JPS5855290B2 - Radial gate bottom water stop device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water stop device at the bottom of a waterway, mainly equipped with a sliding radial gate, for adjusting the discharge of a regular spillway installed deep in a water storage dam.

The purpose of the present invention is to prevent cavitation, vibration, and other problems that occur at the bottom of the outlet of a discharge channel when a radial gate at a high water depth of 60 m or more discharges water at a small opening. To obtain a water stop device at the bottom of the discharge channel.

A four-way water-stopping radial gate is installed as a control gate at the discharge pipe of the regular spillway facility installed in the deep part of the water storage dam, that is, the outlet of the discharge channel, and by operating this gate, full opening, full closing, and partial discharge are performed. .

There are two types of radial gates: a sliding type, which only has the function of rotating for opening and closing, and a so-called crimp type, which also has the function of crimping and separating the gate from the opening of the discharge pipe. be.

Many spillway facilities of this type require small openings for discharge.

In this case, the crimp type is disadvantageous, and the sliding type is suitable.

The sliding type opens and closes water at high water depths by simply rotating the gate and raising and lowering it.

Measures against cavitation, which tends to occur downstream of the gate due to the high-speed flow of the discharged water.Especially, when discharging at a small opening of about 500% or less, the discharged water may become abnormally turbulent, disabling the aeration function, or causing cavitation, vibration, etc. Special consideration must be given to the water stop at the bottom of the discharge channel to avoid problems.

In a high water depth gate, the strength of the pressure at which the lower edge 2 of the gate 1 contacts the rubber pad 4 of the discharge channel 3 is 1.
Since 5 times or more is required, contact is made with high pressure, for example, using the door body's own weight and a hydraulic cylinder.

Therefore, the lower end edge 2 of the gate 1 is pushed into the rubber pad 4 by about 3%, for example, by the door's weight and hydraulic pressure.

And the remaining dent 1 in the rubber pad 4 after raising the gate 1
3 is about 1.5%.

This slight deformation is due to water depth of 55? ? There is no problem with the flow velocity at around Z, but when the water is discharged at a high speed at a depth of 60 m or more, even a slight unevenness in contact with the high-speed flow may induce cavitation downstream.

This can cause the gate to vibrate and cause damage to the water channel.

As a countermeasure, sufficient aeration should be performed in the area where cavitation occurs, or a device should be installed that does not generate negative pressure in that area.

This invention relates to the former, that is, a device that performs aeration, and the rubber pad 4 is secured by a pad 6, a rubber clamp 7, and a bolt 8 so that the top surface of the rubber pad 4 is aligned with the bottom surface 5 of the discharge waterway 3. Fix it.

For example, when the width of the top surface of the rubber pad 4 is 180% and the width of the flat portion 16 between the contact position with the lower end 2 of the gate 10, that is, the residual recess 13 and the downstream side, is 110%, the width of the top surface of the rubber presser 7 is 110%. The width of the part that is on the same plane as the bottom surface 5 of the discharge channel is set as 50%, and the rubber presser fitting 7 on the downstream side is
A small offset 9 with a depth of 0% was formed.

The width of this small offset portion in the water flow direction was 50%, and the bolt 8 was disposed in this portion.

In order to supply air to this small offset 90 part, a large offset 9' is provided one step lower following this small offset part, an air box 10 is buried in the bottom of the discharge channel, and an air hole 12 is installed in contact with the stepped wall 11. Formed.

As shown in FIG. 2, when the opening degree of the radial gate 1 is small, the direction of the water jetting out is diagonally downward as shown by the arrow 14, and without the offset 9, the discharged water flows along the surface of the gate. The air flows downward and flows into the air box 10, disabling the function of the air hole and causing problems such as cavitation and vibration.

In the water stop device of the present invention, a flat portion 15 of a slight width is provided downstream from the gate contact line of the rubber pad, following the bottom surface 5 of the discharge channel, and offsets 9, 9' are formed following the flat portion 15. Air is supplied to the air hole 12 of the air box 10.

As a result, the discharged water is rectified by the flat portion 15 without causing cavitation, and the discharged water is jetted out beyond this offset, and the discharged water does not flow into the air hole 12.

Therefore, the small opening of the gate 1 can be maintained for a long period of time without causing any inconvenience in the vicinity of this water stop device.

If the opening degree of the gate 1 is increased, the direction of the discharged water flow will be parallel to the discharge channel, so there will be no problem.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a gate provided with a bottom water stop device of the present invention, and FIG. 2 is an enlarged vertical sectional side view of the water stop device of the present invention, viewed with the bottom surface of the discharge channel horizontal. In the drawing, code 1 is the gate, 2 is the lower edge, 3 is the spillway, and 4
is the rubber pad, 5 is the bottom, 6 is the pad, 7 is the rubber presser,
8 is a bolt, 9 and 9' are offsets, 10 is an air box, 11 is a step wall, 12 is an air hole, 13 is a residual recess, 14 is an arrow indicating the direction of water flow, and 15.16 is a flat portion.

Claims (1)

[Claims] 1. The top surface of the bottom water stopper rubber and the top surface of the rubber clamp on the downstream side are arranged on the same plane as the bottom of the discharge channel of the high water depth radial gate, and the downstream part of this rubber clamp A bottom water stop device for a radial gate, characterized in that a small offset part for preventing cavitation is formed, followed by a large offset part for supplying air to prevent cavitation at a lower level.