JPH0137738Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention relates to a mixing device for a floating sludge concentrator, especially for floating and concentrating sludge and floats generated in sewage treatment plants or sewage treatment plants. This invention relates to a mixing device for a floating sludge thickening device.

"Prior Art" FIGS. 8 and 9 are schematic explanatory diagrams showing different types of conventional floating sludge concentrators, which are the background of this invention. Both floated sludge concentrators 1 and 10 (hereinafter referred to as concentrators) shown in FIGS. 8 and 9 move sludge 18 into a separated liquid 20 filled in a thickening tank 20 using the buoyancy of air bubbles.
The sludge is made to float inside the sludge and concentrated as floating sludge 22.

In the concentrator 1 shown in FIG. 8, pressurized water 12 in which air has been dissolved is depressurized by a decompression part 4, that is, a primary pressure regulating valve or an ejector, and the fine bubbles generated there are attached to sludge 18 in a mixing part 6. , into the separation liquid 21 of the concentration tank 20.

When the decompression section 4 and the mixing section 6 are installed underwater, there are problems in their maintenance and management, and they are usually arranged separately outside the concentration tank 20. Therefore, in the conventional concentrating device 1, the distance from the pressure reduction section 4 and the mixing section 6 to the air outlet 5 formed inside the tank becomes long, and the mixed air ends up joining in the middle of the piping. It did not adhere to the sludge, and the bubbles became coarse. Then, the coarse air bubbles floated independently in the separated liquid 21, agitated the floating sludge 22, and reduced the sludge concentration efficiency.

Therefore, in Japanese Utility Model Publication No. 17667/1983, a floated sludge concentrator was disclosed to solve these problems, and in particular, a concentrator 10 as schematically shown in FIG. 9 was proposed. In this concentration device 10, a cylindrical operation chamber 26 whose partition wall reaches the tank bottom _20b is formed in the center of the concentration tank 20,
A decompression section 14 and a mixing section 16 are provided in the operation chamber 26, respectively. Then, the mixing section 16
A plurality of air outlets 24 connected to the air outlet 24 are formed on the outer periphery of the operation chamber 26 at regular intervals and open into the concentration tank 20 . In the concentrating device 10 disclosed in the publication configured in this way, the pressure reducing section 14 and the mixing section 1
6 etc. can be provided in the concentrating tank 20, and it has become possible to shorten the distance from the pressure reducing part 14 to the mixing part 16 and the distance to the blow-off port 24 compared to the previous one.

``Problems to be solved by the invention'' However, in the concentrating device disclosed in Japanese Utility Model Publication No. 58-17667, as shown in FIG.
0, a cylindrical operation chamber 26 must be formed separately, and a cylindrical operation chamber 26 must be formed separately from the pressure reduction section 14 to the mixing section 16.
The problem arises that not only is the distance to the air outlet 24 still long, but the civil engineering structure is complicated and difficult to construct.

``Purpose of the invention'' Therefore, the main purpose of this invention is to provide a floating sludge thickener that can be installed underwater, not only simplifies the civil engineering structure of the thickener, but also improves the sludge flotation concentration efficiency. The purpose of the present invention is to provide a mixing device.

``Means for solving the problem'' In order to achieve the above purpose, the main means adopted by this invention is a floating sludge concentration method in which the sludge is made to float to the top of the tank and concentrated by attaching air bubbles to the sludge. A mixing device of the device, a decompression mechanism disposed in the separated liquid in the tank and generating the bubbles;
The tank includes a mixing section for feeding sludge into the upper vicinity of the pressure reduction mechanism and causing the bubbles to adhere to the sludge, and the pressure reduction mechanism is operated from outside the tank.

"Operation" When pressurized water containing dissolved air is passed through a pressure reduction mechanism adjusted by operation from outside the tank, the pressure is reduced and bubbles are generated. When the air bubbles generated by the pressure reduction mechanism are mixed with sludge in the mixing chamber installed close to the pressure reduction mechanism, the air bubbles can be mixed with sludge and deposited without leaving any distance.
Immediately, microbubbles adhere to this sludge, and the buoyancy of the bubbles causes the sludge to float in the separated liquid, forming a floating sludge layer at the top of the tank.

``Effects of the invention'' This invention eliminates the need for an operation room provided in the center of the tank, compared to the conventional one, so the civil engineering structure of the thickening tank can be extremely simplified.

Furthermore, since a pressure reduction mechanism can be installed in the separated liquid, compared to the conventional case where a separate operation chamber is formed in the center of the tank, it prevents bubbles from coalescing into coarse particles and increases the flotation concentration rate of sludge. be able to.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

``Example'' Figure 1 is a vertical sectional view showing an embodiment of the device of this invention, Figure 2 is a plan view of the embodiment device shown in Figure 1,
3 to 6 are explanatory views showing modifications of the pressure reducing mechanism shown in FIG. 1, and FIG. 7 is an explanatory view showing an example of use of the embodiment device shown in FIG. 1.

First, for convenience of explanation, an outline of a typical concentrating device 10' in which this invention is used will be explained using FIG. 7. The concentrating device 10' includes a concentrating tank 20 having a substantially circular outer shape, which stores a separated liquid 21, and has a pedestal 28 whose upper portion protrudes above the water surface approximately in the center thereof. This pedestal 28 has
The floating sludge scraper 30 rotates around the entire circumference of the opening upper surface 20 _a of the thickening tank 20 with this as the center of rotation.
(hereinafter referred to as a scraping machine) is attached, and one end side _30a of this scraping machine 30 is rotatably pivoted. The other end 30 _b of the scraper 30 is placed on the upper end of the side wall of the concentration tank 20 via a rotary rotor 32 as a movable free end. The scraper 30 includes an open upper surface portion 20 of the concentration tank 20.
A bucket 34 and the like are attached to scrape up the floating sludge 22 that has floated to the top of the tank a _and is undergoing the stationary concentration process.

The floating sludge 22 scraped up by the bucket 34 is discharged into a trough 36 formed on the outer peripheral surface of the upper end of the side wall of the thickening tank 20. Note that the scraper 30 is not limited to the type described here, and other types such as a chain flight type can also be used.

In the concentrator 10' including such a configuration,
A sludge pipe 40 and a pressurized water pipe 42 are introduced into the bottom 20 _b of the thickening tank 20 toward the center thereof. Sludge 18 generated during filth treatment or sewage treatment is injected into the sludge pipe 40, and pressurized water 12 containing dissolved air is sent into the pressurized water pipe 42. The introduced sludge pipe 40 and pressurized water pipe 42 are further drawn into the separated liquid 21 in the thickening tank 20, and are arranged in the lower part of the frame 28 in this separated liquid 21. This is an embodiment of this invention. It is connected to a mixing device 50.

As shown in FIG. 1, this mixing device 50 has a hollow cylindrical shape, and has a connection port 60 for the pressurized water pipe 42 formed at its lower end, and an air outlet 12 that opens directly above at its upper end.
4 is open. Above this air outlet 124, there is a saucer-shaped buttful 6 that intersects directly above the air outlet 124.
4 is attached via a support plate 65. The support plate 65, as shown in FIG.
Four pieces are attached to the outer circumferential surface of the mixing device 50 at an angle of about 90 degrees at regular intervals. This baffle 64 is used, for example, to change the sludge mixture that has ascended through the mixing device 50 into a horizontal flow, and is used to prevent air bubbles from adhering to the separated liquid 21 stored in the thickening tank 20 (Fig. 1). This is to uniformly disperse the sludge.

Note that the buffer 64 may be omitted depending on the case. The shape is also not limited to a plate shape, but may be a plate-like plate, or it may be installed upside down like a turned plate when attached to the mixing device 50. good.

Connection port 60 and outlet 124 of this mixing device 50
A hollow mixing chamber 61 is formed between the mixing chamber 61 and a pressure reducing mechanism 51, which is an example of a pressure reducing section, particularly on the connection port 60 side of the mixing chamber 61. Furthermore, a connection port 62 for communicating the above-mentioned sludge pipe 40 with this mixing chamber 61 is formed in a side wall portion of the mixing device 50. Note that, normally, the separation liquid 21 enters this hollow mixing chamber 61.

This pressure reducing mechanism 51 includes a valve body 54 formed in the shape of an inverted truncated cone and a valve seat 56 formed so as to fit into each other in accordance with the shape of the valve body 54. Among these, the valve seat 56 is held by a valve seat receiver 58 fixed to the inner surface of the mixing device 50,
The upper end side of the valve body 54 protrudes from the buttful 64,
The lower end side is attached to a valve rod 52 that is fitted into a valve seat receiver 57. That is, this valve stem 52 is
This is to raise and lower the valve body 54 to form an appropriate gap between it and the valve seat 56, and to adjust the size of this gap appropriately. For example, if this gap is set appropriately for a predetermined flow rate of pressurized water flowing in from the pressurized water pipe 42, this pressurized water will be depressurized in the mixing chamber 61, and the air dissolved in the pressurized water will become bubbles. It will be withdrawn.

For this reason, a boss 70 is formed at the top end of the valve stem 52, and a male threaded portion 68 of an appropriate length is formed following the boss 70. this house,
The male threaded portion 68 passes through the buffle 64 and is screwed into a nut 66 fixed on the buffle 64, and the boss 70 is connected to a handle 72 provided on the top of the pedestal 28. By this,
The valve stem 52 is rotated by remote control from above and can be freely adjusted up and down. Accordingly, the valve body 54 also becomes movable up and down while rotating.

Note that the handle 72 for turning the valve stem 52 of this mixing device 50 connects one end 30 _a of the scraper 30 to the pedestal 28 .
It is mounted on a rotatable shaft 74 (FIG. 7) that is mounted on the upper part of the shaft. Also, for example, the mixing device 50
Air bubbles may adhere directly to the surface, and a portion of the air bubbles may become coarse, producing large air bubbles. For this reason, we focused on the fact that the coarse bubbles leaving the mixing device 50 rise directly above the inside of the pedestal 28, and in the middle of the pedestal 28 there is an inclined guide 28 _a for distributing the rising coarse bubbles around the pedestal 28. is provided. and,
Around the upper part of this pedestal 28, there is a tilt guide _28a.
Vertical guides 28 _b are formed at regular intervals to further raise the coarse air bubbles sorted out and release them into the air without disturbing the floating sludge 22 .

Next, the functions of the mixing device 50 having such a configuration will be explained. First, referring to FIG. 7, sludge 18 is injected into the sludge pipe 40 arranged as described above, and pressurized water 12 in which air is dissolved is injected into the pressurized water pipe 42. The injected pressurized water 12 and sludge 18 reach the mixing device 50 disposed in the separated liquid 21, and enter the mixing device 50 separately from the connection ports 60 and 62 of the mixing device 50 shown in FIG. sent. That is,
The pressurized water 12 entering the connection port 60 flows through the handle 72
The separated liquid 21 passes through a predetermined gap formed between the valve seat 56 and the valve body 54 (virtual line valve body in FIG. 1), which has been rotated and raised upward by the operation of
and the sludge 18 is sent to the mixing chamber 61 into which it is flowing. The pressurized water 12 sent to the mixing chamber 61 is depressurized and generates bubbles. Since the bubbles here adhere to the unconcentrated sludge in the separated liquid 21 immediately after generation, the bubbles do not coalesce with each other and become coarser into larger-diameter bubbles. Then, the sludge 18 with bubbles attached is pushed up by the subsequent pressurized water 12 and sludge 18 that are newly sent into the mixing chamber 61 one after another, and is pushed up from the air outlet 124 in the thickening tank 20 (first
It flows out into the separation liquid 21 shown in the figure). At this time,
Batsuful 64 suppresses the flow of sludge 18 directly above, changes the flow horizontally, and
8 is uniformly dispersed in the separation liquid 21. If the amount of pressurized water is to be changed during the process, the handle 72 may be turned to appropriately change the degree of opening of the gap between the valve body 54 and the valve seat 56.

FIGS. 3 to 6 are explanatory cross-sectional views of essential parts showing examples of the pressure reducing mechanism 51 in FIG. 1, respectively. In the modification shown in FIG. 3, compared to the valve body 54 in FIG. 1, the valve body _54a is formed in a disk shape,
The difference is that when the valve stem 52 lowers, it engages and closes the upper part of the valve seat 58.

In the modification shown in FIG. 4, compared to the valve body _54a in FIG. 3, a disc-shaped valve body _54b engages with the lower part of the valve seat 58 as the valve stem 52 rises. They differ in some respects.

In the modification shown in FIG. 5, compared to the valve body 54 in FIG. 1, a valve body _54c is formed in a substantially conical shape on the valve stem 52, and is fitted in a manner that corresponds to the shape of the valve body _54c . A valve body _58c is formed in the valve body 58c.

In the modification shown in FIG. 6, the valve body _54b is formed in the shape of an inverted truncated cone, and when the valve stem 52 is lowered, it fits into a chamfered portion 59 formed at the upper end of the valve seat _58b .

In this embodiment, the case where the sludge pipe and the pressurized water pipe are introduced into the bottom of the thickening tank has been described above. However, in addition to this, it is also conceivable to configure the sludge pipe and pressurized water pipe to be introduced into the tank from the upper part of the tank.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the device of this invention, FIG. 1 is a longitudinal sectional view thereof, FIG. 2 is a plan view of the embodiment device shown in FIG. 1, and FIGS. 3 to 6 are 1st
FIG. 7 is an explanatory diagram showing an example of use of the embodiment device shown in FIG. 1, and FIGS. 8 and 9 are the background of this invention. FIG. 1 is a schematic explanatory diagram showing a conventional floating sludge thickening device. Explanation of symbols, 10'...Floated sludge thickener, 1
2... Pressurized water, 18... Sludge, 40... Sludge pipe,
42... Pressurized water pipe, 50... Mixing device, 51...
Decompression mechanism, 61...mixing chamber.

Claims (1)

[Scope of utility model registration request] A mixing device for a floating sludge concentrator that floats the sludge to the top of the tank and concentrates it by attaching air bubbles to the sludge, which comprises: a decompression mechanism that is disposed in the separated liquid in the tank and generates the air bubbles; A mixing device for a floated sludge concentrator, comprising: a mixing unit for feeding sludge into the upper vicinity of the pressure reducing mechanism and causing the bubbles to adhere to the sludge, and in which the pressure reducing mechanism is operated from outside the tank.