JPH0250247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a cylinder gate for taking in surface water, etc. from a dam reservoir, a sedimentation pond, etc.

(Prior Art) In general, a cylinder gate is provided with a plurality of water intake cylinders that are vertically expandable and retractable, and the upper end of the uppermost cylinder serves as a water intake opening in the shape of a bell mouth. Floats are connected above, the lower end of the bottom cylinder is communicated with the water conduit, the water intake is positioned below the water level by the float and follows the water level, and each cylinder guides the support. It is configured to move up and down. In such a cylinder gate, the water intake cylinders other than the lowest stage are kept floating in a predetermined position due to the buoyancy of the float. Each water intake cylinder is designed so that it will not collapse even if the water level in the pond drops below the intake port and the inside of each cylinder becomes negative pressure (atmospheric pressure), and currently no security gates are installed. It is.

(Problem to be Solved by the Invention) However, in the above conventional technology, when negative pressure is generated in the cylinder, the watertight rubber that seals off water between each cylinder is damaged by the water pressure of the pond water, and leaks from between the upper and lower cylinders. The cylinder vibrates violently as a high-speed stream of water flows into the cylinder. In order to prevent such vibrations, a safety gate such as a valve has conventionally been provided separately, but there is a problem in that the benefit of the cylinder gate is halved.

This invention was made in view of the above-mentioned circumstances, and even if the pressure inside the cylinder becomes negative, it is possible to bring the inside of the cylinder into a water pressure balanced state without installing a separate safety gate, and it is watertight. The objective is to obtain a cylinder gate that can prevent rubber damage and cylinder vibration.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a plurality of water intake cylinders that are vertically expandable and a water intake basin provided at the upper end of the topmost cylinder, and a water intake basin that In a cylinder gate in which a float is connected above, the lower end of the lowermost cylinder is communicated with the water conduit, and the lowermost cylinder is moved up and down using a support as a guide, the lowermost cylinder is vertically movable, and under normal conditions, the lower end of the lowest cylinder is The watertight rubber installed in the section keeps the periphery of the opening of the water conduit watertight, and when the outside water level falls below the intake basin and the pressure inside the cylinder gate drops to a predetermined value or more, the upward force from the outside water pressure will be applied inside the gate. It is characterized in that the lowest cylinder is provided with an inclined part or a stepped part so that the water becomes higher than the pressure, raises the lowest cylinder, and allows outside water to flow into the cylinder. In the buoyancy action surface construction means of this invention, in a normal cylinder internal and external water pressure balance state, the downward sum of the dead weight (W) of the lowest cylinder and the cylinder internal water pressure (IP) is due to the external water pressure (OP) outside the cylinder. upward force (buoyancy)
When the outside water level becomes lower than the intake basin, that is, in an emergency (at the time of negative pressure), the upward force (buoyancy) due to the outside water pressure (OP) becomes equal to the cylinder's own weight (W) and the internal water pressure ( If the slope or stepped portion (e.g. bulge portion) is larger than the downward force caused by IP) and the sliding packing resistance (Fg),
Form in the bottom cylinder.

(Function) According to the present invention, in the normal water intake state, the lower end of the cylinder at the lowest stage is pressed against the opening edge of the water conduit, making it watertight, and water is cut off, making it watertight. In an emergency, the water pressure inside the cylinder decreases and becomes negative pressure (atmospheric pressure), so the buoyant force from the outside water pressure acts on the slope or step, and the lowest cylinder is automatically raised slightly. The watertight seal at the lower end was broken, and pond water flowed in from between this and the upper edge of the headrace opening, filling the headrace and cylinders, resulting in a balance between internal and external water pressure, which caused damage to the watertight rubber between each cylinder. There is no vibration in the cylinder, and stable water intake is possible, making it possible to maintain the security of the cylinder gate.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

In the drawing, reference numeral 1 denotes a cylinder gate, which has water intake cylinders 2, 3, and 4 configured to be expandable and retractable in the vertical direction, and is connected to a support arm 15 having a guide roller 14 at the tip of a support arm 13 that is erected on a reservoir 5, etc. It is designed to be supported and guided up and down according to changes in the water level. Note that in FIGS. 2 to 5, the support column 13, guide roller 14, and support arm 15 are omitted. The upper end of the uppermost cylinder 2 is fixed with a water intake basin 6 which is flared outward, and the lower end of the lowermost cylinder 4 is fixed to the upper end of the uppermost cylinder 2.
A watertight rubber 12 is provided in communication with the buried water conduit 7. Although not shown, a locking ring is fixed to the connecting portion of each water intake cylinder 2, 3, and 4, and a guide roller is interposed therebetween, and a watertight packing is attached to each of them, thereby facilitating expansion and contraction. Water other than surface water is leveled and prevented from flowing into the cylinder gate 1.

Further, on the upper surface of the water intake basin 6, a substantially top-shaped hollow float 8 is attached with a plurality of bolts and nuts (not shown) so that the intervals can be adjusted. The lowermost cylinder 4 is provided with a stepped portion 9 so that buoyancy acts thereon. In the first embodiment shown in FIG. 1, most of the upper part of the lowermost cylinder 4 except for the lower part 4A is made into an enlarged diameter part 4B with a larger diameter, and a stepped part 9 is formed. The area (A) of this stepped portion 9 is usually
In an emergency when W+IP・A>OP・A (set 1) is satisfied and the water pressure (IP) in the cylinder has decreased, W+
It is designed to satisfy IP・A+Fg<OP・A (equation 2). Here, W is the dead weight of the lowermost cylinder 4, OP is the water pressure outside the cylinder, and Fg is the sliding resistance of the watertight rubber. By allowing such buoyancy to act, in the unlikely event that the pressure inside the cylinder gate 1 drops and becomes a negative pressure state, the lowermost cylinder 4 will float slightly because the above two equations are satisfied. , outside water flows in between the upper edge of the opening of the water conduit 7 and the lower end of the cylinder 4, and the inside of the cylinder gate 1 can be maintained in a hydraulically balanced state. Therefore, there is no damage to the watertight gaskets provided between the water intake cylinders 2, 3, and 4, and no vibration of the cylinders 2, 3, and 4 occurs.

In the second embodiment shown in FIG. 2, the lowermost cylinder 4 has the smallest diameter at its lower end 4A,
The upper end enlarged diameter part 4B is a tapered pipe whose maximum diameter is larger than the diameter of the intermediate cylinder 3, and is designed to satisfy the above-mentioned formulas 1 and 2 in the same manner as the first embodiment shown in FIG. It is structured in such a way that it can be expected to work and be effective.

Furthermore, in the third embodiment shown in FIG.
A buoyancy tank 10 is installed on the upper outer periphery of the bottom cylinder 4.
is provided, and an appropriate number of water passage holes 11 are provided on the inner circumferential surface of the buoyancy tank 10 (wall of the cylinder 4) to maintain the same pressure as the cylinder internal pressure.
The area A of is designed to satisfy the above-mentioned equations 1 and 2, as in the first embodiment shown in FIG. Therefore, in this third embodiment as well, when the pressure inside the cylinder gate 1 becomes negative, the pressure inside the buoyancy tank 10 decreases, and the same effects as in the first embodiment can be expected.

4 and 5 show a fourth embodiment, in which the upper water intake cylinder has a large diameter and is located on the outside, and the lower outer periphery of the lowermost cylinder 4 is designed so that buoyancy acts on it. A buoyancy tank 10 is provided. A watertight rubber 12 is also provided at the lower end of each water intake cylinder 2, 3, and 4, and as shown in Figure 5, when the dam water level drops, the cylinder gate 1 reaches its lowest position. In this state, the balance between the forces acting on the upper and lower surfaces of the buoyancy tank 10 is lost, the buoyancy increases, and when the inside of the cylinder gate 1 becomes negative pressure, the cylinder gate 1 is configured to float slightly. Note that by providing an appropriate number of water holes (not shown) on the inner peripheral surface of the buoyancy tank 10 (wall surface of the lowermost cylinder 4), the water intake cylinder 2 can be placed at the lowermost position as in the third embodiment. Even if it is not, if the pressure inside the cylinder gate 1 becomes negative, the pressure inside the buoyancy tank 10 will also drop, the lowermost cylinder 4 will float, and outside water can flow in to achieve a water pressure balance state.

In each of the above embodiments, when the lowermost cylinder 4 rises slightly and outside water flows into the cylinder gate 1 as shown in FIG.
The earth and sand accumulated on the outside of the opening periphery are washed away together with the outside water, and watertightness can be ensured when the lowermost cylinder 4 is lowered again.

(Effects of the Invention) The cylinder gate according to the present invention is provided with an inclined part or a stepped part on which buoyancy acts on the lowest cylinder when the pressure inside the cylinder gate drops below a predetermined pressure (negative pressure state). Therefore, when the pressure becomes negative, the lowest cylinder automatically rises slightly and outside water flows into the cylinder gate from its lower end, creating a water pressure balance state and preventing damage to the watertight rubber provided between each cylinder. In addition to preventing vibration of each cylinder,
Each cylinder can also be designed with a water level difference, making it lighter, allowing stable water intake without the need for a separate security gate, and achieving outstanding effects such as being able to sweep away accumulated sediment around the opening of the headrace channel. play.

[Brief explanation of drawings]

The drawings show a schematic configuration of an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of the first embodiment, FIG. 2 is a longitudinal sectional view of the second embodiment, and FIG. 3 is a longitudinal sectional view of the third embodiment. FIG. 4 is a vertical cross-sectional view of the fourth embodiment, and FIG. 5 is a vertical cross-sectional view showing the state of the cylinder gate at the lowest position in the fourth embodiment. 1... Cylinder gate, 2, 3, 4... Water intake cylinder, 4B... Expansion section, 5... Reservoir, 6
... Water intake basin, 7 ... Headrace channel, 9 ... Step section, 10
...Buoyancy tank, 11...Water hole.

Claims (1)

[Claims] 1 A plurality of water intake cylinders 2 to 4 are provided vertically expandable and retractable, a water intake tray 6 is provided at the upper end of the uppermost cylinder 2, a float 8 is connected above the water intake tray 6, and the lower end of the lowermost cylinder 4 In the cylinder gate 1, which is connected to the water conduit 7 and can be moved up and down using the pillar 13 as a guide, the lowermost cylinder 4 is vertically movable. 12 to maintain the periphery of the opening of the water conduit 7 in a watertight state,
When the water level of the outside water falls below the water intake basin 6 and the pressure inside the gate 1 becomes negative, the upward force due to the outside water pressure becomes greater than the pressure inside the gate 1, causing the lowest cylinder 4 to rise and the outside water to flow out. A cylinder cage characterized in that the lowermost cylinder 4 is provided with a sloped portion or a stepped portion 9 so as to flow into the cylinder 4.