JPH0320547Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention relates to the structure of an intake hole provided in a corner casing on the discharge side for drawing air into the casing and suction pipe of a once-through water turbine.

[Prior art and its problems]

Once-through turbines may or may not have a suction pipe. When a suction pipe is provided, an intake hole is provided in the corner casing to adjust the water level within the suction pipe, and air is introduced into the water turbine via an intake valve attached to the outside of the corner casing. On the other hand, when a suction pipe is not provided, an intake hole is similarly provided in the corner casing in order to prevent the vibration of the water turbine caused by the upper part of the corner casing being filled with runner discharge water during operation of the water turbine. In this case, the structure is such that air is naturally introduced at all times during operation, and there is no need to adjust the amount of intake air, so no intake valve is provided. During normal load operation, most of the energy of the flowing water is absorbed by the runner, so the kinetic energy of the runner drainage is small. Therefore, even if the discharged water collides with the corner casing, it will not splash upwards.
Even if it does splash up, it is very slight and falls down due to its own weight, so water does not spout from the intake hole.
However, during load shedding or startup, a considerable amount of energy remains in the runner discharge water, so some of the water that collides with the corner casing splashes upward along the inner surface of the corner casing, and the water is ejected from the intake hole. There was a drawback. This will be explained based on FIG. In the figure, 1 is the inlet pipe, 2
3 is a guide vane, 3 is a water wheel casing, 4 is a water wheel runner, 4a is a runner blade, 4b is a water wheel shaft, 5 is a corner casing, and 5a is an intake hole. Water flowing into the water turbine casing from the inlet pipe 1 is adjusted by the guide vane 2 and enters the runner 4, which drives the runner 4 and is discharged into the corner casing 5. Part of the water that collided with the corner casing 5 at this time
Wo springs upward along the inner surface of the corner casing 5 and is ejected from the intake hole 5a.

[Purpose of invention]

In view of the above-mentioned circumstances, the purpose of this invention is to provide an intake hole structure that does not impede the original function of the intake hole and does not cause water to spout out even during load interruption.

[Key points of the idea]

In order to achieve the above object, this invention has an inclined surface that extends inward from the opening of the intake hole and faces the water splashing up inside the corner casing.
An inclined projecting portion is provided to guide the splashed water toward the inner side of the corner casing.

[Example of idea]

FIG. 1 shows an embodiment of this invention, and the same components as in FIG. 2 are given the same reference numerals and their explanations will be omitted. In this embodiment, the slanted overhang extends inward from the inner opening of the conventional intake hole 5a, has an inclined surface facing the splashing water in the corner casing, and guides the splashing water toward the inside of the corner casing 5. A section 5b was provided. By providing this inclined overhanging portion 5b, a portion of the water _W1 colliding with the corner casing 5 is reduced to the overhanging portion 5.
The water was guided by the inclined surface b and returned to the original water flow W, and no longer spouted out from the intake hole 5a.

[Effect of idea]

According to this invention, since the inner opening of the intake hole has an inclined surface facing the splashing water and an inclined projecting part for guiding the water flow, a part of the water that collides with the corner casing is absorbed by the inclined surface. The water is guided by the sloping surface of the overhang and merges with the original water flow, and does not spout out from the intake hole.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an embodiment of this invention, Figure 2 is a sectional view showing an embodiment of this invention.
The figure is a sectional view of a conventional example. 5...Corner casing, 5a...Intake hole, 5b...
Slanted overhang.

Claims (1)

[Scope of utility model registration request] An intake hole provided on the outer periphery of a corner casing on the discharge side of a once-through water turbine, which extends inward from an opening of the intake hole and has an inclined surface facing upward flowing water in the corner casing;
An intake hole for a once-through water turbine, characterized in that an inclined projecting portion is provided for guiding the splashed water toward the inner side of the corner casing.