JPS6328983Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device that reduces the energy of a jet flow, such as a jet flow gate, which adjusts the amount of water discharged in the middle of a dam water discharge pipe. Generally, a jet flow gate is installed in the middle of a dam water discharge pipe to adjust the amount of water discharged, as described above. However, this jet flow gate cannot greatly dissipate the energy of the jet to reduce the impact on structures downstream, that is, it has a large energy reduction effect, and the jet is released with almost no energy reduction. . Therefore, it is necessary to protect the structure by some kind of energy reduction means on the downstream side of the jet flow gate.

Typical conventional discharge methods include the underwater discharge method and the air discharge method. The aerial discharge type is also known as a water splash type deenergized water discharge system, and requires a fairly large open waterway downstream from the water outlet, and since the water is caused to jump in this waterway, there is a problem of noise generation. In addition, the underwater discharge type installs an energy reduction pond downstream of the water outlet and discharges water into this pond, which has less impact on the downstream side and generates less noise, and is suitable when a large space for the energy reduction device cannot be taken up. However, it is necessary to increase the water depth of the deenergization pond considerably. In addition to the above, an in-pipe discharge type is also known, and is used as a method when there is no space for a water-jumping type deenergized discharge and it is necessary to discharge the water into the air due to the location.

This idea was created to provide the most effective energy reducing device by improving the underwater discharge type energy reducing device mentioned above. A jet jet barrier whose upper end is inclined toward the upstream side is provided at a predetermined distance on the downstream side, and after the jet water collides with the barrier and is deenergized, it passes over the upper surface of the top of the barrier. The reason lies in the fact that it is made to flow.

Hereinafter, embodiments of this invention will be described in detail based on the drawings.

In the drawing, 1 is a jet flow gate,
A door body 4 is provided in the middle of a water discharge pipe 2 (or a water discharge port) of a dam, and is disposed on the downstream side of the gate water discharge port (opening of an orifice portion 3) so as to be movable up and down. Reference numeral 5 denotes a de-energizing pond located downstream of the gate water outlet, 6 a ceiling slab installed above the de-energizing reservoir, and 7 a barrier wall installed over the entire width of the de-energizing reservoir 5, downstream of the de-energizing reservoir. It makes up the wall. The barrier wall 7 has an inclined barrier plate 7A that directly receives the jet jet whose upper end is inclined toward the upstream side at a predetermined angle θ with respect to the bottom surface 5A of the energy-reducing pond, a top plate (overflow plate) 7B, and a bottom plate 7C. and both side plates 7D, 7
E, the inclined barrier wall plate 7A is integrally constituted by
The front edge of the upper end of the ceiling slab 6 is located in substantially the same vertical plane as the downstream end 6A of the ceiling slab 6. Then, the distance L between the jet impingement position of the inclined barrier plate 7A and the gate water outlet (opening of the orifice part 3), the height H, width W, inclination angle θ of the inclined barrier plate 7A, and the reduction of the water discharge pipe 2. The height _H2 from the bottom surface 5A of the pond and the length of the top plate 7B are set based on the installation water depth, diameter D, etc. of the water discharge pipe 2. In addition, the overflow height h is determined by the discharge amount,
The distance C between the upper surface of the barrier top plate 7B and the lower surface of the ceiling slab 6 is selected to be smaller than the overflow height h and to such an extent that the flowing water does not separate from the lower surface of the ceiling slab 6. In addition, the bottom plate 7C and both side plates 7D and 7E of the barrier wall 7
is firmly fixed to anchors (not shown) buried in the bottom surface 5A and side walls 5B and 5C of the energy reduction pond 5.

8 is a water discharge channel, and the deenergized water is discharged from the downstream water outlet.

Although the barrier wall 7 is constructed of a steel structure in the above embodiment of this invention, it may be a composite structure of a steel structure and a concrete structure, or a concrete structure.

According to this invention, the jet water jetted out from the water outlet (opening of the orifice part 3) of the jet flow gate 1 passes through the water in the deenergization pond 5 and collides with the inclined barrier plate 7A, and most of the jet water flows downward. Most of the energy of the jet is reduced by colliding with the bottom plate 7C, and flows backwards and rises along the side plates 7C and 7D, colliding with the front edge of the top plate 7B and the downstream end 6A of the ceiling slab. The water flows out from between the gaps, quietly overflows the top end plate 7B, reaches the discharge channel 8 on the downstream side, and is discharged.

Since this idea has the above-mentioned configuration, it is possible to reduce the volume of the deenergization pond, shorten the distance to the barrier wall (end sill), and lower the water depth inside the deenergization pond. It is very simple because there are no objects, there is no mixing of air into the flowing water, and the water flowing over the barrier top plate 7B is a regular flow, which has an extremely large force reduction effect and prevents the generation of noise and There are high expectations for its effects, as there is no impact on the downstream side, the civil engineering work is simple, the construction period can be shortened, and the cost of constructing energy reducing devices can be significantly reduced.

It goes without saying that the barrier wall 7 can be appropriately provided with reinforcing members to ensure sufficient rigidity.

[Brief explanation of the drawing]

FIG. 1 is a central longitudinal cross-sectional side view showing an embodiment of this invention, and FIG. 2 is a cross-sectional plan view taken along the line A--A in FIG. 1...Jet flow gate, 2...Water pipe,
3... Orifice part (water outlet), 5... Deenergization pond,
6... Ceiling slab, 7... Cliff wall, 7A... Sloped barrier board, 7B... Cliff top plate.

Claims (1)

[Scope of utility model registration request] On the downstream side from the water outlet of a jet flow gate, etc., a jet jet barrier wall with the upper end inclined toward the upstream side is installed over the entire width of the energy reduction pond, and a ceiling slab of the energy reduction pond is installed. The distance between the bottom surface of the ceiling slab and the top surface of the barrier top is made smaller than the overflow height above the barrier top, and the water flows over the ceiling slab. An energy reducing device characterized by being selected to the extent that it does not peel off from the lower surface of the device.