goes up, it can prevent that a water pressure rise arises in the upper stream side of a water turbine runner, and can aim at improvement in safety.

  Further, the labyrinth seal or the mechanical seal provided in the attachment portion between the water turbine main shaft and the runner is configured to be attached to the water turbine main shaft after the draining member is attached to the water turbine main shaft. Thereby, a structure is simplified and the gap adjustment of a draining member and a labyrinth seal or a mechanical seal can be performed easily.

  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 so 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 a schematic sectional drawing which shows the conventional Francis turbine. It is a schematic top view which shows the conventional Francis turbine. It is principal part sectional drawing which shows the conventional Francis turbine.

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 portion 29 Second bypass pipe

Claims (4)

An annular water conduit comprising an inner peripheral wall having an opening on one end side and a closed end on the other end side, and an outer peripheral wall disposed outside the inner peripheral wall;
A turbine main shaft rotatably supported via a bearing in an internal space formed by an inner peripheral wall of the annular water conduit;
A runner attached to one end of the turbine spindle so as to rotate integrally with the turbine spindle;
A generator coupled to the turbine spindle;
A casing that is connected to one end side of the annular conduit, and that is disposed on the outer periphery of the runner in order to allow running water from the annular conduit to flow into the runner;
A plurality of guide vanes for accelerating flowing water taken from the casing and introducing it into the runner ;
An external gear attached to the plurality of guide vanes, a guide ring arranged to surround the plurality of guide vanes, and an internal gear meshing with the external gear attached to the inner periphery of the guide ring; A hydroelectric power generation Francis turbine , comprising: a guide vane opening / closing means comprising: a plurality of guide vanes, wherein the opening of the plurality of guide vanes is varied by rotating the guide ring . 2. The Francis turbine for hydroelectric power generation according to claim 1, further comprising a bypass mechanism for discharging the flowing water from the annular conduit without going through the runner when the load of the generator is disconnected. 3. The Francis turbine for hydroelectric power generation according to claim 1 , wherein the generator is connected to the turbine shaft via a power transmission mechanism provided on the other end side of the turbine main shaft. The mounting portion between the runner and the water turbine main shaft includes a labyrinth seal or mechanical seal for maintaining water tightness, and a draining member disposed between the water wheel main shaft and the labyrinth seal or mechanical seal. The hydrostatic power generation Francis turbine according to any one of claims 1 to 3 , wherein the labyrinth seal or the mechanical seal is attached to the turbine spindle after the draining member is attached to the turbine spindle.

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