JPS6153554B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-stage hydraulic machine, and particularly to a multi-stage hydraulic machine that drains water accumulated in the outer circumferential area of each stage runner during idling operation to enable long-term phasing operation and standby operation. Concerning multi-stage hydraulic machines.

In general, water turbines and pump turbines that are directly connected to a synchronous generator perform phase adjustment operation by fully closing the movable guide vane and inlet valve to push down the water surface around the runner in order to improve the drop in power factor of the electrical system. or standby operation is required. When running a pump turbine, etc., the inlet valve is fully closed, so if water leaks into the runner chamber from the fully closed movable guide vane, the water pressure in the spiral casing decreases, and the air in the runner chamber flows into the casing. There is a risk of it getting inside. Therefore, to prevent this,
Normally, water is supplied into the casing by opening the water leakage replenishment valve installed on the water leakage replenishment pipe connecting the iron pipe upstream of the inlet valve and the casing, so that the pressure inside the casing becomes slightly higher than the pressure inside the runner chamber. I have to. In this way, in order to maintain the pressure inside the casing higher than the pressure inside the runner chamber, water leakage from the fully closed movable guide vane to the runner chamber side cannot be avoided, and the seal between the runner outer circumference and the fixed part cannot be avoided. Since cooling water is supplied to the runner to prevent overheating, water accumulates around the runner and forms a wall of water.
When idling in such a state, the runner blades stir up the surrounding water, increasing the shaft input necessary for idling and imparting a large amount of energy to the water. A part of this energy will raise the temperature of the water around the runner, and this temperature rise is not a particular problem if the idling operation is short, but in phase adjustment operation or standby operation, the runner is idling for a long time. As a result, the temperature rise increases, and the runner expands thermally, becomes larger, and comes into contact with the fixed part while rotating, which may result in galling or damage to the runner. To avoid this problem, in the case of a single-stage pump turbine, a leakage drain pipe is installed on the lower cover side to drain water around the runner, releasing the energy given to the water to the outside and preventing temperature rise. At the same time, the shaft input is reduced.

In this way, in the case of a single-stage pump water turbine, the lower part of the lower cover is immediately buried in concrete, and there is no need for disassembly and assembly, so a leakage drain pipe can be easily installed. However, when it comes to multi-stage hydraulic machines, structures such as return channels and return vanes are added that connect the adjacent high-pressure stage runner chambers and low-pressure stage runner chambers, making the structure complex. Because it must be disassembled and reassembled, water cannot be drained in the same way as a single-stage pump turbine, and the question is how to drain the wall of water that forms around the outer periphery of the runner during idle operation to the outside. was becoming a big problem.

Therefore, the purpose of the present invention is to solve the above problems,
To provide a multi-stage hydraulic machine capable of long-term idling operation by draining water accumulated near the outer periphery of each stage runner during phase adjustment or standby operation to the outside.

Therefore, in order to achieve the above object, the present invention fixes a plurality of runners on the main shaft of a water turbine, arranges a speed ring integrally equipped with a lower cover below the outside of each stage of runners, and In the case where the ivy runner chambers are connected by a return passage, at the boundary between the lower cover or speed ring of the runners in the other stages except the runner in the lowest pressure stage among the plurality of runners mentioned above and the fixed member located outside these. An annular airtight chamber is formed, and this airtight chamber is connected to a runner chamber near the outer periphery of each stage of runners by a drain pipe passing through the lower cover.
Furthermore, it is characterized in that a drain pipe is led out from the airtight chamber.

Embodiments of the present invention will be described below by taking as an example a three-stage pump turbine having a movable guide vane only at the highest pressure stage.

In FIG. 1, reference numeral 1 indicates a water turbine main shaft, and high pressure stage, intermediate pressure stage, and low pressure stage runners 2, 3, and 4 are fixed to the water turbine main shaft 1 in this order from above. Among these, the high-pressure stage runner 2 is covered with a high-pressure stage upper cover 5 and a high-pressure stage lower cover 6, and a movable guide vane 8 is rotatably supported between the outer peripheries of these upper and lower covers 5 and 6. The opening degree can be adjusted. A speed ring 9 holding a stay vane 9a is connected to the outside of the upper and lower covers 5 and 6, and a spiral casing 10 is integrally connected to the outside of the speed ring 9.

On the other hand, an intermediate pressure stage speed ring 11 equipped with a stay vane 11a and manufactured integrally with the lower cover 12 of the intermediate pressure stage runner 3 is disposed radially outward of the intermediate pressure stage runner 3. runner 5
A stay vane 13a is provided on the outside in the radial direction,
Also, a low pressure stage speed ring 13 manufactured integrally with the lower cover 14 of the low pressure stage runner 5 is arranged.

Further, between the high pressure stage runner 2 and the intermediate pressure stage runner 3, a return flow path ring 15 having a return blade 15a is disposed, and this return flow path ring 15 is connected to the high pressure stage lower cover 6 and the intermediate pressure stage runner 3. It is held between the stage speed ring 11 and the stage speed ring 11. Similarly, a return flow path ring 16 provided with return blades 16a is arranged between the intermediate pressure stage runner 3 and the low pressure stage runner 4.
is held between the intermediate pressure stage speed ring 11 and the low pressure stage speed ring 13. Further, each of the return flow path ring 15, intermediate speed ring 11, return flow path ring 16, and low pressure stage speed ring 13 is stacked coaxially in the vertical direction and is fitted into the inner hole 19 of the outer cylinder 18. . moreover,
The flow path between the return vane 15a and the stay vane 11a is a flow path 20 provided with a blade formed inside the outer cylinder 18.
On the other hand, the flow path between the return vane 16a and the stay vane 13a is communicated by a flow path 21 provided with a blade formed in the outer cylinder 18.

Thus, an annular airtight chamber 22 is formed at the boundary between the outer periphery of the lower cover 6 and the inner periphery of the speed ring 9, which is a fixed member, and this airtight chamber 22 and the runner near the outer periphery of the high pressure stage runner 2 are connected to each other. The chamber is connected to the chamber by a plurality of leakage drain pipes 23 that penetrate the lower cover 6, and the airtight chamber 22 is connected to the leakage drain pipe 24.
is led out, and a drain valve 25 is installed on the pipe.

Further, an annular airtight chamber 26 is formed at the boundary between the outer periphery of the intermediate pressure stage speed ring 11 and the inner periphery of the outer cylinder 18 which is a fixed member, and this airtight chamber 26 and the vicinity of the outer periphery of the intermediate pressure stage runner 3 What is the runner chamber of the lower cover 1?
A leakage drain pipe 28 is led out from the airtight chamber 26, and a drain valve 29 is installed on the pipe.

Furthermore, from the outer periphery of the runner chamber of the low-pressure stage runner 4, there is a water leakage drain pipe 30 that passes through the lower cover 14.
is directly led out, and a drain valve 31 is installed on the pipe.

Note that a suction pipe 32 is connected below the lower cover 14 of the low-pressure stage runner 4.

In order to perform phase adjustment operation or standby operation of the three-stage pump turbine according to the embodiment of the present invention configured as described above, compressed air is forced into the runner chamber with the inlet valve and movable guide vane 8 fully closed. Then, the water surface L in the runner chamber is pushed down to below the runner 4 at the lowest pressure stage. Prior to such idle running, the drain valves 25, 29 and 31 are fully opened in advance. Then, the fully closed movable guide vane 8
Of the water leaking into the high-pressure stage runner chamber from the runner and the cooling water supplied to the runner seal section, the water accumulated on the outside of the high-pressure stage runner 2 is drained to the outside through the leakage drain pipe 23, the airtight chamber 22, and the water leakage drain pipe 24. Drained. On the other hand, water accumulated on the outside of the medium pressure stage runner 3 is removed from the leakage drain pipe 27, the airtight chamber 26 and the water leakage drain pipe 2.
8 and is discharged to the outside. Further, water accumulated on the outside of the runner 4 at the lowest pressure stage is directly discharged to the outside through the leakage drain pipe 30.

In this way, the water that accumulates in the outer peripheral area of each stage's runner during long-term idle operation is discharged to the outside separately through the leakage drain pipe of each stage, so that the thermal energy given to the water leakage is released to the outside. By doing so, it is possible to prevent the temperature of the runner from rising and accidents resulting in damage to the runner due to galling, and at the same time, it is possible to reduce shaft input and perform safe idling operation.

In order to drain water accumulated near the stay vanes 11a of the intermediate pressure stage and the stay vanes 13a of the low pressure stage to the outside, FIG.
A leakage drain pipe 35 is led out from 0, a water leakage drain valve 36 is installed on the pipe, and a water leakage drain pipe 37 is led out from the flow path 21 near the stay vane 13a of the low pressure stage speed ring 13, and the water leakage is drained on the pipe. An example in which a valve 38 is incorporated is shown. With this configuration, the water flowing into the runner chamber from the intermediate pressure stage stay vane 11a and the low pressure stage stay vane 13a is blown away by the runner, and the flow path 20,
It can be expected that the water accumulated from the stay vanes 21 to the stay vanes 11a and 13a can be actively drained to the outside.

Although the above embodiment describes an example in which the present invention is applied to a three-stage pump water turbine, it goes without saying that the present invention can be widely applied to multi-stage hydraulic machines having two stages or four stages or more.

As is clear from the above description, according to the present invention, an annular airtight chamber is formed at the boundary between the lower cover or speed ring of each stage runner and the outer member thereof, and the airtight chamber and each stage runner Since the runner room near the outer periphery is connected to the runner chamber through a drain pipe that penetrates the lower cover and drained to the outside, water that accumulates around the outer periphery of the runner during idle operation can be drained to the outside through the drain pipe. By discharging the thermal energy given to the water leakage to the outside, the temperature of the runner is prevented from rising, and accidents leading to galling and damage to the runner can be prevented, and the shaft input is reduced to allow safe idling operation. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a half-longitudinal cross-sectional view showing a three-stage pump-turbine according to an embodiment of the present invention, and FIG. 2 is a half-longitudinal cross-sectional view of the three-stage pump-turbine constructed to carry out the present invention. 1... Water turbine main shaft, 2... High pressure stage runner, 3... Medium pressure stage runner, 4... Low pressure stage runner, 7... High pressure stage speed ring, 8... Movable guide vane, 11... Medium pressure stage speed ring, 12... Lower cover, 13...Low pressure stage speed ring, 15, 16...Return flow path ring, 18...
Outer cylinder, 22, 26... airtight chamber, 23, 27... leakage drain pipe, 24, 28... water leakage drain pipe.

Claims (1)

[Claims] 1. A plurality of runners are fixed on the main shaft of the water turbine, and a speed ring integrally provided with a lower cover is arranged below the outer side of the runners at each stage, and the adjacent runner chambers are connected to each other as a return passage. In the case where an annular airtight chamber is formed at the boundary between the lower cover or speed ring of the runners of the plurality of runners mentioned above except for the runner of the lowest pressure stage and the fixing member located outside these. The multi-stage hydraulic machine is characterized in that the airtight chamber and the runner chambers near the outer periphery of the runners of each stage are connected by a drain pipe passing through the lower cover, and furthermore, the drain pipe is led out from the airtight room to the outside. 2 The airtight chamber is formed in an annular shape so as to surround the outside of the runner chamber, and the airtight chamber and the runner chamber are connected by a plurality of drain pipes arranged at equal intervals in the circumferential direction. A multi-stage hydraulic machine according to claim 1, characterized in that: