JP6842068B2 - Water intake screen installed in the surface water intake device - Google Patents

Description

The present invention relates to an intake screen that is attached to a surface water intake device from a river or an irrigation canal and is used for efficient water intake in water supply facilities and hydroelectric power generation facilities that require water.

In order to take in river water and supply it as tap water, etc., as a device for taking in surface water from water sources such as rivers and irrigation canals, an intake screen is slanted down toward the downstream side in the upper opening of the box-shaped main body. A gradient-mounted water intake device is provided by the applicant (see Patent Document 1). This intake device is installed in the intake weir, and when the surface water of the river that overflows the intake weir flows down the surface of the intake screen, the water that has passed through the intake screen is taken into the box-shaped device body, and the eyes of the intake screen. Dust such as fallen leaves and earth and sand that is larger than the opening does not pass through the intake screen, and is removed by flowing downstream together with water that is not taken into the intake screen (surplus water), so there is very little clogging due to dust. , Stable water intake can be secured.

However, in the above-mentioned water intake device, in order to obtain a large amount of water intake, it is necessary to increase the area of the water intake screen, but since the width of the water intake weir is limited, the dimensions of the water intake screen are set in the water flow direction. Need to be stretched for a long time. For that purpose, since the water intake screen is arranged and used with an inclination angle in the flow direction of the water flow, it is necessary to raise the height of the water intake screen and extend it to the downstream side. When used by attaching to a weir, the height of the water intake screen is limited, so it may not be possible to secure a sufficient amount of water intake. In addition, when installing in a new intake weir, the height of the intake weir must be increased, and the revetment work on the upstream side of the intake weir must be increased by that amount and extended to the upstream side. There is a demerit that the cost is high.

Furthermore, when the height of the intake screen is increased and the screen dimension is extended to the downstream side, the water level inside the intake device main body is the upper limit of the lower end of the intake screen, so that it is the water level of the surface water on the upstream side. The height difference between the two becomes large, and the water level inside the main body of the water intake device becomes low. Therefore, when this water intake device is used for hydroelectric power generation, there is a demerit that the effective head becomes small and the amount of power generation becomes small.

On the other hand, there is also provided an apparatus in which the water intake screen is arranged substantially horizontally and water is taken from a small irrigation canal having a small gradient (see Patent Document 2). This water intake device is provided with weir plates on the upstream side and the downstream side, respectively, and the water intake screen is arranged substantially horizontally on the upper part of these weir plates. When installed in an irrigation canal, this device dams up the water flow with a weir plate provided on the upstream side, guides the water flow to the water intake screen surface arranged from the raised water surface, and penetrates the water intake screen when the water flow flows through the water intake screen surface. The water is taken in, and the dust larger than the opening of the water intake screen flows downstream together with the water (surplus water) that is not taken into the water intake screen. Even with this water intake device, in order to obtain a large amount of water intake, it is necessary to increase the screen area, and since the width of the irrigation canal is restricted, it is necessary to extend the dimension to the downstream side. Since the intake screen is arranged almost horizontally, there is no need to increase the height of the device. Therefore, there is an advantage that a sufficient amount of water intake can be secured even when it is installed in an existing waterway. Further, since the water level inside the main body of the apparatus can be kept high, it is possible to minimize the decrease in the effective head in hydroelectric power generation.

However, when the amount of water in the irrigation canal decreases and no surplus water is generated, dust accumulates on the downstream side of the intake screen, and if a small amount of dust accumulates, the effect of flushing the dust downstream with the water flow is exhibited when the amount of water recovers, and it accumulates. Although the dust is removed, when a large amount of dust is accumulated, the dust cannot be washed away downstream when the amount of water is restored, and the accumulated dust blocks the water flow, and there is a concern that the water overflows from the water channel. Therefore, when the amount of water is small, it is necessary to periodically manually discharge the accumulated dust, which may cause a maintenance burden.

Japanese Patent No. 3075928 Japanese Unexamined Patent Publication No. 2016-148136

An object of the present invention is an intake screen capable of securing a large amount of water intake without increasing the height of the intake screen and easily removing dust accumulated on the surface of the intake screen, and water intake to which the screen is attached. To provide the device.

The water intake screen of the present invention is a water intake screen attached to the upper surface opening of the water intake device main body, and has at least two screens having different inclination angles in the flow direction of the surface water, and the screen located on the upstream side is a screen. The screen is mounted on an oblique downward slope toward the downstream side of the surface water flowing down the surface, and the most downstream screen is mounted at an inclination angle smaller than the inclination angle of the screen located on the upstream side or horizontally. .. This water intake screen can be composed of at least two screens, an upstream screen and a downstream screen, and when the inclination angle of the downstream screen satisfies the above condition and is composed of a plurality of screens, the most downstream screen. It suffices that the tilt angle of the side screen satisfies the above condition.

The screen is preferably a wedge wire screen composed of wire bars arranged orthogonally to the flow direction of surface water.

Further, there is also provided a water intake device characterized in that the water intake screen is attached to the upper surface opening of the box-shaped main body or the upper surface opening of the water tank provided at the head portion of the intake weir. This water intake device is provided with a water flow stop means for taking out the taken water and sending it to a water use facility, and the water flow stop means is a water gate attached to the water intake device, and the water guide is provided. It is preferable that the means is a water pipe and the water flow stopping means is a valve attached at the attachment part of the water pipe or in the middle of the water pipe, and further, the water use facility is a hydraulic power generation facility and the water flow stopping means. Is preferably a guide vane.

In addition, the water flow stop means sends a signal that detects an abnormality in the water taken in, such as a decrease in water pressure in the pipeline or a decrease in the water level in the water tank due to a decrease in water intake capacity, or a signal that is transmitted at predetermined regular intervals. It is preferable to detect and perform the water flow stop operation for a predetermined fixed time or while detecting an abnormality.

In the water intake screen of the present invention, the screen located on the upstream side having a large inclination angle does not accumulate dust on the screen surface and can maintain a stable water intake amount, and the screen on the most downstream side having a small inclination angle or horizontal is a screen. The amount of water that permeates the screen increases, the amount of water taken per unit area is large, and a large amount of water can be taken efficiently. Therefore, use an intake screen in which the number and area of screens located on the upstream side with a large inclination angle and the area of the most downstream screen with a small inclination angle are appropriately set depending on the conditions of the river or irrigation canal where the water intake device is installed. Therefore, the required amount of water intake can be secured, the height of the water intake device can be kept low, and the position of the lower end portion of the water intake screen can be raised. Therefore, the water level inside the main body of the water intake device can be kept high, and it is possible to prevent a decrease in the effective head in hydroelectric power generation.

On the other hand, with long-term use, dust gradually adheres to the water intake screen, and when the amount of water in rivers and irrigation canals is small, dust accumulates on the most downstream screen surface with a small inclination angle, resulting in a decrease in water intake capacity. Water can be guided by a water flow stop means such as a water gate attached to the water intake device, a valve installed at the attachment part of the water pipe or in the middle of the water pipe, or a guide vane built in the hydraulic power generation device. By stopping the water flow, the water taken from the screen located on the upstream side with a large inclination angle flows back from the most downstream side screen with a small inclination angle, and the accumulated dust and the dust that has entered the gap of the intake screen are washed away downstream. The washing effect is exhibited, and the water intake capacity can be restored again.

Even if it does not necessarily have a function to stop the water flow, the water that could not be taken up by the screen located on the upstream side with a large inclination angle is accelerated when flowing down the screen surface, and becomes the most downstream side screen surface with a small inclination angle. When it reaches, the effect of pushing away the dust becomes large, and the effect is small as compared with the case where it has the function of stopping the water flow, but it can exert the effect of suppressing the decrease in the water intake capacity to some extent.

Further, by using the wedge wire screen as the water intake screen and arranging the wire bar to be arranged so as to be orthogonal to the water flow direction of the surface water, the surface water can be efficiently taken.

The perspective explanatory view of the water intake device to which the water intake screen of this invention is attached. FIG. 3 is a perspective explanatory view of an example in which the water intake device shown in FIG. 1 is installed in an intake weir. FIG. 5 is a cross-sectional explanatory view of a water intake mechanism by the water intake device shown in FIG. An explanatory perspective view in which three water intake devices shown in FIG. 1 are connected in parallel. FIG. 5 is a perspective explanatory view of an example in which the water intake device shown in FIG. 4 is installed in an intake weir. The explanatory view of the difference in the water level inside the apparatus main body between the conventional intake apparatus and the intake apparatus attached with the intake screen of this invention. Explanatory drawing about the accumulation of dust in the intake screen of this invention. Explanatory drawing of backwash in the water intake screen of this invention. FIG. 5 is a cross-sectional explanatory view of a water intake device in which the water intake screen of the present invention is attached to an opening on the upper surface of a water tank provided in a head portion of an intake weir. A cross-sectional explanatory view of a conventional water intake device.

An embodiment of the present invention using two screens, an upstream screen and a downstream screen, as water intake screens will be described in detail below with reference to the drawings.

FIG. 1 is a perspective explanatory view of an intake device to which the intake screen 10 of the present invention is attached, and FIG. 2 is a perspective view of an embodiment in which the intake device to which the intake screen 10 is attached is installed in an intake weir 40 such as a river or an irrigation canal. It is explanatory drawing. The water intake screen 10 has a screen having two screens, an upstream screen 12 and a downstream screen 13, in the upper opening of the apparatus main body 11 including a pair of side plates 16, a back plate 17, a front plate 18, and a bottom plate 19. A water intake screen 10 connected via a connecting plate 15 is attached, and a surface water receiving plate 14 is attached above the front plate 18 at the front portion of the upstream screen 12 of the water intake screen 10. Then, the surface water 20 blocked by the intake weir 40 is received by the upper ends of the pair of side plates 16 and the surface water receiving plate 14.

As shown in FIG. 3, the inflow water 22 received by the surface water receiving plate 14 flows down the surface of the upstream screen 12, and at that time, the permeated water 23 that has passed through the upstream screen 12 is a box-shaped device main body. Water is taken into 11. Then, the flowing water 24 that does not pass through the upstream screen 12 and is not taken into the apparatus main body 11 passes through the screen connecting plate 15 and the downstream screen together with dust such as fallen leaves and earth and sand that are larger than the opening of the upstream screen 12. The permeated water 25 that has flowed into the surface of the 13 and has passed through the downstream screen 13 is taken into the device main body 11, and the water that does not permeate and is not taken into the device main body 11 is discharged from the downstream screen 13 together with dust as surplus water 26. , The surface water 21 on the downstream side of the river shown in FIG. Then, the water taken into the inside of the apparatus main body 11 is sent as a water guide stream 29 to a water use facility (not shown) by the water pipe 30.

In the intake screen 10 shown in FIG. 3, the upstream screen 12 is attached at an inclination angle θ toward the flow direction of the surface water, and the downstream screen 13 is attached substantially horizontally, and the amount of permeated water 25 per area. The ratio of is higher than that of the upstream screen 12. Furthermore, even if the downstream screen 13 is extended to the downstream side in order to obtain a larger amount of permeated water, the difference in height between the upstream front end and the downstream rear end of the downstream screen 13 is not so large. It doesn't grow. In this embodiment, the downstream screen 13 is mounted substantially horizontally, but if the tilt angle is smaller than the tilt angle θ of the upstream screen 12, it may be mounted with an tilt angle instead of horizontal. From the viewpoint of efficiently securing a large amount of water intake by increasing the amount of water that passes through the screen and keeping the height of the device low, the smaller the tilt angle, the better, and it should be installed almost horizontally. preferable.

FIG. 4 shows an example in which an intake device having an intake screen 10 attached to a river having a wide river or the like is installed. Three of these intake devices are connected in parallel, and each of the three surfaces of the intake screen 10 is paired. It is connected via the side plate 16. Then, FIG. 5 shows the connected water intake device installed on the intake weir 40. As described above, the water intake device to which the water intake screen 10 of the present invention is attached can be applied to rivers and irrigation canals of various river widths.

As shown in FIG. 10, in the conventional water intake device 50, a water intake screen 52 is attached to the upper surface opening of the device main body 51 on only one surface diagonally downward toward the downstream side. In this water intake device 50, the inflow water 22 received from the surface water of the river flows down the surface of the water intake screen 52, and when the water intake device 50 flows down, the permeated water 23 that has passed through the water intake screen 52 is taken into the device main body 51 and is taken into the water guide pipe. At 30, it is sent to the water use facility as a headrace 29. The water that does not pass through the water intake screen 52 and is not taken into the device main body 51 becomes surplus water 26 and is discharged to the downstream side of the water intake device 50 together with the dust 100.

In the water intake device 50, as described above, the dust 100 is efficiently removed from the surface of the water intake screen 52 by the surplus water 26, but in order to efficiently remove the dust 100, the amount of the surplus water 26 must be a certain value or more. In order to increase the amount of water in the permeated water 23 and secure a large amount of water intake, it is necessary to increase the area of the water intake screen 52, increase the height of the device, and take water. The size of the screen 52 must be extended downstream.

As described above, in the conventional water intake device 50, the height of the device is increased in order to secure the amount of water intake. On the other hand, as described above, in the water intake device to which the water intake screen 10 of the present invention is attached, the downstream screen 13 having a small attachment inclination angle, a large proportion of permeated water, and a large amount of water intake per unit area is used in combination. By doing so, the amount of water intake is secured without increasing the height of the device. As shown in FIG. 6, the difference in height of these devices causes a difference of Δh in the water level (W.L.) of the water taken into the device main body 11 and the device main body 51. That is, in all the devices, the surface water receiving plates 14 and 54 are set to the same height according to the water level of the surface water on the upstream side in order to take water, but in the conventional water intake device 50, the water intake is set to the same height. The size of the screen 52 is extended to the downstream side, and the lower end of the extended water intake screen 52 is the upper limit of the water level (WL) inside the apparatus main body 51.

On the other hand, in the water intake device to which the water intake screen 10 of the present invention is attached, a downstream screen 13 having a small inclination angle is attached so that more permeated water can be obtained as described above (shown in the figure). The lower end of the downstream screen 13 is the upper limit of the water level (WL) in the apparatus main body 11. Therefore, as shown in FIG. 6, in the water intake device to which the water intake screen 10 of the present invention is attached, the water level (WL) in the device main body 11 is held at a high position without increasing the height of the device. It is higher by Δh than the water intake device 50. Therefore, when the conventional water intake device 50 is used for hydroelectric power generation, there is a problem that the effective head becomes small and the amount of power generation becomes small, but the water intake device to which the water intake screen 10 of the present invention is attached has such a problem. Does not occur.

Further, even when the downstream side screen 13 is attached so as to have an inclination angle rather than being substantially horizontal, if the inclination angle is smaller than the inclination angle θ of the upstream side intake screen 12, the same action and effect as described above can be obtained. Can be done.

On the other hand, as shown in FIG. 7, since the downstream screen 13 is attached horizontally or at a small inclination angle, dust 100 may accumulate on the screen surface during long-term use or when the amount of water in a river or irrigation canal is small. The flowing water 24 flowing down on the screen surface of the downstream side screen 13 is a water flow in which the flow velocity is increased by the inflow water 22 flowing down on the screen surface of the upstream side intake screen 12, and is simply installed horizontally. Although the dust removing ability is larger than that of the water intake screen, the dust 100 may be accumulated when used for a long time.

However, as shown in FIG. 8, the water intake device equipped with the water intake screen 10 can provide a means for removing the dust 100 accumulated by the backwash. In this water intake device, the water taken into the main body 11 of the device is sent to the water use facility as a water flow 29 through the water pipe 30, but by stopping the water flow 29 (indicated by an X in FIG. 8), the device The water taken into the main body 11 can be used as the backwash water 27, back-permeated through the downstream screen 13, and discharged together with the accumulated dust 100 as the backwash discharge water 28 to the downstream outside the device to wash away the dust 100. it can.

The means for stopping the water guide flow 29 can be performed by closing the valve 31 provided in the water pipe 30 shown in FIG. This valve 31 can be provided at the attachment portion of the water pipe 30 as shown in the figure, or can be provided between the water intake device and the water use facility. Further, the valve 31 detects an abnormality in the water taken in, such as a decrease in water pressure in the pipeline or a decrease in the water level in the water tank due to a decrease in water intake capacity, or a signal transmitted at predetermined periodic intervals. By detecting S and closing it, it is preferable that the water conveyance flow 29 can be stopped for a predetermined fixed time or while detecting an abnormality. Furthermore, even if the water gate provided in the water storage tank or the water use facility is a hydroelectric power generation facility, the water flow 29 is stopped by a guide vane installed in the power generation device and connected to the water pipe 30. Good. Even when a water gate or a guide vane is used, as in the case of the valve 31, an abnormality in the intake water is detected, or the headrace flow 29 is stopped at predetermined periodic intervals. Then, by regularly backwashing at intervals according to the conditions of the river or irrigation canal, which is the water source, it is possible to prevent the accumulation of dust and perform stable water intake.

As shown in FIG. 9, the water intake screen 10 of the present invention is also installed in the upper surface opening of the water tank 43 provided in the head works 41 and 42 provided in the water intake weir. In this installation, the water intake screen 10 may be installed directly in the upper surface opening of the water tank 43, but the pair of side plates 16, the back plate 17, and the front plate are excluded except for the bottom plate 19 of the water intake device shown in FIGS. The water intake screen 10 is installed on the 18th. Since the water intake screen 10 attached in this way does not have the bottom plate 19, the permeated waters 23 and 25 that have passed through the upstream screen 12 and the downstream screen 13 are stored in the water tank 43. A water pipe 30 is installed in the water tank 43 via a water gate 32. Then, the floodgate 32 detects the signal S in the same manner as the valve 31 described above, and opens and closes in the same manner as the valve 31 described above.

Further, the water intake screen of the present invention is a wedge wire screen, the wire bars constituting the screen are arranged orthogonal to the water flow direction, the cross section of each wire bar is triangular, and the base of the triangle is the screen surface. It is preferably arranged in.

Regarding the above-described embodiment of the present invention, the mode in which the water intake screen 10 is attached to the box-shaped water intake device main body 11 or the upper surface opening of the water tank 43 provided in the drop works 41 and 42 has been described. It is clear from the above description that the intake screen of the present invention is also applied to an intake device or an intake facility having a similar structure for taking in surface water of a water source such as a river or an irrigation canal.

In the above description, an embodiment of an intake screen having two screens, an upstream screen and a downstream screen, has been described. However, a plurality of screens are used as the upstream screen, and the downstream screen is the most downstream screen. It is clear that the same effect is exhibited even in the case of the above configuration.

The water intake device of the present invention can be used not only for water supply facilities and hydroelectric power generation facilities, but also for industrial water, agricultural water, and the like.

10 Water intake screen 11 Device body 12 Upstream screen 13 Downstream screen 14 Surface water receiving plate 15 Screen connecting plate 16 Side plate 17 Back plate 18 Front plate 19 Bottom plate 20 Surface water (upstream) 21 Surface water (downstream)
22 Inflow water 23 Permeated water 24 Downflow water 25 Permeated water 26 Surplus water 27 Backwash water 28 Backwash discharge water 29 Headwater flow 30 Water pipe 31 Valve 32 Water gate 40 Intake dam 41, 42 Head construction 43 Water tank 50 Intake device (conventional equipment) ) 51 Device body (conventional device)
52 Water intake screen (conventional equipment) 54 Surface water receiving plate (conventional equipment)
100 Dust θ Tilt angle S signal
WL water level Δh water level height difference

Claims (9)

An intake screen attached to the upper opening of the main body of the water intake device, which has at least two screens having different inclination angles in the flow direction of the surface water, and the screen located on the upstream side is the screen of the surface water flowing down the surface. An intake screen that is mounted on an oblique downward slope toward the downstream side, and the most downstream screen is mounted at a tilt angle or horizontally that is smaller than the tilt angle of the screen located on the upstream side thereof. The water intake screen according to claim 1, wherein the screen comprises a wedge wire screen composed of wire bars arranged orthogonally to the flow direction of surface water. A surface water intake device according to claim 1 or 2, wherein the water intake screen according to claim 1 or 2 is attached to the upper surface opening of the box-shaped main body. A surface water intake device according to claim 1 or 2, wherein the intake screen according to claim 1 or 2 is attached to an opening on the upper surface of a water tank provided at a head portion of an intake weir. The surface water intake device according to claim 3 or 4, further comprising a water guiding means for taking out the taken water and sending it to a water use facility, which has a water flow stopping means. The surface water intake device according to claim 5, wherein the water flow stop means is a water gate attached to the water intake device. The surface water intake device according to claim 5, wherein the water guiding means is a water pipe, and the water flow stopping means is an attachment portion of the water pipe or a valve attached in the middle of the water pipe. The surface water intake device according to claim 5, wherein the water use facility is a hydroelectric power generation facility, and the water flow stopping means is a guide vane. The water flow stop means detects a signal that detects an abnormality in the water taken in, or a signal that is transmitted at a predetermined periodic interval, and detects a water flow stop operation for a predetermined fixed time or an abnormality. The surface water intake device according to any one of claims 3 to 8, wherein the surface water is taken while the water is taken.

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