JPH0322481B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a de-energizing tank that de-energizes discharged water discharged from two large and small flow rate regulating valves provided in a dam and causes it to flow downstream.

[Conventional technology]

Conventionally, dams are provided with large and small discharge ports each having two large and small flow rate regulating valves, and the respective flow rate regulating valves are operated depending on the discharge amount. Each outlet is provided with an energy reducing tank, and FIGS. 3 and 4 show an example of a conventional energy reducing tank. In this figure, 1 is a large diameter main pipe, and 2 is a thin branch pipe branched from the main pipe.

Behind the large-diameter discharge port 3 at the end of the main pipe 1 is a main flow regulating valve 4 consisting of a jet flow gate or the like.
and a spare gate 5 are provided.

Also, a sub-flow regulating valve 9 and a preliminary gate 10, such as a jet flow gate, are provided behind the small-diameter discharge port 8 at the end of the branch pipe 2.

In FIG. 3, 11 is a main energy reducing tank provided in front of the outlet 3, 12 is a sub energy reducing tank provided in front of the outlet 8,
A downstream weir 13 is provided in front of the main energy reduction tank 11, and water discharged from the outlet 3 flows into the main energy reduction tank 11, collides with the downstream weir 13 while being reduced in energy, and then flows out into the outflow path 14. It is structured as follows.

In addition, the water discharged from the discharge port 8 is
2 and flows into the main deenergization tank 11 from the communication port 16 on the front side thereof while being deenergized.

[Problem that the invention seeks to solve]

In conventional dam discharge equipment, as mentioned above, separate deenergization tanks 11 and 12 are provided for the discharge ports 3 and 8 at the tips of the main pipe 1 and branch pipe 2, respectively, so a large site area is required. However, there were problems such as higher construction costs and longer construction periods.

The purpose of this invention is to solve the problems of the conventional energy reducing tank as described above, by using one energy reducing tank to reduce energy discharged from the discharge ports of both the main pipe and the branch pipe. It is to be able to do so.

[Means for solving problems]

The technical measures taken to solve the above problems are to provide a discharge port leading to a large diameter main pipe in the center of the upstream wall, and a discharge port leading to a small diameter branch pipe on one side of the same upstream wall. In addition, the angle is such that the water is discharged toward the center of the shock plate, and after the water discharged from both outlet ports collides with the shock plate, it passes through the water channel below the shock plate and flows out over the downstream weir. At the same time, the part of the upper part of the impact plate facing the outlet is made into an inclined part that goes down to the downstream side, and the cross-sectional shape of this inclined part is bent into a chevron shape with the central part protruding in the downstream direction. The part following the lower end is a vertical part, and this vertical part is also bent into a chevron-shaped cross section similar to the inclined part, and the lower end of the vertical part is made considerably deeper than the upper end of the downstream weir of the energy reduction tank. A screen with energy reducing and rectifying effects was installed between the downstream side and the downstream weir.

[Effect]

This invention has the above configuration, and the powerful water discharged from the large flow outlet and the small flow outlet provided on the upstream wall of the energy reduction tank collides with approximately the center of the inclined part of the impact plate and is reduced. After being energized, it flows down along the vertical part following the lower end and sinks below the water surface in the de-energization tank.
As it passes through the water channel below the impact plate, the direction of the flow changes from downward to upward, and the force is further reduced as it flows downstream, but the cross-sectional shape of the impact plate is shaped like a chevron with the center protruding downstream. Because it is bent, the water that hits the impact plate flows both downward and laterally, and its energy is reduced by hitting the side wall of the energy reducing tank. Also, the water flowing upward through the channels below the shock plate is further attenuated through the screen.

〔Example〕

In the embodiment shown in FIGS. 1 and 2, 21 is a large diameter main pipe, and 22 is a small diameter branch pipe branched from this main pipe.

Reference numeral 23 denotes a deenergization tank, which has a large-diameter outlet 25 communicating with the main pipe 21 at the center of its upstream wall 24, and a small-diameter outlet 26 communicating with the branch pipe 22 on the side thereof. Flow rate regulating valves 27 and 28 such as jet flow gates are provided at the ports, respectively.

Reference numeral 31 is an impact plate, with a sloped portion 3 extending downward from its upper end.
2, it is inclined downward from the upper end to the downstream side, and the lower end of this inclined part 32 forms a vertical part 33.

Further, a water channel 29 is formed between the lower end of the vertical part 33 and the bottom of the energy reducing tank 23, and a downstream weir 34 is formed on the downstream side of the energy reducing tank 23, and the lower end of the vertical part 33 of the impact plate 31 is connected to the upper end of the downstream weir 34. Make it quite deep.

Further, as shown in FIG. 1, the horizontal cross-sectional shape of the impact plate 31 is bent so that the central part becomes a mountain shape protruding toward the downstream side, and both sides are the inner surfaces of both side walls of the energy reducing tank 23. Fix it by welding or other means.

A discharge port 26 communicating with the branch pipe 22 is connected to the shock plate 3.
It is provided at an angle such that water is discharged toward approximately the center of the inclined part 32 of the first part. The lower half of the upstream wall 24 extends downstream as shown in FIG. The lower edge is bent upstream to form a lower impact plate part 38, and a deflector part 39 facing upstream is also provided near the upper part of the downstream weir 34.

40 is a fixed screen provided from the front side of the impact plate 31 toward the upper side of the downstream weir 34. In the illustrated example, there are two screens 40, upper and lower, but
An opening 41 may be provided between the screen 40 and the outflow path 35 following the downstream weir 34. Further, both sides of the screen 40 are fixed to both side walls of the energy reducing tank 23.

In the case of this embodiment, large and small flow rate regulating valves 27, 2
8, the jet stream discharged from the discharge ports 25 and 26 collides with approximately the center of the inclined portion 32 of the impact plate 31,
It flows down along the vertical part 33, but this inclined part 32
Since the vertical portion 33 is bent in a mountain shape in the horizontal cross section, a portion of the discharged water flows laterally and hits the side wall of the energy reducing tank 23, thereby reducing its energy. Therefore, energy reducing tank 2
If the width of 3 is increased and the length in the lateral direction is increased, the force reduction effect can be enhanced.

Further, as described above, the water that hits the impact plate 31 and flows down while being deenergized passes through the water channel 29 and flows upward, and is further deenergized and flows from the upper end of the downstream weir 34 to the outflow path 35.

When the amount of water is small, the water that has passed through the waterway 29 flows from the upper end of the downstream weir 34 to the outflow path 35 via the opening 41. Also, as the water volume increases and the flow speed becomes faster, the water that has flowed up through the water channel 29 passes through the many small holes of the screen 40, is weakened, and is rectified and directed toward the outflow channel 35, and is then flowed upward through the water channel 29. The water does not pass through the screen 40 and collides with the lower surface of the screen, changes direction, becomes a flow with reduced energy, and heads toward the outflow path 35, so that no dust accumulates at the bottom of the screen 40.

In addition, the lower impact plate 38 and the deflector part 3
7, 39, the water flowing down the vertical part 33 hits the lower impact plate 38, and some of the water flows backward and upwards and hits the deflector part 37, consuming energy and flowing inside the energy reducing tank. The impact friction between water and water further consumes energy. Moreover, since the impact plate 31 is bent to have a chevron-shaped cross section, lateral flow also occurs, resulting in a large energy-reducing effect.

In this way, the water that has passed through the waterway 29 hits the downstream weir 34 and is deenergized and flows upward, but the deflector portion 39 prevents the water on the downstream side from swelling up and prevents ripples in the flow path. Ru.

〔effect〕

This invention provides an energy-reducing tank having an impact plate as described above, in which a large-diameter outlet leading to a large-diameter main pipe is provided in the center of an upstream wall, and a small-diameter outlet leading to a small-diameter branch pipe is provided in the same upstream wall. It is installed on one side of the shock plate and is angled so that the water is discharged toward the center of the shock plate, so even in discharge equipment that has a large-diameter main pipe and a small-diameter branch pipe, only one energy-reducing tank can be used. It can be done.

The direction of the small-flow outlet is aimed at approximately the center of the slope of the shock plate, so that the large-flow discharge water and the small-flow discharge water are concentrated at approximately the center of the slope of the shock plate. Even though there are two, there is no need to increase the width of the energy reducing tank.

Since the lower end of the impact plate is considerably deeper than the upper end of the downstream weir, the lower end of the impact plate is submerged in the water in the energy reduction tank. Therefore, the powerful water flow that enters the energy reducing tank hits the inclined part of the impact plate, changes its direction downward and flows down, submerges in the water in the energy reducing tank, and changes the direction of the flow upward underwater. Therefore, the flow velocity of the water is greatly reduced due to water resistance, and the force is reduced by colliding with the downstream weir, and then flows to the downstream outlet, so the force reduction effect is extremely large.

Since the sloped part and the vertical part of the impact plate are bent in a chevron-shaped cross section, the jet released from the outlet hits the sloped part of the impact plate and flows downward, but at this time,
Some of the water is also diverted laterally due to the inner surface of the shock plate bent into a chevron shape, and hits both side walls of the energy reduction tank. Therefore, the force reduction effect in the width direction is also obtained, which increases the force reduction effect, and the length in the upstream and downstream directions can be made very short, so in order to utilize the side walls for force reduction, the width direction can be made wider. However, it can still be manufactured in a small size and at low cost.

Since a screen was installed between the downstream side of the impact plate and the downstream weir, which has a force-reducing and rectifying effect, the water flows upward through the water channel at the bottom of the impact plate, and water that still has energy passes through the screen. This has the effect of sufficiently reducing energy as it encounters greater resistance and is deenergized, and at the same time is rectified into a quiet flow and exits to the outflow path.

In addition, when a stepped portion is formed by extending the lower half of the upstream wall toward the downstream side as in the example, the distance between the impact plate and the portion of the upper half of the upstream wall with large and small discharge ports is set to be sufficient. can be taken. Therefore, the force of the return flow that bounces off the shock plate becomes sufficiently small at the outlet, and a portion of the return flow does not directly connect with the downstream wall below the step, that is, the upstream wall above the step. Since it hits the area, it has the effect of preventing vibration of the flow control valve.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional plan view of the energy reducing tank of the present invention;
The figure is a vertical side view of the same as above, FIG. 3 is a cross-sectional plan view of a conventional energy reducing tank, and FIG. 4 is a vertical side view of the same. 21... Main pipe, 22... Branch pipe, 24... Upstream wall, 25... Large diameter outlet, 26... Small diameter outlet, 31... Shock plate, 32... Inclined part, 33...
Vertical section, 34...downstream weir, 40...screen.

Claims (1)

[Claims] 1. In a deenergization tank with an impact plate facing the discharge water discharged from the discharge port provided on the upstream wall, the discharge port leading to the large diameter main pipe is provided in the center of the upstream wall, and the discharge port leading to the large diameter main pipe is installed in the center of the upstream wall. A communicating outlet is provided on one side of the upstream wall, and the angle is set so that the water is discharged toward the center of the shock plate. After the water from both outlets collides with this shock plate, it flows into the water channel below the shock plate. through,
In addition to allowing the flow to flow over the downstream weir, the upper part of the impact plate facing the outlet is made into a sloped part that goes down to the downstream side, and the cross-sectional shape of this sloped part is such that the central part protrudes in the downstream direction. The vertical part is bent into a chevron-shaped cross section similar to that of the slope, and the lower end of the vertical part is bent from the upper end of the downstream weir of the energy-reducing tank. An impact type energy reducing tank characterized by being considerably deep and further provided with a screen having energy reducing and rectifying effects between the downstream side of the impact plate and the downstream weir.