JP7552382B2 - Water blocking method for draft pipe of vertical shaft water turbine - Google Patents

Description

The present invention relates to a method for water blocking the draft pipe of a vertical shaft water turbine.

There are two types of waterwheels that turn generators in hydroelectric power generation: vertical-shaft and horizontal-shaft. In a vertical-shaft waterwheel, the generator is installed above the vertically extending waterwheel shaft, and a suction pipe is connected below the vertical-shaft waterwheel to guide water supplied from an upstream reservoir into a discharge channel or river.

Generally, at hydroelectric power plants, detailed inspections, maintenance, and repairs are regularly carried out on the inside of hydroelectric machinery, such as the vertical shaft water turbines mentioned above, and the power generation equipment, and in order to carry out these inspections, the hydroelectric machinery and power generation equipment must be disassembled.

However, when the water level of a river rises significantly due to heavy rains caused by the recent rapid weather changes, river water may flow into the suction pipe and flood the interior of the hydroelectric power plant through disassembled parts of the hydroelectric machinery and power generation equipment. For this reason, when inspecting hydroelectric machinery, power generation equipment, and other hydroelectric turbine generators, it is necessary to stop the water flow through the suction pipe connected to the hydroelectric turbine.

Conventionally, after removing the water turbine, water was stopped by covering the opening at the upper end of the draft pipe (the water turbine side). However, if several days pass between removing the water turbine and covering it, it is difficult to reliably prevent flooding damage caused by sudden weather changes.

Patent Document 1 discloses a method of sealing the suction pipe against water using a partition that separates the inside of the suction pipe into a turbine side and a tailrace (river) side, and a rubber seal that expands when air is introduced to seal the gap between the partition and the inner surface of the suction pipe.

JP 2007-198174 A

The above-mentioned Patent Document 1 discloses a method for sealing the suction pipe while the water turbine is installed, but there is concern that if inspection and maintenance are carried out over a long period of time, the water-stopping ability (sealing ability) may decrease due to deterioration of the material, etc.

The present invention was made in consideration of the above points, and provides a water-stopping method for the draft pipe of a vertical shaft water turbine that is easy to install, can prevent flooding damage caused by sudden weather changes, and can maintain water-stopping performance for the long term.

The present invention has been made to solve the above problems, and one aspect of the present invention is a method for water-stopping the suction pipe of a vertical-shaft water turbine having a vertical rotating shaft and a suction pipe connected below the vertical-shaft water turbine for directing suction water from the vertical-shaft water turbine to a discharge channel, the method comprising the steps of: installing a scaffold for supporting a closing member using scaffolding components carried into the suction pipe from an inspection manhole opened in a wall portion at the upper end of the suction pipe on the vertical-shaft water turbine side while the vertical-shaft water turbine is installed; and installing a pair of semicircular annular metal scaffolds carried into the suction pipe from the inspection manhole. This method for stopping water flow in the suction pipe of a vertical shaft water turbine includes a first assembly step of installing a first annular closure plate above the closure member support scaffold by horizontally positioning a first member; a second assembly step of installing a second closure plate that blocks the central opening of the first closure plate by horizontally positioning a pair of semicircular metal second members carried into the suction pipe from the inspection manhole ; an arrangement step of positioning the first closure plate at a water stopping position where the closure plate comprising the first and second closure plates can stop water in the suction pipe; and a second assembly step being carried out after the arrangement step.

In one aspect of the present invention, the draft pipe may have an expansion pipe at the upper end, the diameter of which increases as it moves away from the vertical shaft water turbine.

In one aspect of the present invention, in the placement process, the first closure plate may be lifted toward the vertical shaft water turbine using an air supply pipe that takes in outside air into the draft pipe as a fulcrum.

In one aspect of the present invention, the placement step may be configured to place a plurality of height-adjustable support members between the first closure plate and the closure member support scaffold.

In one aspect of the present invention, the disposing step may be configured to dispose a packing material between the first closure plate and the inner surface of the draft pipe.

In one aspect of the present invention, the packing material may be configured to be on the first closure plate and have an outer diameter larger than that of the first closure plate.

The present invention provides a method for watertightness of the suction pipe of a vertical shaft water turbine that is easy to install, prevents flooding damage caused by sudden weather changes, and maintains watertightness for the long term.

FIG. 1 is a diagram showing a schematic configuration of a hydroelectric power generation facility to which a draft pipe water blocking method for a vertical shaft water turbine according to an embodiment of the present invention is applied. FIG. 2 is a partially enlarged cross-sectional view showing the structure around the vertical shaft type Francis turbine 11. FIG. 3 is a top view of one embodiment of the draft closure member 20. As shown in FIG. FIG. 4 is a cross-sectional view showing the draft closing member 20 installed in the draft pipe 14. FIG. 5 is a diagram for explaining the process up to the installation of the work scaffold 31 and the closing member supporting scaffold 30 inside the suction pipe 14. FIG. 6 is a diagram showing the configuration of the closing member supporting scaffold 30. As shown in FIG. FIG. 7 is a diagram showing how the semicircular closing plate 21A is divided and carried into the draft pipe 14. As shown in FIG. FIG. 8 is a diagram showing a state in which the first closure plate 21 is lifted up by the lever block 51. As shown in FIG. FIG. 9 is a diagram showing a state in which a plurality of jack units 40 are arranged between the first closure plate 21 and the closure member supporting scaffold 30. As shown in FIG. FIG. 10 is a diagram for explaining a method for sealing the draft pipe 14 of the vertical shaft type Francis turbine 11 in the embodiment, and also shows a state in which the second closing plate 22 is attached. FIG. 11A is an exploded plan view showing the first closing plate 27 of the modified example. FIG. 11B is a cross-sectional view of the first closing plate 27 taken along line XI-XI of FIG. 11A. FIG. 12A is a top view showing a modified example of the draft closing member 29. FIG. FIG. 12B is a cross-sectional view of the draft closure member 29 shown in FIG. 12A taken along line XII-XII.

First, a hydroelectric power generation facility to which the draft pipe water blocking method for a vertical shaft water turbine of the present invention is applied will be described with reference to the drawings.
[Hydroelectric power generation facilities]
Fig. 1 is a schematic diagram showing the configuration of a hydroelectric power generation facility to which the method for cutting water in the draft pipe of a vertical shaft type water turbine according to the present embodiment is applied. Fig. 2 is a partially enlarged cross-sectional view showing the structure around a vertical shaft type Francis turbine 11.

The vertical-shaft water turbine generator 100 shown in FIG. 1 is installed in a power plant building 101. The generator 13 in the vertical-shaft water turbine generator 100 is installed, for example, on the first above-ground floor of the power plant building 101, and the vertical-shaft Francis water turbine (vertical-shaft water turbine) 11 is installed, for example, on the first basement floor. A vertical-shaft water turbine, which has a water turbine and generator arranged one above the other, can reduce the floor area of the building compared to a horizontal-shaft type, so it can be installed without being restricted by topographical constraints.

The vertical-shaft water turbine generator 100 includes an inlet pipe 12 that guides high-pressure water from an upstream reservoir to a vertical-shaft Francis turbine (vertical-shaft water turbine) 11, a vertical-shaft Francis turbine 11 that circulates the water guided by the inlet pipe 12, a generator 13 driven by the vertical-shaft Francis turbine 11, and a suction pipe 14 that guides the water that has passed through the vertical-shaft Francis turbine 11 to a discharge channel (river) 90.

The inlet pipe 12 is connected to the volute casing 16 of the vertical-shaft Francis turbine 11, and high-pressure water flows in from the inlet pipe 12. As shown in FIG. 2, the runner 17 arranged inside the volute casing 16 generates power by rotating with the high-pressure water introduced into the volute casing 16. The amount of high-pressure water flowing into the runner 17 is adjusted by guide vanes 18 provided on the outer periphery of the runner 17.

A main shaft 19 extending vertically is connected to the rotating shaft O1 of the runner 17 in the vertical-shaft Francis turbine 11, and a generator 13 is connected to the upper end of the main shaft 19.

The generator 13 is composed of a rotor (not shown) connected to the upper end of the main shaft 19 and a stator (not shown) arranged around the rotor, and is connected to the runner 17 via the main shaft 19.

The suction pipe 14 is attached downstream of the impeller outlet 17b of the runner 17, extends vertically downward from directly below the runner 17, and curves toward the discharge channel 90 (river) side as shown in FIG. 1. As shown in FIG. 2, an expansion pipe 14A that gradually expands vertically downward from the impeller outlet 17b is arranged at the upper end of the suction pipe 14 connected to the impeller outlet 17b, and reduces the flow velocity of the water flowing out from the impeller outlet 17b, converting velocity energy into pressure energy.

As shown in Figures 1 and 2, an inspection manhole 141 is opened in the pipe wall of the expansion pipe 14A at the upper end of the draft pipe 14 on the vertical shaft type Francis turbine 11 side, allowing inspection workers to enter and exit the draft pipe 14. In addition, two air supply pipes 142 are provided in the expansion pipe 14A. By taking in outside air into the draft pipe 14 through this pair of air supply pipes 142, it is possible to prevent noise and the like generated in the draft pipe 14 due to the swirling flow at the blade outlet 17b of the runner 17.

The draft closing member 20 shown in Figure 1 is used to stop water flow inside the suction pipe 14 when inspecting, maintaining, etc. the vertical shaft Francis turbine 11 and the generator 13. As shown in Figure 2, the draft closing member 20 is installed at the lower end side of the expansion pipe 14A of the suction pipe 14, below the inspection manhole 141 and the pair of air supply pipes 142. The draft closing member 20 is installed almost horizontally inside the suction pipe 14 that extends vertically, and stops water flow inside the suction pipe 14 by blocking it.

Fig. 3 is a plan view showing the draft closing member 20 of this embodiment. Fig. 4 is a cross-sectional view showing a state in which the draft closing member 20 is installed in the draft pipe 14.
As shown in Figures 3 and 4, the draft closure member 20 is composed of a first closure plate 21, a second closure plate 22, and a pair of pressing members 23 made of metal, plate rubber packings (packing material) 24A, 24B, and a sealing material 25, and its overall outline when viewed from above (Z direction) is circular.
The outer diameter of the draft closing member 20 coincides with the inner diameter of the diffuser 14A of the suction pipe 14 at a predetermined position on the lower end side. The draft closing member 20 is installed watertightly with respect to the suction pipe 14. Here, "watertight" means a state in which the inside of the suction pipe 14 is blocked by the draft closing member 20 to stop water from entering.

As shown in FIG. 3, the first closure plate 21 is composed of a pair of semicircular annular closure plates (first members) 21A. The pair of semicircular annular closure plates 21A are arranged horizontally with their arc centers aligned with the central axis O2 of the suction pipe 14, forming an annular shape that follows the cylindrical shape of the suction pipe 14, thereby forming a circular opening in the center (hereinafter, central opening 21B).

A locking portion 21b is provided at a predetermined position on the upper surface 21a of each semicircular annular closure plate 21A, which is used when lifting the first closure plate 21 upward. The locking portion 21b, which is L-shaped in cross section, is provided at the center of gravity of the semicircular annular closure plate 21A and maintains the horizontal position of the semicircular annular closure plate 21A.

As shown in FIG. 4, a first plate rubber packing 24A is disposed on the outer peripheral edge of the upper surface 21a of the first closure plate 21 to seal the gap between the outer peripheral edge of the first closure plate 21 and the wall of the suction pipe 14. As shown in FIG. 3, the first plate rubber packing 24A has an annular shape that conforms to the outer shape of the first closure plate 21 as viewed in the axial direction, and is fixed to the first closure plate 21 by the pressing member 23.

As shown in Figures 3 and 4, the pressing member 23, the first plate rubber packing 24A, and the first closing plate 21 each have a number of screw holes 26 formed therein, and the pressing member 23 is tightened by a number of screws inserted into each of the screw holes 26, thereby fixing the first plate rubber packing 24A to the first closing plate 21.

The first plate rubber packing 24A has an outer diameter slightly larger than that of the first closing plate 21. The outer peripheral edge of the first plate rubber packing 24A is compressed by the pressing member 23 while inserted between the outer peripheral edge of the first closing plate 21 and the inner wall surface 14b of the suction pipe 14, sealing the gap between them. The gap into which the first plate rubber packing 24A is inserted is filled with a sealing material 25 that is airtight and stretchable. For example, a liquid gasket such as foam rubber is used as the sealing material 25.

As shown in FIG. 3, the second closure plate 22 is made up of a pair of semicircular plate members (second members) 22A, which are combined to form an overall circular shape. As shown in FIGS. 3 and 4, the second closure plate 22 is arranged on the upper surface 21a side of the first closure plate 21 so as to block the central opening 21B of the first closure plate 21. Since the diameter of the second closure plate 22 is slightly larger than the diameter of the central opening 21B, placing the second closure plate 22 on the first closure plate 21 blocks the entire central opening 21B.

A number of screw holes 26 are formed on the outer periphery of the second closure plate 22 and the inner periphery of the first closure plate 21 (each semicircular annular closure plate 21A), and the second closure plate 22 is fixed to the first closure plate 21 by a number of screws inserted into each of the screw holes. A ring-shaped second plate rubber packing 24B is disposed between the first closure plate 21 and the second closure plate 22, and an airtight and stretchable sealing material 25 is filled between these members. In this way, the second closure plate 22 is attached to the first closure plate 21 without any gaps.

As shown in FIG. 4, the draft closure member 20 is installed on the closure member support scaffold 30 assembled inside the suction pipe 14 via multiple jack units (support members) 40. The jack units 40 can be screw-type, rack-type, electric-type, or manual-type.

The draft closure member 20 is supported from below by the closure member support scaffolding 30 and a plurality of jack sections 40, and is lifted upward by lever blocks (registered trademark) 51 attached to a pair of air supply pipes 142.
The draft closure member 20 is supported at the raised height by the jacks 40. The draft closure member 20 is supported from below by the scaffolding 30 for supporting the closure member and from above by the lever block 51, so that the stable installation state in the suction pipe 14 is maintained for a long period of time.

In this embodiment, the draft closure member 20 as described above is used to separate the inside of the suction pipe 14 into the runner 17 side and the discharge channel 90 side, thereby sealing off the water in the suction pipe 14.

[Water-stopping method for the draft pipe of a vertical-shaft Francis turbine]
Next, a method for closing the draft pipe 14 of the vertical shaft type Francis turbine 11 using the above-mentioned draft closing member 20 will be described.
5 to 10 are diagrams for explaining a method of waterproofing the draft pipe 14 of the vertical shaft type Francis turbine 11 in this embodiment.

Figure 5 is a diagram for explaining how to install the work scaffold 31 and the scaffold for supporting the closure member 30 inside the suction pipe 14. Figure 6 is a diagram showing the configuration of the scaffold for supporting the closure member 30.

First, as shown in Figure 5, a work scaffold 31 is set up inside the suction pipe 14 with the vertical shaft Francis turbine 11 (runner 17) still installed. The work scaffold 31 is set up so that it projects outward from the inspection manhole 141, allowing workers to enter and exit the suction pipe 14. The work scaffold 31 is set up until the closing of the suction pipe 14 is completed, but the work scaffold 31 is not shown in Figures 6 and onwards.

Next, the scaffolding 30 for supporting the closure member is installed below the work scaffolding 31 inside the suction pipe 14 (scaffolding installation process). For example, as shown in FIG. 6, the scaffolding 30 for supporting the closure member is created by welding multiple steel materials (scaffolding components) 32 brought in through the inspection manhole 141 to each other in a lattice pattern while also welding each steel material 32 to the inner wall surface 14b of the suction pipe 14. At this time, the multiple steel materials 32 are welded in a lattice pattern so that their top surfaces are aligned with each other.

FIG. 7 is a diagram showing how the semicircular closing plate 21A is divided and carried into the draft pipe 14. As shown in FIG.
7, the semicircular closure plates (members) 21A are carried in one by one from the inspection manhole 141 and assembled into a ring shape in the suction pipe 14 (first assembly step). The pair of semicircular closure plates 21A formed into a ring shape are joined together by welding, and the first closure plate 21 is temporarily placed on the closure member support scaffold 30.

Then, the first plate rubber packing 24A is attached to the upper surface of the annular first closure plate 21, which is temporarily placed on the closure member support scaffolding 30, using the pressing member 23. The outer peripheral edge of the first plate rubber packing 24A attached to the first closure plate 21 before it is lifted protrudes slightly radially outward from the outer peripheral edge of the first closure plate 21.

FIG. 8 is a diagram showing a state in which the first closure plate 21 is lifted up by the lever block 51. As shown in FIG.
8, for example, the first closure plate 21 is lifted up toward the vertical shaft type Francis turbine 11 using a lever block 51 connected to a pair of air supply pipes 142. At this time, the lever block 51 is attached to each of the locking portions 21b of the pair of semicircular annular closure plates 21A constituting the first closure plate 21, and the first closure plate 21 is lifted up above the expansion pipe 14A with each air supply pipe 142 as a fulcrum.

The expansion pipe 14A of the suction pipe 14 has a diameter that decreases as it goes upward. Therefore, by pulling the first closure plate 21 upward inside the expansion pipe 14A, the outer peripheral edge of the first plate rubber packing 24A attached to its periphery enters between the outer peripheral edge of the first closure plate 21 and the inner wall surface 14b of the suction pipe 14, and adheres closely to the pipe wall. The first closure plate 21 stops at a predetermined position (water stop position) in the vertical direction by being compressed (placement process).

FIG. 9 is a diagram showing a state in which a plurality of jack units 40 are arranged between the first closure plate 21 and the closure member supporting scaffold 30. As shown in FIG.
9, a plurality of jack parts 40 are arranged between the lifted first closure plate 21 and the closure member support scaffold 30, and fixed to the upper surface of the closure member support scaffold 30 by welding. The number and arrangement positions of the jack parts 40 are appropriately set so as to suitably support the horizontal position of the first closure plate 21. By adjusting the tension height of each jack part 40 at the position where the first closure plate 21 is lifted, the draft closure member 20 in close contact with the pipe wall of the suction pipe 14 is supported from the lower surface side, and the draft closure member 20 is maintained in the water stop position.

FIG. 10 is a view showing a state in which the second closing plate 22 is attached.
Next, as shown in Fig. 10, the second closing plate 22 is installed to close the central opening 21B of the first closing plate 21 (second assembly process). Specifically, after placing the second plate rubber packing 24B on the first closing plate 21, the pair of semicircular plate members 22A are carried in one by one in a divided state through the inspection manhole 141, and assembled into a circular shape in the suction pipe 14 to form the second closing plate 22. After placing the second closing plate 22 on the first closing plate 21 via the second plate rubber packing 24B, the second closing plate 22 is attached to the first closing plate 21 by tightening with bolts. Furthermore, the second closing plate 22 is welded to the first closing plate 21, thereby closing the central opening 21B of the first closing plate 21 with the second closing plate 22.

Next, the portions where the first plate rubber packing 24A and the second plate rubber packing 24B are inserted are caulked with a sealant 25. By caulking the portions where the packings are inserted between the members with the sealant 25, the gaps that occur between the members are filled, improving watertightness.
This completes the installation of the draft closing member 20 into the suction pipe 14, and the draft closing member 20 thus installed seals off water from within the suction pipe 14.

According to the above-mentioned water-stopping method for the draft pipe 14 of the vertical-shaft Francis turbine 11, when carrying out inspection, maintenance, etc., the draft closure member 20 can be installed in the draft pipe 14 while the vertical-shaft Francis turbine 11 is still installed. In other words, since the draft closure member 20 can be installed in the draft pipe 14 before disassembling the vertical-shaft Francis turbine 11, it is possible to reliably prevent flooding damage to the installation floor of the vertical-shaft Francis turbine 11.

The intervals at which inspections and maintenance of the vertical-shaft Francis turbine 11 and generator 13 are carried out vary depending on the hydroelectric power plant, but they are often carried out at intervals of approximately 10 to 20 years. The generator 13 and then the vertical-shaft Francis turbine 11 are disassembled, but because it takes several days from removing the runner 17 of the vertical-shaft Francis turbine 11 to sealing the draft pipe 14 with a lid, there was a risk of flooding on the floor where the turbine is installed in the power plant building 101. Until now, inspections have been carried out to avoid the rainy season and periods with many typhoons, but the risk of flooding due to recent heavy rains has increased, so it was necessary to quickly stop the water from entering the draft pipe 14.

By adopting the watertight method for the draft pipe 14 of the vertical-shaft Francis turbine 11 of this embodiment, the generator 13 and the vertical-shaft Francis turbine 11 can be disassembled while the draft pipe 14 is watertight using the draft closing member 20 installed in advance inside the draft pipe 14. Therefore, even if the disassembly work takes several days, flood damage inside the power plant building 101 during that time can be reliably prevented.

In addition, the expansion pipe 14A of the suction pipe 14 on which the draft closure member 20 is installed is tapered in diameter as it moves upwards, so that if water from the river flows back into the suction pipe 14, the draft closure member 20 is pushed upward, further compressing the first plate rubber packing 24A, further enhancing the water-stopping effect of the suction pipe 14. In this way, by installing the draft closure member 20 before dividing the vertical shaft Francis turbine 11, the risk of flooding in the unlikely event of backflow from the river can be more effectively reduced.

In addition, the draft closure member 20 is lifted upward while its lower side is supported by the closure member support scaffold 30 and multiple jack units 40. Therefore, the load of the draft closure member 20 can be distributed to the closure member support scaffold 30 via the multiple jack units 40. Even if a malfunction occurs in the lifting structure of the draft closure member 20, the lower closure member support scaffold 30 can prevent the draft closure member 20 from tilting or falling, so the draft closure member 20 can be stably installed in the suction pipe 14 and the installed state can be maintained for a long period of time.

The draft closure member 20 used in the water-stopping method for the draft pipe 14 of the vertical shaft Francis turbine 11 of this embodiment is not limited to the configuration described above and can be modified as appropriate.

Figure 11A is a plan view showing an exploded view of the first closing plate 27 of a modified example, and Figure 11B is a cross-sectional view taken along line XI-XI of the first closing plate 27 of Figure 11A. Figure 12A is a top view showing a modified example of the draft closing member 29, and Figure 12B is a cross-sectional view taken along line XII-XII of the draft closing member 29 shown in Figure 12A.

The pair of semicircular annular closure plates 21A constituting the first closure plate 21 described above has only one locking portion 21b used when lifting with the lever block 51 at a position overlapping the center of gravity of each first closure plate 21, but for example, as in the first closure plate 27 shown in FIG. 11A, each semicircular annular closure plate 27A may have two locking portions 21b. By locking the lever block 51 to a pair of locking portions 21b evenly arranged on both sides of each semicircular annular closure plate 27A through the center of gravity position, it is possible to prevent the semicircular annular closure plate 27A from swaying sideways when lifting. This makes it easier to maintain the horizontal position of each semicircular annular closure plate 27A, and the first closure plate 27 can be lifted upward in a stable state.

One semicircular annular closure plate 27A is provided with multiple (four) support parts 27d that support the other semicircular annular closure plate 27A from the underside 27c. Two support parts 27d are provided on each radial side of the semicircular annular closure plate 27A, and protrude from each side toward the other semicircular annular closure plate 27A. These multiple support parts 27d prevent misalignment of the butted ends when a pair of semicircular annular closure plates 27A are combined in an annular shape.

In addition, in the above-mentioned first closing plate 21, the second closing plate 22 having a diameter larger than the central opening 21B is arranged on the upper surface 21a side of the first closing plate 21, but as shown in Figures 12A and 12B, the second closing plate 28 having a diameter substantially equal to the central opening 27B of the first closing plate 27 may be inserted into the central opening 27B to close it. The second closing plate 28 is supported by a pair of second closing plate support parts 27f provided on the lower surface 27c side of each semicircular annular closing plate 27A to prevent it from falling out of the central opening 27B.
Such a draft closing member 29 may be used in the water blocking method for the draft pipe 14 of the vertical shaft type Francis turbine 11 of this embodiment.

One embodiment of the invention has been described in detail above with reference to the drawings, but the specific steps of the water-stopping method and the configuration of the draft closing member are not limited to those described above, and various design changes can be made without departing from the spirit of the invention.

For example, in the above embodiment, when lifting the draft closure member 20, it is lifted upward using the pair of air intake pipes 142 as a fulcrum, but this is not limited thereto. For example, if only the generator 13 is to be inspected, the draft closure member 20 may be lifted using the runner 17 of the vertical-shaft Francis turbine 11 as a fulcrum. When inspecting the vertical-shaft Francis turbine 11, it is preferable to use the air intake pipes 142.

The pair of air supply pipes 142 are not limited to the shape shown in the figure, and air supply pipes 142 having other shapes, such as an inverted T-shape, may be provided.

In addition, in the above embodiment, the draft closure member 20 is lifted to the water-stopping position by the lever block 51, and the position is maintained from below by multiple jack units 40 to stop water flow, but the water-stopping method is not limited to this.

For example, if the air supply pipe 142 is not installed in the suction pipe 14, instead of lifting the draft closure member 20 using the lever block 51, the draft closure member 20 may be positioned in the water stopping position by lifting the draft closure member 20 from below using multiple jack parts 40.

The member that lifts the draft closure member 20 from below is not limited to the jack portion 40, but may be a spring member or the like.

11...vertical shaft type Francis turbine (vertical shaft type water turbine), 13...generator, 14...draft tube, 14A...expander, 21, 27...first closure plate, 21A...semicircular annular closure plate (first member), 21B, 27B...central opening, 22...second closure plate, 22A...semicircular plate member (second member), 24A...plate rubber packing (packing material), 27d...support part, 28...second closure plate, 30...scaffolding for supporting closure member, 32...steel material (scaffolding component), 40...jack part (support member), 90...spillage, 100...vertical shaft type water turbine generator, 141...inspection manhole, 142...air supply pipe, O1...rotating shaft

Claims (6)

A method for sealing the draft pipe of a vertical shaft type water turbine generator, which includes a vertical shaft type water turbine having a vertical rotation shaft and a draft pipe connected below the vertical shaft type water turbine and directing the draft water from the vertical shaft type water turbine to a discharge channel, comprising the steps of:
a scaffold installation process for installing a closing member supporting scaffold using scaffolding components carried into the draft pipe through an inspection manhole opened at the upper end of the draft pipe on the vertical shaft type water turbine side while the vertical shaft type water turbine is installed;
a first assembly step of horizontally arranging a pair of semicircular metal first members carried into the suction pipe from the inspection manhole to install an annular first closure plate above the closure member support scaffold;
a second assembly process of horizontally arranging a pair of semicircular second members made of metal carried into the suction pipe from the inspection manhole to install a second closure plate that closes a central opening of the first closure plate;
and a positioning step of positioning the first closure plate at a water stopping position where the closure plate including the first closure plate and the second closure plate can stop water in the draft pipe,
The method for water blocking the draft pipe of a vertical shaft water turbine, comprising carrying out the second assembly step after the arranging step. The draft pipe has an expansion pipe at the upper end thereof, the expansion pipe being shaped to expand in diameter as it moves away from the vertical shaft type water turbine.
A method for water blocking the draft pipe of a vertical shaft water turbine according to claim 1. In the placing step,
The first closing plate is lifted toward the vertical shaft water turbine using an air supply pipe that takes in outside air into the draft pipe as a fulcrum.
A method for water blocking the draft pipe of a vertical shaft water turbine according to claim 1 or 2. In the placing step,
A plurality of height-adjustable support members are disposed between the first closure plate and the closure member support scaffold;
A method for water blocking the draft pipe of a vertical shaft water turbine according to any one of claims 1 to 3. In the placing step,
5. The method for water-sealing a draft pipe of a vertical shaft water turbine according to claim 1, further comprising disposing a packing material between the first closing plate and an inner surface of the draft pipe. The method for water-stopping the suction pipe of a vertical shaft water turbine according to claim 5, wherein the packing material on the first closure plate has an outer diameter larger than that of the first closure plate.

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