JPS634024B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust system for a multi-stage hydraulic machine, and more particularly to an exhaust system for a multi-stage hydraulic machine that operates to push down the water surface during pump startup or phase adjustment operation.

When hydroelectric power plants have higher heads and the head exceeds the performance limits of single-stage pump-turbines, multi-stage pump-turbines are used. Many conventional multi-stage pump turbines do not have movable guide vanes, so they have no choice but to use an underwater startup method when starting the pump. However, the submersible starting method has the drawback that as the capacity of the machine increases, the shaft input when starting the pump becomes extremely large, which adversely affects the system and is economically disadvantageous. Therefore, in recent large-capacity multi-stage hydraulic machines, phase adjustment operation in which the generator is motored to idle the runners when the water surface is depressed, and a phase adjustment operation in which the runner is idled while the water surface is depressed, and a phase adjustment operation in which the water surface is depressed in order to quickly respond to pumping operation, have been adopted. It is required that the runner be idly rotated in the direction of the pump to perform pumping standby operation.

However, because the flow path shape of multistage pump turbines is complex, it is difficult to completely exhaust the compressed air from the runner chambers of the low pressure stages without causing exhaust congestion. It was difficult to start the pump or perform phase adjustment operation under the lowered condition.

The present invention was devised in consideration of the above circumstances, and is designed to reliably and efficiently pump air into the runner chambers and flow paths of each low-pressure stage after operating a multi-stage hydraulic machine equipped with movable guide vanes to push down the water surface. The object of the present invention is to provide an exhaust system for a multi-stage hydraulic machine that can completely exhaust the air.

An embodiment of the exhaust system for a multi-stage hydraulic machine according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which the present invention is applied to a two-stage pump-turbine. In the figure, reference numeral 1 indicates the main shaft of the two-stage pump-turbine, and this main shaft 1 has a high-pressure stage runner 2, a low-pressure stage runner 3 and are fixed at a distance in the axial direction via a spacer 4. The high pressure stage runner 2 is housed in a high pressure stage runner chamber 5, while the low pressure stage runner 3 is housed in a low pressure stage runner chamber 6.

An upper cover 7 is arranged above the high-pressure stage runner 2, while a lower cover 8 is arranged below the high-pressure stage runner 2. A movable guide vane 10 whose opening degree can be adjusted is arranged radially outward. The movable guide vane 10 has a guide vane operating link mechanism 11 connected to the upper end of its upper stem 10a, and the guide vane is opened and closed by a guide ring 12, as is known in the art.

Furthermore, a spiral casing 14 integrally provided with a stay vane 13 is disposed radially outward of the movable guide vane 10.

On the other hand, below the low-pressure stage runner 3, a lower cover 16 integrally provided with a stay vane 15 is arranged, and the lower end of this lower cover 16 is connected to a suction pipe 17. An intermediate speed ring 18 that also serves as an upper cover for the low pressure stage runner 3 is installed between this lower cover 16 and the lower cover 8 on the high pressure stage side.
is equipped with a plurality of return blades 19, and a return flow path is formed between the blades.

Further, an outer cylinder 21 having a return passage 20 therein is disposed outside the intermediate speed ring 18 and the lower cover 16.

A water sealing device 22 is provided between the runner crown 2a of the high pressure stage runner 2 and the upper cover 7, and this water sealing device 22 is connected to the cover liner 23 on the upper cover 7 side and the runner crown 2a on the side of the runner crown 2a. It is constituted by a labyrinth passage 24 between the sealing ring 2b and the sealing ring 2b. Similarly, a water sealing device 25 is also provided between the runner crown 3a of the low pressure stage runner 3 and the intermediate speed ring 18, and this water sealing device 25 is a seal between the intermediate speed ring 18 and the runner crown 3a. It is constituted by a labyrinth passage 26 between it and the stop ring 3b.

Furthermore, a high-pressure stage exhaust chamber 28 is formed radially inward of the water sealing device 22 of the high-pressure stage runner 2, and an exhaust hole is formed in the runner crown 2a of the high-pressure stage runner 2 so as to communicate with this exhaust chamber 28. 29 is drilled. One end 30a of an exhaust pipe line 30 that can exhaust air to the outside is connected to the ceiling surface of the exhaust chamber 28.

Similarly, a low pressure stage exhaust chamber 31 is formed radially inward of the water sealing device 25 of the low pressure stage runner 3.
The low pressure stage runner 3 is connected to the exhaust chamber 31.
The runner crown 3a has an exhaust hole 32 formed at the runner outlet end. The above exhaust chamber 31
An exhaust passage 33 is opened on the ceiling surface of the engine, and the exhaust passage 33 is bored across the intermediate speed ring 18 and its return blades 19, and is connected to the exhaust pipe 34.
It is now possible to exhaust air to the outside through the

In this way, the runner crown 2a of the high pressure stage runner 2 is provided with the water sealing device 22, the exhaust chamber 28, and the exhaust hole 29.
The exhaust system consisting of the exhaust pipe line 30 and the exhaust pipe line 30 is connected to the runner crown 3a of the low pressure stage runner 3, and the water sealing device 25,
By providing an exhaust system consisting of an exhaust chamber 31, an exhaust hole 32, an exhaust passage 33, and an exhaust pipe line 34, the compressed air in the high-pressure stage runner chamber 5 and high-pressure stage runner chamber 6 is released into the exhaust pipes 30, 34. The structure is such that the exhaust gas can be exhausted by this, thereby eliminating exhaust congestion.

Next, the procedure for starting the pump using the two-stage pump turbine configured as described above will be explained.

In FIG. 2, compressed air is blown into the high-pressure stage runner chamber 5 through a compressed air supply pipe (not shown) with the movable guide vane 10 fully closed, and the water below the runner chamber 5 is returned to the vane 19 and the return flow path. 20
The water is pushed downward through the low-pressure stage runner chamber 6, and the water surface is pushed down until the water level WL is directly below the low-pressure stage runner 3, as shown in FIG. Thereafter, the high-pressure stage runner 2 and low-pressure stage runner 3, which have reduced rotational resistance, are started toward the pump by a relatively small-capacity starting device, and at the same time as they are connected in parallel with the system, exhaust from the exhaust pipe line 30 is started. .

As the exhaust progresses, the water level WL inside the suction pipe 17 increases.
rises, and the water that has accumulated on the low-pressure stage runner 3 is blown outward in the radial direction by the centrifugal force of the runner.
As shown in the figure, the return flow path 20 is filled with water, and at this time, air with low specific gravity remains in the center of the low-pressure stage runner 3, and its outer periphery is surrounded by a water wall. As the exhaust progresses further and the water surface reaches the high pressure stage runner 2, the centrifugal force of the high pressure stage runner 2 causes the water to be blown radially outward, but since the movable guide vane 10 is fully closed, the high pressure stage runner chamber The water inside 5 sticks to the outside, and the surface of the water wall gradually moves inward in the radial direction until it reaches the state shown in FIG. However, the high pressure stage runner chamber 5
When the volume of the air in the low pressure stage runner chamber 6 becomes approximately equal to the volume of the air remaining in the low pressure stage runner chamber 6, the exhaust pipe 34 on the side of the low pressure stage runner chamber 6 is opened to start exhausting, and the high pressure stage and After completing exhaustion while balancing the water filling level of the low pressure stage, the movable guide vane 10 is opened and water pumping operation begins.

In the above-mentioned exhaust process, exhaust congestion tends to occur in the runner chambers of each low pressure stage into which the water filled in the high pressure stage runner chamber flows, but according to the present invention, An exhaust hole 32 is bored in the runner crown of the low pressure stage runner 3 other than the runner, and an exhaust chamber 3 is provided on the outlet side of the exhaust hole 32.
1, an exhaust pipe line 33 communicating with the outside from the exhaust chamber 31 is bored across the return vane 19, and a seal including a labyrinth passage 26 is provided outside the exhaust chamber 31 and on the back side of the runner crown. water device 2
5, the compressed air in the runner chamber 6 of the low pressure stage can be exhausted to the outside without causing exhaust congestion.

In the embodiment described above, the labyrinth passages 24 and 26 as a water sealing device were provided between the runner crown of each stage runner and the upper cover on the fixed side or the intermediate speed ring, but other implementations of the water sealing device are possible. For example, as shown in FIG. 5, a plurality of fins 36 may be provided radially outside the exhaust chamber 31 on the back side of the runner crown 3a in the radial direction. According to such embodiments,
Water attempting to move radially inward through the gap between the runner crown 3a and the intermediate speed ring 18 is stopped by the lift caused by the centrifugal force of the fins 36.
Appropriate water sealing effect can be obtained.

Further, in the embodiment shown in FIG. 1, exhaust holes 29 and 32 formed in the runner crown of each stage of runner are provided substantially parallel to the axis of the main shaft 1 of the water turbine. However, as shown in FIG. 6, for example, in the case of the low-pressure stage runner 3, the center line of the exhaust hole 32 is adjusted so that the outlet 32o of the exhaust hole 32 opens at a position closer to the main shaft 1 than the inlet 32i. It may be provided at an angle with respect to the main shaft 1 of the water turbine.
With this configuration, a lift is generated due to the difference in velocity head from the exhaust chamber side toward the flowing water surface depending on the radius difference between the inlet and outlet positions, so the water cannot be completely sealed by the water sealing device and the exhaust air cannot be completely sealed. It works by discharging the water that has flowed into the room toward the flowing water surface to prevent the exhaust pipe entrance from being blocked, and even if the inside of the runner is filled with water up to the exhaust hole entrance on the flowing water surface, the water will still flow into the exhaust chamber. This prevents the air from flowing into the runner chamber to some extent, and allows the stagnant air in the runner chamber to be more completely exhausted.

In FIG. 7, the outer periphery is integrally fixed to the intermediate speed ring 18 between the outlet 32o of the exhaust hole 32 of the runner crown and the inlet 33i of the exhaust passage 33 that crosses the intermediate speed ring 18.
This is an example in which a disk-shaped partition plate 40 is provided with a constant annular gap 38 between it and the inner peripheral surface. According to this embodiment, even when water enters the exhaust chamber 31, the water is pushed to the outer circumferential side of the exhaust chamber 31 due to the difference in specific gravity between water and air and the action of centrifugal force. Since the air and water are stuck together and separated, only air is guided to the exhaust pipe 33 from the annular gap 38 close to the main shaft 1 of the water turbine, making it possible to perform more complete exhaustion.

In FIG. 8, the shape of the exhaust pipe line 41 in the exhaust chamber 31 is an L-shaped pipe, and the opening end 41a is set at the top of the innermost circumference of the exhaust chamber 31.
Based on the principle that water is separated into the outer periphery and air is separated into the inner periphery and upward within the chamber, more complete exhaustion is possible.

In the above-mentioned embodiments, the present invention was applied to a two-stage pump turbine in which a movable guide vane was provided only on the high-pressure stage runner side, but a movable guide vane was also provided on the low-pressure stage runner side. The invention is also applicable not only to two-stage pump-turbines but also to three-stage or more pump-turbines.

Since the present invention has the above-mentioned configuration, when the pump is started or when the phase adjustment operation is performed under conditions where the water surface is pushed up,
In particular, the air in the runner chamber can be exhausted without causing exhaust congestion in low-pressure stage runners, and this allows smooth pump startup without adversely affecting the system in multi-stage pump turbines with complex flow path shapes. Furthermore, it is possible to perform phase adjustment operation that improves the power factor of the entire system.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing a two-stage pump turbine to which the present invention is applied, and FIGS. 2 to 4 are vertical cross-sectional views showing the progress of pump startup operation under a state in which the water surface is depressed.
5 to 8 are cross-sectional views showing other embodiments of the water sealing device provided on the runner crown of the low pressure stage runner. 1... Main shaft, 2... High pressure stage runner, 3... Low pressure stage runner, 5... High pressure stage runner chamber, 6... Low pressure stage runner chamber, 7... Upper cover, 8... Lower cover, 1
0......Movable guide vane, 16...Lower cover,
18... Intermediate speed ring, 20... Return channel, 22, 25... Water sealing device, 24, 26... Labyrinth passage, 28, 31... Exhaust chamber, 29, 3
2...exhaust hole, 30, 34...exhaust pipe line.

Claims (1)

[Scope of Claims] 1. A plurality of runner chambers supported by a main shaft of a water turbine in a plurality of runner chambers in which a previous stage runner chamber and a next stage runner chamber are connected by a return passage formed by return blades. A runner is provided, a movable guide vane is provided on the outside of at least the runner chamber of the highest pressure stage, an exhaust hole is provided in the runner crown that penetrates from the runner flow path side to the rear side, and an exhaust chamber is provided on the outlet side of this exhaust hole. A multi-stage hydraulic machine, which has an exhaust pipe connected to the outside from the exhaust chamber, and is further provided with a water sealing device on the radial outer circumference of the exhaust chamber, and is equipped with a low-pressure stage other than the highest-pressure stage runner. An exhaust hole is provided in the runner crown of the runner that penetrates from the runner flow path side to the back side, an exhaust chamber is provided on the outlet side of this exhaust hole, and an exhaust pipe line communicating from this exhaust chamber to the outside is connected across the return vane. 1. An exhaust system for a multi-stage hydraulic machine, characterized in that a water sealing device is provided on the radial outer periphery of the exhaust chamber. 2. The exhaust system for a multi-stage hydraulic machine according to claim 1, wherein the water sealing device is constituted by a labyrinth passage formed between a runner, a runner crown, and an intermediate speed ring. . 3. The exhaust device for a multi-stage hydraulic machine according to claim 1, wherein the water sealing device is constituted by a plurality of fins arranged radially on the back side of the runner crown. 4 The exhaust hole bored in the runner crown is characterized in that the center line of the hole is inclined with respect to the axis of the main shaft of the water turbine so that the outlet side is located radially inward than the inlet side. An exhaust system for a multi-stage hydraulic machine according to claim 1.