JPH0975613A - Vertical drum screen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vertical drum screen excellent in treatment efficiency by using a cylindrical screen by vertically providing the cylindrical screen in raw water to be treated and permeating the raw water through the screen. SOLUTION: A cylindrical filter screen 4 is arranged in a treatment tank 1 so that the center axial line thereof is made almost vertical. A screw blade 7 generating rising force by rotational driving is arranged in the screen 4 so as to revolve in close vicinity to the inner peripheral surface of the screen 4. A supply pipe 20 supplying raw water to be treated into the screen 4 is connected to the tank 1 and the filtrate discharge pipe 21 communicating with the outer periphery of the screen 4 is connected to the tank 1 at predetermined height. Further, a discharge port 6 is formed to the place corresponding to the upper end of the screw blade 7 of the screen and higher than the discharge pipe 21 to be connected to a discharge chute 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for performing solid-liquid separation treatment on wastewater containing fiber and solids such as domestic wastewater.

[0002]

2. Description of the Related Art Wastewater of this type contains a large amount of solids mainly composed of fibers. Therefore, for the solid-liquid separation treatment, it is necessary to simultaneously remove and discharge the separated solids. There is. As a device therefor, the present applicant has already proposed a rotary drum screen according to Japanese Utility Model Laid-Open No. 7-9409. The structure is briefly described.Wedge wires of triangular cross section are arranged in parallel with a minute interval to form a drum, and the drum is rotatably supported so that its central axis is horizontal and It is configured to supply treated raw water to. As the treated raw water passes through the drum, solids such as fibers are captured by the drum, but since the drum is rotating, sludge-like solids are lifted by the rotation of the drum, and then the inner peripheral surface of the sludge is collected. Roll down along. The solid content captured by the drum repeats the above-mentioned rise and rolling fall due to the rotation of the drum, whereby the solid content gradually grows larger. In addition, the wedge wire, which is the material for the drum, is set in a state in which the wedge wire is inclined at a predetermined angle with respect to the axial direction of the drum, so that the solid content that repeatedly rolls and drops is gradually moved in the axial direction of the drum, and finally, the drum. It is discharged from the end of the.

[0003]

Therefore, in the above-mentioned conventional apparatus, about 1/3 of the lower side of the horizontally installed drum is set.
Will function as a substantial filtering surface. Further, since the solid content captured by the drum needs to be rolled and dropped, the rotation speed of the drum is, for example, 12 to 16 rpm.
Limited to low rpm. Therefore, in the above-mentioned conventional apparatus, since the ratio of the substantial filtration area is small and the rotation speed of the drum is low, the processing amount per unit time is small. Therefore, in order to increase the throughput,
It is necessary to increase the diameter and the axial length of the drum, resulting in inconveniences such as an increase in the size of equipment and an increase in cost.

Further, the solid content captured by the drum increases as it repeatedly rolls and falls as described above, and is moved in the axial direction of the drum to be removed, but it remains attached to the drum to some extent. So need drum cleaning. In the above-mentioned conventional apparatus, since the treated raw water is configured to pass through in the radial direction of the drum for filtration, the solid content adheres to the drum relatively firmly. Therefore, in cleaning the drum, high-pressure cleaning water and high-pressure air are sprayed from the outer peripheral side of the drum, which results in the problem that a pump and a compressor are required and the running cost increases.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a vertical drum screen which uses a cylindrical screen and is excellent in processing efficiency.

[0006]

Means and Actions for Solving the Problems
In order to achieve the above object, a cylindrical filtration screen is installed inside the processing tank with its central axis oriented substantially vertically, and is rotatably driven inside the filtration screen to raise the lifting force. A screw blade for generating the water is disposed so as to swirl close to the inner peripheral surface of the filtration screen, and a supply pipe for supplying raw treatment water to the inside of the filtration screen is provided to be connected to the treatment tank. In addition, a filtrate discharge pipe communicating with the outer peripheral side of the filtration screen is provided at a position of a predetermined height of the processing tank, and at a location corresponding to the upper end portion of the screw blade of the filtration screen. A discharge port is formed at a position higher than the filtrate discharge pipe, and a discharge chute for guiding the solid content dropped from the discharge port to the outside of the processing tank is provided. And it is characterized in that is.

Therefore, in the present invention, the filtration screen is immersed in the treated raw water supplied to the treatment tank, and the treated raw water supplied to the inside of the filtration screen moves the screen from the inner surface side to the outer surface side. The solid content contained in the treated raw water is captured by the screen by passing to the screen. Therefore, the solid content corresponding to the size of the mesh of the screen is removed from the filtrate flowing into the filtrate discharge pipe connected to the outer peripheral side of the filtering screen. That is, since filtration occurs in the entire portion immersed in the treated raw water, the filtration area is widened and the treatment efficiency is improved.

On the other hand, the screw blades are swirling on the inner surface side of the filtration screen, so that the solid content deposited on the screen is pushed upward by the screw blades, and finally passes through the discharge chute and a predetermined location. Sent to. In particular, when a protrusion is formed on the outer peripheral portion of the screw blade as described in claim 2, solids such as fibers adhere and deposit on the protrusion, which causes the inner peripheral surface of the filtration screen to be deposited. As it rubs and acts like a brush, solids can be removed from the screen more efficiently. Therefore, the cycle of cleaning the filter screen becomes long, and the cleaning operation is simplified.

Further, according to a third aspect of the present invention, a communication pipe communicating with the inner bottom of the filtration screen is provided.
The filtrate discharge pipe is disposed at a position higher than the connection portion to the treatment tank, and the overflow port is formed at a predetermined position in the up-down direction of the communication pipe. Since it rises and overflow occurs, clogging of the screen can be known by the overflow from the communication pipe.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described more specifically with reference to the drawings. FIG. 1 is a vertical side view specifically showing an example of a drum screen according to the present invention, in which a cylindrical processing tank 1 is erected on a base 3 via a base frame pipe 2. Its base frame tube 2
Is a pipe-shaped member having a diameter smaller than that of the processing tank 1,
The lower end of the processing tank 1 is joined to the flange formed on the upper end thereof.

Inside the processing tank 1, a cylindrical screen 4 is arranged on the same axis. As shown in FIG. 2, the screen 4 is formed by arranging wedge wires 4a having a triangular cross section in a cylindrical shape, and has a length substantially the same as that of the processing tank 1.

The lower end of the screen 4 is joined to the upper end of the base frame pipe 2 or its flange so as to communicate with the base frame pipe 2, and the upper end thereof is attached to the upper end of the processing tank 1. It is joined to the top plate 5. Therefore, the inside of the processing tank 1 is formed in a double cylindrical shape. A discharge port 6 is formed in the vicinity of the upper end of the screen 4 by cutting out a part thereof.

Inside the cylindrical screen 4 described above,
The screw blades 7 having an outer diameter slightly smaller than the inner diameter are arranged on the same axis. The screw blade 7 is formed on the outer peripheral surface of a cylindrical body 8 having a diameter smaller than that of the screen 4 and arranged on the same axis. The screw blade 7 is rotated along the inner peripheral surface of the screen 4 by rotating the cylindrical body 8. It is configured to turn.

That is, support plates 9 and 10 extending in the radial direction are attached to each of the upper end and the lower end inside the cylindrical body 8, and the support shaft 1 is provided at the center of the support plate 9 on the lower end side.
1 is integrally mounted, and a bearing 12 for rotatably supporting a support shaft 11 is provided on the upper portion of the base 3.
Is provided. On the other hand, at the center of the support plate 10 on the upper end side, a rotary shaft 13 is integrated so as to project upward, and the rotary shaft 13 is rotatably supported by a bearing 14 attached to the top plate 5. The sprocket 15 is integrally attached to the upper end portion.

The upper part of the outer surface of the processing tank 1 is
A geared motor 16 having an output shaft directed upward is attached, and a sprocket 17 integrated with the output shaft is provided.
The sprocket 15 attached to the rotating shaft 13 is connected by a chain 18. That is, the screw blade 7 is rotated by the geared motor 16. The rotation direction is the direction in which the screw blade 7 generates a pushing force (arrow direction in FIG. 3).

The screw blade 7 has a cylindrical body 8
Is provided between the lower end of the screen 4 and the height of the discharge port 6 of the screen 4. An auxiliary screw blade 19 having a lead angle opposite to that of the screw blade 7 is attached to the outer peripheral surface of the upper end portion of the cylindrical body 8.

A minute projection 7a is formed on the outer periphery of the screw blade 7. As the shape of the protruding portion 7a, various shapes can be adopted as needed, and several examples thereof are shown in FIGS. 5 to 8. That is, in the example shown in FIG. 5, the outer peripheral portion of the screw blade 7 is cut into a rectangular shape. Further, FIG. 6 shows a saw-toothed protrusion 7a formed by cutting the outer peripheral portion of the screw blade 7 obliquely with respect to the radial direction. Further FIG.
Shows a protrusion 7a formed by cutting the outer peripheral portion of the screw blade 7 in a V-shape in the radial direction. And FIG.
Shows an example in which the projecting portion 7a is formed by pins standing on both upper and lower surfaces of the outer peripheral portion of the screw blade 7.

A treated raw water supply pipe 20 is connected to the base frame pipe 2. On the other hand, a filtrate discharge pipe 21 is connected to the processing tank 1 at a predetermined height. That is, the treated raw water is supplied from the treated raw water supply pipe 20 to the inside of the screen 4, and the filtrate passing through the screen 4 is discharged from the filtrate discharge pipe 21 to a predetermined location.

The filtrate discharge pipe 21 is connected to the upper end of the screw blade 7, that is, at a position slightly lower than the discharge port 6 in the screen 4. A discharge chute 22 is connected to the discharge port 6 of the screen 4. The discharge chute 22 is a tubular member,
It penetrates the peripheral wall of the processing tank 1 and extends to the outside of the processing tank 1 from the discharge port 6.

A drain pipe 24 having a drain valve 23 is connected to the bottom of the base frame pipe 2. A deodorizing pipe 25 is connected to the upper end of the processing tank 1. A communication pipe 26 that connects the deodorizing pipe 25 and the drain pipe 24 is provided. This communication pipe 2
An overflow portion 27 is provided in the middle portion of 6. The overflow portion 27 is for adjusting the liquid level height inside the screen 4, and for example, one of the chambers divided into two chambers by a slide plate 28 having an opening as shown in FIG. Communication pipe 26
, And the other end is connected to a predetermined storage part (not shown) through the outflow port 29. Therefore, by moving the slide plate 28 up and down to change the height of the opening, the liquid level inside the communicating pipe 26, that is, the liquid level inside the screen 4 communicating with this is adjusted. It is like this.

Next, the operation of the above-mentioned drum screen will be described. When the treated raw water is supplied from the raw water supply pipe 20 with the drain valve 23 closed, the treated raw water is fed from the inside of the base frame pipe 2 into the inside of the screen 4. The treated raw water supplied to the inside of the screen 4 passes through the screen 4 and also spreads to the inside of the treatment tank 1. However, due to the pressure loss due to the screen 4, the liquid level inside the screen 4 is It will be slightly higher than the liquid level. On the outside of the screen 4, the liquid level rises to the vicinity of the place where the filtrate discharge pipe 21 is connected,
As a result, the lower part of the screen 4 is immersed in the treated raw water and the filtrate.

A part of the treated raw water supplied to the inside of the screen 4 rises inside the screen 4 as it is,
The other part flows so as to traverse the screen 4 from the inner peripheral side to the outer peripheral side or from the outer peripheral side to the inner peripheral side by the flow accompanying the continuous supply of the treated raw water. In that case, since the solid content contained in the treated raw water cannot pass through the screen 4, it is captured by the screen 4,
On the outside, the filtrate from which the solid content has been removed is present. In that case, since the pressure difference between the inside and the outside of the screen 4 is zero, the solid content contained in the treated raw water is not pressed firmly against the screen 4, and there is no particular cause for clogging.

On the other hand, the treated raw water that has risen inside the screen 4 as it is finally passes through the screen 4 from the inner peripheral side to the outer peripheral side and is filtered, and the solid content contained therein is captured by the screen 4. It The filtrate from which the solid content has been removed in this manner is sent out from the filtrate discharge pipe 21.

The screw blade 7 is rotationally driven by the geared motor 16 while the filtration is performed as described above. As described above, the rotation direction is the direction in which the screw blade 7 generates a pushing-up force, and since the outer peripheral edge of the screw blade 7 is extremely close to the inner peripheral surface of the screen 4, the solid matter captured by the screen 4 is Minutes are pushed upward by this screw blade 7. In this case, if the protrusion 7a is formed on the outer peripheral portion of the screw blade 7, the protrusion 7a is entangled with the solid content mainly composed of the fibers contained in the treated raw water. Gradually solidifies the gap between the clew blade 7 and the inner peripheral surface of the screen 4, and as a result, the fiber component deposited on the protrusion 7a or the fiber component and the solid component are accumulated in the screen 4. Acts as a brush that rubs the peripheral surface. Therefore, the solid content captured by the screen 4 is sent upward while being peeled off by the fiber content and solid content attached and deposited on the protrusion 7a.

The solid content thus sent upward is
Finally, it is sent out from the upper end portion of the screw blade 7 to the discharge port 6 in the screen 4, and then discharged from the discharge chute 22 to a predetermined position. That is, the screw blades 7 carry out the solid content captured by the screen 4 to the outside, and at the same time, the clogging of the screen 4 is eliminated.

Further, since the communication pipe 26 communicates with the inside of the screen 4 through the base frame pipe 2 and the drain pipe 24, the liquid level inside the communication pipe 26 is the same as that inside the screen 4. It matches the height of the liquid surface. In other words, the liquid level inside the screen 4 is equal to or lower than the liquid level set by the slide plate 28 in the overflow portion 27 to which the communication pipe 26 is connected.

When the screen 4 becomes clogged as a result of continuing the filtration as described above, the pressure loss in the screen 4 gradually increases, and the liquid level inside the screen 4 gradually increases. At the same time, the liquid level inside the communication pipe 26 also gradually increases. As a result, when the liquid level reaches the liquid level set by the slide plate 28, the raw treated water overflows from the opening formed in the slide plate 28 and leaks to the outside. Therefore, if the raw treated water overflows in the overflow portion 27, it can be known that the clogging of the screen 4 has progressed to a certain extent. In that case, the supply of the treated raw water is stopped, the drain valve 23 is opened to drain the treated raw water from the inside of the treatment tank 1, and the screen 4 is washed. As described above, the solid content captured by the screen 4 is pushed up by the screw blades 7 and discharged to the outside. Therefore, the screen 4 is less likely to be clogged, and therefore the cleaning frequency of the screen 4 is extremely low. Will be things.

In the above-mentioned example, the screw blade 7 is configured to be driven at its upper end portion via the geared motor 16 and the chain 18, but in the present invention,
The drive type of the screw blades 7 can be any type as required, and is not limited to the one shown in the above example. Further, the cylindrical screen is not limited to the one configured by the wedge wire described above, and may be formed by an appropriate mesh material.

[0029]

As described above, according to the present invention,
Since a cylindrical screen is erected in the treated raw water and the treated raw water is allowed to permeate through the screen in that state, the entire circumference of the screen functions as a filtering surface, and at the same time, the entire circumference of the screen is filtered simultaneously. Therefore, according to the present invention, it is possible to secure a wide filtration surface by the small cylindrical screen and perform the solid-liquid separation treatment efficiently. Further, in the present invention, since the solid content in the treated raw water is captured by the screen without causing a pressure difference between the inside and the outside of the cylindrical screen, clogging of the screen is unlikely to occur,
Moreover, by swirling the screw blades on the inner peripheral side of the screen, the solid content on the inner peripheral surface side of the screen is sent upward, preventing clogging of the screen and keeping the frequency of screen cleaning extremely low. As a result, running costs can be reduced.

Further, the drum screen of the present invention has a small installation area required for so-called vertical placement, is space efficient, and takes out solid contents from the upper portion of the processing tank to the outside. When the solid content is dehydrated, there is an advantage that supply of the solid content to the dehydration equipment and installation of the dehydration equipment will be easier than ever before.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example embodying the present invention.

FIG. 2 is a partial cross-sectional view for explaining an arrangement of wedge wires forming a screen.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a side view with a partial cross section showing the structure of the overflow portion.

FIG. 5 is a partial view showing an example of a protrusion formed on a screw blade.

FIG. 6 is a partial view showing another example of a protrusion formed on a screw blade.

FIG. 7 is a partial view showing still another example of the protrusion formed on the screw blade.

FIG. 8 is a partial view showing an example of a protrusion formed by a pin formed on a screw blade.

[Explanation of symbols]

 1 Treatment Tank 4 Screen 6 Discharge Port 7 Screw Blade 16 Geared Motor 20 Treated Raw Water Supply Pipe 21 Filtrate Discharge Pipe 22 Discharge Chute 26 Communication Pipe 27 Overflow Part

Claims (3)

[Claims] 1. A screw for installing a cylindrical filter screen inside a processing tank with its central axis oriented substantially vertically, and being rotationally driven to generate an ascending force inside the filter screen. The blades are arranged so as to swirl close to the inner peripheral surface of the filtration screen, and a supply pipe for supplying raw treatment water into the filtration screen is connected to the treatment tank, and A filtrate discharge pipe communicating with the outer peripheral side of the filtration screen is provided at a predetermined height position of the processing tank, and the filtrate discharge pipe is provided at a position corresponding to the upper end of the screw blade of the filtration screen. A special feature is that a discharge port is formed at a higher position and a solid discharge chute that guides the solid content falling from the discharge port to the outside of the processing tank. A vertical drum screen to be used. 2. The vertical drum screen according to claim 1, wherein a protrusion is formed on an outer peripheral portion of the screw blade. 3. A communication pipe communicating with the inner bottom portion of the filtration screen is disposed so as to extend to a position higher than a connection portion of the filtrate discharge pipe to the processing tank, and the communication pipe is provided at a predetermined position in the vertical direction. The vertical drum screen according to claim 1 or 2, wherein an overflow port is formed.