JPH0480165B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to upstream water level control using an automatic up-and-down mechanism for a rubber weir using air, water, or a combination of air and water as the internal medium.

Conventional rubber weirs only have a mechanical automatic lodging device, which collapses the weir when it exceeds a certain set water level as the amount of rainfall increases on the upstream side. It could not function as a dam again unless it was revived.

Furthermore, when a rubber weir collapses, it suddenly collapses completely, causing severe changes in the water level downstream, which can sometimes have an adverse effect.

In the past, there were rubber weirs equipped with a three-value automatic levitation mechanism, but the temporal inflow and discharge of internal media were not considered, and they were designed to be approximately the same. During heavy rains, there were cases where the water level exceeded a dangerous level or a hunting phenomenon occurred.

In other words, because the amount of internal media discharged over time is small and inappropriate during heavy rains, the water level may not rise in time and exceed the dangerous water level, or even when the amount of water flowing into the river on the upstream side has stabilized, the water level system may not be adequate. If the response of the rubber weir is faster than the response (the time it takes for the amount of water inflow to appear on the water level), the weir will collapse or rise excessively, and even though the amount of water inflow is stable, the upstream This causes the so-called hunting phenomenon in which the water level moves up and down.

This hunting phenomenon will be explained in more detail based on FIG. 1.

In the same figure, it is a diagram showing the flow rate of water,
The solid line shows the inflow flow rate of water, the dashed-dotted line shows the overflow flow (flow rate over the weir), shows the upstream water level (solid line) and the height of the rubber weir (dotted-dash line), and shows the internal medium flowing into the rubber weir. Shows inflow and discharge flow rates.

In all cases, the horizontal axis is the time axis.

The figure shows the water level being about 20 cm above the target water level.
This figure shows the response and water level changes of the conventional three-value automatic undulating mechanism when the inflow flow rate of water is stabilized.

First, in the figure, the upper and lower limit water levels are set 20 cm above and 20 cm below the target set water level, so the upstream water level touches the upper limit set water level in the initial stage, so the detection device is activated and the detection signal is used. The medium inside the rubber weir is then discharged.

As a result, the height of the rubber weir decreases, the overflow of water increases, and the water level begins to decrease.

When the water level reaches the target water level, the medium discharge is stopped.

Even if the discharge of the medium is stopped, the rubber weir collapses faster than the water level system can respond, so the overflow is still large, and the water level further decreases, reaching the lower limit set water level.

When the water level reaches the lower limit set water level, the medium begins to flow into the rubber weir, but at this time, the rubber weir rises faster than the corresponding water level system, so the height of the rubber weir exceeds the water level and the overflow amount becomes zero. condition occurs, the water level rises and reaches the target water level, the inflow of media stops, and
After the height of the rubber weir becomes constant, the state of zero overflow continues until the water level reaches the height of the rubber weir again.

Since air is sucked into the rubber weir up to the upper limit pressure, even if the water level exceeds the height of the rubber weir and overflow begins, the water level continues to rise until it reaches the upper limit set water level.

Therefore, the medium in the rubber dam begins to be discharged again, and the previous cycle is repeated.
The ups and downs of the rubber weir and the ups and downs of the water level are repeated, causing a so-called hunting phenomenon.

The present invention relates to an automatic raising and lowering mechanism for a rubber weir that overcomes these drawbacks, and its purpose is to improve the water level during heavy rain by taking into account the inflow and discharge speeds of the medium in the rubber weir. The object of the present invention is to provide a rubber weir that can cope with uplift and hunting phenomena.

The configuration of the present invention will be explained based on FIG. 2.

A is a three-value setting water level detection means that detects that the water surface is at the three values of the upstream target setting water level, upper limit setting water level, and lower limit setting water level, and B is a three-value setting water level detection means that detects the water level in the rubber weir based on the signal from the same detection means. A medium inflow/discharge control means for controlling the inflow/discharge of the medium and its speed; C is a medium inflow means operated by the control means B; and D is a medium discharge means similarly operated by the control means B. It is.

The control means B discharges the medium from the weir body at a high speed when the upstream water level reaches the upper limit set water level, and causes the medium to flow into the medium at a slow speed when the upstream water level reaches the lower limit set water level. Control as follows.

The present invention is configured as described above, and discharges the medium from inside the rubber weir from the detection of the upper limit set water level to the target set water level, works to lower the water level, and from the detection of the lower limit set water level to the target setting. Until the water level is detected, the medium flows into the rubber weir and moves in the direction of raising the water level.

Therefore, the rubber weir does not completely collapse suddenly, which prevents negative effects on downstream areas, and because it can be automatically raised and lowered, water can be used more effectively.

In addition, by setting the speed at which the medium is discharged from the rubber weir to be fast, it is possible to prevent the water level from rising beyond the dangerous water level during heavy rains, and to set the inflow speed of the medium to be appropriately slow in accordance with the corresponding speed of the water level system. By doing so, the hunting phenomenon can be prevented and the upstream water level can be maintained constant within a certain range.

An embodiment of the present invention illustrated in FIGS. 3 and 4 will be described below.

The width of this river is 30m, the river bed slope is 1/1000,
The inflow flow rate is 7 m ³ /sec in a stable state, the target water level of the rubber weir is 2.9 m, the upper water level is 0.2 m higher than that, 3.1 m, and the lower water level is 2.7 m, 0.2 m lower than 2.9 m. It is.

Air is used as the internal medium, and its inflow flow rate is 0.3Kg/min, and the discharge flow rate is 3Kg/min.
It is min.

FIG. 3 is a schematic explanatory diagram of the automatic undulation mechanism in a rubber weir, and in the same figure, 1 is a rubber weir;
The left side of Rubber Weir 1 is upstream.

This rubber weir 1 is undulated by the inflow and discharge of air.

2 is an inflow valve that allows the same medium to flow into the rubber weir 1 via an inflow pipe 3 and an inflow/discharge pipe 4;
is a discharge valve that discharges the medium in the rubber weir 1 through an inflow and discharge pipe 4.

6 is the water surface, which is in a state where water is overflowing the upper surface of the rubber weir 1.

On the upstream side, 7 is an electrode rod for detecting the upper limit set water level 10, which detects changes in capacitance due to contact with the water surface and indicates whether the water level has reached or fallen below the upper limit set water level. It is a level sensor that allows you to know. Similarly, 8 and 9 are the target setting water level 11 and the lower limit setting water level 1, respectively.
2 is an electrode rod that detects the presence of water surface.

13 is the dangerous water level.

Note that the inflow pipe 3 is designed to be narrow, and the inflow and discharge pipe 4 is designed to be wide.

The operation of this automatic raising and lowering mechanism of the rubber dam will be explained with reference to FIG.

FIG. 4 is a diagram corresponding to FIG. 1.

Assume that the inflow flow rate of water is stabilized under the same initial conditions as described for the conventional rubber weir, that is, in a state where the water level exceeds the target set water level by about 20 cm.

First, since the water surface touches the electrode rod 7, an upper limit water level detection signal is generated, and this signal opens the discharge valve 5, and the medium is discharged from the rubber dam 1.

As a result, the height of the rubber weir decreases, the amount of water overflowing the rubber weir increases, and the water level begins to decrease.

Since the inlet/discharge pipe 4 used to discharge this medium has a large diameter, the discharge amount over time is large, so the time for the rubber weir to collapse is short, and it can cope with the rise in water level during heavy rains, which can reach the dangerous water level 13. Never.

When the water level decreases to the target water level, it is detected that the electrode rod 8 has left the water surface, and the discharge valve 5 is closed to stop discharging the medium.

Even if the discharge of the medium stops, the rubber weir collapses faster than the water level system can accommodate, so the overflow is still large, and the water level further decreases, reaching the lower limit set water level.

When the water level reaches the lower limit set water level and it is detected that the electrode rod 9 has separated from the water surface, the inflow valve 2 is opened in response to the detection signal and the medium is allowed to flow into the rubber weir 1.

Near this point, the overflow rate of water falls below the inflow rate, and the water level begins to rise due to the erection of the rubber weir.

The medium inflow speed (0.3 kg/min in this example) is set so as to achieve a rising speed of the rubber weir with a slope slightly stronger than the rising slope of this water level, and the diameter of the inflow pipe 3 is appropriately set accordingly. Design it small.

By doing this, the rise of the rubber weir will work to control the vertical movement of the water level.

Even when the water level reaches the target set water level and the inflow valve 2 is closed, if the inflow flow rate of water is constant, the overflow flow will not become zero, and after that the water level will gradually fall within the range of the upper and lower set water levels. It settles within the range, and hunting does not occur after all.

In the above embodiments, the temporal inflow and discharge of the internal medium of the rubber weir were determined by the diameter of the pipe, but it is possible to control the throttle valve by providing a throttle valve with different opening degrees. It is also conceivable to set the temporal inflow and discharge amounts according to the following.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the hunting phenomenon caused by the conventional automatic undulating mechanism of a rubber dam, Fig. 2 is a diagram corresponding to the claims related to the present invention, and Fig. 3 is a schematic explanation of the automatic undulating mechanism of a rubber dam in an embodiment according to the present invention. FIG. 4 is an explanatory diagram of the operation and phenomena of the automatic raising and lowering mechanism of the rubber dam in this embodiment. 1... Rubber weir, 2... Inflow valve, 3... Inflow pipe, 4... Inflow/discharge pipe, 5... Discharge valve, 6...
...Water surface, 7...Upper limit water level electrode, 8...Target water level electrode, 9...Lower limit water level electrode, 10...Upper limit setting water level, 11...Target setting water level, 12...Lower limit setting water level, 13... ...dangerous water level.

Claims (1)

[Claims] 1 In a rubber weir that changes the height of the weir body by the inflow and discharge of internal media, a 3-value set water level that detects that the water surface is at the above three set water levels: the upstream target set water level, its upper limit set water level, and lower limit set water level It consists of a detection means, a medium inflow/discharge control means for controlling the inflow/discharge of the internal medium and its speed based on a signal from the detection means, a medium inflow means operated by the control means, and a medium discharge means. , the control means controls the medium to be discharged from the weir body at a high speed when the upstream water level reaches the upper limit set water level, and to flow the medium into the weir body at a slow speed when the upstream water level reaches the lower limit set water level. A rubber weir characterized by: