JP5163966B2 - Filter stirrer using floating filter media - Google Patents

Description

  The present invention relates to a stirrer for a filter using a floating filter material that enables high-speed filtration and precision filtration to treat sewage and industrial wastewater generated in a sewage treatment plant, or to purify lakes, rivers, etc. Further, the present invention relates to the improvement of a stirrer for floating filter media that can reduce the stirring power by low-speed rotation and prolong the life of the filter media.

Conventionally, a downflow type sand filtration apparatus is well known, and an upflow type filtration apparatus that performs solid-liquid separation in an upward flow using a resinous filter medium or a fiber filter medium having a low specific gravity is also well known. The upward flow type filtration device using the floating filter material such as resin filter material and fiber filter material of the upward flow type filtration device supplies the stock solution from the bottom of the filtration tank and allows the filter material layer to pass through. The product is separated into solid and liquid, and the filtrate is taken out from the upper part of the filtration tank. The clogged filter medium layer is washed and stirred with a stirrer to regenerate the filter medium. Floating filter media such as resin filter media and fiber filter media have the advantages of low specific gravity, easy clogging of the clogged filter media layer, and a small amount of washing water used.
For example, in order to demonstrate the stirring force of the filter medium and the mounting of the stirrer, an upward flow type filtration device in which a stirring blade having the same diameter as the filtered water outlet is extended to the vicinity of the floating filter medium layer is disclosed in Patent Document 1 the applicant of this invention has proposed.
In addition, a conical water collecting nozzle is suspended from the ceiling wall of the filtration tank, and a stirrer is installed at the bottom of the filtration tank to minimize the dead space of the stirring flow generated at the base of the water collecting device, thereby achieving smooth stirring efficiency. A water collecting device for obtaining the above is also proposed in Patent Document 2 by the applicant of the present invention.

No. 2-2404 (Utility Model Registration Request, Fig. 1) Japanese Patent Laid-Open No. 10-277315 (Claim 1, FIG. 3)

A conventional filtration apparatus using a floating filter medium has a structure in which a filter medium layer is formed with a floating filter medium in a filtration chamber, and the stock solution is passed through the filter layer in an upward flow. In the filtration device using the floating filter medium, the area of the lower surface of the filter medium layer is the filtration area of the filtration tank, high-speed filtration is possible, and the filter medium is light, so that it is easy to wash.
However, as in Patent Documents 1 and 2, the shape of the stirring blade that protrudes radially from the rotating shaft and goes straight in the rotational direction generates only a swirling flow in the horizontal direction when the filter medium layer is washed as the stirring blade rotates. In the middle of the filtration chamber, the filter medium flows, but in the upper part of the filtration chamber, the flow of the filter medium is small and the stirring effect is weak. The above stirring blade shape has a large water flow resistance during rotation and consumes power. In order to maintain the rotation speed of the stirrer without reducing the fluidity of the filter medium, the current value cannot be lowered and the power cannot be reduced. Since there is no water flow to flow above and below the filtration chamber, the floating filter material below is in contact with the agitating blade and the agitating blade is perpendicular to the rotation direction. As a result, the filter medium life is shortened.
This invention is an improvement of the agitator of a filter using a floating filter medium, improves the blade shape of the agitating blade, generates a swirling flow and an upward flow at the same time, and reduces the cleaning efficiency and the rotational speed by reducing the rotational speed. The purpose is to reduce.

The gist of the present invention is a filtration apparatus for supplying a stock solution to a sealed filtration tank containing a floating filter medium and performing solid-liquid separation with a filter medium layer of the floating filter medium. of the stirring blade was fastened, intended to constitute the agitator outlet end of the stirring blade and extends in the rotational direction behind the obliquely upward with respect to the drive shaft, is disposed in filtration layer near the lower surface of the filter material layer, stirred By rotating the wings, horizontal swirling horizontal flow and vertical swirling upward flow can be generated. A horizontal swirling horizontal flow caused by the rotation of the stirring blades generates a horizontal swirling flow in the vicinity of the stirring blades, and an upward swirling flow of the vertical swirling winds up the filter medium at the bottom of the tank, causing the vertical swirling to pass through the tank. Generate a flow. The floating filter media that forms the filter media layer is flowed, the clogged material trapped on the lower surface of the filter media layer is peeled off, the turbulent flow is applied to the floated filter media, the floating filter media collides, and the trapped material trapped in the floated filter media And regenerate the filter media layer.

The stirring blade that is fixed to the drive shaft and extends obliquely upward has an inclination angle α of 30 ° to 40 °, and the blade surface of the stirring blade swirling around the drive shaft is in sliding contact with the sewage. As the wing rotates, a vertical swirling upward flow and a horizontal swirling horizontal flow are generated at the same time, and the sewage in the entire filtration chamber can flow.
In addition, the stirring blade that is fixed to the drive shaft and extends obliquely upward has an outflow end and an inflow end that are formed in an R shape, and has three stirring blades. With the blade, the balance of the stirrer can be maintained, and even if the flowing floating filter medium comes into contact with the tip of the blade of the stirring blade, the filter medium is not damaged, and the life of the filter medium is prolonged.
Furthermore, the diameter of the stirrer that stirs the filter medium layer is 30 to 60% of the inner diameter of the filter tank, and the filter medium layer can be unraveled by flowing the water stored in the entire inside of the filter chamber.
The stirring blade that is fixed to the drive shaft is disposed at a height of 40 to 65% of the filtration chamber. By the rotation of the stirrer, the upward flow of the vertical swirl and the lower portion of the stirring blade are added to the upper portion of the stirring blade. To generate an upward flow of circulation. The upward flow of the vertical swirl generated by the rotation of the stirrer winds the filter medium at the bottom of the filtration chamber upward, circulates and flows the floating filter medium throughout the filtration chamber, and finely clogs cloggings. It is possible to prevent clogging of the screen on the washing drain side.

Upflow filtration apparatus according to the present invention, since the blade tip portion of the stirring blade of the stirrer was erected on the bottom of the tank and extending in the rotational direction behind the obliquely upward with respect to the drive shaft, horizontal in the water filtration chamber The lateral swirl flow in the direction and the upward flow in the vertical direction can be generated, and the cleaning effect is enhanced. The floating filter medium forming the filter medium layer is circulated and flowed, the flowing floating filter medium is collided, and the clogged material captured between the filter mediums is finely separated. Further, since the blade tip corners of the stirring blades inclined obliquely upward are formed in the R shape, the filter medium life can be extended without damaging the filter medium. Since there is little resistance due to the rotation of the stirring blade, the current value can be lowered, power can be reduced, and power consumption can be saved.

It is a longitudinal cross-sectional view of the filter using the floating filter medium which concerns on this invention. Similarly, it is a side view of a stirrer according to the present invention. Similarly, it is a top view of a stirrer. Similarly, it is a conceptual diagram of one stirring blade fixed to the drive shaft. Similarly, it is a longitudinal cross-sectional view of a filtration tank provided with a stirrer according to the present invention. It is a conceptual diagram which shows the flow state of the cleaning filter medium of the improved filter tank. It is a conceptual diagram which shows the flow state of the washing | cleaning filter medium of the conventional filter tank. It is a side view which compares the blade position of the stirring blade of the conventional stirrer, and the height of the reference stirring blade.

The stirrer of the filter using the floating filter medium according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of the filter using the floating filter medium according to the present invention, and the filter tank 1 is sealed. The filter chamber 2 in the filtration tank 1 contains a light filter medium 3 having a light specific gravity or a foamed filter medium 3 such as a granular foam filter medium, and the stock solution is supplied from a supply pipe 4 connected to the tank bottom 1a of the filter tank 1. Then, the filter medium layer 5 is formed in the filtration chamber 2. A cylindrical water collection nozzle 6 disposed in the upper part of the filtration chamber 2 is connected to a water collection pipe 7 connected to the top 1 b of the filtration tank 1, and treated water from which impurities are separated by the filter medium layer 5 is collected in the water collection pipe 7. Extract from.
A drive shaft 8 is erected in the filtration chamber 2 through the center of the tank bottom 1 a of the filtration tank 1, and a stirring blade 9 is fixed to the upper end portion of the drive shaft 8 to constitute a stirrer 10. When the floating filter medium forming the filter medium layer 5 traps and clogs impurities, the stirrer 10 is operated by the drive unit 11 disposed at the lower end of the drive shaft 8 to stir and wash the floating filter medium 3.

2 and 3 are a side view and a plan view of a stirrer according to the present invention, in which a corner 8c of an inflow end 9a and an outflow end 9b is formed in an R shape on a drive shaft 8 standing on a tank bottom 1a. The stirrer 10 having a flat plate shape is fixed, and the outflow end 9b of the stirring blade 9 is extended obliquely upward in the rearward direction of rotation with respect to the drive shaft 8 . The stirring blade 9 fixed to the drive shaft 8 has an inclination angle α of 30 ° to 40 °, and the stirrer 10 is disposed in the vicinity of the filter layer lower surface 5 a of the filter medium layer 5.
The stirring blade 9 swirling around the drive shaft 8 generates a swirling flow in the vertical direction by the differential pressure generated by rotating the stirrer stirring blade 9 simultaneously with the horizontal swirling horizontal flow. Specifically, the floating filter media 3... Below the filtration tank 1 are sucked by the inflow end 9 a of the stirring blade 9 and discharged from the outflow end 9 b of the stirring blade 9 to the upper side of the filtration tank 1 with speed. In the vicinity of the tank wall of the filtration tank 1, the floating filter media 3... Descend from the upper side to the lower side, and the floating filter medium 3. Vigorous turbulence occurs due to the horizontal and vertical swirling flows generated in the filtration tank 1, and the floating filter media 3... The stirrer 9 causes the sewage to flow, peels the clogged material trapped on the lower surface of the filter medium layer 5, crushes the contaminants trapped between the floating filter media 3 and 3, and regenerates the filter medium layer 5. Even when the floating filter medium 3 flowing is in sliding contact with the blade surface of the stirring blade 9, the R-shaped corners 9c of the inflow end 9a and the outflow end 9b do not damage the floating filter medium 3, and the filter medium life is long. Become.
As shown in FIG. 3, in the embodiment of the present invention, the stirring blade 9 fixed to the drive shaft 8 has three stirring blades 9, and the balance of the stirrer 10 can be maintained by the three stirring blades 9. .
FIG. 4 is a conceptual diagram of a single agitating blade fixed to the drive shaft. In the embodiment of the present invention, the inclination angle α of the agitating blade 9 fixed to the drive shaft 8 that generates the upward swirling flow is generated. Is set to α = 37.7 °.

FIG. 5 is a longitudinal sectional view of the filtration tank according to the present invention, and the stirring blade 9 fixed to the drive shaft 8 is disposed at 40 to 65% of the height H of the filtration chamber 2. The stirrer 10 generates a vertical swirling upflow due to the rotation of the stirring blades 9 in the upper part of the filtration chamber 2 and an upflow in the lower part of the filtration chamber 2, The floating filter 3 is wound upward to generate a vertical swirling flow that cuts the filtration chamber 2 vertically. At the same time, a horizontal horizontal swirling flow is generated in the vicinity of the stirring blade 9.
In the embodiment of the present invention, the blade tip of the stirring blade 9 is disposed below the filter layer lower surface 5 a of the filter medium layer 5 by h = 126 mm.
As shown in FIG. 6, the contaminants trapped between the floating filter media 3 and 3 by unraveling the filter media layer 5 by flowing the sewage in the entire inside of the filtration chamber 2 by the upward flow and horizontal flow caused by the rotation of the stirring blade 9. The filter media layer is regenerated by finely peeling the filter media.
When the filter medium layer 5 of the floating filter medium 3 is clogged, the filter tank 1 shown in FIG. 5 rotates the stirrer 10 while supplying wash water from the water collection nozzle 6 at the top of the filter tank 1 to form the filter medium layer 5. The floating filter medium 3... Is flowed, the clogged material trapped on the filter layer lower surface 5 a is peeled off, the foreign matter trapped between the floating filter media 3 and 3 is crushed to regenerate the filter medium layer 5, and raw water Washing waste water is discharged from the supply pipe 4. The opening of the supply pipe 4 and the outflow of the floating filter media 3 ..., the screen to prevent the inflow of such residue in the filtration chamber 2 (not shown) Yes and stretched, by the flow of washing wastewater, supply The clogging of the screen stretched around the tube 4 is also prevented.

In the conventional filter medium agitation apparatus using the floating filter medium of Patent Document 1, the agitator is extended to the vicinity of the filter medium layer with the blade diameter being the same as the diameter of the filtered water outlet. A conventional testing machine for performing a comparative test has the following specifications.
Body tank height 1900mm
Body tank inner diameter φ850
Filtration area 0.56m ²
Stirrer power 3.7 kW
Operating current value 15A
Rated current 16A (200V)
Using this conventional filter media stirrer, wash water is supplied from the water collection side at the top of the filtration tank, and the stock solution supply side at the bottom is washed for the position, blade shape, blade diameter, and rotation speed of the stirrer. The stirrer was tested while discharging the waste water.

The filter medium layer was confirmed to be washed with the stirring device of the above-mentioned tester specification at a rotation speed of 504 rpm.
As shown in FIG. 7, the flow of the floating filter medium forming the filter medium layer in the filtration chamber was observed, but the movement of the filter medium at the top of the filter chamber was only a horizontal swirling flow, and the upper and lower circulating flows were hardly observed. It was. In order to cause the filter medium to flow up to the upper part of the filtration tank with a conventional stirring device, it is necessary to increase the stirring power and increase the rotational speed.
Further, when the rotational speed is decreased from 504 rpm to 390 rpm, the current value decreases from 15.0 A to 12.2 A, but the flow of the floating filter material in the upper part of the filtration chamber becomes extremely poor, and the cleaning efficiency is lowered.

In order to swirl the filter medium in the upper part of the filtration chamber not only in the horizontal direction as shown in FIG. 7 but also in the vertical direction, the blade shape was examined.
As shown in FIGS. 2 and 3, the three plate-like stirring blades 9 that extend the slanting blade 9 at the outflow end 9 b obliquely upward in the rotational direction with respect to the drive shaft 8 are fixed to the drive shaft 8. And the stirrer 10 of this invention was comprised.
Using the stirrer 10 of the present invention in the filter tank of the above tester specification,
・ The specification of the blade diameter, blade height position, and rotation speed was changed, and the fluidity, stirring power, current value, and filter medium life of the floating filter medium 3 by stirring the filter medium were examined. A comparative test was conducted.

First, the blade diameter d of the stirrer 10 of the present invention was comparatively examined using φ290, φ320, φ400, and φ500.
Table 1 is a performance comparison of the rotational speed and current value depending on the blade diameter d of the stirring blade 9 of the stirrer 10 of the present invention. The result shows that the larger the blade diameter d of the stirring blade 9 is, the floating filter medium 3. The flow of .. was improved, and as shown in Table 1, it was possible to reduce the rotational speed and the current value.

Using the stirrer 10 of the present invention in which the blade diameter d of the stirring blade 9 is φ290, the blade position of the conventional stirrer 417 mm below the filter layer lower surface 5a forming the filter medium layer 5 and the filter layer lower surface 5a are placed close to each other. The performance was compared with the blade position.
The closer the stirrer 10 of the present invention is to the filter layer lower surface 5a, the better the movement of the floating filter medium 3 ... in the upper part of the filtration chamber 2 forming the filter medium layer 5, but the floating filter medium 3.・ ・ The fluidity of This is because if the stirrer 10 of the present invention is disposed above the filtration chamber 2, the vertical swirling flow generated by the stirrer 10 cannot be applied to the lower portion of the filtration chamber 2.
FIG. 8 is a side view for comparing the height of the reference stirring blade 9 and was installed at a position 292 mm higher than the height of the conventional stirrer (126 mm below the filter layer lower surface 5 a of the filter medium layer 5). By installing the blade position of the stirring blade 9 at a position 292 mm higher than the height of the conventional stirrer, the stirrer 9 in which the outflow end 9b of the stirring blade 9 extends obliquely upward is shown in FIG. A horizontal swirling flow is allowed to act on the upper floating filter medium 3... And a vertical swirling flow is generated in the entire filtration tank 1, and the entire filtration chamber 2 is allowed to flow, so that the floating filter medium 3 can be washed efficiently. Was confirmed.

The filter media was continuously washed with the blade diameter d of the conventional agitator and the agitator blade 9 of the agitator 10 of the present invention being φ290, φ320, φ400, and φ500, and the wear test of the filter media during the washing was confirmed.
Table 2 shows a cumulative ratio of the amount of waste filter material on the drain side, where the vertical axis represents the ratio (%) of the total weight of the filter medium residue to the initial weight, and the horizontal axis represents the number of times of washing (times). The filter medium residue is a contaminant in which a part of the filter medium is damaged or peeled off when the floating filter medium 3 is washed.
When the stirring blade 9 of the stirrer 10 of the present invention has a blade diameter d of φ400 and the rotational speed is 300 rpm, the floating filter medium 3 is least worn, and the cumulative ratio is about 1/2 compared with the conventional stirrer. The following wear occurred. Therefore, it was confirmed that the life of the floating filter medium 3 was prolonged.

Table 3 shows the results of performance comparison between the conventional stirrer having the same cleaning effect and the stirrer 10 of the present invention. When the blade diameter d of the stirrer 10 of the present invention is φ400, the floating filter medium 3 at the time of cleaning the filter medium The movement of... Is also good, and the use power can be reduced by extending the rotation speed of the stirrer 10, and the life of the filter medium can be extended.

A stirrer for a filter using a floating filter medium according to the present invention has a plurality of plate-like stirring blades fixed to a drive shaft erected on the bottom of a tank, and the blade tip portion of the stirring blade is rotated with respect to the drive shaft. Since the agitator is configured to extend diagonally upward in the rear direction, it is possible to circulate and flow the filter medium forming the filter medium layer through the entire filtration chamber by generating a swirling flow in the horizontal direction and the vertical direction. It is high, does not damage the floating filter medium, and the resistance of the stirring blade is small, so that power can be reduced.
Therefore, it can be applied to a filtration device for treating sewage and industrial wastewater generated at a sewage treatment plant or purifying lakes, rivers, etc., and enables high-speed filtration and microfiltration.

DESCRIPTION OF SYMBOLS 1 Filtration tank 2 Filtration chamber 1a Tank bottom 1b Top part 3 Floating filter medium 5 Filter medium layer 5a Filter layer lower surface 8 Drive shaft 9 Stirring blade 9a Inlet end 9b Outlet end 9c Corner 10 Stirrer D Inner diameter d Diameter H Height α Inclination angle

Claims (5)

In a filtration apparatus for supplying a stock solution to a sealed filtration tank (1) containing a floating filter medium (3 ...) and performing solid-liquid separation with a filter medium layer (5) of the floating filter medium (3 ...) A plurality of flat stirring blades (9...) Are fixed to the drive shaft (8) standing on the bottom (1a), and the outflow end (9b) of the stirring blade (9) is attached to the drive shaft (8). On the other hand, a filter using a floating filter medium, which extends obliquely upward to the rear of the rotation direction to constitute a stirrer (10) and is arranged in the vicinity of the filter layer lower surface (5a) of the filter medium layer (5). Stirring device. The floating filter medium according to claim 1, wherein the stirring blade (9) which is fixed to the drive shaft (8) and extends obliquely upward has an inclination angle (α) of 30 ° to 40 °. A stirrer for a filter using a filter. The stirring blade (9) which is fixed to the drive shaft (8) and extends obliquely upward has an inflow end (9a) and an outflow end (9b) formed in an R shape, and has three stirring blades ( The stirrer for a filter using the floating filter medium according to claim 1 or 2, characterized in that 9). The floating filter medium according to any one of claims 1 to 3, wherein a diameter (d) of the agitator (10) is 30 to 60% of an inner diameter (D) of the filtration chamber (2). The filter stirrer used. The stirring blade (9) fixed to the drive shaft (8) is arranged at 40 to 65% of the height (H) of the filtration chamber (2). A stirrer for a filter using the floating filter medium according to Item 1.