JP3174441B2 - Underwater agitator for lake water - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the destruction of a thermocline by agitating lake water in a dam, a lake, a reservoir or the like.
The present invention relates to an underwater stirrer for preventing the elution of nutrient salts from bottom sediment, activating bottom water, and destroying freshwater red tide on the surface.

[0002]

2. Description of the Related Art Conventionally, as a stirring device for lake water, a stirrer has been installed directly at the bottom of a lake, and the surrounding water has been sucked in through a strainer attached below the stirrer and discharged upward. According to this method, the bottom of the lake up to a depth of about 20 meters is stirred, and when the depth of the reservoir exceeds 20 meters, the stirrer is suspended near the water depth of 20 meters using a buoy, and a long cylinder is connected to the suction port of the stirrer. do it,
Suction the bottom water. A method is also known in which the impeller of a stirrer also suspended in water is turned upside down and water sucked from above is discharged in a lateral direction. When the water depth is large, attaching a long cylinder to the suction port of the stirrer is the same as the above method.

[0003]

According to the above methods, it is possible to destroy a thermocline, prevent elution of nutrients from sediment, activate bottom water, etc. within a radius of about 100 meters. Although possible, it has the drawback of generating freshwater red tide on the surface of the stored water, and it was necessary to take additional measures to destroy this.

[0004]

According to the present invention, in the above-mentioned hanging type stirring apparatus, a lower suction horizontal discharge stirrer and an upper suction horizontal discharge stirrer are vertically stacked, and the rotating shafts of both the stirrers are changed. By arranging them coaxially, the freshwater red tide especially on the surface layer is destroyed, propagation is prevented beforehand, and simultaneously the activation of bottom water is attempted. When the lake reaches a depth of about 40 meters, a hollow cylinder with the other end reaching the lake bottom is connected to the lower agitator suction port.

[0005]

According to the present invention, the freshwater red tide generated on the surface of the lake is sucked and discharged to the middle part of the lake, and the low temperature of the low temperature which is sucked from the bottom of the pond and discharged to the middle of the lake is also formed. By mixing with the bottom water, the red tide can be destroyed and the propagation of the red tide can be prevented. When the bottom of the lake reaches a depth of about 40 meters, the hollow cylinder is installed at the suction port of the lower stirrer to suck up the bottom water, destroy the thermocline, prevent nutrients from being eluted from the sediment, It is also possible to further activate water.

[0006]

FIG. 1 shows an embodiment of the present invention. A stirrer 1 is an underwater electric mixer 3 with rotating blades at the center of a vertical cylindrical body 2.
A discharge section 7 comprising two horizontal disks 4, 5 and a rectifying projection 6 is provided below the cylindrical body 2, and the mixer 3 urges the lake water sucked from above the cylindrical body 2 to discharge the lake water. It discharges from a part to a horizontal direction. On the lower surface of the discharge unit 7,
Electric mixer 3 'with same cylindrical body 2' and discharge section 7 '
Are arranged upside down, and the rotation axes of the mixers 3, 3 'are the same. A strainer formed of a mesh body for preventing suction of solid matter is stretched at each suction port of the cylindrical bodies 2 and 2 '. An eye nut 8 is planted at an appropriate position on the upper surface of the discharge unit 7 and used as a knot of a wire 9 when the stirrer is suspended in water. A buoy 10 with a buoy is arranged on the lake surface, and the stirring device is suspended in the water by holding the upper end of the wire 9. The mixer 3, 3 ′ drive cable 11 is connected to a ground power supply via the barge 10.

[0007] The stirring device is suspended in water at a depth of about 20 meters. The mixer has a maximum flow rate of 9.0 cubic meters /
Min, the maximum flow rate is 3.4 meters / second
It is installed on a table and stirs water within a radius of about 100 meters around the stirrer. When the depth of the lake bottom reaches 3 to 40 meters, a hollow cylinder with the other end open near the lake bottom is connected to the suction port of the stirrer that sucks downward and discharges laterally from the stirrer. So that it sucks up.

For comparison with the embodiment of the present invention, FIGS. 3 to 7 show a conventionally known underwater stirring device. The apparatus shown in FIG. 3 is of a hanging type with a lower suction and an upper discharge, and has a configuration similar to the present invention. FIG. 4 shows a well-known type of lower-suction upper-discharge lake-bottom-mounted type, FIG. 5 shows a hanging type with upper-suction lateral discharge, and FIG. 6 shows a long cylinder provided above the stirrer of FIG. FIG. 7 shows an arrangement in which a long cylinder is provided on the upper side as in the embodiment shown in FIG.

As shown in FIG. 8, a stainless steel strainer 12 and a cloth or paper filter 13 are provided on the cylindrical body 2 of the suction port in the suction port of the embodiment shown in FIGS. It is prevented from being sucked into the agitator and damaging the blades of the mixer.

[0010]

As described above, according to the present invention, the water near the lake surface and the water near the lake bottom are simultaneously sucked and discharged in the middle part of the water in the horizontal direction, so that both of them can be spread over a wide range around the stirrer. As it is agitated and mixed, the effect of agitation in water is enhanced as compared with the conventional underwater agitator causing one-way flow, and the destruction and bottom of the water thermocline that the conventional device has. In addition to preventing the elution of nutrients from the water and the activation of sediment water, the destruction and propagation of freshwater red tide on the surface can be prevented. It is possible to perform a favorable maintenance.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of an underwater stirring device according to the present invention.

FIG. 2 is a conceptual diagram showing a water flow around an underwater stirrer according to the present invention.

FIG. 3 is a conceptual diagram showing a water flow around a conventional lower suction upper discharge suspension type stirring device.

FIG. 4 shows a well-known agitator with a bottom suction and a top discharge, which is widely known in the prior art.

FIG. 5 shows a conventional upper suction horizontal discharge suspended stirrer.

FIG. 6 shows a hanging type stirrer provided with a long cylinder above the stirrer of the embodiment of FIG. 5 to cope with water depth.

FIG. 7 shows a conventional suspension type of upper suction and lower discharge.
This shows an example in which a long cylinder is provided above as in the embodiment.

FIG. 8 is a partial sectional view showing a state where a strainer and a filter are provided at a suction port of the stirrer of the embodiment of FIGS. 5 to 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stirrer 2, 2 'Cylindrical body 3, 3' Mixer 4, 4 'Horizontal disk 5, 5' Horizontal disk 6, 6 'Rectifying protrusion 7, 7' Discharge part 8 Eye nut 9 Suspension wire 10 11 Drive cable 12 Strainer 13 Filter

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C02F 1/00 C02F 7/00 B01F 7/00 F04D 13/12 F04D 13/08

Claims (2)

(57) [Claims] 1. A stirrer of the type suspended from the water surface, wherein a stirrer for lower suction lateral discharge and a stirrer for upper suction lateral discharge are vertically stacked and arranged so that the rotation axes of both stirrers are coaxial. An underwater stirring device for lake water, characterized in that: 2. The underwater stirrer according to claim 1, wherein a hollow cylinder having the other end opened near the lake bottom is connected to a suction port of the stirrer for downward suction and lateral discharge.