JPS627409A - Method and apparatus for separating suspended particles by sedimentation - Google Patents

Abstract

PURPOSE:To effectively separate suspended particles by sedimentation, by arranging a large number of fins faced to the flow direction of a laterally directed suspension stream at an angle of 45-90 deg. in a sedimentation tank so as to hold parallel intervals in horizontal and vertical planes. CONSTITUTION:When a suspension stream W flows through the main flow passage 10 between upper and lower fins as a laminar parallel stream W', wake vortex streets 14 are generated in the boundary parts between the main flow passage 10 and fin pockets 13 and the suspended particles flowing in a state carried on the laminar parallel stream W' are involved in the wake vortex streets 14. The involved floc particles are flowed in the recirculation streams 15 in the pockets 13 to be impinged to each other while recirculated and revolved and flow so as to sweep the surfaces of the fins to be flocculated and granulated. The grown flocs are gravitationally fallen to enter the laminar parallel stream W' thereunder and collect the floc particles therein to be again flowed in the lower side pocket 13 and further grown to be successively sedimented and separated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for sedimentation and separation of suspended particles in a sedimentation tank.

[Conventional technology]

Conventionally, as this type of sedimentation separation method and device,
The invention disclosed in Japanese Patent Application No. 0-6663 (hereinafter referred to as the conventional device) is known, and this conventional device has a suspension flow flowing through a large number of inclined thin plates 1 arranged at parallel intervals in a settling tank. It has a structure in which a large number of fins 2 are provided protrudingly at right angles to the direction a as shown in FIG.

C Problems to be Solved by the Invention] In the conventional device, when a suspension flow flows through the flow path between the inclined thin plates 1, a problem occurs at the laminar parallel flow area of the main flow path and the boundary between the main flow path and the fin pocket 3. Flock particles in a suspended flow flowing in a laminar parallel flow exhibiting three patterns: a trailing vortex train with the upper edge of the upstream fin as a boundary layer separation point, and a circulating flow rotating at low speed within the fin pocket 3. are sequentially moved to the trailing vortex street by the action of gravity, flow into the circulating flow in the fin pocket 3 along with the behavior of this trailing vortex street, and aggregate due to collisions between the particles and the particles and the fin plate surface. The fin pocket 3 is formed into a groove-shaped cross-sectional shape as shown in FIG. 12 surrounded from three sides with no openings on the floc settling surface (pocket bottom wall surface). Therefore, there is a problem that the settled floc particles adhere to and accumulate as sludge on the inner bottom and inner corners of the fin pocket 3, and there is a drawback that suspended particles cannot be effectively separated by sedimentation. Ta.

In addition, when the above-mentioned adhesion and accumulation of sludge occurs, this sludge removal work (cleaning work) must be performed frequently with the inside of the sedimentation tank empty.

[Purpose of the invention]

The purpose of the present invention is to provide a sedimentation separation method and method for efficient sedimentation separation of suspended particles by increasing the frequency of contact and collision between settled flocs and suspended particles, promoting floc growth, and modifying the floc structure. Our goal is to provide that device.

[Summary of the invention]

In order to achieve the above object, the sedimentation separation method of the present invention causes the floc particles in the suspended flow W flowing through the main flow M10 between the upper and lower fins as a laminar parallel flow W' to separate the upstream fin edges from a boundary layer. The particles are caught up in the wake vortex line 14, which flows into the circulation flow 15 in the pocket between the row fins, and the particles collide with each other and with the fin plate surface. The grown flocs are granulated into large particles by ui, and the grown flocs sequentially descend by gravity from the lower opening of the pocket part 13, enter the suspension flow W flowing below as a laminar parallel flow W', and this suspension flow This method is characterized in that floc particles floating in the floc are captured and flowed into the circulating flow 15 in the lower pocket, where they further enlarge and are sequentially sedimented and separated. The sedimentation separator of the present invention has a large number of fins 12 facing at an angle θ of 45 to 90 degrees with respect to the flow direction a of the horizontal suspension flow W in the sedimentation tank 5 at parallel intervals in the horizontal plane and the vertical plane. A main channel 10 is formed between the upper and lower fins through which the suspended flow W flows as a laminar parallel flow W', and pocket portions 13 whose upper and lower surfaces open into the main channel 10 are formed between the row fins. is formed, and when the suspension flow W flows through the main channel 10, a trailing vortex row 14 with the upstream fin edge as a boundary layer separation point and a circulation flow 15 inside the pocket are generated. It is something.

[Embodiments of the invention]

Hereinafter, a sedimentation separation apparatus directly used for carrying out the sedimentation separation method of the present invention will be explained with reference to the drawings of FIGS. 1 and 2.

This suspended particle sedimentation aft device is installed in the sedimentation tank 5 at an angle θ(
In this embodiment, a large number of fins 12 facing each other at θ=60° are arranged as shown in FIG. By doing so, a main channel 10 in which the suspended flow W flows as a laminar parallel flow W' is formed between the upper and lower fins, and a pocket portion 13 whose upper and lower surfaces are open to the main channel 10 is formed between the row fins. There is.

In the sedimentation separator configured in this way, when the suspended flow W flows through the main channel 10 between the upper and lower fins as a laminar parallel flow W', an upstream fin edge is formed at the boundary between the main channel 10 and the fin pocket 13. A trailing vortex train 14 is generated with the boundary layer separation point at the boundary layer separation point, and the suspended particles flowing in the laminar parallel flow W' become laminar parallel flow W' due to the action of inertia and gravity. It deviates from the flow and gets caught up in the wake vortex row 14. At this time,
Since a circulating flow 15 rotating at a low speed is formed in the pocket portion 13 of the fin 12, the floc particles caught up in the trailing vortex row 14 flow into the pocket circulating flow 15.
As the particles circulate and swirl within the boget portion 13, collisions occur between the particles and between the particles and the fin plate surface, and by repeating this collision action, the particles aggregate while sweeping the fin plate surface, and are gradually granulated into larger particles. And the fin pocket part 13
The flocs grown inside the pocket part 13 are successively lowered by gravity from the lower opening of the pocket part 13 and enter the suspension flow W flowing below as a laminar parallel flow W' in a perpendicular state, and the flocs floating in this suspension flow W are The particles are captured and the lower pocket part 13
It flows again into the circulating flow 15 inside the pocket, further enlarges in this lower pocket, and is sequentially sedimented and separated.

That is, the flocs successively increase the frequency of contact and collision with suspended particles to promote growth, and the floc structure is gradually modified into a larger floc structure, which reaches the bottom of the sedimentation tank in a short time and is efficiently sedimented and separated. That will happen.

In this case, the flocs release the water and fine air contained in the flocs by repeating swirling and contact collisions, thereby weakening the buoyancy of the particles, and irregular particle shapes also have a small surface area. Modified into a circular floc shape with good sedimentation efficiency.

Circulation of a small swirling flow is important for the formation, growth or modification of the flocs. Since the sedimentation separator according to the present invention generates a small swirling circulation flow 15, it is possible to effectively create coagulated flocs with good sedimentation separation.

The shape of the vortex in the pocket portion 13 (the shape of the circulating flow 15) is determined by the ratio of the interval P of the fins 12 to the height 2, and is hardly influenced by the channel height d. When P/ff1-1, one circular circulating flow 15 is created, and when P/ff1-0.5, two circulating flows 15a and 15b rotating in opposite directions are created as shown in FIGS. 6, 10, and 11. It is formed as follows, P/l
, -2 or more, the suspended flow W enters the inside of the pocket and no vortex is formed, or even if it is formed, it becomes an extremely small vortex, so there is no use value.

The cross-sectional length dimension of the fin 12 is from number 1 to 101.
The horizontal length of the entire fin is determined by the strength of the fin, the installation method, the size of the settling tank 5, etc. Also,
The material of the fins 12 may be any non-corrosive material such as synthetic resin, metal, concrete, etc.

FIG. 3 shows a second embodiment in which the cross-sectional shape of the fins 12 is approximately dogleg-shaped, and a pocket portion 13 with an opening on the upper and lower surfaces is formed between the opposite dogleg-shaped fins 12, and FIG. A third embodiment is shown in which the cross-sectional shape of the fins 12 is an inverted T-shape, and pocket portions 13 with openings on the upper and lower surfaces are formed between the inverted T-shaped fins 12, and FIGS. 5 and 6 show the cross-sectional shape of the fins 12. The fourth fin has a triangular and rhombic shape, and a pocket portion 13 with an opening on the upper and lower surfaces is formed between the triangular and rhombic fins 12. A fifth embodiment is shown in FIG. 7, in which the cross-sectional shape of the fins 12 is arcuate, and the arcuate fins 12 facing in opposite directions are shown in FIG.
A sixth embodiment is shown in which a pocket portion 13 with an opening on the upper and lower surfaces is formed between the fins, and FIG.
A seventh embodiment is shown in which a pocket portion 13 with an opening on the upper and lower surfaces is formed between crank-shaped fins 12 facing in opposite directions, and FIG. An eighth embodiment is shown in which a pocket portion 13 with an opening on the upper and lower surfaces is formed between two rows of doglegged fins 12 in each row facing each other, and FIG. It has a cross-sectional shape of a vertical flat plate having protrusions, and a pocket part 13 with an upper and lower surface opening is provided between each vertical flat plate fin 12 facing in the flow direction of the suspended flow (in this case, two circulation flows 15a and 15b are formed in the upper and lower parts of the pocket). 9 shows a ninth embodiment in which a 3D film is formed.

In addition, FIG. 11 shows that the cross-sectional shape of the fin 12 is a crank shape having vertically extending plate portions at the upper and lower ends of the diagonal plate portion, and the upper and lower ends of the crank-shaped fin 12 are connected to a hanging member 17 (this hanging member 17). The materials are rods, wire lobes, etc., and are suspended in the sedimentation tank 5 at a predetermined distance from a beam (not shown) installed above the sedimentation tank 5, and a weight is attached to the lower end as necessary). A tenth embodiment is shown in which pocket portions 13 with openings on the upper and lower surfaces are formed between the fins 12 in fixed rows.

The method of sedimentation and separation of floc particles (suspended particles) in the second to tenth embodiments is the same as that in the first embodiment described in FIG. 2, so detailed explanation will be omitted.

[Effects of the Invention] Since the method for sedimentation and separation of suspended particles according to the present invention is as described above, it increases the frequency of contact and collision between settled flocs and suspended particles, promotes the growth of flocs, and improves the structure of flocs. By modifying the method, it is possible to efficiently perform sedimentation and separation of suspended particles.

In addition, in the apparatus for sedimentation and separation of suspended particles according to the present invention, the upper and lower surfaces of the fin pocket portion are open to the main flow channel, so that when the settled flocs rotate in the pocket and descend one by one, they are separated from the suspended particles. Since it slides down the fin plate surface while repeating contact and collision, it is possible to cleanly sweep the fin plate surface.
The problem of sludge adhesion and accumulation that occurs in conventional devices can be easily solved.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a sedimentation separation device showing an embodiment of the present invention, Fig. 2 is an explanatory diagram of a sedimentation separation method using the same device, and Figs. 3 to 11 show the cross-sectional shape and arrangement of the fins. Different embodiments of the device of the present invention (second to first
FIG. 12 is a conventional explanatory diagram corresponding to FIG. 2 of the present invention. W... Lateral suspension flow, W'... Laminar parallel flow, a.
...Flow direction of suspension flow, 12...Fin, 13...
Pocket portion, 14...Wake vortex row, 15...Circulation outflow Applicant's agent Patent attorney Takehiko SuzueFigure 1Figure 2W゛Figure 3Figure 6Figure 7Figure 11Figure 12

Claims (2)

[Claims] (1) The floc particles in the suspended flow flowing in the main channel between the upper and lower fins as a laminar parallel flow are caught in a wake vortex street with the upstream fin edge as the boundary layer separation point, and this wake vortex street Along with this movement, the flocs flow into the circulation flow inside the pocket between the rows of fins, aggregate and granulate into large particles due to collisions between the particles and between the particles and the fin plate surface, and the grown flocs flow through the opening at the bottom of the pocket. The flow descends sequentially due to gravity and enters the suspended flow flowing below as a laminar parallel flow. The floc particles suspended in this suspended flow are captured and flowed into the circulating flow in the lower pocket, where they are further A method for sedimentation and separation of suspended particles, characterized in that the particles are enlarged and then sedimented and separated in sequence. (2) 45 mm in the direction of the horizontal suspension flow in the settling tank
A large number of fins facing each other at an angle of ~90° are arranged so as to maintain parallel spacing in a horizontal plane and a vertical plane to form a main channel in which a suspended flow flows as a laminar parallel flow between the upper and lower fins, A pocket portion whose upper and lower surfaces are open to the main channel is formed between the row fins, and when the suspension flow flows through the main channel, a wake vortex train with the upstream fin edge as a boundary layer separation point and circulation inside the pocket are formed. 1. A sedimentation separation device for suspended particles, characterized in that a flow is generated.