JPS6261834B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a three-branch structure for high water pressure pipes in hydroelectric power generation equipment. In general, in hydroelectric power generation facilities, for economical reasons, taking into account water volume, head, etc., water is conveyed using a single penstock to a structurally possible location, and at the bottom of the penstock, the water is divided into three branch pipes. It is being implemented to supply power generation equipment. In the conventional three-branch structure, as shown in Fig. 1, a main pipe a and three branch pipes b ₁ , b ₂ , b ₃ are connected to a spherical shell c with an extension line of the axes of these pipes. They were connected via this shell c so that they intersect in plane at the center of the spheres, and water was guided as shown in Figure 2. However, such a conventional planar three-branched structure has the following defects. (1) Since it is a plane intersection, the width of the installation plane (width in the direction perpendicular to the direction of the main pipe) is large. (2) When buried underground, the loose area of the bedrock becomes large, and resistance to external rock pressure and water pressure is low. (3) Due to the above, reinforcement measures against earthquake loads and initial ground pressure are required. (4) If the installation plane width is wide, anisotropy of the rock mass is more likely to be encountered, and measures are required to equalize its strength. (5) If the width of the installation room of a tunnel structure is large compared to the height, large concentrated stress will occur in each part of the branch pipe due to the influence of rock creep, making it easy to break and resulting in low safety. (6) Out of the three branch pipes, the outer two branch pipes have a large bending angle with respect to the main pipe, and therefore have a large water head loss. In view of the above, it is an object of the present invention to provide a three-branched structure that eliminates these defects. The gist of this invention is that a spherical shell is concentrically connected to the end of a cylindrical main pipe, and three branch pipes are connected to the shell so that the extension line of the axis passes through the spherical center of the shell. In the three-branch structure of connected high water pressure pipes, the three branch pipes are given a diameter of 43% or less of the diameter of the shell, and the extension lines of their axes form three The intersecting angles are equal to each other and are branched radially, and the intersecting angles between the extension line of the axis of the main pipe and the extension lines of each of the axes of the three branch pipes are equal to each other, and is a three-branch structure of high water pressure pipes formed at an angle of 70 degrees or less. Hereinafter, the configuration of the present invention will be explained with reference to the illustrated embodiments. 3 to 6, the end portion of the cylindrical main pipe 1 is expanded into a tapered shape, and the cut end of the spherical shell 3 is connected so as to be in contact with this tapered end portion 2. Therefore, An extension line M of the axis of the main pipe 1 passes through the spherical center O of the shell body 3. 4,5,
Reference numeral 6 denotes a branch pipe of the same diameter, the proximal end of which is connected to communicate with the shell 3, and the extension line X of the axis of the branch pipe 4 passes through the spherical center O and is an extension of the axis of the main pipe 1. Line M
The branch pipe 5,
The extension lines Y and Z of the axis 6 also pass through the ball center O, and
The three intersection angles α formed by the extension lines X, Y, and Z of the axes of these three branch pipes are mutually equal, and the extension line M of the axis of the main pipe 1 is the extension line of the axis of the three branch pipes. The three intersecting angles β formed with the extension lines X, Y, and Z of the axis are also equal to each other. As a result, the branch pipes 4, 5, and 6 are radially branched in an axially symmetrical manner with respect to the axis of the main pipe 1. Further, the inner diameter of each of the branch pipes 4, 5, and 6 is approximately 1/2.5 of the inner diameter of the shell body 3 in the embodiment. In setting this inner diameter, first, the inner diameter of the branch pipe is determined as a cross section through which the required flow rate can flow. In addition, the diameter of the branch pipe is based on the road construction limit standard of 4.5 m below the bridge girder when transporting the branch pipe on a trailer, and the maximum diameter value as the transport limit is 3.4 m.
becomes. The intersection angle α of the branch pipes 4, 5, and 6 is
This angle comes from the construction limits of welding work, etc.
For example, if the intersection angle α is set to 60 degrees at the center of the branch part of three branch pipes, which is an angle that allows easy welding work, the shell body 3 to which each branch pipe 4, 5, and 6 with a diameter of 3.4 m can be attached is The diameter will be 8.0m. In this case, the diameter of each branch pipe is 42.5% of the diameter of the shell 3, and if it is less than this value, it means that the shell 3 will be larger, and construction will be easier. Therefore, in view of construction limits and transportation limits, the diameters of the branch pipes 4, 5, and 6 are determined to be 43% or less of the diameter of the shell body 3. Furthermore, the three intersection angles β are determined by the inner diameter of the shell 3 and the fluid pressure, and in the experimental example, the range of 45 degrees to 70 degrees is determined by the prevention of the vacuum vortex phenomenon of the fluid and the fluid flow rate. This value was preferable in terms of suppressing vibrations that occur and in terms of high fluid pressure resistance. 7 is a stiffening ring for reinforcing the connection between the shell 3 and the branch pipe. In the three-branch structure of the present invention, the pressure water that flows from the main pipe 1 to the shell body 3 via the terminal part 2 is divided into three branch pipes 4, 5, and 6, and flows down as shown in FIG. The power is supplied to a power generation device (not shown) connected to each terminal. In this invention, as described above, the extension lines of the axes of the three branch pipes three-dimensionally intersect at the spherical center of the spherical crown-shaped shell,
Their intersecting angles are equal to each other, and the extension line of the axis of the main pipe 1 also passes through the center of the sphere and intersects with the extensions of the axes of the three branch pipes at the same angle, and this intersection angle is the minimum possible value. It is configured so that
Therefore, the width of the installation surface, that is, the installation width in the direction perpendicular to the axis of the main pipe at the downstream end of the shell, is 14.5 m in the conventional three-branch structure when the diameter of the shell is 8 m. According to this invention, the length is 8.4 m at the same location. In this way, it is about 1/2 that of the conventional planar three-branch structure, so
The defects (1) to (5) in the planar branch described above are eliminated. In other words, in drilling with dynamite,
In general, a depth of 3
A crack of approximately 1.5 m is created, and this area becomes an area where the rock is loosened and tilted. Therefore, concrete reinforcement is applied to this area in order to provide resistance to earth pressure and water pressure from the outside, and this reinforcement measure simplifies the construction work as the installation width is small. Furthermore, since the installation width can be made smaller, the degree of encountering directional forces from the rock mass is reduced, and
The influence of rock creep on each part of the branch pipe is reduced, improving safety. Also,
Since the extensions of the axes of the three branch pipes are bent at the same angle β as small as possible with respect to the extension of the main pipe's axis, the defect (6) mentioned above has been greatly improved. , the experimental head loss in the example is:
As shown in the table below, the amount was significantly reduced compared to the conventional three-branch structure, and the three branch pipes exhibited similar performance.

[Table] Since the difference in head loss is 1.5m,
For example, if we calculate the economic effect of a 1 million Kw power generation facility at a head height of 400 m, we will obtain an energy source equivalent to 3,750 Kw. In addition, vibrations caused by the vacuum vortex phenomenon of fluid and fluid flow velocity are suppressed, and it exhibits high strength against high fluid pressure. Even if one of the three branch pipes is closed, the other two The branch pipe has the effect of dividing water under similar conditions and having the same effect.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a conventional three-branch structure;
FIG. 2 is an explanatory perspective view showing a piping situation using a conventional three-branch structure, FIGS. 3 to 7 show an embodiment of the present invention, FIG. 3 is a side view, and FIG.
FIG. 5 is a front view as viewed from the Q arrow in FIG. FIG. 2 is an explanatory perspective view showing a piping state using a three-branch structure. 1... Main pipe, 3... Shell body, 4, 5, 6... Branch pipe, M... Extension line of the axis of the main pipe, X, Y, Z...
An extension of the axes of the branch pipes 4, 5, and 6, O...center of the ball.

Claims (1)

[Scope of Claims] 1. A spherical shell is concentrically connected to the end of a cylindrical main pipe, and the three branch pipes connect the shell so that an extension of the axis passes through the spherical center of the shell. In the three-branch structure of the high water pressure pipe connected to the shell, the three branch pipes are given a diameter of 43% or less of the diameter of the shell, and the extension lines of their axes form each other. The three intersecting angles are equal to each other and are branched radially, and the intersecting angles between the extension line of the axis of the main pipe and the extension line of each of the axes of the three branch pipes are equal to each other, and The three-branch structure of the high water pressure pipe is characterized by the intersection angle being less than 70 degrees.