Rotating movable weir for overflow dike

Abstract

To provide a turning type movable weir of an overflow bank capable of simplifying maintenance work in the turning type movable weir, reducing its maintenance cost, and reducing danger to a river manager in an emergency such as a flood of a river.SOLUTION: The turning type movable weir 1 of the overflow bank installed on the overflow bank 3 and making water flow from a river to a regulating pond or a retarding area when the river floods is provided with a plurality of erected weir columns 4 and gate plates 5 arranged between the weir columns 4 to dam water, and the gate plates 5 are turnably supported on the weir columns 4 by turning shafts 11 directed to the right and left. The rotating shaft 11 is provided at a position one third of the vertical dimension of the gate plate 5 from the bottom, the position of the center of gravity of the gate plate 5 is located below the rotating shaft 11, and a stopper 13 that comes into contact with the gate plate 5 to regulate rotation is attached to the weir column 4.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a rotary movable weir of an overflow dike installed on an overflow dike that allows water to flow from a river to a regulating pond or a swimming area during a flood in the river.

Background Art

[0002] Some flood control dikes of rivers may have an overflow dike that is set one step lower than the height of the surrounding dikes. The overflow dike is connected to a regulating pond or a swimming area adjacent to the river, and during a flood in the river, part of the water is allowed to flow from the river to the regulating pond or the swimming area. In this overflow dike, it is known to install a movable weir and move the movable weir as needed during a flood in the river to allow water to flow from the river to the regulating pond or the swimming area.

[0003] For example, as shown in Patent Document 1, the movable weir has weir columns erected on both sides of the overflow dike, and a gate plate that stands up and falls between these weir columns. In addition, a hydraulic cylinder is provided on the back of the gate plate, and a power device for operating the hydraulic cylinder is provided, and the gate plate is erected or fallen using the hydraulic cylinder. The operation of this hydraulic cylinder is performed by a river administrator operating the hydraulic cylinder. In the movable weir installed on this overflow dike, normally, the gate plate is erected by the hydraulic cylinder so that water does not flow from the river to the regulating pond or the swimming area (blocking the water), and during a flood in the river, the hydraulic cylinder is operated to cause the gate plate to fall so that water flows from the river to the regulating pond or the swimming area.

[0004] In such a conventional movable weir, a hydraulic cylinder for erecting and falling the gate plate is provided, but during an emergency such as a flood in the river, the hydraulic cylinder must be operated to cause the gate plate to fall so that water flows from the river to the regulating pond or the swimming area. Therefore, it is necessary to regularly check whether the hydraulic cylinder operates normally, and there is a problem that maintenance work for the hydraulic cylinder and its power device is required and maintenance costs are incurred.

[0005] Furthermore, during river floods, river administrators operate the hydraulic cylinders of the movable weir at river management buildings to divert water from the river to a regulating reservoir or floodplain. This presents a problem because, during emergencies such as river floods, river administrators have to work near the overflow weir, which can be dangerous. Moreover, even when the river level drops back to normal, river administrators still need to operate the hydraulic cylinders of the movable weir to raise the gate plates, which is a cumbersome process. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2002-309558 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention has been made in view of these problems, and its purpose is to provide a rotatable movable weir for overflow that simplifies maintenance work on rotatable movable weirs, reduces maintenance costs, and mitigates the danger posed to river administrators in emergencies such as river floods. [Means for solving the problem]

[0008] The present invention relates to a rotatable movable weir for an overflow weir, which is installed on an overflow weir to divert water from the river to a regulating reservoir or floodplain during river floods. The weir comprises a plurality of erected weir pillars and gate plates positioned between the weir pillars to block the water, with the gate plates being rotatably supported on the weir pillars by pivot axes extending to the left and right. When the water level exceeds the upper edge of the gate plate, the water pressure will cause the gate plate to rotate and collapse.This is a rotating, movable overflow weir in which the pivot axis is located one-third of the way down from the bottom of the gate plate's vertical dimension, the center of gravity of the gate plate is located below the pivot axis, and a stopper is attached to the weir column to contact the gate plate and restrict its rotation. The gate plate has an airfoil-shaped cross-section, and when the gate plate is rotated to a horizontal position, the upper surface is flat and the lower surface is curved and bulging. In the event of a river flood, the water pressure acting on the gate plate causes it to rotate and collapse, allowing water to flow from the river to a regulating reservoir or floodplain. [Effects of the Invention]

[0009] According to the present invention, gate plates placed between weir pillars rotate and collapse due to the water pressure acting on them during river floods, thereby diverting water from the river to a regulating reservoir or floodplain. This eliminates the need for hydraulic cylinders and power devices to raise and lower the gate plates. As a result, maintenance work on the rotating weir is simplified, maintenance costs are reduced, and the rotating weir itself can be manufactured at a low cost. Furthermore, in emergencies such as river floods, river administrators will no longer need to work on or near overflow weirs, thus reducing the risks to them. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of the rotatable movable weir of the overflow dike according to the present invention. [Figure 2] Figure 2A is a plan view of the weir pillars of a rotating movable weir, and Figure 2B is a side view of the weir pillars of a rotating movable weir. [Figure 3] This is a front view of the gate plate of a rotating movable weir. [Figure 4] This is a side view of the gate plate. [Figure 5] This is an exploded perspective view showing the installation of the dam pillars and gate plates. [Figure 6] Figure 6A is a partial cross-sectional side view showing the attachment of the pivot shaft to the gate plate, and Figure 6B is a partial cross-sectional front view showing the attachment of the pivot shaft to the gate plate. [Figure 7] Figure 7A shows the situation when there is no water inside the overflow weir, and Figure 7B shows the situation when the water level inside the overflow weir is low. [Figure 8] Figure 8A shows the situation when the water level inside the overflow weir is rising, and Figure 8B shows the situation when the water level inside the overflow weir exceeds the upper edge of the gate plate. [Figure 9] Figure 9A shows the gate plate inside the overflow weir rotating, and Figure 9B shows the gate plate inside the overflow weir rotating and then collapsing. [Figure 10] Figure 10A shows the water flow within an overflow weir in a gate plate with an airfoil cross-section, and Figure 10B shows the water flow within an overflow weir in a gate plate with a rectangular cross-section. [Modes for carrying out the invention]

[0011] One embodiment of the rotating movable weir for overflow dikes of the present invention will be described with reference to the drawings. As shown in Figure 1, the rotatable movable weir 1 of the overflow weir according to this embodiment is installed on the overflow weir 3 provided on the river embankment 2, and is used to divert water from the river to a regulating reservoir or floodplain during river floods.

[0012] The rotating movable weir 1 of the overflow weir is installed along the entire length of the overflow section within the overflow weir 3, and comprises multiple erected weir pillars 4 and gate plates 5 placed between adjacent weir pillars 4. In Figure 1, there are seven weir pillars 4 and six gate plates 5, but the number of weir pillars 4 can be two to six or eight or more, and the number of gate plates 5 can be one to five or seven or more.

[0013] As shown in FIGS. 2A and 2B, the weir column 4 is composed of a parent pile 6 such as an H-shaped steel that can be inserted into the ground and a precast concrete block 7 that is attached so as to cover the upper part of the parent pile 6 and appears on the ground surface. Also, the shape of the precast concrete block 7 is made to match the shape of the overflow dam. Note that the weir column 4 is not limited to the precast concrete block 7 as described above, and cast-in-place concrete may also be used.

[0014] As shown in FIG. 3, the gate plate 5 is provided between adjacent weir columns 4 on the left and right, has a long shape in the left and right direction, and closes the space between the weir columns 4. The upper end A of this gate plate 5 is set at a position slightly lower than the height T of the levee 2. Also, the gate plate 5 is rotatably supported by the weir column 4 by a rotating shaft 11 in the left and right directions, and is normally supported by the weir column 4 in a standing state (a state facing up and down), and rotates and falls down during a flood in the river. Here, the left and right directions are the direction of the total length of the overflow section of the overflow dam 3, that is, the direction in which a plurality of weir columns 4 provided on the overflow dam 3 are arranged, and are indicated by an arrow S in FIGS. 1 and 3. Also, the gate plate 5 has an airfoil cross-sectional shape, and when the gate plate 5 rotates and falls down (the state where the gate plate 5 rotates and becomes horizontal), as shown in FIG. 4, the upper surface 51 becomes a flat surface and the lower surface 52 becomes a curved surface with a bulge. Note that the cross-sectional shape of the gate plate 5 is not limited to an airfoil shape, and the cross-sectional shape of the gate plate 5 may be another shape such as a rectangular shape.

[0015] As shown in FIG. 5, the support of the gate plate 5 to the weir column 4 is provided with rotating shafts 11 on both the left and right sides of the gate plate 5, and bearings 12 for fitting these rotating shafts 11 are provided on the weir columns 4 on both sides, respectively. This bearing 12 is, for example, a ball bearing. However, it is not limited to a ball bearing. Although the rotating shaft 11 is provided on the gate plate 5 and the bearing 12 is provided on the weir column 4, alternatively, the bearing 12 may be provided on the gate plate 5 and the rotating shaft 11 may be provided on the weir column 4.

[0016] The attachment of the rotating shaft 11 to the gate plate 5 is, as shown in FIGS. 6A and 6B, attached at a position one-third from the bottom of the vertical dimension L of the gate plate 5. The position one-third from the bottom of the vertical dimension L of the gate plate 5 is the acting position of the resultant force of the water pressure acting on the gate plate 5 when the water level reaches the upper end of the gate plate 5. By setting the position where the rotating shaft 11 of the gate plate 5 is attached to a position one-third from the bottom of the vertical dimension L of the gate plate 5, when the water level reaches the upper end of the gate plate 5, the gate plate 5 will remain stationary in a standing state without rotating.

[0017] Also, in the gate plate 5, as shown in FIG. 6A, the center of gravity position G is set to be below the attachment position of the rotating shaft 11. For example, the gate plate 5 has an outer periphery 53 formed of an iron plate with a hollow interior, and a steel material 54 for the framework is arranged inside. At this time, by adjusting the steel material 54 arranged inside, the center of gravity position G of the gate plate 5 is set to be below the attachment position of the rotating shaft 11. In this way, since the center of gravity position G of the gate plate 5 is below the attachment position of the rotating shaft 11, the gate plate 5 is supported by the weir column 4 in a standing state. Note that the structure of the gate plate 5 is not limited to the above structure, and other structures may also be used.

[0018] Also, a stopper 13 for restricting the rotation of the gate plate 5 is provided on the rotating movable weir 1 of the overflow dam. That is, in the adjacent weir columns 4 with the gate plate 5 disposed therebetween, stoppers 13 are attached to the upper parts inside thereof (shown in FIG. 5). When the gate plate 5 is in a standing state, the upper part of the gate plate 5 is restricted from rotating toward the river side by abutting against the stopper 13.

[0019] Also, a sealing material (not shown) for preventing water from flowing through the gap is provided between the weir column 4 and the gate plate 5. Note that this sealing material does not interfere with the rotation of the gate plate 5.

[0020] Next, the operation of the rotating movable weir of the overflow dam will be described. When the river is at its normal water level, there is no water inside the overflow weir 3, and in the rotating movable weir 1, as shown in Figure 7A, the gate plate 5 remains stationary in an upright position without rotating.

[0021] Next, when the river water level rises and water flows into the overflow weir 3, for example, if the water level inside the overflow weir 3 is lower than the pivot axis 11 of the gate plate 5, the water pressure acting on the gate plate 5 will cause it to rotate, as shown in Figure 7B. At this time, the point where the resultant force of the water pressure acting on the gate plate 5 acts is below the pivot axis 11 of the gate plate 5, so the rotation of the gate plate 5 will cause the upper part of the gate plate 5 to rotate toward the river. However, the rotation of the gate plate 5 that is trying to rotate is restricted by the stopper 13 installed on the upper part of the weir pillar 4, and the gate plate 5 remains stationary in an upright position. In other words, the overflow weir 3 uses the gate plate 5 to block the water and prevent it from flowing into the regulating reservoir or floodplain. The gate plate 5 remains stationary in an upright position, as shown in Figure 8A, until the water level inside the overflow weir reaches the upper end of the gate plate 5, thereby preventing water from flowing into the regulating reservoir or floodplain.

[0022] As the river level rises further, and the water level inside the overflow weir 3 exceeds the upper end of the gate plate 5 (slightly lower than the height of the embankment 2) (as shown in Figure 8B), the water pressure acting on the gate plate 5 causes it to rotate (as shown in Figure 9A). At this time, the point where the resultant force of the water pressure acting on the gate plate 5 acts is above the rotation axis 11 of the gate plate 5. As a result, the rotation of the gate plate 5 causes the upper part of the gate plate 5 to rotate toward the regulating reservoir or floodplain (opposite to the river side), and the gate plate 5 collapses (as shown in Figure 9B). Consequently, water flows from the river to the regulating reservoir or floodplain at the overflow weir 3. In this case, the gate plate 5 has an airfoil-shaped cross-section, with the upper surface 51 being a flat surface and the lower surface 52 being a curved, bulging surface. As shown in Figure 9B, the gate plate 5 is angled from horizontal (the downstream side is angled downwards, angled downwards to the left in Figure 9B). This reduces the resistance of the gate plate 5 when water flows through it, allowing water to flow smoothly within the overflow weir 3.

[0023] In this way, by installing the rotatable movable weir 1 on the overflow weir 3, which is one level lower than the height of the embankment 2, even when the water level rises to nearly the height of the embankment 2 during a river flood, the rotatable movable weir 1 prevents water from immediately flowing from the river to the regulating reservoir or floodplain. When the water level inside the overflow weir 3 exceeds the upper edge of the gate plate 5, the gate plate 5 of the rotatable movable weir 1 rotates and collapses, allowing water to flow from the river to the regulating reservoir or floodplain at the overflow weir 3. When the river water level drops back to the normal level, the water inside the overflow weir 3 disappears. As a result, the center of gravity G of the gate plate 5 is located below the mounting position of the rotation axis 11, and the gate plate 5 returns to an upright position between the weir pillars 4.

[0024] Furthermore, experiments were conducted on the water flow in gate plates 5 with different cross-sectional shapes. When the water level inside the overflow weir 3 exceeds the upper edge of the gate plate 5 (during a river flood), if the cross-sectional shape of the gate plate 5 is airfoil-shaped, the water flow will be such that the gate plate 5 is angled from horizontal to horizontal (the downstream side is angled downward, angled downward to the left in Figure 10A), as shown in Figure 10A. This reduces the resistance of the gate plate 5 when water flows through it, improving the water flow inside the overflow weir 3, and thus allowing water to flow smoothly from the river to the regulating reservoir or floodplain during a river flood.

[0025] On the other hand, as shown in Figure 10B, if the cross-sectional shape of the gate plate 5 is a simple rectangle, the downstream side of the gate plate 5 will be angled upwards. As a result, the resistance of the gate plate 5 when water flows will increase, the water level inside the overflow weir 3 will rise, and it will become difficult to sufficiently drain water from the river to the regulating reservoir or floodplain during river floods. This experiment revealed that by making the cross-sectional shape of the gate plate 5 airfoil-shaped, the water flow within the overflow weir 3 is improved, allowing sufficient water to be directed to the regulating reservoir or floodplain during river floods.

[0026] As explained above, according to this embodiment, when the water level inside the overflow weir 3 exceeds the upper end of the gate plate 5 during a river flood, the water pressure acting on the gate plate 5 causes it to rotate and collapse, allowing water to flow from the river to a regulating reservoir or floodplain. By rotating the gate plate 5 using the water pressure acting on it, there is no need for equipment such as hydraulic cylinders and power devices that raise and lower the gate plate as in the conventional method. This simplifies the maintenance work on the rotatable movable weir 1 and reduces maintenance costs. Moreover, because equipment such as hydraulic cylinders and power devices are not required, the rotatable movable weir 1 itself can be manufactured at a lower cost, and construction costs can be reduced.

[0027] Furthermore, in emergencies such as river floods, river administrators will no longer need to work near the overflow dam, thus reducing the risks to river administrators and ensuring their safety.

[0028] Furthermore, in the rotatable movable weir 1, the weir pillars 4 are composed of main piles 6 and precast concrete blocks 7, which simplifies the manufacturing of the weir pillars 4 and the installation of the weir pillars 4 within the overflow dam 3, thereby reducing costs and shortening the construction period. [Explanation of Symbols]

[0029] 1... Rotating movable weir of the overflow weir, 2... Embankment, 3... Overflow weir, 4... Weir pillar, 5... Gate plate, 6... Main pile, 7... Precast concrete block, 11... Rotating shaft, 12... Bearing, 13... Stopper, 51... Top surface, 52... Bottom surface, 53..., Outer circumference, 54... Steel material.

Claims

1. A rotating, movable weir for an overflow weir, installed on an overflow weir to divert water from the river to a regulating reservoir or floodplain during river floods, It is equipped with multiple erected weir pillars and gate plates placed between the pillars to block the water. The gate plate is rotatably supported on the weir column by pivot axes that extend to the left and right, and the pivot axes are positioned at one-third of the way up from the bottom of the gate plate's vertical dimension, and the center of gravity of the gate plate is located below the pivot axes, so that the gate plate can rotate and collapse due to water pressure when the water level exceeds the upper end of the gate plate. A stopper is attached to the weir pillar to contact the gate plate and restrict its rotation. The gate plate has an airfoil-shaped cross-section, and when the gate plate is rotated to a horizontal position, the upper surface is flat and the lower surface is curved with a bulge. A rotating, movable overflow weir characterized by the fact that, during river floods, the water pressure acting on the gate plates causes the gate plates to rotate and collapse, thereby diverting water from the river to a regulating reservoir or floodplain.

2. In the rotating movable weir of the overflow weir described in claim 1, Multiple weir pillars form a rotatable, movable overflow weir consisting of main piles inserted into the ground and precast concrete blocks or cast-in-place concrete installed to cover the tops of the main piles.

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