JP2003126844A - Floatation thickening equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide flotation thickening equipment to scrape scum from upper layer of scum by mitigating the shock caused by scraping operation of floatation thickened scum and prevent spreading of sludge during scraping operation. SOLUTION: This floatation thickening equipment is equipped with scum swirling blades (7) which are fixed vertically to a rotating drive shaft (6) in a concentration tank (1) and immersed into the floatation thickened scum layer, a scum partition plate (9) having a plenty of holes (9a) which divide the scum layer in the vertical direction is fixed to the rotating drive shaft (6) above the scum swirling blades (7) and made to pass by underneath of a scraper, and a discharge port (3) of a stock solution feed pipe (2) near the bottom of the concentration tank (1). Sludge is supplied to the whole downside of swirl moving scum layer (8) where homogeneous scum layer is formed and pushed against the scum partition plate (9) and pushed upward through holes (9a) so that dense scum layer (8) is formed. Thus, upper side of all swirl moving scum layer (8) can be uniformly scraped out by the scraper (10) without leaving unscraped scum and without disturbing the scum layer (8) by scraping operation.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an atmospheric levitation device,
The present invention relates to improvement of a flotation concentrator that scrapes scum floating on the surface of water such as a pressure flotation device or a sedimentation tank.

[0002]

2. Description of the Related Art Conventionally, a flotation tank equipped with a scum removing device is well known. Then, as a scum removal device for the flotation tank, a discharge nozzle was provided at the center of the circular sedimentation tank, and the wastewater was jetted horizontally from a height half the liquid depth
A scum removal device that scoops scum into a scum box arranged on the inner peripheral wall of a circular sedimentation tank, provided with a floating-sink type scum blocking plate whose top is floated above the water surface and a rotatable scum draw plate, It is publicly known as described in JP-A-8-309107. In addition, an inlet for sludge is provided at the bottom of the flotation tank, a scraper that cuts scum on a vertical rotation axis, and a scraping plate is provided on a chain that circulates along the outer peripheral edge of the scraper, and the cut scum is removed. An example of the scraper moved to the central hopper is disclosed in Japanese Unexamined Patent Publication No. 9-2898.
It is known as described in Japanese Patent No. 5784.

[0003]

The conventional problem as a scum scraping device is to scrape it evenly from the upper end of the scum. Do not disturb the scum layer by the scraping operation. There is no leftover zone or sludge is replaced even if there is one. Maintenance is easy, such as a structure in which fibrous materials are not caught. In the case of normal pressure levitation, the water surface load is 5 to 10 times that of pressurized levitation, and the scum scraping should be continuous operation. However, in addition to general items such as processing capacity and materials, the above consideration is especially required.

In a device provided with a floating / sink type scum blocking plate and scum blocking plate, scum collected by the circulating scum blocking plate is blocked by the scum blocking plate and can be collected in the scum box. However, the floating scum floated in the vicinity of the center part, and there was a risk that the scum that was not concentrated in a compacted manner could be collected. As for the heavy-duty floating sludge that is difficult to be deaerated like normal pressure floating, the scum blocking plate disturbed the scum layer, and there was a risk that it would pass through the scum blocking plate and float. A flotation tank equipped with a scraper that cuts scum and a scraping plate that circulates is suitable for a normal-pressure levitation device that has a large water area load, but the scraper that rotates and revolves The structure of the plate became complicated, and the fibrous material was easily caught, which made maintenance difficult. Then, it is necessary to supply power to the electric motor as a rotary drive source in the central portion of the concentrating tank by sliding power supply, which makes the structure more complicated. In order to solve the above problems, an object of the present invention is to provide a flotation concentrating device capable of mitigating impact caused by a scraping operation and preventing sludge from escaping during scraping and scraping the scum from the upper layer portion.

[0005]

Means for Solving the Problems The gist of the present invention is to supply a stock solution containing a flocculant from the bottom of a cylindrical concentrating tank so that flocculated flocs are floated and a flocculated scum is removed by a scraper. In a scraping concentrator, a scum rotary vane is fastened to a rotary drive shaft hanging down in the central part of the concentrating tank so as to be embedded in the floated concentrated scum, and the stock solution is provided near the bottom of the concentrating tank. With the discharge port of the supply pipe opened upward, even with fixed sludge supply,
Sludge is supplied to the entire lower surface of the rotating scum layer to form a uniform scum layer. Then, the rotating scum layer can be scraped off by a scraping machine.

A scum split plate for vertically splitting the scum layer is fixedly attached to the rotary drive shaft above the scum rotary blade, and a large number of through holes are provided in the scum split plate so that the scum split plate is provided near the scraper. It is passed along with the scum rotary vanes, and the flotation sludge is pressed against the scum dividing plate to increase the compacting force of the scum, improving the concentration performance and pushing it up to the upper stage of the scum dividing plate, forming a dense scum layer. To be done. The entire upper surface of the rotating and moving scum layer placed on the scum dividing plate can be scraped evenly by a scraping machine. And
The scum layer is not disturbed by the scraping operation, and is not left unscratched.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The apparatus according to the present invention is configured as described above, and a foaming agent and a coagulant are added to a stock solution, or pressurized air is pressed into the stock solution to which a coagulant is added. When the stock solution is supplied to the concentrating tank, the flocs rise to the lower surface of the scum dividing plate due to buoyancy. The scum layer circulates the concentration tank with scum rotary vanes that rotate around a rotary drive shaft, and sludge is evenly supplied to the entire lower surface of the scum layer that rotates from a fixed supply pipe. The scum layer is pressed against the horizontal lower partition of the dividing plate to increase the consolidation force,
Concentration performance is improved to form a uniform scum layer. The scum that has been pushed up from many openings in the scum dividing plate and the concentrated sludge flows and moved to the upper layer is rotated on the water surface together with the scum dividing plate, and the rotating scum is fixed to the concentration tank with a scraping machine to remove the scum layer. Scrap the entire upper surface. Since the scum is placed on the scum dividing plate and the upper layer of the scum is scraped off by the scraping machine, it is possible to prevent the impact caused by the scraping operation from being transferred to the concentration zone and at the same time prevent the sludge from escaping. It is discharged to the scraping machine without leaving any scratches.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flotation concentrator according to the present invention will be described in detail with reference to the drawings. First, FIG. 1 is a vertical cross-sectional view of the flotation concentrator, in which a stock solution is inserted into a lower side wall of a cylindrical concentrating tank 1. The discharge port 3 of the pipe 2 is opened upward, and the bubbles generated by the addition of the foaming agent and the sludge in the stock solution are adsorbed by the addition of the coagulant, and the concentrate 3 is discharged from the discharge port 3 of the stock solution supply pipe 2. 1, sludge is floated and concentrated by buoyancy, and a part of sludge having a high specific gravity is precipitated. An electric motor 5 with a speed reducer is placed on a pedestal 4 suspended from the upper end of the cylindrical concentration tank 1, and a rotary drive shaft 6 connected to the electric motor 5 with a speed reducer hangs down in the center of the concentration tank 1. is there. One or two scum rotary vanes 7 are fixed to the rotary drive shaft 6 along its axis in a substantially vertical state, and are buried in the floated and concentrated scum layer 8. The floating sludge supplied from the fixed stock solution supply pipe 2 is
The scum layer 8 is circulated by the scum rotary vanes 7 and is evenly supplied to the entire lower surface of the rotating scum layer. In addition,
As described above, the stock solution supplied to the concentrating tank 1 may be floated at atmospheric pressure, but the dissolved air is supplied into the stock solution without adding a foaming agent to press the deposited bubbles to the solid particles. It is also good to levitate.

As shown in FIG. 1, the scum layer 8 of the concentration tank 1
A disc-shaped scum dividing plate 9 for vertically dividing the whole of the above is disposed on the upper end of the scum rotary vane 7, and the central portion of the scum dividing plate 9 is fixed to the rotary drive shaft 6. The float-concentrated scum layer 8 is divided into a float-concentration zone 8a of a lower layer and a scum scraping zone 8b of an upper layer, and is rotated together with the scum rotary vane 7. By supplying the scum by the scum rotary vanes 7 and pressing it against the scum dividing plate 9, the compaction force increases and the concentration performance increases. FIG. 2 is a plan view of the scum dividing plate. The scum dividing plate 9 is provided with a large number of through holes 9a, and sludge (scum) in the flotation concentration zone pressed against the scum dividing plate 9 passes through the through holes 9a. The scum dividing plate 9 is pushed up from above to form the scum scraping zone 8b.

As shown in FIG. 1, a scraper 10 for concentrated sludge, one end of which is suspended from a pedestal 4 of the thickening tank 1 and the other end of which is supported by the tank wall of the thickening tank 1, includes a scum dividing plate 9. It is arranged in the vicinity. FIG. 3 is a vertical cross-sectional side view of the scraper.
The transfer screw 12 is inscribed in the scum discharge pipe 11, and a scraping inlet 11a is horizontally opened on the side surface of the scum discharge pipe 11 in the rotation direction of the scum dividing plate 9.
The base end of the scum scraping plate 13 is connected to the scraping inlet 11a, and the tip of the scum scraping plate 12 is connected to the scum dividing plate 9.
Is slid on the surface of. The scum dividing plate 9 is the rotary drive shaft 6
To rotate the floating scum in the scum scraping zone 8b on the water surface. The scum layer 8 is formed by the scraper 10 with the scum fixed to rotate around the lower part of the scraper 10.
The upper stage is scraped, and the scraped scum is sent to the outside of the concentration tank 1 by the transfer screw 12 and discharged from the scum discharge port 14.

The scraper 10 evenly scrapes the entire surface of the scum above the scum dividing plate 9, and the scum layer 8 by the scraping operation.
It does not disturb and does not leave scratches. The scum of the flotation concentration zone 8a is pushed up from the through hole 9a on the upper stage of the scraped scum dividing plate 9 to form the scum scraping zone 8b again, and the scraper 10 continuously scrapes the scum. To do. At the lower end of the vertical rotary shaft 6, a sinker 15 for settling sludge
The sludge settling on the bottom of the concentration tank 1 is scraped to the sludge pit 16 and discharged from the sludge pipe 17. A separation water drain pipe 18 is connected to the lower side wall of the concentration tank 1,
The separated water that has been subjected to solid-liquid separation is extracted from the vicinity of the upper side of the scraper 15. The drainage pipe 18 is connected to a water level controller 19 and adjusts the liquid level of the concentration tank 1. Reference numeral 20 is a driving machine for the transfer screw 12.

[0012]

As described above, in the flotation concentrator according to the present invention, a uniform scum layer is formed, and scum can be scraped from the scum upper layer portion concentrated in a compacted manner without disturbing the scum layer. it can. That is, in the conventional device in which sludge is supplied from the fixed-type undiluted solution supply pipe and the scum is collected by the scum draw plate, the floating scum floats in the vicinity of the central portion and is not concentrated in a compacted manner. There was a risk that the scum could be collected and floated through the scum draw plate. Further, in the levitation separation tank provided with the scraper for cutting the scum and the scraping plate that circulates, the structure of the scum recovery device was complicated and maintenance was difficult. Is a rotating drive shaft that hangs down in the center of the concentrating tank, and a scum rotary blade is fixed to the floating concentrated scum so that the scum layer goes around. Sludge is supplied to the entire lower surface of the moving scum layer to form a uniform scum layer.

A scum dividing plate for vertically dividing the scum layer is fixed to the rotary drive shaft above the scum rotating blade, and a large number of through holes are provided in the scum dividing plate so that the scum dividing plate is provided near the lower part of the scraper. As it is passed, the floating sludge pressed against the scum dividing plate is pushed up to the upper stage of the scum dividing plate, so that the consolidation force of scum increases, the concentration performance improves, and a scum layer with high density is formed. The entire upper surface of the rotating scum layer can be scraped evenly by a scraping machine. Further, the scum layer is not disturbed by the scraping operation and is not left unscratched.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a flotation concentrator according to the present invention.

FIG. 2 is a plan view of a scum dividing plate obtained by cutting the concentrating tank of FIG. 1 along the line AA.

FIG. 3 is a vertical cross-sectional side view of the scraper, which is obtained by cutting the concentrating tank of FIG. 1 along the line BB.

[Explanation of symbols]

1 thickener 2 Stock solution supply pipe 3 outlets 6 rotary drive shaft 7 scum rotary vanes 9 scum dividing plate 9a through hole 10 scraper

Claims (2)

[Claims] 1. A concentrating device for supplying a stock solution containing a flocculant from the bottom of a cylindrical concentrating tank (1) to float flocculated flocs and scrape the floated and concentrated scum with a scraper (10). In the concentrating tank (1), a scum rotary vane (7) is fastened to a rotary drive shaft (6) suspended in the central portion of the concentrating tank (1) so as to be embedded in a floating and concentrated scum layer, and A flotation concentrator, characterized in that an outlet (3) of a stock solution supply pipe (2) is opened upward in the vicinity of the bottom of the tank (1). 2. A scum dividing plate (9) for vertically dividing a scum layer is fixed to a rotary drive shaft (6) above the scum rotating blade (7), and the scum dividing plate (9) is fixed to the scum dividing plate (9). 2. The flotation concentrator according to claim 1, wherein a large number of through holes (9a ...) Are provided to allow passage through the vicinity below the scraper.