JP7836712B2 - Scum removal device - Google Patents

Description

This invention relates to a scum removal device.

In sewage treatment plants, scum removal devices are installed in treatment tanks such as sedimentation tanks to remove scum (dust, debris, lipids, etc. that float on the water surface and have a specific gravity less than water). The scum removal device includes a pipe skimmer positioned so that a portion of it is submerged in the sedimentation tank. The pipe skimmer is formed in a cylindrical shape with its axial direction aligned with the liquid surface (see, for example, Patent Document 1 below). The pipe skimmer has an opening that opens radially. The pipe skimmer is configured to be rotatable around its axis between a recovery position where a portion of the opening is submerged in water and an open position where the entire opening is open to the outside air.
In this configuration, moving the pipe skimmer to the collection position allows scum to flow into the pipe skimmer through the opening. The scum that flows into the pipe skimmer flows axially through it before being discharged from the treatment tank.

Japanese Patent Publication No. 2009-291728

Incidentally, in pipe skimmers, the circumferential ends of the opening are connected by a joint to increase the strength of the pipe skimmer itself. Therefore, when scum is collected, if the pipe skimmer is moved to the collection position, the scum around the joint is blocked by the joint, making it difficult for it to flow into the pipe skimmer. In conventional scum removal devices, removing the scum accumulated around the joint requires manual work, indicating that there is still room for improvement in terms of maintainability.

This invention provides a scum removal device that can improve maintainability.

To address the above issues, this disclosure adopts the following characteristics.
(1) A scum removal device according to one aspect of the present disclosure comprises a pipe skimmer formed in a cylindrical shape with its axial direction oriented along the liquid surface and a portion of which is immersed in the liquid, the pipe skimmer having an opening that opens radially, and a pipe body provided so as to be rotatable around an axis along the liquid surface between a recovery position where a portion of the opening is located in the liquid and an open position where the entire opening is open to the outside air, a connecting portion connecting portions of the opening that face each other in the circumferential direction around the axis, and a protruding portion provided at a position that overlaps the connecting portion when viewed from the radial direction, protruding radially outward from the pipe body, and at least a portion of which is located in the liquid at the recovery position, the protruding portion is provided with a guide wall that gradually increases the axial dimension of the protruding portion as it moves from the outside to the inside in the radial direction.

According to this embodiment, when the pipe skimmer is moved to the recovery position, the scum accumulated around the connection can be guided along the outer surface of the protruding part to the opening. This allows for efficient scum recovery and improves maintainability.

(2) In the scum removal device according to the embodiment of (1) above, it is preferable that the protruding portion is detachably attached to the pipe body.
According to this embodiment, since a protrusion can be attached to an existing pipe gap, it is possible to improve maintainability while suppressing an increase in equipment costs.

(3) In a scum removal device according to the embodiment of (1) or (2) above, the guide wall comprises a first guide wall extending toward the second axial side from a portion located on the first axial side with respect to the connection portion toward the radially outward side, and a second guide wall extending toward the first axial side from a portion located on the second axial side with respect to the connection portion toward the radially outward side, wherein the protruding portion is preferably formed in a triangular shape in which the radially outward ends of the first guide wall and the second guide wall are connected to each other.
According to this embodiment, the scum accumulating around the connection point is more easily guided to the parts of the opening located on both sides of the connection point in the axial direction. This allows for more efficient scum recovery.

According to each of the above embodiments, maintainability can be improved.

This is a schematic diagram of the scum removal device. This is a cross-sectional view corresponding to line II-II in Figure 1, showing the pipe gap in the open position. This is a view from arrow III in Figure 2. This is a cross-sectional view corresponding to Figure 2, which shows the state of the pipe gap at the retrieval position. This is a plan view corresponding to Figure 3, which shows the state of the pipe gap at the retrieval position. This is a plan view corresponding to Figure 3, which shows a modified example. This is a plan view corresponding to Figure 3, which shows a modified example. This is a plan view corresponding to Figure 3, which shows a modified example. This is a plan view corresponding to Figure 3, which shows a modified example. This is a cross-sectional view corresponding to Figure 2, which is a modified example.

Next, embodiments of the present invention will be described based on the drawings. In the embodiments and modifications described below, corresponding components may be denoted by the same reference numerals and their descriptions may be omitted. In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," not only strictly represent such arrangements but also represent states where relative displacement occurs within tolerances or angles and distances sufficient to achieve the same function. Furthermore, in this embodiment, "facing each other" includes not only cases where the orthogonal directions (normal directions) of the two surfaces coincide, but also cases where the orthogonal directions intersect.

[Scum Removal Device 1]
Figure 1 is a schematic diagram of the scum removal device 1.
As shown in Figure 1, the scum removal device 1 is installed in a treatment tank 2, such as a sedimentation tank, at a sewage treatment plant. The scum removal device 1 is equipped with a pipe skimmer 10.

<Pipe Skimmer 10>
The pipe skimmer 10 collects scum S floating on the liquid surface of the treatment tank 2 and discharges the collected scum S from the treatment tank 2. The pipe skimmer 10 is installed in the part of the treatment tank 2 located downstream in the direction of the treated water flow.

The pipe gap 10 comprises a pipe body 20, a connecting portion 21, and a protruding portion 22.
The pipe body 20 is formed in a cylindrical shape with its axial direction intersecting (perpendicular to) the flow direction and along the liquid surface of the treated water. The pipe body 20 is placed in the treatment tank 2 with a portion of it immersed in the treated water. In the illustrated example, the axis O of the pipe body 20 is located below the liquid surface. An opening 20a is formed in a portion of the pipe body 20 in the circumferential direction. The opening 20a penetrates the pipe body 20 radially and extends in the axial direction. The angle between the axis O of the pipe body 20 and both ends of the opening 20a in the circumferential direction (first end 20b and second end 20c) (the central angle of the opening 20a) is set to, for example, 90° or less. Note that the pipe body 20 may be a cylindrical shape other than a cylindrical shape (for example, a rectangular tube) as long as it is formed in a cylindrical shape with its axial direction along the liquid surface.

The pipe skimmer 10 is configured to rotate around axis O by a rotation mechanism (not shown). Specifically, the pipe skimmer 10 rotates between a recovery position where a portion of the opening 20a is submerged in liquid (see Figure 4) and an open position where the entire opening 20a is exposed to the outside air (see Figure 2).

Figure 2 is a cross-sectional view corresponding to the line II-II in Figure 1. Figure 3 is a view taken along arrow III in Figure 2.
As shown in Figures 2 and 3, the connecting portion 21 is a reinforcing member of the pipe body 20. The connecting portion 21 connects the two opposing ends 20b and 20c of the opening 20a in the circumferential direction. Therefore, the connecting portion 21 partitions the opening 20a in the axial direction. The connecting portion 21 is formed in an arch shape with a radius of curvature equal to that of the pipe body 20. In this embodiment, the connecting portion 21 is formed integrally with the pipe body 20. However, the connecting portion 21 may be formed separately from the pipe body 20. The connecting portion 21 may connect the first end 20b and the second end 20c in a straight line. Furthermore, the connecting portion 21 may extend in a direction intersecting the circumferential direction or be formed in a grid shape.

Multiple connection sections 21 are provided at intervals in the axial direction. Therefore, the opening 20a is divided into multiple sections in the axial direction. The spacing between adjacent connection sections 21 may be equal or different.

The protruding portions 22 are positioned to overlap with each connecting portion 21 when viewed from the radial direction. Each protruding portion 22 is detachably attached to the pipe body 20. Each protruding portion 22 has a similar configuration. Therefore, in the following description, the configuration of one protruding portion 22 will be explained using that as an example. Note that the protruding portions 22 may be provided corresponding to each connecting portion 21, as in this embodiment, or they may be provided corresponding to only one of the connecting portions 21.

The protruding portion 22 comprises a stay 31 and a protruding portion body 32.
The stay 31 is attached to the first end 20b of the pipe body 20 so as to straddle the connecting portion 21 in the axial direction. The stay 31 comprises a base portion 31a and a hook portion 31b.

The base portion 31a extends axially along the outside of the pipe body 20, parallel to the first end portion 20b. As shown in Figure 3, the base portion 31a straddles the connecting portion 21 in the axial direction. As shown in Figure 2, the base portion 31a straddles the first end portion 20b in the direction along the tangent line L passing through the first end portion 20b on the outer surface of the pipe body 20 when viewed from the axial direction (hereinafter simply referred to as the tangential direction).

As shown in Figures 2 and 3, the hook portions 31b are formed at both axial ends of the base portion 31a. Each hook portion 31b is formed in an L-shape when viewed from the axial direction. Each hook portion 31b extends radially inward from one tangential end of the base portion 31a, and then extends tangentially to the other end. That is, each hook portion 31b crosses the first end 20b, passes through the opening 20a, and then wraps around to the inside of the pipe body 20. A fastening member 35, such as a bolt, is provided at the tip of each hook portion 31b (the portion located inside the pipe body 20). The tip of the fastening member 35 penetrates the hook portion 31b and is pressed against the inner circumferential surface of the first end 20b. As a result, the first end 20b is sandwiched between the base portion 31a and the tip of the fastening member 35, and the protruding portion 22 is fixed to the pipe body 20. Note that the method of fixing the protruding portion 22 to the pipe body 20 can be changed as appropriate.

The protruding portion body 32 is fixed to the base portion 31a, protruding radially outward from the pipe body 20. The protruding portion body 32 comprises two guide walls (a first guide wall 41 and a second guide wall 42). The protruding portion body 32 is formed in an isosceles triangular shape, open to both sides in the tangential direction (circumferential direction), by the combination of the guide walls 41 and 42 with the base portion 31a. Note that the protruding portion body 32 may also be configured so that at least one opening in the circumferential direction is closed.

As shown in Figure 3, the radial inner end of the first guide wall 41 is fixed to the axial first side end of the base portion 31a. The first guide wall 41 extends radially outward, inclined toward the axial second side. The radial inner end of the first guide wall 41 is located at least axially to the first side (outside) of the connection portion 21. On the other hand, the radial outer end of the first guide wall 41 is positioned at the same axial position as the axial center of the connection portion 21.

The second guide wall 42 is formed symmetrically to the first guide wall 41, with respect to the axial center of the base portion 31a. Specifically, the radial inner end of the second guide wall 42 is fixed to the axial second side end of the base portion 31a. The second guide wall 42 extends inclined toward the axial first side as it extends radially outward. The radial inner end of the second guide wall 42 is located at least axially second (outside) of the connection portion 21. On the other hand, the radial outer end of the second guide wall 42 is positioned at the same axial position as the axial center of the connection portion 21.

The radial outer ends of each guide wall 41 and 42 are connected by welding or the like. In the example shown in Figure 3, the angle θ between each guide wall 41 and 42 is approximately 30°.

As shown in Figure 2, when viewed from the axial direction, both tangential ends of the protruding body 32 (each guide wall 41, 42) are located on either side of the base portion 31a. At the retrieval position shown in Figure 4, one tangential end of the protruding body 32 is located between the first end 20b and the uppermost end of the pipe body 20. On the other hand, the other tangential end of the protruding body 32 is located at the same position as the lowermost end of the pipe body 20.

In this embodiment, the protruding part body 32 is designed to move in and out of the treated water as the pipe skimmer 10 rotates between the recovery position and the open position. Specifically, when the pipe skimmer 10 is in the open position, at least the tip (radially outer end) of the protruding part body 32 is located above the water surface. On the other hand, when the pipe skimmer 10 is in the recovery position, the tip of the protruding part body 32 is immersed in the liquid.

[Scum removal method]
Next, a method for removing scum S in the treatment tank 2 using the scum removal device 1 described above will be explained.
In the treatment tank 2, the scum S floating on the surface of the treated water flows downstream in the direction of flow. As a result, the scum S accumulates around the pipe skimmer 10.

In the scum removal device 1, the open position shown in Figures 2 and 3 is the initial state, and the pipe skimmer 10 is rotated between the open position and the recovery position to remove scum S accumulated in the treated water. When the pipe skimmer 10 is in the open position, the opening 20a faces upward, and the entire opening 20a is open to the outside air. Therefore, when the pipe skimmer 10 is in the open position, scum S contained in the treated water does not flow into the pipe skimmer 10.

Figures 4 and 5 are explanatory diagrams of the operation of the scum removal device 1, where Figure 4 is a cross-sectional view corresponding to Figure 2, and Figure 5 is a plan view corresponding to Figure 3.
For example, during maintenance of the treatment tank 2, in order to remove the scum S accumulated around the pipe skimmer 10, the pipe skimmer 10 is rotated to the recovery position shown in Figures 4 and 5. When this happens, the first end 20b of the pipe body 20 of the pipe skimmer 10 enters the liquid, and a part of the opening 20a is opened in the liquid. As a result, the scum S floating on the liquid surface enters the pipe body 20 through the opening 20a along with the treated water. The scum S that enters the pipe body 20 flows axially through the pipe body 20 and is then discharged from the treatment tank 2.

Here, as the pipe skimmer 10 moves to the recovery position, the tip of the protruding portion 22 enters the liquid as the first end portion 20b enters the liquid. As a result, the scum S floating on the liquid surface, located around the connection portion 21, flows along the outer surfaces of the guide walls 41 and 42. Specifically, as the scum S moves downstream (inward in the radial direction) in the flow direction with the treated water, it flows outward in the axial direction (see arrow in Figure 5). Consequently, the scum S flows into the pipe body 20 through the portions of the opening 20a located on both sides in the axial direction relative to the connection portion 21. That is, the scum S flowing along the outer surface of the first guide wall 41 flows into the pipe body 20 through the portion of the opening 20a located on the first side in the axial direction relative to the connection portion 21. On the other hand, the scum S flowing along the outer surface of the second guide wall 42 flows into the pipe body 20 through the portion of the opening 20a located on the second side in the axial direction relative to the connection portion 21.
After maintenance is complete, return the pipe gap 10 to the open position shown in Figures 2 and 3.

Thus, in this embodiment, a protruding portion 22 is provided that protrudes radially outward from the pipe body 20 at a position that overlaps with the connection portion 21 when viewed from the radial direction, and the protruding portion 22 is provided with guide walls 41 and 42 that increase the axial dimension of the protruding portion 22 as it moves from the radial outside to the inside.
With this configuration, when the pipe skimmer 10 is moved to the recovery position, the scum S accumulated around the connection part 21 can be guided along the outer surfaces of the guide walls 41 and 42 to the opening 20a. This allows for efficient recovery of the scum S and improves maintainability.

In this embodiment, the protruding portion 22 is configured to be detachably attached to the pipe body 20.
With this configuration, the protrusion 22 can be attached to the existing pipe gap 10, thereby improving maintainability while suppressing an increase in equipment costs.

In this embodiment, the protruding body 32 is configured to be triangular in shape when viewed from the tangential direction (circumferential direction).
This configuration makes it easier to guide the scum S that accumulates around the connection part 21 to the parts of the opening 20a located on both sides in the axial direction relative to the connection part 21. As a result, the scum S can be recovered more efficiently.

(Other forms of torture)
While preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications are possible without departing from the spirit of the present invention. The present invention is not limited by the above description, but only by the appended claims.

In the embodiment described above, a configuration was described in which each of the pair of guide walls 41 and 42 extends at an inclination with respect to the radial direction, but the configuration is not limited to this. The projection body 32 may, for example, be configured such that one of the pair of guide walls 41 and 42 (for example, the first guide wall 41) extends linearly in the radial direction, as shown in Figure 6.
In the embodiment described above, the protruding body 32 was described in a triangular shape when viewed from the tangential direction, but the configuration is not limited to this. The protruding body 32 may be formed in a trapezoidal shape, for example, as shown in Figure 7. In this case, the radial outer ends of the first guide wall 41 and the second guide wall 42 are connected via a straight wall 50 that extends linearly in the axial direction.

In the embodiments described above, a configuration was described in which the guide walls 41 and 42 are formed over the entire radial direction, but the configuration is not limited to this. The guide walls 41 and 42 only need to be formed over at least a portion of the radial direction, as shown in Figure 8, for example. That is, the projection body 32 can be configured such that its axial dimension gradually increases in a portion of the radial direction due to the guide walls 41 and 42.
In the embodiment described above, the projection body 32 was described as being formed by straight guide walls 41 and 42, but the configuration is not limited to this. The projection body 32 may be formed in the shape of a protrusion or the like, as shown in Figure 9, for example, with the projection extending radially outward when viewed from the tangential direction.

In the embodiment described above, the protrusion 22 is described as being detachably attached to the pipe body 20, but the configuration is not limited to this. For example, as shown in Figure 10, the protrusion 22 may be formed integrally with the connecting portion 21. In this case, the protrusion 22 may connect the first end 20b and the second end 20c of the pipe body 20 and function as a reinforcing member of the pipe body 20. Alternatively, the protrusion 22 may be formed integrally with the pipe body 20.

In the embodiment described above, a configuration was described in which the tip of the protruding part body 32 is immersed in water during the process in which the pipe gap 10 moves from the open position to the recovery position, but the configuration is not limited to this. When the protruding part body 32 is in the recovery position, it is sufficient that at least a part of the guide walls 41 and 42 is immersed in the liquid. That is, when the protruding part body 32 is in the recovery position, the tip of the protruding part body 32 may be located above the liquid surface. Also, when the protruding part body 32 is in the open position, a part of the protruding part body 32 may be immersed in the liquid.
However, as the pipe gap 10 moves from the open position to the recovery position, the protruding part body 32 is immersed in the liquid, pushing aside the scum S accumulated around the connection part 21 on both sides in the axial direction as the protruding part body 32 enters the liquid. This divides the scum S accumulated around the connection part 21 in the axial direction, and the scum S can be effectively guided to the opening 20a along the guide walls 41 and 42. For this reason, the protruding part body 32 may have a shape that becomes sharper as it goes downward (towards the other end in the tangential direction). This makes it easier for the protruding part body 32 to push aside the scum S accumulated around the connection part 21 as it moves towards the recovery position.

Furthermore, without departing from the spirit of the present invention, the components in the embodiments described above can be replaced with well-known components as appropriate, and the various modifications described above can be combined as appropriate.

1: Scum removal device 10: Pipe skimmer 20: Pipe body 20a: Opening 21: Connection part 22: Protruding part 41: First guide wall (guide wall)
42: Second guide wall (guide wall)
O: Axis line

Claims (2)

It is formed in a cylindrical shape with the direction along the liquid surface as its axis, and is equipped with a pipe gap in which a portion is immersed in the liquid.
The aforementioned pipe gap is,
A pipe body having a radially opening, which is rotatable around an axis along the liquid surface between a recovery position where a portion of the opening is submerged in the liquid and an open position where the entire opening is exposed to the outside air,
A connecting portion that connects a part of the first end and a part of the second end of the opening that are opposite each other in the circumferential direction around the axis,
The pipe body is provided with a protruding portion that, when viewed from the radial direction, overlaps with the connecting portion, and which protrudes radially outward from the pipe body, and at least a portion of which is located in the liquid at the recovery position,
The aforementioned protrusion is
A projection body having a guide wall that gradually increases the axial dimension of the projection as it extends from the radially outer side to the inner side,
The system includes a stay for detachably attaching the protruding body to the pipe body,
The aforementioned stay is,
On the outside of the pipe body, a base portion extends along the first end so as to straddle the connecting portion in the axial direction,
A scum removal device comprising: hook portions formed at both ends of the base portion in the axial direction relative to the connecting portion, and which wrap around to the inside of the pipe body by straddling the first end through the opening . The aforementioned guide wall is
A first guide wall extending from the portion located on the first axial side with respect to the connection portion toward the second axial side as it extends radially outward,
The device comprises a second guide wall that extends from a portion located on the second axial side with respect to the connection portion toward the first axial side as it extends radially outward,
The scum removal device according to claim 1 , wherein the protruding body is formed in a triangular shape in which the radial outer ends of the first guide wall and the second guide wall are connected to each other.