Rotatable movable weir for overflow bank

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 for an overflow levee that is installed on an overflow levee to allow water to flow from a river to a regulating pond or retarding basin during a river flood. [Background technology]

[0002] River levees may have overflow levees, which are sections that are one level lower than the surrounding levees. Overflow levees are connected to adjacent regulating ponds or retarding basins, and allow some of the water from the river to flow into the regulating ponds or retarding basins during floods. It is known that such overflow levees are equipped with movable weirs that can be moved as needed, such as during river floods, to allow water to flow from the river into a regulating pond or a floodplain.

[0003] As shown in Patent Document 1, for example, a movable weir has weir pillars erected on both sides of an overflow levee, and a gate plate that can be raised or lowered is provided between these pillars. A hydraulic cylinder is provided on the back of the gate plate, and a power unit is provided to operate the hydraulic cylinder, so that the gate plate can be raised or lowered using the hydraulic cylinder. The hydraulic cylinder is operated by the river administrator. In the movable weir installed on this overflow levee, under normal circumstances, a gate plate is raised by a hydraulic cylinder to prevent water from flowing from the river into the regulation pond or retarding basin (by damming up the water), and in the event of a river flood, the hydraulic cylinder is activated to tilt the gate plate, allowing water to flow from the river into the regulation pond or retarding basin.

[0004] Such conventional movable weirs are equipped with hydraulic cylinders to raise and lower the gate plates, but in emergencies such as river flooding, the hydraulic cylinders must be activated to lower the gate plates and allow water from the river to flow into a regulating pond or retarding basin. This requires regular checks to ensure that the hydraulic cylinders are operating properly, which requires maintenance work for the hydraulic cylinders and their power units, resulting in maintenance costs.

[0005] Furthermore, when a river floods, the river administrator operates the hydraulic cylinder of the movable weir in a river management building or other location to allow water to flow from the river into a regulation pond or retarding basin. This means that in emergencies such as river floods, the river administrator must work near the overflow levee, which can be dangerous. Furthermore, when the river water level drops back to normal, the river administrator must also operate the hydraulic cylinder of the movable weir to raise the gate plate, which is a tedious process. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-309558 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention was made in consideration of these problems, and its purpose is to provide a rotary movable weir for an overflow levee that simplifies maintenance work for rotary movable weirs, reduces maintenance costs, and reduces the danger to river managers in emergencies such as river floods. [Means for solving the problem]

[0008] The present invention is a rotating movable weir of an overflow levee that is installed on an overflow levee and allows water to flow from a river into a regulating pond or retarding basin when the river floods. The overflow levee comprises a plurality of upright weir pillars and gate plates that are placed between the weir pillars to hold back the water. The gate plates are rotatably supported on the weir pillars by a rotating shaft extending left and right, the rotating shaft being located at the bottom one-third of the vertical dimension of the gate plate, and the center of gravity of the gate plate is located below the rotating shaft. A stopper that abuts against the gate plate and restricts its rotation is attached to the weir pillars, and when the river floods, the water pressure acting on the gate plate causes the gate plate to rotate and collapse, allowing water to flow from the river to the regulating pond or retarding basin. [Effects of the Invention]

[0009] According to this invention, when a river floods, the gate plates placed between the weir pillars rotate and collapse due to the water pressure acting on them, allowing water to flow from the river into a regulating pond or retarding basin, eliminating the need for equipment such as hydraulic cylinders and power units to raise and lower the gate plates.This simplifies the maintenance work for a rotary-type movable weir, reduces maintenance costs, and also enables the rotary-type movable weir itself to be manufactured inexpensively. Furthermore, in the event of an emergency such as a river flood, the river administrator will no longer need to carry out work on or near the overflow levee, thereby reducing the risk to the river administrator. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a pivotable movable weir of an overflow dike according to the present invention. [Figure 2] FIG. 2A is a plan view of a weir pillar of a pivotable movable weir, and FIG. 2B is a side view of the weir pillar of the pivotable movable weir. [Figure 3] FIG. 10 is a front view of the gate plate of the pivotable movable weir. [Figure 4] FIG. [Figure 5] FIG. 2 is an exploded perspective view showing the attachment state of the weir pillar and the gate plate. [Figure 6] FIG. 6A is a partially cross-sectional side view showing the attachment of the rotary shaft to the gate plate, and FIG. 6B is a partially cross-sectional front view showing the attachment of the rotary shaft to the gate plate. [Figure 7] FIG. 7A shows the state when there is no water in the overflow levee, and FIG. 7B shows the state when the water level in the overflow levee is low. [Figure 8] FIG. 8A shows the state when the water level in the overflow levee is rising, and FIG. 8B shows the state when the water level in the overflow levee has exceeded the upper end of the gate plate. [Figure 9] FIG. 9A shows the gate plate inside the overflow levee when it is rotating, and FIG. 9B shows the gate plate inside the overflow levee when it has rotated and fallen down. [Figure 10]Figure 10A shows the flow of water within an overflow dam with a gate plate having a wing-shaped cross section, and Figure 10B shows the flow of water within an overflow dam with a gate plate having a rectangular cross section. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of a rotary movable weir for an overflow weir of the present invention will be described with reference to the drawings. As shown in Figure 1, the rotary movable overflow dam 1 of this embodiment is installed on an overflow dam 3 provided on a river levee 2, and allows water to flow from the river to a regulation pond or floodplain during river floods.

[0012] The overflow dike's pivotable movable weir 1 is installed over the entire length of the overflow section within the overflow dike 3, and comprises a plurality of erected weir pillars 4, and gate plates 5 placed between adjacent weir pillars 4. Although Fig. 1 shows seven weir pillars 4 and six gate plates 5, the number of weir pillars 4 is not limited to this, and the number of gate plates 5 may be two to six or eight or more, and one to five or seven or more.

[0013] As shown in Figures 2A and 2B, the weir pillar 4 consists of a parent pile 6, such as an H-beam, that extends up and down and can be inserted into the ground, and a precast concrete block 7 that is attached to the top of the parent pile 6 and appears at the ground surface. The shape of the precast concrete block 7 is made to match the shape of the overflow levee. Note that the weir pillar 4 is not limited to the precast concrete block 7 described above, and cast-in-place concrete may also be used.

[0014] As shown in Figure 3, the gate plate 5 is provided between adjacent weir pillars 4 on the left and right, and is elongated from side to side to close the space between the weir pillars 4. The upper end A of this gate plate 5 is located slightly lower than the height T of the levee 2. The gate plate 5 is rotatably supported on the weir pillars 4 by a pivot shaft 11 facing left and right, and is normally supported on the weir pillars 4 in an upright position (facing up and down), but rotates and collapses during river floods. The left and right direction here refers to the direction of the entire length of the overflow section of the overflow levee 3, that is, the direction in which the multiple weir pillars 4 provided on the overflow levee 3 are lined up, and is indicated by arrow S in Figures 1 and 3. Furthermore, the cross section of the gate plate 5 is wing-shaped, so that when the gate plate 5 rotates and falls down (when the gate plate 5 rotates and becomes horizontal), the upper surface 51 becomes a flat surface and the lower surface 52 becomes a curved surface with a bulge, as shown in Fig. 4. The cross section of the gate plate 5 is not limited to being wing-shaped, and the cross section of the gate plate 5 may be another shape, such as a rectangle.

[0015] As shown in Figure 5, the gate plate 5 is supported by the weir pillar 4 by providing a rotating shaft 11 on each of the left and right sides of the gate plate 5, and by providing bearings 12 on the weir pillars 4 on both sides into which the rotating shafts 11 are fitted. These bearings 12 are, for example, ball bearings. However, they are not limited to ball bearings. Note that while the rotating shaft 11 is provided on the gate plate 5 and the bearing 12 is provided on the weir pillar 4, it is also possible to provide the bearing 12 on the gate plate 5 and the rotating shaft 11 on the weir pillar 4 instead.

[0016] 6A and 6B, the pivot shaft 11 is attached to the gate plate 5 at a position 1 / 3 from the bottom of the vertical dimension L of the gate plate 5. This position 1 / 3 from the bottom of the vertical dimension L of the gate plate 5 is the position where the resultant force of water pressure acts on the gate plate 5 when the water level reaches the upper end of the gate plate 5, and by attaching the pivot shaft 11 of the gate plate 5 to a position 1 / 3 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 not rotate but will remain stationary in an upright position.

[0017] 6A, the center of gravity G of the gate plate 5 is positioned below the attachment position of the rotary shaft 11. For example, the outer periphery 53 of the gate plate 5 is formed from an iron plate, making the interior hollow, and steel members 54 for the framework are placed inside the hollow. At this time, by adjusting the steel members 54 placed inside, the center of gravity G of the gate plate 5 is positioned below the attachment position of the rotary shaft 11. In this way, by positioning the center of gravity G of the gate plate 5 below the attachment position of the rotary shaft 11, the gate plate 5 is supported by the weir pillar 4 in an upright state. Note that the structure of the gate plate 5 is not limited to the above structure, and other structures may be used.

[0018] The overflow levee's rotating movable weir 1 is also provided with stoppers 13 that restrict the rotation of the gate plates 5. That is, stoppers 13 are attached to the top of the inner sides of the adjacent weir pillars 4 between which the gate plates 5 are placed (as shown in Figure 5), and when the gate plates 5 are in the upright position, the gate plates 5 come into contact with the stoppers 13, restricting the tops of the gate plates 5 from rotating toward the river.

[0019] In addition, a seal (not shown) is provided between the weir pillar 4 and the gate plate 5 to prevent water from flowing through the gap. This seal is designed not to interfere with the rotation of the gate plate 5.

[0020] Next, the operation of the rotary movable weir of the overflow dam will be explained. When the river is at a normal water level, there is no water in the overflow levee 3, and in the rotary-type movable weir 1, the gate plate 5 does not rotate but remains stationary in an upright position, as shown in FIG. 7A.

[0021] Subsequently, when the river water level rises and water flows into the overflow levee 3, for example, if the water level in the overflow levee 3 is lower than the pivot axis 11 of the gate plate 5, the gate plate 5 will attempt to rotate due to the water pressure acting on it, as shown in Figure 7B. At this time, the resultant force of the water pressure acting on the gate plate 5 is below the pivot axis 11 of the gate plate 5, so the upper part of the gate plate 5 attempts to rotate toward the river. However, the rotation of the gate plate 5 is restricted by the stopper 13 attached to the upper part of the weir pillar 4, and the gate plate 5 remains stationary in an upright position. In other words, in the overflow levee 3, the gate plate 5 blocks water, preventing it from flowing into the regulation pond or retarding basin. The gate plate 5 remains stationary in an upright position as shown in Figure 8A until the water level in the overflow levee reaches the upper end of the gate plate 5, thereby preventing water from flowing into the regulation pond or retarding basin.

[0022] When the water level in the river rises further and the water level inside the overflow levee 3 exceeds the upper end of the gate plate 5 (a position slightly lower than the height of the levee 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 position at which the resultant force of the water pressure acting on the gate plate 5 acts is above the pivot axis 11 of the gate plate 5, so that the upper part of the gate plate 5 rotates toward the regulation pond or retarding basin (opposite the river), causing the gate plate 5 to collapse (as shown in Figure 9B). As a result, at the overflow levee 3, water flows from the river into the regulation pond or retarding basin. In this case, the cross section of the gate plate 5 is wing-shaped, with the upper surface 51 of the gate plate 5 being flat and the lower surface 52 being a curved, bulging surface, so that the gate plate 5 is angled from the horizontal as shown in Figure 9B (the downstream side is angled downward, or angled downward to the left in Figure 9B), which reduces the resistance of the gate plate 5 when water flows and allows water to flow smoothly within the overflow levee 3.

[0023] In this way, by installing the rotary weir 1 on the overflow levee 3, which is one step lower than the height of the levee 2, even if the water level rises to nearly the height of the levee 2 during a river flood, the rotary weir 1 prevents water from immediately flowing from the river into the regulation pond or retarding basin. When the water level in the overflow levee 3 exceeds the upper end of the gate plate 5, the gate plate 5 of the rotary weir 1 rotates and falls, allowing water to flow from the river into the regulation pond or retarding basin at the overflow levee 3. When the water level in the river drops back to its normal level, the water in the overflow levee 3 disappears. As a result, the center of gravity G of the gate plate 5 is positioned below the attachment position of the rotation shaft 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 through gate plates 5 with different cross-sectional shapes. When the water level in the overflow levee 3 exceeds the upper end of the gate plate 5 (during a river flood), if the cross-sectional shape of the gate plate 5 is wing-shaped, the flow of water will be such that the gate plate 5 is angled diagonally from the horizontal (the downstream side is diagonally downward, or diagonally downward to the left in Figure 10A), as shown in Figure 10A. This reduces the resistance caused by the gate plate 5 when water flows, improving the flow of water within the overflow levee 3. In other words, water can be efficiently diverted from the river to the regulation pond or retarding basin 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 made a simple rectangular shape, the downstream side of the gate plate 5 will be slanted upward, which will increase the resistance of the gate plate 5 when water flows, causing the water level in the overflow levee 3 to rise, making it difficult to sufficiently drain water from the river into the regulation pond or retarding basin during a river flood. This experiment showed that by making the cross-sectional shape of the gate plate 5 wing-shaped, the water flow within the overflow levee 3 is improved, and water can be sufficiently diverted into the regulation pond or floodplain during river floods.

[0026] As described above, according to this embodiment, when the water level in the overflow levee 3 exceeds the upper end of the gate plate 5 during a river flood, the gate plate 5 disposed between the weir pillars 4 rotates and collapses due to the water pressure acting on the gate plate 5, thereby allowing water to flow from the river into the regulating pond or retarding basin. Rotating the gate plate 5 using the water pressure acting on the gate plate 5 in this way eliminates the need for conventional equipment such as hydraulic cylinders and power units to raise and lower the gate plate. This simplifies the maintenance work for the rotary movable weir 1 and reduces its maintenance costs. Furthermore, eliminating the need for equipment such as hydraulic cylinders and power units allows the rotary movable weir 1 itself to be manufactured inexpensively, thereby reducing construction costs.

[0027] Furthermore, in emergencies such as river flooding, river administrators will no longer need to work near overflow levees, reducing the risk to them and ensuring their safety.

[0028] Furthermore, in the rotating movable weir 1, the weir pillar 4 is composed of a main pile 6 and a precast concrete block 7, which simplifies the production of the weir pillar 4 and the installation of the weir pillar 4 within the overflow levee 3, reducing costs and shortening the construction period. [Explanation of symbols]

[0029] 1...rotating movable weir for overflow dam, 2...levee, 3...overflow dam, 4...weir pillar, 5...gate plate, 6...support pile, 7...precast concrete block, 11...rotating shaft, 12...bearing, 13...stopper, 51...upper surface, 52...lower surface, 53...periphery, 54...steel.

Claims

1. A rotary movable weir of an overflow levee that is installed on an overflow levee and allows water to flow from the river to a regulation pond or a floodplain during a river flood. It is equipped with multiple erected weir pillars and gate plates that are placed between the weir pillars to block water, The gate plate is rotatably supported on the weir pillar by a rotation shaft extending left and right, the rotation shaft is located at a position one-third from the bottom of the vertical dimension of the gate plate, and the center of gravity of the gate plate is located below the rotation shaft, A stopper that contacts the gate plate and restricts its rotation is attached to the gate pillar. A rotating movable overflow weir characterized in that when a river floods, the water pressure acting on the gate plate causes it to rotate and collapse, allowing water to flow from the river into a regulation pond or retarding basin.

2. The rotary movable weir of the overflow dam according to claim 1, The gate plate has a wing-shaped cross section, and when the gate plate is rotated and horizontal, the upper surface is flat and the lower surface is curved with a bulge. This is a rotating movable weir for an overflow dam.

3. The rotary movable weir of the overflow dam according to claim 1 or 2, The multiple weir pillars are a revolving movable overflow dam consisting of support piles inserted into the ground and precast concrete blocks attached to cover the top of the support piles.

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