JPS5856766B2 - Weir automatic levitation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention automatically lowers and raises a weir such as a bag-like weir that is erected by pressurizing air or water or both into the interior,
This invention relates to an automatic levitation device for a weir that automatically adjusts the water level of a river on the upstream side of the weir.

Conventional weirs such as bag-shaped weirs made of flexible materials use a device that uses the opening and closing of valves that interlock floats to supply high-pressure air or water to the interior, raise it up, discharge it, and lower it down. However, since there are moving parts such as the valves, there is a problem that the device for operating the weir may malfunction.

In addition, conventional weirs such as bag weirs lack the ability to adjust the water level of the river upstream of the weir, so they have had to rely solely on opening and closing the intake gate to adjust the amount of water intake.

The operation of opening and closing the intake gate is complicated, and it has been found that when the amount of river water increases, the cultivated land in the upstream area of the weir suffers from poor drainage.

The present invention solves the above-mentioned problems, and has a configuration that does not have any moving members, and is capable of automatically and safely lowering and raising weirs such as bag-shaped weirs, and also raises the weirs of rivers upstream of the weirs. The object of the present invention is to provide an automatic weir lowering and automatic water level adjustment device that can automatically adjust the water level.

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, 1 is a weir body that crosses the river and the river bed 2.
This is a bag-shaped weir made of flexible material installed in the area.

3 is a clamp device, and 4 is a bank. The bag-like weir 1 has an air chamber 1a connected to an air supply source such as an air pump (not shown), supplies water and air to the inside to stand up, and discharges water and air to fall down.

A water level and pressure adjustment chamber 5 whose bottom is lower than the river bed 2 is attached by cutting out the embankment 4 near the bag weir 1, and communicates with the flowing water of the river 7 on the upstream side of the bag weir 1 via a headrace channel 6. .

The diameter of the water conduit 6 is set to be sufficiently large so that the water level of the upstream river 7 and the water level of the water level and pressure adjustment chamber 5 are always equal.

The water pressure control room 8, which is isolated from the water level and pressure control room 5, has a bottom lower than the river bed 2 and communicates with the water level and pressure control room 5 through the water introduction hole 9. The bag-like weir 1 can be communicated with the flowing water of the river 11 on the downstream side via a bent first siphon pipe 10 whose end is opened in the water pressure adjustment chamber 5 and the downstream river channel 111 .

The bottom 10a of the top of the first siphon pipe 10 is set at a height slightly lower than the planned water level 12 of the river 7 on the upstream side.

The water pressure adjustment chamber 8 and the water chamber 1b in the bag-shaped weir 1 communicate with each other via a water pipe 40 that extends horizontally at a height near the riverbed.

Next, a device A for pressurizing air into the bag-like weir 1 will be described.

An air tank 13 isolated from the water pressure adjustment chamber 8 is used to perform the central function of the device and is sealed, and is connected to a second siphon pipe 14 and a U-shaped It is possible to communicate with the water pressure adjustment chamber 8 via the first siphon-on-break pipe 15 .

The second siphon pipe 14 has one end opened into the water pressure adjustment chamber 8 at a height lower than the river bed 2, and the other end opened into the air tank 13 at a height lower than the standing water level on the downstream side of the bag-shaped weir 1. The top of the weir is located at a height slightly lower than the planned weir raising water level 12.

Further, the bottom of the U-shaped portion of the first siphon-on-break pipe 15 is located at a height slightly higher than the upright water level 29 on the downstream side of the bag-shaped weir 1.

The air tank 13 is connected to the bag-shaped weir 1 via a ventilation pipe 17 from an air injection pipe 16 whose one end is opened near the ceiling of the air tank 13.
It is possible to communicate with the air chamber 1a of.

The lower end of the vertical portion of the air injection pipe 16 opens into the submerged water level and pressure control chamber 5 at a height above the river bed 2.

A water tank 18 provided above the air tank 13 and isolated from the air tank 13 communicates with the air tank 13 via a water injection pipe 19.

The sealed water storage tank 18 is connected to a siphon operation box 21 via a second siphon break pipe 20 extending from its upper surface and having a U-shaped end.

Further, an auxiliary siphon-on break pipe 37 connected to the second siphon-on break pipe 20 on the side of the siphon operation box 21 at a height higher than the downstream standing water level 29 communicates with the top of the second siphon-on pipe 14. .

In the above description, the second siphon-on pipe 14 is for injecting water into the air tank 13 and the water tank 18 while the bag-shaped weir 1 is being erected, and the first siphon-on break pipe 15 is for
In order to ensure the completion of the air supply work and to prevent the flow of water for air injection, the siphon action of the second siphon pipe 14 is cut off before the air supply work is completed.

Furthermore, the second siphon-on-break pipe 20 is for supplying the air necessary for the water to fall from the water tank 18 after the flood has ended, and the U-shaped portion at the lower end of this pipe 20 is for supplying air. This is to prevent water injection before the completion of air supply work due to the drastic drop in river water levels before and after work.

Furthermore, the auxiliary siphon-on break tube 37 simultaneously stops the siphon action of the second siphon tube 14, and the second siphon-on break tube 37
The water column of the siphon break pipe 20 is divided, and the water column of the water storage tank 1 is divided.
8 to communicate with the atmosphere.

The enclosed siphon operation box 21 is installed in the flowing water of the river 11 on the downstream side of the bag-shaped weir 1.
It is possible to communicate with the flowing water of the downstream river 11 through the siphon pipe 22, and with the atmosphere through the raised air guide pipe 23.

A manual valve 24 is provided in the middle of the air guide pipe 23.
The degree of communication of the conduit can be adjusted.

The siphon operation box 21 is connected to a water level adjustment box 27 via an operation pipe 26 whose lower part is U-shaped and rises from the inside and extends horizontally.
are in contact with the top.

Note that the siphon operation box 21 may be provided upstream of the weir if the water drinking adjustment function is not required.

Opening lower end 25 of the intake pipe 25 inside the siphon operation box 21
a. Opening upper end 20a of the U-shaped portion of the second siphon-on-break tube 20 and operation! '26 upper end 26a of U-shaped part
is set at a height slightly higher than the downstream upright water level 29 of the bag weir 1 in the downstream river 11.

The bottom 22a of the top of the third siphon pipe 22 is at the same height as the downstream collapsed water level 28 of the bag weir 1 in the downstream river 11.

In the above description, the intake pipe 25 has the opening lower end 25b in the air tank 13 positioned at a slightly higher height than the opening lower end,
It is a bent pipe whose horizontal portion is at a height higher than the planned water level 12.

This intake pipe 25 is for supplying air into the air tank 13 after the flood ends.

The siphon operation box 21 and the third siphon tube 22 are
In order to prevent the water stored in the air tank 13 and water tank 18 from flowing away, the intake pipe 25 and the second siphon-on break pipe 2 are connected to each other.
This is for submerging the opening of 0 in water.

Next, the air pressure inside the bag-like weir 1 is detected and excess air is discharged, and when the bag-like weir 1 is collapsed, the inside of the bag-like weir 1 is communicated with the atmosphere, and further, the raising operation of the bag-like weir 1 is controlled. The device B that immediately before cutting off the communication between the inside of the bag-like weir 1 and the atmosphere will be described.

Inside the water level and pressure adjustment chamber 5, there is provided an air pressure adjustment box 32 with an enclosed shape to perform the central function of the device.

The air pressure adjustment box 32 communicates with the air chamber 1a in the bag-like weir 1 via the air pressure adjustment pipe 32 that communicates with the ventilation pipe 17, and
It communicates with the atmosphere either directly through an upwardly rising exhaust pipe 34 or through water stored in the water level and pressure control chamber 5.

The lower opening 434a of the exhaust pipe 34 is lower than the opening 33a of the air pressure adjustment pipe 33 to the air pressure adjustment box 32, and is lower than the water level in the bag-shaped weir 1 that is raised corresponding to the planned layer raising water level 12. It is located at a low height.

The second siphon-on break pipe 20 constitutes a part of the above-mentioned device A for pressurizing air, and also constitutes a part of this device B, and also extends into the air pressure adjustment pipe 32. , the lower end 20b of the opening is used for air press-fitting work 32
It opens near the bottom.

An air sealing tank 35 is formed in the middle of the second siphon-on-break pipe 20, and a communication pipe 36 that protrudes laterally from the upper part of the air sealing tank 35 and hangs down is opened into the water level and pressure adjustment chamber 5. are doing.

The opening lower end 36a of the communication pipe 36 is located at a lower height than the river bed 2.

In the above description, the communication pipe 36 exposes the open lower end 34a of the exhaust pipe 34 to the air when the bag-like layer 1 is collapsed, allowing the interior of the bag-like layer 1 to communicate with the atmosphere and ensuring reliable exhaust. .

Further, the exhaust tank 35 supplies water to submerge the opening lower end 34a of the exhaust pipe 34 in water immediately before the bag-like layer 1 rises, and to isolate the inside of the bag-like layer 1 from the atmosphere.

In addition, the water conduit 6 described above constitutes a part of this device, and the exhaust pressure is determined based on the pressure head of the flowing water of the upstream river.
This is to ensure its rationality.

Next, a device C for supplying and discharging water into the bag-like layer 1 until the bag-like layer 1 reaches a desired weir height will be described.

The first siphon pipe 10 and the water flow pipe 40 constitute the central structure of this device C, and the first siphon pipe 10 adjusts the water level in the water pressure adjustment chamber 8 by the siphon action, and controls the water level in the bag-like layer 1. On the other hand, the water pipe 40 has the function of supplying and discharging water into the bag-like layer 1 according to the water level in the water pressure adjustment chamber 8.

The enclosed water level adjustment surface 27 is provided in the water level and pressure adjustment chamber 5, and extends downward from the lower part through a hanging pipe 30 whose lower end is opened at a height near the river bed 2. It communicates with the water.

The water level adjustment surface 27 has a ceiling portion located at a higher height than the planned layer raising water level 12, and is connected to the first siphon pipe via a third siphon break pipe 31 rising from the ceiling portion and extending horizontally. It communicates with the top of 10.

Third siphon-on break pipe 31 within water level control surface 27
The lower end 31a of the opening is located at the same height as the planned layer raising water level 12.

The third siphon-on break pipe 31 communicates with the flooded water in the water pressure control chamber 8 through its opening lower end 31b at a height lower than the river bed, and is slightly higher than the water level just before the bag-shaped layer 1 rises, that is, the downstream rising water level 29. They are connected via a connecting pipe 38 at the height.

The communication pipe 38 further communicates with a pipe end 31c hanging down to the bottom of the water tank 18 and a fourth siphon-on-break pipe 39.

Here, the fourth siphon-on break pipe 39 opens at a height lower than the planned layer raising water level 12, senses air injection work, and sucks air, and the third siphon-on break pipe 31 ( The portion on the right side of the connecting pipe 38 in the illustrated example receives the air.

In addition, the third siphon-on break tube 31 on the left side in the illustrated example
remains in the U-shaped portion of the operating tube 26, which is provided for the purpose of preventing the siphon action of the first siphon tube 10 from ceasing before the end of the air injection work due to sudden changes in the water surface before and after the start of the air injection work. This is to remove water using air pressure.

The device according to the present invention having the above configuration includes an automatic water level adjustment mechanism for the planned layer raising water level of the river upstream of the weir, an automatic bag layer lodging mechanism, and a bag layer erecting preparation mechanism.

Next, the operation of the device according to the present invention will be explained.

First, the automatic water level adjustment mechanism will be described. As shown in FIG. 1, when the bag-like layer 1 is standing up, the inside of the water level adjustment surface 2T is communicated with the atmosphere through the operation pipe 26 and the air guide pipe 23.

When the water level of the upstream river 7 is lower than the planned layer raising water level 12, the first siphon pipe 10 is connected to the third siphon break pipe 31. Since it communicates with the atmosphere through the water level adjustment surface 21 and does not cause siphon action, the first siphon pipe 10
The amount of water flowing out through the hole is small, and the cross section of the water introduction hole 9 is sufficiently large, so that the water level in the water pressure adjustment chamber 8 and the pressure head inside the bag layer 1 are lower than the upstream river 1.
The water level is approximately equal to the water level of the air chamber 1a, and the bag-like layer 1 moves in the direction of standing up due to the buoyancy of the air press-fitted into the air chamber 1a.

In order to continue the standing movement, it is necessary to inject water, but this water is replenished from the upstream river 7 through the water pipe 40 due to natural pressure, so the bag-like layer 1 maintains the planned water level of the upstream river 1. Continue standing up until reaching the rising water level 12.

However, when the water level of the upstream river 1 becomes higher than the planned layer raising water level 12, the opening lower end 31a of the third siphon-on break pipe 31 is submerged in water as the water level in the water level adjustment surface 27 rises, and the first siphon-on break pipe 31 is submerged in water. The tube 10 is isolated from the atmosphere.

Due to the shielding from the atmosphere, a siphon effect acts on the first siphon pipe 10, and the amount of water flowing out through the inside of the first siphon pipe 10 increases significantly, and the supply of water from the water introduction hole 9 cannot keep up, resulting in a drop in water pressure. The water level in the control chamber 8 becomes lower.

When this flooded water level becomes lower than the water level in the water chamber 1b of the bag-shaped weir 1, the water in the water chamber 1b is discharged through the water pipe 40 due to the difference in pressure head, and the bag-shaped weir 1 operates to collapse.

Note that when the bag-like weir 1 is collapsed, the air in the air chamber 1a functions as a float.

As described above, by repeating both the raising and lowering operations of the bag weir, it is possible to maintain approximately the planned layer raising water level at all times.

Movements that demonstrate the above principle are not observed except when there is a sudden increase or decrease in flow rate, and normally a light siphon is formed and a constant water level is maintained in an equilibrium state.

Next, the lodging mechanism will be explained.

Immediately before the lodging movement starts, that is, in the upright state of the bag-shaped weir 1 shown in FIG. 1, the water level adjustment box 27 is in communication with the atmosphere.

In the event of a large increase in water such as a flood, when the water level of the downstream river 11 rises and reaches the downstream collapsed water level 28 of the bag weir 1, the running water flows into the siphon operation box 21 through the third siphon pipe 22.

When the water level of the water that has flowed into the siphon operation box 21 rises and the opening upper end 26a of the operation tube 26 is submerged, regardless of the water level of the upstream river I, the operation tube 26, the third
The interior of the siphon-on break tube 31 and the first siphon-on tube 10 is isolated from the atmosphere.

As a result, a siphon effect is activated in the second siphon tube 10, and the amount of water flowing out through the first siphon tube 10 increases dramatically, and the replenishment from the water guide hole 9 cannot keep up.
The water level in the water pressure control chamber 8 has decreased significantly, and the water level in the water chamber 1 of the bag-shaped weir 1
The water b is discharged from the water pipe 40 and the bag-shaped weir 1 begins to collapse.

However, the air chamber 1a of the bag-like weir 1 is isolated from the outside and acts as a float when it is toppled.

Due to the collapse of the bag-shaped weir 1, the water level of the upstream river 7 and, by extension, the water level in the water level and pressure adjustment chamber 5 also decreases.

The air pressure adjustment box 32 communicates with the flooded water in the water level and pressure adjustment chamber 5 via the communication pipe 36 and the water sealing tank 35 provided in the second siphon-on-break pipe 20, so that the water pressure inside the air pressure adjustment box 32 is θ. becomes low, the water in the air pressure adjustment box 32 is pushed down by the air from the air chamber 1a, and the air in the air chamber 1a is discharged from the ventilation pipe 17 via the air pressure adjustment pipe 33 and the exhaust pipe 34.

In this state, the bag-like weir 1 will further collapse.

Upstream river 7, water level and pressure adjustment chamber 5, and air pressure adjustment box 3
When the water level 2 further decreases and the open lower end 34a of the exhaust pipe 34 is completely exposed, the air chamber 1a of the bag-like weir 1 completely communicates with the atmosphere.

Therefore, the bag-like weir 1 is completely collapsed as shown in FIG. 2 without any air remaining in the air chamber 1a of the bag-like weir 1.

In addition, if the water ejector is formed by integrating the water guide hole 9 and the first siphon pipe 10 as shown in the illustrated example, the water pressure adjustment chamber 8
water is sucked out by the first siphon pipe 10, and the water level in the water pressure control chamber 8 becomes lower than the water level in both the upper and downstream rivers 7 and 11. The water pressure of the running water forces the fabric to fold, creating an even better lodging condition.

Note that since air is sucked into the air tank 13 immediately before it is raised, there is no risk that it will stand up during a flood or that the air tank 13 will float up.

Next, the standing mechanism will be explained.

The air tank 13 communicates with the water pressure adjustment chamber 8 through a second siphon pipe 14, and the opening lower end 25b of the intake pipe 25 is provided at a position slightly higher than the flood water level in the water pressure adjustment chamber 8 immediately before standing. Therefore, there is a negative pressure near the lower end of this opening.

Therefore, during lodging, the water level inside the siphon operation box 21, which is linked to the water level of the downstream river 11 by the third siphon pipe 22, decreases, and as shown in FIG.
When the lower opening end 25a of the intake pipe 25 is exposed, the balance between the water columns on the left and right sides of the intake pipe 25 is broken, and air is supplied into the air tank 13 (in the figure, bubbles are indicated by a plurality of semicircles).

) is carried out.

From this point on, the river water level drops rapidly, and the opening upper end 26a of the operation tube 26 and the second siphon-on break tube 2
Even if the upper end 20a of the first opening 20a is exposed in the air, the lower end thereof is U-shaped, so water in the water tank 18 may flow into the air tank 13 before the air supply is completed, or There is no risk that the siphon of the siphon tube 10 will break.

The supplied air floats to the top of the air tank 13, excess water is removed from the second siphon tube 14, and the exchange of air and water continues.

In this way, as shown in FIG. 4, when the supply of air into the air tank 13 is completed and the water level drops to the bottom of the first siphon-on break pipe 15, air is sucked into the second siphon-on break pipe 14. Then, the siphon of the second siphon tube 14 is cut off.

On the other hand, since the lower end of the second siphon-on break tube 20 is U-shaped, even if the water level rises slightly due to vibrations, the air supply will not be interrupted and the By the siphon break tube 37,
Since the water column inside the second siphon-on-break tube 20, which is under negative pressure, communicates with the atmosphere, the water column is divided, and the pressure balance between the upper water column and the left and right water columns in this tube 20 is broken. , is sucked into the water storage tank 18 and the air-sealed tank 35.

The water in the water tank 18'j6 and the air sealing tank 35 descends into the air conditioning surface 32 and the air tank 13, respectively.

Regarding the water in the water storage tank 18, we will continue to explain further, but as for the water in the air-sealing tank 35, the air pressure adjustment surface 32 is filled with water as this water falls, and the inside of the bag-shaped layer 1 is filled with water. Blocked from the atmosphere, the bag-like layer 1 is formed as shown in FIG.
You can now prepare for air injection.

As for the inside of the air tank 13, as water falls from the water tank 18, the water level inside the air tank 13 rises.

When the water surface reaches the upper opening of the first siphon-on break pipe 15, the water tank 18 is again cut off from the atmosphere and becomes under negative pressure, remaining in the U-shaped portion of the second siphon-on break pipe 20. The water is sucked into the water tank 18,
Once again, the water tank 18 is communicated with the atmosphere as shown in FIG. 5, and water continues to be supplied to the air tank 13.

Then, when the opening lower end 25b of the intake pipe 25 is submerged in water, the entire air tank 13 is cut off from the atmosphere, and the pressure in the upper air tank is increased by the water pressure inside the air tank 13.
Air is pumped into the collapsed bag-like layer 1 through the vent pipe 6 and the ventilation pipe 17.

It is expected that water will enter the air pressure tube 16 due to condensation or the like, but this water will be discharged from the opening into the water level and pressure adjustment chamber 5.

However, due to this opening, the lower part of the air injection pipe 16 is filled with water until the start of pressure feeding, but this water is removed from the air during pressure feeding in the vertical part of the air injection pipe 16 by thickening the cross section. It is separated and released into the submerged water inside the water level and pressure adjustment chamber 5.

In this way, the pressure feeding of air is completed, and as shown in FIG. 6, the water in the water tank 18 is sufficiently discharged, and the water level in the tank is lowered to the bottom of the U-shaped part of the fourth siphon-on break pipe 39. Then, air enters the third siphon-on-break pipe 31 on the right side in the illustrated example from the connecting pipe 38, and the water contained therein falls vertically.

Therefore, the middle of the water column of this third siphon-on break pipe 31 becomes atmospheric pressure, and the third siphon-on break pipe 3 connected to the first siphon pipe 10 above from the communication pipe 38
The water column in 1 is sucked into the first siphon tube 10,
The first siphon tube 10 is cut open to the atmosphere.

Further, the water on the water level adjustment surface 27 also descends, and the operating tube 26 also communicates with the atmosphere, leaving only the water column at the right end of the operating tube 26 at the 0-shaped portion.

On the other hand, when air is pressurized, the bag-like layer 1 begins to stand up as shown in FIG.

As a result, the water level of river 7 on the upstream side also begins to rise, but
Since no water is discharged from the siphon pipe 10, the pressure head in the bag-like layer 1 becomes almost equal to the pressure head in the upstream river 7, and the upright movement becomes active, and as it stands up, it flows from the upstream river 7 to the water flow pipe 40. Through this, water is pumped in by natural pressure, and the water levels of the bag layer 1 and the upstream river γ rise in parallel.

In this way, when the water level in the water pressure adjustment chamber 8 reaches the sideward protruding portion of the communication pipe 38, the third siphon-on break pipe 31, the first siphon-on pipe 10, and the water level adjustment surface 27 on the left side in the figure and the other operating tube systems are isolated from the atmosphere and the air within them remains contained, with the third siphon-on-break tube 31. As the water pressure from the openings of the first siphon pipe 10 and the water level adjustment surface 27 increases as the weir progresses, the water remaining in the right end U-shaped portion of the operating pipe 26 is removed by air, and the water is removed again. a water level control surface 27 communicating with the atmosphere, and a first siphon tube 10;
The water level inside becomes almost equal to the water level of the upstream river 7, and the water level adjustment function becomes normal, and the upright movement continues until the predetermined planned layer raising water level 12 is reached.

After that, when the water continues to decrease further and the water level of the downstream river 11 reaches one end of the third siphon pipe 22, the siphon of the third siphon pipe 22 is cut off, and the siphon operation box 21 is cut off from the river and the next We are in a position to face a flood.

As mentioned above, once the device of the present invention is used, the C-cut can be automatically operated by flowing river water without any risk of failure, since no moving parts are used in the device that operates the weir body. It is possible to control the up-and-down movement of the weir body according to the water level of the river, and since no power is used, the weir body can be operated economically and is very convenient.

Further, the weir can be arbitrarily lowered by manually tightening the manual valve 24, and raised by opening it, but it is safe because it will never stand up during a flood.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the case where an embodiment of the present invention is applied to a pouch-like layer, FIG. 2 is a schematic diagram showing the state of the present invention device when the pouch-like layer is in a collapsed state, and FIG. FIG. 4 is a schematic diagram showing the state of the device of the present invention at the time of starting air supply to the air tank; FIG. FIG. 5 is a schematic view showing the state of the apparatus of the present invention at the time of starting air pressure feeding to the bag-like layer, and FIG. 6 is a schematic view showing the state of the apparatus of the present invention at the time of starting to raise the bag-like layer. A... Device that pressurizes air into the weir body, B...
... Exhausts excess air and communicates the inside of the weir with the atmosphere,
Furthermore, a device for blocking communication between the inside of the weir and the atmosphere, C...
... Device for supplying and discharging water into the weir body, 1... Bag-like layer (weir body) 2... River bed, 5... Water level and pressure adjustment chamber, 6... ... Water conduit, 8 ... Water pressure control room, 10 ... First siphon pipe, 12 ...
・・・G↑Both layer raising water level, 13・・・・・・Air tank, 1
4...Second siphon tube, 15...
1st siphon-on break pipe, 16... Air injection pipe, 17... Ventilation pipe, 18... Water storage tank, 19... Water injection pipe, 20. ...Second siphon break tube, 21...Saifon operation box, 22...Third siphon tube, 23...
...Air guide pipe, 25...Intake pipe, 26...
...Operation tube, 27...Water level adjustment surface, 28...
...Lodging water level on the downstream side, 29... Upright water level on the downstream side, 31... Third siphon-on-break pipe,
32... Air pressure adjustment surface, 33... Air pressure adjustment pipe, 34... Exhaust pipe, 35...
Sealed tank, 36...Communication pipe, 37...Auxiliary siphon-on break pipe, 39...4th siphon-on break pipe, 40...Communication pipe Water pipe.

Claims (1)

[Scope of Claims] 1. A weir body made of a flexible material that is installed on a riverbed so as to cross a river and accommodates air for generating buoyancy and water for standing up, and the weir body has a bottom portion lower than the riverbed. a water level and pressure adjustment chamber that communicates with the upstream flowing water of the river via a water conduit, a water pressure adjustment chamber whose bottom is lower than the river bed and communicates with the water level and pressure adjustment chamber through a water introduction hole, and a sealed air tank; A sealed water tank disposed above the air tank, a water injection pipe communicating the water tank and the air tank, one end of which opens into the water pressure adjustment chamber at a height lower than the riverbed, and the other end of which is opened to the water pressure adjustment chamber. Weir body 0) A second siphon pipe that opens into the air tank at a height lower than the downstream rising water level and whose top is located at a height slightly lower than the planned layer raising water level, and a second siphon pipe whose top section is downstream of the weir body. Flowing water on the downstream side can flow in during a flood through a third siphon pipe located at the height of the side-lodging water level,
A siphon operating box that communicates with the atmosphere via an air guide pipe extending upward, one end opening into the siphon operating box at a height slightly higher than the downstream rising water level, and the other end opening at a height slightly higher than the one end. a bent-shaped intake pipe which opens into the air tank and whose top is located at a height higher than the planned layer raising water level; a second siphon-on break pipe located at a height slightly higher than the downstream standing water level, extending from inside the siphon operation box to the water tank and communicating with the upper part of the water tank; and a second siphon-on pipe in the air tank. a bent-shaped first siphon-on break pipe whose bottom part is located at a height slightly higher than the upright water level on the downstream side; □An auxiliary siphon-on break pipe connected to the second siphon-on break pipe at a height higher than the side standing water level; a ventilation pipe extending from the upper part of the weir; one end connected to the ventilation pipe and the other end connected to the second siphon-on break pipe; an air injection pipe that opens in the tank at a height higher than the opening end of the intake pipe and the opening end of the first siphon-on break pipe, and opens halfway in the water level and pressure adjustment chamber at a height lower than the riverbed; a device for pressurizing air into the weir body; an air pressure regulating pipe connected to the ventilation pipe via an air pressure regulating pipe and disposed within the water level and pressure regulating chamber; and a lower end connected to the air pressure regulating pipe. Opening in the air pressure adjustment surface at a height lower than the height of the opening end and lower than the water level in the weir body that stands up corresponding to the planned layer raising water level, and the upper end is at a height lower than the planned layer raising water level. and a second siphon-on-break pipe extending from the water tank, the other end of which is opened within the air pressure adjustment surface at a lower height than the lower end of the exhaust pipe. It consists of a sealed air tank, and a communication pipe extending from the top of the sealed tank and opening into the water level air conditioning chamber at a lower end at a height lower than the riverbed. a device for discharging the weir, communicating the inside of the weir with the atmosphere when the weir is collapsed, and further blocking communication between the inside of the weir and the atmosphere immediately before the weir is raised; and a height near the river bed. a water pipe that communicates the weir body and the water pressure adjustment chamber, one end of which opens into the water pressure adjustment chamber at a height near the river bed, and the other end of which opens downstream of the weir body at a height near the river bed; A first siphon pipe whose top pipe bottom is located at a height slightly lower than the water level for raising the planned layer, and a first siphon pipe whose bottom opens into the water level and pressure control chamber at a height lower than the river bed and whose ceiling part is located at a height lower than the planned layer raising water level. A water level adjustment box located at a height higher than the water level, one end opening into the water level adjustment box at a height higher than the planned layer raising water level, and the other end bent within the siphon operation box so that water can be stored. An operating pipe whose opening end is located at a height slightly higher than the downstream standing water level, one end from above opened into the water level adjustment box at the height of the planned layer raising water level, and the other end from above opened into the water storage box. a third siphon-on break pipe that opens near the bottom of the tank, opens at the top of the first siphon pipe in the middle of the pipe, and opens into the water pressure adjustment chamber at a height lower than the riverbed; A third siphon-on-break pipe is interposed in the middle of the siphon-on-break pipe of No. 3, is connected to the third siphon-on-break pipe in the water pressure control chamber at a height slightly higher than the downstream rising water level, and leads to the water storage tank. and a fourth siphon-on-break pipe connected to a third siphon-on-break pipe in the water storage tank and opened at a height lower than the planned layer raising water level. An automatic levitation device for a weir, comprising: a device for supplying and discharging water into the weir body until the height of the weir reaches a desired weir height.