JPH0526885B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a dam gate installed to divert water from a drainage canal, diversion channel, etc., which dams up running water at normal times, and during floods. This invention relates to an automatic dam raising gate for responding to floods, which can automatically discharge water by fully opening the gate.

(Prior Art) Gates installed in rivers include tenter gates and the like. In the gate shown in FIG. 6, a pair of arms 3 are fixed to a horizontal main shaft 2 rotatably supported above a waterway 1, and an arc-shaped gate body 4 centered around the main shaft is fixed to the upstream end of the arm 3. A counterweight 5 is suspended near the downstream end of the arm 3. In this case, the center of gravity of the movable part of the gate should be lowered so that the gate body 4
movement is reduced. Furthermore, a float arm 6 is fixed to the end of the main shaft 2 extending laterally across the river, facing toward the upstream side. This float arm 6
A float 8 floating in a float chamber 7 provided upstream of the main shaft 2 is connected via a suspension rod 9. Further, the float chamber 7 is communicated with the upstream waterway of the door body 4 via an overflow weir 10, and furthermore, the float chamber 7 is communicated with the downstream waterway of the door body 4 via a small-diameter outlet 11.

Note that when multiple gates are installed, due to restrictions in water usage practices, they are installed very close together, and the water level difference between the upstream and downstream gates may be only a few centimeters even when the gates are fully closed. In such a case, it is necessary to suppress the degree of rise and fall of the float 8 as the gate opens and closes to within a few centimeters, and for this purpose, the length of the float arm 6 must be sufficiently long compared to the upstream length of the arm 3. has been made smaller. In addition, the height of the weir crest of the overflow weir 10 is set slightly lower than the water level that should be raised at the upstream weir, and the overflow cross-sectional area is made smaller than the cross-sectional area of the outlet 11 to reduce the overflow water depth. The weir length of the overflow weir 10 is made sufficiently large in order to make the overflow weir sufficiently large.

Further, although not shown, a stopper is provided below the downstream side of the arm 3, and when the gate is fully opened, the arm 3 comes into contact with this and is configured to maintain a constant posture of the arm 3. .

Next, the effect will be explained.

When the upstream water level of the door body 4 becomes slightly higher than the crest of the overflow weir 10, overflow occurs and the water level in the float chamber 7 becomes almost equal to the upstream water level, causing the float 8 to rise. The arm 3 rotates in conjunction with the operation of the float arm 6, the door body 4 moves in the opening direction, and the gate becomes open. As a result, the water flow passing through the gate increases and the rise in the upstream water level is suppressed. Then, as the upstream water level decreases and approaches the top of the overflow weir 10, the overflow amount decreases, so the amount of water in the float chamber 7 is discharged from the outlet 11, and the amount of water in the float chamber 7 is increased. The water level becomes almost the same height as the downstream water level, and as the float 8 descends, the door body 4 moves in the closing direction and the gate is closed. Next, the water upstream is dammed up again by the gate body 4 and the water level rises, so the above-described operation is repeated to keep the water level upstream of the gate almost constant.

Further, as described above, since the length of the float arm 6 is sufficiently small, the upstream water level will not be greatly deviated due to insufficient movement of the door body 4. Furthermore, even during a flood, the door body 4 will operate in the opening direction sequentially as the water level rises up to a certain height, and once the flood level reaches a certain height, the entire door body 4 will move above the water surface. Flood communication will be improved.

(Problems to be Solved by the Invention) The first problem with the prior art is that the float 8 requires a very large planar area. That is, as the float 8 moves up and down, the force acting on the float 8 decreases, and as described above,
Since it is necessary to significantly reduce the length of the float arm 6 to shorten the range of movement of the float 8, the torque acting on the main shaft 2 becomes even smaller, and therefore a very large float 8 is required.

The second problem is that even if there is no need to raise the dam in the event of a flood, a portion of the door body 4 remains submerged in the water, obstructing the flow of running water.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic dam-raising gate that is capable of raising the dam at normal times, but stopping the dam-raising during floods and adjusting the gate to a fully open state.

(Means for Solving the Problems) In order to achieve the above object, the configuration of the present invention is as follows:
An arm is provided on the main shaft that crosses the waterway so as to be freely rotatable in the upstream and downstream directions, and a door body for damming the waterway is provided at the upstream end of the arm, and the main shaft is moved upstream of the main shaft along the waterway. A float chamber is provided in the chamber, the upstream water channel and the downstream channel of the door body are communicated through the float chamber, a float is arranged in the float chamber with a small gap between the float and the chamber wall, and the float is suspended. A float arm is attached to the main shaft in conjunction with the arm so that it is almost horizontal when the float is at an intermediate position between an upper limit position and a lower limit position, and the float forms a sealed part at the lower part and a water guide part at the upper part. , the water guide section is provided with a water guide device that communicates with the downstream water channel of the door body, a counterweight is attached to the arm extending downstream from the main shaft at a position above the axis of the arm, and a counterweight is attached to the arm extending downstream from the main shaft, The weight is determined when the upstream water level is raised to the upper limit water level by the gate body when the downstream water level is the planned water level.
It is characterized in that the weight of the entire movable part is balanced when the water level in the float chamber is at an intermediate height.

(Function) Since the present invention is constructed as described above, as the float moves up and down, the water downstream of the door body is discharged and guided into the water guide section, so that the acting force acting on the float does not become weak. Furthermore, since there is no need to reduce the degree of elevation of the float, the float can be made very small by increasing the length of the float arm.

In addition, when it is necessary to raise the dam, especially when it is close to fully closed, the resistance of the gate due to water pressure increases, so a large operating force is required. The closer the valve is to closing, the greater the operating force in the closing direction is obtained due to the eccentric force, and since the water level difference between upstream and downstream becomes larger, the operating force in the opening direction is also obtained.

Furthermore, when the waterway rises and reaches the flood level, the float approaches its upper limit position and the center of gravity of the entire movable part comes to the downstream side of the main shaft, so the gate opens due to the eccentric force of its own weight and the gate body is positioned above the water surface. be done. Afterwards, when the flood water subsides and it becomes necessary to raise the dam, the weight of the float automatically pulls down the gate and resumes dam raising.

(Example) An example of the present invention will be described based on FIGS. 1 to 5.

As shown in FIGS. 1 and 2, the gate 12
Approximately, a pair of arms 15 are fixed to a main shaft 14 that is rotatably supported on the upper part of the water channel 13, and an arc-shaped door body 16 that is attached to the upstream end of the arm 15 and is centered on the main shaft 14. It consists of a float 17 for actuating the arm 15.

The float 17 is arranged in a float chamber 18 provided on the upstream side of the main shaft 14 with a small gap between the float chamber 17 and the chamber wall.
It communicates with a still water chamber 21 via an overflow weir 20 connected to a water pipe 19 communicating with the lower part of the door, and the still water chamber 21 communicates with an upstream waterway of the door body 16 via a flow port 21a. Furthermore, a door body 16 is provided in the float chamber 18.
A small diameter outlet 22 communicating with the downstream waterway is bored. Further, a float arm 23, which will be described later, is connected to a suspension rod 24 provided on the upper part of the float 17, and is fixed to the end of the main shaft 14.

Further, a counterweight 26 is attached near the downstream end of the arm 15 via a support member 25, and the weight of the counterweight 26 or its horizontal position is determined by the upper limit of the upstream water level when the downstream water level is the planned water level. With the dam raised to the water level,
It is determined that the entire movable part of the gate 12 is balanced when the water level in the float chamber 18 is at an intermediate height between the planned water level and the upper limit water level. In addition, the height of the counterweight 26 is configured such that its vertical position is freely adjustable in the above state, and the operating force is fully opened in all states between the above state and the fully closed state of the gate 12. It is appropriately determined so as not to be biased in either direction. Note that a stopper 27 is provided on the downstream side of the arm 15 so that the movable portion remains at a fixed position in the fully open state.

The float arm 23 is fixed to the main shaft so that it is almost horizontal when it is at an intermediate position between the upper limit position and the lower limit position of the float 17, and the angle of the float arm 23 is such that the angle of depression in the fully closed state and the angle of elevation in the fully open state are equal to each other, and the gate is closed. The amount of movement caused by the lifting and lowering of the float 17 as the float 12 opens and closes is minimized. The length of the float arm 23 is shortened so that the water level for restarting weir raising, which will be explained later, is sufficiently high, but it is usually about half the length of the upstream side of the arm 15, which is about half the length of the upstream side of the arm 15. It can be made very long by about 2.5 times.

The lower part of the float 17 is formed with a sealed part 17a, and the upper part of the water guide part 17b is communicated with the downstream channel of the gate 12 via a water guide device 28, which will be described later, and a small-diameter vent 17c is bored in the upper end thereof. It communicates with the atmosphere. The planar area of the float 17 must be large enough to provide sufficient operating force at all gate opening angles, and to sufficiently reduce the movement of the gate 12 when it is close to fully closed, as will be detailed later. Of course, since the tolerance between the upstream water level and the planned water level is set to be as small as possible, in reality, the gate 12, where the downstream water level is the lower limit water level and the upstream water level is the planned water level, is in the float chamber. If the water level within 18 reaches the upper limit water level, gate 1 will be activated.
2 is opened and the gate 12 is closed when the water level reaches the lower limit.

Further, the height of the sealed portion 17a is made sufficiently large so that its lower end is always underwater, and the sealed portion 17a is
The height of the upper end of 7a is the height of the door body 1 when opened during a flood.
The height of the lower end of gate 6 is appropriately determined to be a predetermined height, but when multiple gates 12,... are installed, the most upstream gate 12 is set as above, and the downstream The lower the height, the lower it is by several centimeters.

The water guiding device 28 has one end opened at the lower end of the water guiding section 17b, vertically penetrates the inside of the sealed section 17a, and travels in a vertical zigzag manner with several bendable joints as vertices in the float chamber 18 along the way. Afterwards, it changes direction at right angles and penetrates the walls of the float chamber 18 and the water channel 13, and the other end is opened into the downstream water channel of the gate 12, and its cross section is adjusted appropriately so that the gate 12 opens and closes at an appropriate speed. ing.

The size of the water pipe 19 is made large enough so that even if the flow rate increases rapidly, the gate 12 can fully follow the flow and open quickly, and the overflow weir 20
The height of the weir crest was made slightly lower than the planned water level,
The length of the weir is long to reduce the overflow depth.

Next, the operation will be explained while providing supplementary explanation about the configuration.

In FIG. 5, the horizontal axis shows the gate opening degree based on the fully closed state, and the vertical axis shows the downstream water level, upstream water level, and other heights.

On the horizontal axis, I is the fully closed state, I is the state where the upstream water level starts to rise higher than the planned water level, is the state where the downstream water level has reached the planned water level, and is the gate 12.
V is the state where the center of gravity of the entire movable part is directly above the main axis and the upstream water level is almost at its highest, V is the state where the dam has stopped raising and the door body 16 is about to fly out into the air, and V is the state where the gate body 16 is about to jump out into the air. 16 shows a state in which the lower end of the gate 12 is raised sufficiently high and the gate 12 is fully opened.

FIG. 3 shows the gate 12 in a fully closed state I, with the door body 16 blocking flowing water. The center of gravity of the entire movable part of the gate 12 is shifted to the upstream side, and the eccentric force G is applied to the main shaft 14.
on the upstream side of

FIG. 4 shows the gate 12 fully open, the gate body 16 is completely off the water surface, and the eccentric force G is applied to the main shaft 14.
The arm 15 is held on the downstream side of the stopper 27.

Next, the action between state I and state will be explained. First, the upper limit water level is determined within the allowable error of 2Δh above the planned water level without causing any practical problems. Next, in this state, the curve (lower limit water level) shows the relationship between the downstream water level and the gate opening angle such that the upstream water level becomes the height of the planned water level for each gate 12 opening angle. . As will be understood in the following explanation, the upstream water level will be slightly higher than the planned water level when the gate 12 opens, so the actual downstream water level will be slightly higher than the curve (lower limit water level) and the gate 12 will be slightly higher than the planned water level. On closing, the downstream water level is slightly lower than the curve (lower water level), but the curve (lower water level) illustrated the concept. In addition, the curve shows the center of gravity of the entire movable part at each opening angle.
The effect of eccentricity is shown with the horizontal axis as the horizontal axis in terms of the difference in water level between the inside and outside of the float 17, with the direction in which the gate 12 is about to be closed as positive. This is what is shown. Therefore, the curve shows that the entire movable part of the gate 12 is balanced at each opening angle.
This indicates the water level in the float chamber 18. According to hydraulic principles, the water level difference between the float chamber 18 and the downstream water level changes greatly in proportion to the cube of the overflow water depth, so the upstream water level When the water level becomes slightly higher than the planned water level, the gate 12 opens, and when it becomes slightly higher, the gate 12 closes, and when the upstream water level returns to approximately equal to the planned water level, the gate 12 becomes stationary.

Next, the effects of states between states will be explained. The height of the curve becomes higher when it is opened more than the current state, so the gate 12 will not open unless the upstream water level is higher than the planned water level, so the upstream water level when the water increases will be as shown in the curve. , the upstream water level at the time of water reduction is almost equal to the planned water level, as mentioned above, but in any case,
If the upstream water level is below the planned flow rate, it will generally be maintained between the planned water level and the upper limit water level. In addition, in this situation, the usable upstream and downstream water level difference is small, so it is necessary to accurately adjust the height of the curve, but depending on the weight of the counterweight 26 or the horizontal position, it is possible to adjust the height of the curve accurately. Furthermore, even if the height of the counterweight 26 is adjusted in consideration of the effect near the fully closed state, there is no change in the state, so the adjustment can be easily made.

Next, the effects from state to state will be explained collectively. Once the gate 12 opens to this state during a flood, the height difference between the curves becomes small, so even if the water level decreases and the upstream water level falls below the planned water level during the rising water level, the dam will not be closed or closed as described below. Until the water level of the water channel is lowered to the water level, the water level in the water guide portion 17b and the float chamber 18 are only lowered in parallel, and the gate 12 is not closed. However, in this state, the flow rate exceeds the planned water flow rate, resulting in a flood. do not have. Therefore, next we will proceed to explain the action of opening the gate 12 due to flooding. In this state, the relationship between the downstream water level and the opening angle of the gate 12 is determined by trial calculation. That is, assuming an opening angle in the case of a certain downstream water level, a curve is obtained by moving the curve above the water level by the size of the curve, and on the other hand, the resistance of the gate 12 is determined by the height of the curve, which is the upstream water level, and the curve is The opening angle at which the height difference of the curve becomes a height corresponding to the resistance of the gate 12 is the opening angle at that downstream water level. The state is such that the center of gravity of the entire movable part is directly above the main shaft 14 and the action of the eccentric force G has disappeared.
Approximately, the curve indicating the upstream water level reaches its highest near this point, and the design flood level is determined. After that, as the flow rate increases, the upstream water level gradually decreases, and the difference in water levels between upstream and downstream also decreases, but in state V
, the height of the curve becomes Δh ₇ lower than the upstream water level, the upstream and downstream water levels and the lower end of the gate body 16 have the same height (position), and the gate 12 drains the water in the water guide section 17b. It continues to open while discharging, reaching a fully open state. By the way, as mentioned above, the highest water level will be several centimeters higher than the planned water level during the flood, but due to the design of the channel, the water level is also expected to be 10 to 20 cm higher than normal during floods. Since it was built in such a way that there will be no problems at all.

Next, the fully open state will be explained. Comparing state V and state, the eccentric force G in the direction of opening the gate 12 increases by h ₀ , while the resistance of the gate 12 remains unchanged, so in state, the sealing part 17a has a height of h _0. The opening is exposed in the air, and its upper end is at a high level.Dynamically, the actuating force to open and the resistance to keep it open are in balance.

Next, the operation of restarting the dam raising after the floodwaters disappear and the gate 12 closes will be explained. If the water level drops by Δh ₇ from the above position, first,
When both the actuation force and resistance of gate 12 disappear and further decrease by Δh ₇ , gate 12 begins to close.
The locus of the water line of the float 17 at that time is assumed to be represented by a curve. As the gate 12 closes, the force in the direction of closing the gate 12 increases by the height difference between the curve in the figure and the horizontal line, so a curve drawn using this value with the curve as the horizontal axis is the water level when the gate 12 closes. As shown by the curve showing the opening angle, when the water level drops to the weir raising restart water level shown in the figure, the gate 12 closes at once and the weir raising is restarted, and the upstream water level is maintained almost equal to the planned water level.
The trajectory of the upper end of the sealing portion 17a when the gate 12 is closed is shown by a curved line.

As explained above, first, the second problem of the prior art has been solved. Next, the operation related to solving the first problem will be explained. First, regarding the size of the float 17, in the conventional technology,
Since the entire float 8 was sealed, gate 4
It is unnecessary to explain that the operating force acting on the float 8 was reduced due to the lifting and lowering of the float 8 as the float opened and closed, but in some cases, even if the length of the float arm 6 was varied If calculation is made so that the planar area of the float 8 is small, the operating force acting on the float 8 immediately before the gate 4 stops is only 5% of the water level difference between upstream and downstream, and
The length of the float arm 6 was also only 20% of the gate radius. Therefore, a very large float 8 was required, but in the present invention,
Since water is introduced into the water guide portion 17b as described above, no matter how much the float 17 rises and falls, as long as the water level in the float chamber 18 does not change, the float 1
The operating force acting on float 17 does not decrease, and therefore can open and close approximately 50% of the upstream and downstream water level difference, and the operating force acting on float 17 itself increases approximately 10 times, and similarly, the length of float arm 23 increases. Moreover, the float 17 can be made approximately 2.5 times larger than the conventional technology without being subject to any restrictions, so the planar area of the float 17 can be reduced to approximately 1/25th.

Next, the problem of the size of the float 17 required to suppress the movement of the door body 16 per time to a certain level or less will be explained. First, when the gate 12 is close to fully closed, the gap between the lower end of the gate body 16 and the waterway surface is extremely small, and the speed of the water flow passing below is extremely high, so even a slight movement of the gate body 16 causes The change in flow rate, particularly the rate of change, becomes large, and therefore the movement of the door body 16 must be reduced. However, gate 12 of the embodiment
Since the float 17 is used as a driving means, when the door body 16 starts to move, the resistance is static frictional resistance, so the door body 16 starts to move after a very large operating force is generated on the float 17, but once it starts moving, the door body 16 starts moving. Until the float 17 comes to a standstill, the resistance of the door body 16 changes to dynamic frictional resistance and the resistance force is halved, so the door body 16 will not stop until the float 17 moves significantly and the operating force acting on it is halved.

Therefore, in the present invention, as described above, the angle of the float arm 23 is devised to make the gap between the float 17 and the float chamber 18 as small as possible, and as a result, the float 17 moves very slightly. The water surface in the float chamber 18 just changes.
fluctuates in a direction opposite to the direction of movement of the float 17,
The actuating force acting on the float 17 disappears, and finally, a stopping force acts and the door body 16 is stopped after only a slight movement. The force applied to the door body 16 is the square of the length of the float arm 23 and the force applied to the float 17.
is inversely proportional to the plane area of Therefore, from the condition of the size of the movement of the door body 16 per time, the float 1
When the planar area of the float 17 is determined, the length of the float arm 23 is approximately 2.5 times that of the conventional technology, so the planar area of the float 17 is 2.5 ^1/2 of that of the conventional technology, that is, approximately 6 times It can be reduced to 1. Therefore, the first problem of the prior art is also solved.

Next, an application example will be explained. One of the purposes of the present invention is to ensure that the gate is fully open during a flood, and in the above embodiment, the explanation has been made based on the assumption that the waterway 13 is flat, but the so-called head The gate 12 installed at a place where there is a step in the waterway 13, called a gate, is installed for the purpose of preventing hydraulically lower backwater, and in such a case, the gate 12 is Gate 12 cannot be fully opened because it would cause flooding downstream. In addition, in such a case, as in the situation shown in Figure 5,
Since the water level difference between upstream and downstream is increased by the difference in level, the curve needs to have a shape that is more nearly horizontal. Well, gate 12
It will not open fully during a flood, and the curve can become nearly horizontal. That is, what is considered to be symmetrical in the present invention includes the above-mentioned cases, and is not necessarily limited to the details of the configuration shown in the embodiments.

Next, the issue of usage will be explained.

Due to constraints in water use practices, if the spacing between water distribution locations is narrow and the gates 12 are installed close together, the water level difference between upstream and downstream of the upstream gate 12 may be only a few centimeters even when it is fully closed. . In such a case, since the difference in water level between upstream and downstream is small, the flow velocity passing below the gate 12 is also small. Therefore, the size of the float 17 is determined exclusively from the aspect of operating force, but in this embodiment, the operating torque of the float 17 is increased by more than 20 times, so it is extremely economical and its uses can be expanded. Ru. Note that the curve needs to be close to horizontal in this case as well, but since the curve itself is close to horizontal, the curve can be similar to the example.
Therefore, the direction of the center of gravity of the entire movable part as viewed from the main shaft 14 remains the same as in the embodiment, and only the distance therebetween is reduced.

Next, the significance of reducing the gap between the float 17 and the float chamber 18 will be supplementarily explained.
As described above, one means of the present invention is to make the center of gravity of the entire movable part higher than the main axis 14. Therefore, by reducing the gap in the float chamber 18, the movement of the door body 16 is reduced. Therefore, the center of gravity is raised to assist the operating force of the float 17.

(Effects of the Invention) Since the present invention is configured as described above, the actuation force to the float does not change, so the float arm can be made longer, and the torque that moves the main shaft becomes larger, so the float can be made smaller. It is economical. In addition, compared to the conventional technology, there is no need to adjust the movement distance of the float when raising and lowering it, and there is no complexity in assembling the installation position. Furthermore, once the gate is fully open, the eccentric force exerted by the counterweight causes the gate to completely emerge from the water surface, eliminating any obstruction to flowing water during floods, improving response to floods. When the floodwaters subside and it becomes necessary to raise the dam, the gate body lowers under the weight of the float and can resume raising the dam by itself.

[Brief explanation of the drawing]

Fig. 1 is a side cross-sectional view of an automatic dam-raising gate in response to flooding according to an embodiment of the present invention, Fig. 2 is a plan view of Fig. 1, and Fig. 3 is a side cross-sectional view of the gate in the fully closed state in the embodiment. , Fig. 4 is a side sectional view of the gate in the fully open state in the embodiment, Fig. 5 is a diagram showing the opening degree of the gate and the water level in the embodiment, and Fig. 6 is a side sectional view of the conventional dam raising gate. be. 13... Channel, 14... Main shaft, 15... Arm, 16... Door body, 17... Float, 17a...
...Sealed part, 17b...Water guide section, 18...Float chamber, 23...Float arm, 26...Counterweight, 28...Water guide device,...Planned water level,
... Upper limit water level.

Claims (1)

[Scope of Claims] 1. An arm is provided on a main shaft that crosses a waterway so as to be freely rotatable in the upstream and downstream directions, and a door body for damming the waterway is provided at the upstream end of the arm, and a door body for weiring the waterway is provided along the waterway. A float chamber is provided on the upstream side of the main shaft, the upstream water channel and the downstream water channel of the door body are communicated through the float chamber, and the float is installed in the float chamber with a small gap between the chamber wall and the float chamber. A float arm for suspending the float is attached to the main shaft in conjunction with the arm so that the float is approximately horizontal when it is at an intermediate position between the upper limit position and the lower limit position, and the float has a sealing part at the lower part, A water guide part is formed in the upper part, a water guide device communicating with the downstream water channel of the door body is provided in the water guide part, and a counterweight is provided on the arm extending downstream from the main shaft and located above the axis of the arm. is installed, and the weight of the counterweight is determined by the gate when the upstream water level is raised to the upper limit water level when the downstream water level is the planned water level.
An automatic dam raising gate for responding to floods, characterized in that the weight of the entire movable part is balanced when the water level in the float chamber is at an intermediate height.