Hydraulic and earth engineering – Fluid control – treatment – or containment – Flow control
Patent
1991-07-05
1992-08-18
Corbin, David H.
Hydraulic and earth engineering
Fluid control, treatment, or containment
Flow control
405 92, 405100, E02B 808
Patent
active
051393646
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an automatic swing fishway apparatus to allow fish to swim upstream. The apparatus is installed in dams or weirs and accommodates fluctuations in upstream water levels.
BACKGROUND OF THE INVENTION
As indicated in FIG. 10, this type of apparatus involves a reservoir 2, formed by a dam 1, being connected to stationary fishway 4, formed from a downstream side, via guiding waterway 3, with swing fishway apparatus 5 provided at an intermediate location in the waterway. Water pressure chamber 6 is provided in said waterway, and a fishway device body 7 is housed within said hydraulic chamber and supported by the downstream end (shaft 7a). The upstream end of the fishway device body 7 is lifted by winch 8. A plurality of dividing walls 9 are provided in an upper portion of the fishway device body 7. Fishway device body 7 is tilted corresponding to a water level of reservoir 2 with shaft 7a of the downstream end serving as a fulcrum. In this case, the operator must check the water level and then operate winch 8 to lift fishway body 7 and tilt it to match an upstream water level, so the apparatus is difficult to use, since it responds slowly to fluctuating water levels.
Japanese Utility Model Publication No. 59-17941 discloses an invention in which a fishway device body inclines to match an upstream water level automatically without the use of winch 8. As indicated in FIGS. 11, 12 and 13, frame 11, which provides small openings between side walls 10 on both sides of the waterway, is supported by a shaft on the downstream end while allowing to swing freely. One end of connecting tube 12, which is opened in the bottom of frame 11, opens into the upstream water. Floats 13 in the shape of plates are provided vertically at constant intervals on frame 11. Regulatory chambers 14 are provided within floats 13 and water is fed to the chambers 14 from water feed ports 15 to regulate the buoyancy of floats 13. Therefore, frame 11 is supported by the buoyancy of floats 13 and the water pressure which acts on a bottom surface of frame 11.
Since frame 11 is not floating in the water solely by floats 13, an angle of inclination of frame 11 is set by regulating the buoyancy by introducing water into regulatory chambers 14 from water feed ports 15 at installation.
However, since the buoyancy fluctuates according to the angle of inclination, when the water level in the reservoir rises, frame 11 rises too high resulting in a decrease in an amount of water which overflows floats 13. Thus, when the depth of the overflow water is insufficient, it is not suitable as a fishway. In addition, when the overflow water level is high, an angle of inclination of frame 11 becomes too small in that the water level in the reservoir lowers, resulting in an excessive amount of overflow water. Thus, a fishway is desired which achieves a suitable overflow water depth regardless of the height of the upstream water level.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an automatic swinging fishway device that is able to accurately follow fluctuations in an upstream water level.
In order to accomplish this object, a fishway device body consisting of a fishway section, on which a plurality of dividing walls are provided vertically on a floor plate, and a sealed section beneath the floor, is arranged in an hydraulic chamber, providing the hydraulic chamber on a bottom of a waterway which bypasses a dam or weir. The fishway device body is allowed to rotate freely by means of a main shaft on a downstream side. The hydraulic chamber is connected to an upstream waterway via an overflow dam mounted on the upstream side of the fishway device body, and the hydraulic chamber is connected to the downstream waterway via an outflow port having a cross-sectional area smaller than the length of the overflow dam.
As a result of having the construction described above, the fishway device body is lifted up by the buoyancy of the sealed portion following the flowing in of water that has
REFERENCES:
patent: 4526494 (1985-07-01), Eicher
patent: 4657434 (1987-04-01), Woolnough
Arakeda Kunikazu
Shitami Koji
Tabuchi Toshinori
Takahashi Tatuki
Yokota Tosiyuki
Corbin David H.
Hokokukogyo Co., Ltd.
Nagasaki-Ken
LandOfFree
Automatic swing fishway apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Automatic swing fishway apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic swing fishway apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1243892