JPS6215496Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hydraulic machine such as a water turbine or a pump-turbine, and more particularly to a hydraulic machine that drains leakage water accumulated on the outer periphery of a runner during idling.

A water turbine with a so-called runner undercut structure in which the runner is disassembled and assembled from the discharge ring side,
Hydraulic machines such as pump water turbines have the advantage that runners can be disassembled and inspected easily in a very short period of time compared to general hydraulic machines. By the way, when starting the pump or performing phase-adjusting operation of this hydraulic machine with a bottom runner structure, the guide vane 2 is fully closed and the water level in the draft tube 5 is compressed, as shown in Fig. 1, as in a general hydraulic machine. By pressing down with air and causing the runner 1 to spin idly, the load torque is reduced and power loss is reduced.

In this case, in order to prevent the compressed air from leaking, the water pressure on the outside of the guide vane 2 is made higher than the pressure on the inside, so a considerable amount of water leaks from the small gap in the guide vane 2 to the runner side, resulting in A large amount of water will accumulate between the outer periphery of the runner 1 and the guide vane 2. Since the runner 1 stirs this water, a very large power loss occurs.

Conventionally, in order to reduce this power loss, runner 1
Using the pressure difference between the outer circumferential pressure _P1 and the draft tube side pressure _P2 , the guide vane water leakage is provided through the outer circumferential gap of the runner 1 to the discharge ring 10, the upper cover 3, or both. Water is drained into the draft tube 5 through a drain pipe 6.
In order to simplify the structure of the drain pipe 6, a steel pipe is attached directly to the discharge ring 10 or the upper cover 3, and the opening 8 of the discharge ring into which water leaks from the outer periphery of the runner flows is also shaped like the circular shape of the drain pipe. It has a circular shape according to the cross section as shown in Figure 2.

In operations where the idling time is relatively short, such as during normal pump startup, there is no problem with the conventional structure shown in Figures 1 and 2; Problems arise when idle rotation occurs. As shown in FIG. 2, leakage water drained through the gap at the outer circumference of the runner 1 is affected by the centrifugal force caused by the rotation of the runner 1, and forms a thin curtain-like water film 9 along the outer circumference. By the way, even if a large-diameter drain pipe 6 is used to drain this water film 9 to the draft tube side, since the drain pipe 6 has a circular cross section, only the portion indicated by reference numeral 8a can be effectively utilized. . Therefore, when idling continues for a long period of time, such as during standby operation or phase adjustment operation, the curtain-shaped water film 9 gradually advances inward as leakage water accumulates. When the water film 9 advances to the position indicated by the dotted line 9a, it completely covers the drain opening 8, and the water leaks from the drain pipe 6.
It becomes full and discharged. However, as the thickness of the water film 9 increases in this way, the power loss caused by stirring the water film 9 by the runner 1 gradually increases, and the temperature inside the runner chamber increases accordingly. In addition, the stirring of water creates an unstable operating state, and in some cases, induces abnormal vibrations, which reduces the safety of operating hydraulic machinery and reduces the lifespan of the machine.

The present invention was developed in view of the above-mentioned problems, and is designed to drain water leakage from the guide vane through the water contact gap formed around the entire circumference between the destroyer ring and the bottom ring. However, it is an object of the present invention to provide a hydraulic machine that enables effective drainage and that can significantly reduce power loss during idling of the runner.

An embodiment of the present invention will be described below with reference to FIG. An upper cover 3 is provided above the runner 1, and a guide vane 2 is provided near the outer periphery of the runner 1. Further, a bottom ring 11 is arranged at the lower part of the guide vane 2 so as to be outside the outer diameter of the runner 1, and a disk is installed below the runner 1 to be detachably attached to the bottom ring 11 from below. A charge ring 10 is arranged. An outer circumferential ring is arranged on the outer circumference of the discharge ring 10 so that an annular water contact gap 13 larger than the gap formed by the runner 1 and the bottom ring 11 can be provided between the outer circumference and the bottom ring 11. The outer diameter of the ring is arranged to be larger than the outer diameter of the runner 1. The water contact gap 13 is connected to a water chamber 12 provided on the outer peripheral side of the discharge ring 10 on the non-water contact side via a hole 14, and a drain valve 7 is provided below the water chamber 12. It is designed to connect to the drain pipe provided.

Next, we will discuss its effect. Water leakage from the guide vane on the outer periphery of the runner is caused by the pressure difference between the pressure P ₁ on the outer periphery of the runner 1 and the pressure P ₂ on the draft tube side to the drain pipe 6 via the water contact gap 13, hole 14 and water chamber 12. There will be an influx. By the way, as mentioned above, leakage water drained through the outer circumference of the runner 1 is affected by the centrifugal force caused by the rotation of the runner 1 and forms a thin curtain-like water film 9, which exists as a feature of the runner undercut structure. i.e. descharge ring 10
Since the water contact gap 13 formed between the bottom ring 11 and the bottom ring 11 is located on the outer periphery of this water film 9, the water contact gap 13 is inevitably filled with water leakage from the guide vane, and therefore water is Leakage water can be guided to the drain pipe 6 by making full use of the flow path area of the hole 14 communicating with the chamber 12. Therefore, even if the guide vane continues to idle for a long time, leakage from the guide vane can be effectively drained. Furthermore, since the water contact gap 13 is arranged outside the outer diameter of the runner 1, the gap formed by the discharge ring 10 of the runner 1 can be maintained the same as in the conventional structure without the water contact gap 13. , it is possible to prevent an increase in disk friction loss due to an increase in the gap.

Next, another embodiment of the present invention will be described. Unlike the above-mentioned embodiment, the water chamber 12 is not provided on the outer periphery of the discharge ring 10 on the non-water-contact side, and the water chamber 12 is not provided between the discharge ring 10 and the bottom ring 11, which are present due to the runner undercut structure. The structure is such that one end of the drain pipe 6 is directly connected to the water contact gap 13 that is formed. The rest is the same as the previous embodiment. Even in this structure, since the water contact gap 13 is located on the outer peripheral side of the water film 9, the water contact gap 13 will always be filled with water leaking from the guide vane, and if the drain pipe 6 breaks Leakage water can be guided to the draft tube 5 by making full use of the area.

As explained above, in hydraulic machines such as water turbines and pump water turbines that have a runner undercut structure, by taking advantage of their structural features and making some economical and simple modifications, it is possible to achieve standby operation and harmonization. Even if the runner continues to idle for a long period of time during operation, leakage water from the guide vane can be drained very effectively, and hydraulic characteristics can be maintained at the same level as before, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a conventional hydraulic machine, FIG. 2 is a plan view taken in the X direction of FIG. 1, FIG. 3 is a schematic sectional view showing an embodiment of the hydraulic machine of the present invention, and FIG.
The figure is a schematic sectional view showing another embodiment of the present invention. 1...Runner, 2...Guide vane, 3...Upper cover, 5...Draft tube, 6...Drain pipe,
7... Drain valve, 8... Opening, 9... Water film, 10
... Discharge ring, 11 ... Bottom ring, 12 ... Water chamber, 13 ... Water contact gap, 14 ...
hole.

Claims (1)

[Scope of utility model registration request] A runner, a guide vane arranged on the outside of the runner, a bottom ring that rotatably supports the guide vane and is arranged outside the outer diameter of the runner, a bottom ring that is detachably attached to the bottom ring from below, and a runner. In a hydraulic machine equipped with a discharge ring that covers the bottom and a drain pipe that discharges water leaking from the guide vane when the runner is running idle, the outer diameter of the discharge ring that is installed inside the bottom ring is The outer diameter of the discharge ring is larger than the outer diameter of the runner, and the gap between the outer circumference of the discharge ring and the inner circumference of the bottom ring is formed to be larger than the gap between the outer circumference of the runner and the inner circumference of the bottom ring, creating an annular water contact gap. A hydraulic machine characterized in that this water contact gap is communicated with a drain pipe.