JP3368767B2 - Digestion tank agitator - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a stirring device for an anaerobic digestion tank for sludge.

[0002]

2. Description of the Related Art A sludge anaerobic digestion tank has conventionally been provided with a stirrer for stirring the water in which the sludge is suspended. 3 is a front view showing an example of a conventional digestion tank stirring device, and FIG. 4 is a front view showing an example of a conventional digestion tank stirring device as a whole.

As shown in FIGS. 3 and 4, sludge 4 floats on the surface of the water contained in the digestion tank 1 (hereinafter, the water in which the sludge floats is referred to as "sludge"). 4a is the water surface of the sludge at the time of water sealing. An inspection port 32 is opened at the ceiling of the digestion tank 1, and a blind flange 36 is provided at the inspection port 32.
Is provided. The blind flange 36 is a removable lid. In the digestion tank 1, a cylindrical water sealing pipe 34
Is installed vertically. The upper end of the water sealing pipe 34 is connected to the inspection port 32. The lower end of the water sealing pipe 34 can be submerged in the sludge 4 in the digestion tank 1,
The digestion tank 1 can be sealed.

Inside the digestion tank 1, there is a draft tube 2
A plurality of legs 6 (three in FIG. 3) for arranging are provided with their lower end portions fixed to the tank bottom of the digestion tank 1. The upper ends of the legs 6 are grouped together, and the upper ends of the legs 6 thus grouped together are fixed with the upper ends of the draft tubes 2 via an annular ring plate 27 arranged around them. . Reference numeral 31 is a jig for connecting the upper ends of the legs 6 and the ring plate 27. The lower end of the vertically-arranged draft tube 2 is fixed by legs 6. Further, the lower end of the draft tube 2 is located at a height apart from the tank bottom by a predetermined distance.

On the upper surface of the ring plate 27, four guide bars 22 are vertically provided around the draft tube 2. In addition, in FIG. 3, the illustration of the guide rod on the front side is omitted. Ring-shaped connecting rings 28 and 29 for connecting the guide rods 22 to each other are horizontally provided at the upper end portion and the intermediate portion of the guide rod 22.
Between the left and right guide rods 22a and 22b shown in FIG. 3, a sliding mechanism 2 is slidable at both ends with the guide rods 22a and 22b.
The elevating guide 21 having 1a is the guide rods 22a, 2
It is provided horizontally so as to be slidable with 2b. Lift guide 2
Wire (or chain) mounting holes 24 are provided in the sliding mechanism mounting portions at both ends of the No. 1 and a hoisting wire 38 (or chain) is provided between the inner wall of the tank 1 and the mounting hole 24. It is connected. An arm 23 is vertically provided at the center of the elevating guide 21 downward from the center. An underwater stirrer 3 is provided at the lower end of the arm 23. The stirrer 3 includes a motor 37 attached to the lower end of the arm 23, and a rotatable screw 39 attached to the motor shaft. In addition, the motor 3
A holder 25 is provided at the lower part of 7. Holder 25
Can connect the lower part of the motor 37 and the trumpet part 26 of the holder at the upper end of the draft tube 2, and the agitator 3 can be installed at the top of the draft tube 2 by connecting both parts.

During normal operation, the sludge 4 is agitated by the underwater agitator 3, and the generated gas is collected in a gas holder (not shown) by a gas vent pipe 10 penetrating the outer wall 8 of the tank. In addition, when inspecting or replacing the submersible agitator 3, the water surface of the sludge is set to the water surface 4a at the time of water sealing so that the gas inside is not released to the outside, and then the submersible agitator 3 is carried in and out. There is. The stirrer 3 installed at the top of the draft tube 2 is provided with a lifting guide 2
By the action of the carry-in / carry-out mechanism including the arm 1, the arm 23, the holder 25, and the guide rod 22, the water can be vertically moved inside the tubular body of the water sealing pipe 34 and in the digestion tank 1 below the tubular body. . Here, the length of the arm 23 is such that when the submersible stirrer 3 is installed on the top of the draft tube 2 by the holder 25, the position of the elevating guide 21 is above the water surface 4a of the sludge when water is sealed. It has been adjusted to be. 3 and 4, an arrow A indicates an agitator 3
Shows the direction of sludge flow by the action of. (Hereinafter referred to as "conventional technology")

[0007]

However, the prior art has the following problems. If you set the water level higher when sealing the water, the gas vent pipes will also be sealed, and if you leave it for a long time such as when checking or replacing the submersible stirrer, the gas pressure will increase and explosive gas will suddenly disappear. It passes through the water sealing pipe and is released into the atmosphere, which is dangerous for work.

Therefore, in view of the above points, an object of the present invention is to provide a digestion tank agitator capable of safely inspecting or replacing an underwater agitator without increasing gas pressure in the tank. Especially.

[0009]

The invention according to claim 1 is
In a stirrer for an anaerobic digestion tank for sludge, an upper projection provided on a ceiling of the digestion tank so as to project upward from the ceiling, and having a through hole that communicates the inside of the digestion tank with the outside thereof. Part, inside the through hole and inside the digestion tank, a predetermined gap is formed with the inner wall of the through hole in the through hole, and the lower end portion in the digestion tank is submerged in water in which sludge floats. And a water-sealing pipe that can seal the digestion tank, and a bottom of the water-sealing pipe is erected in a state of being immersed in water in which sludge floats. The upper end and the lower end are open. A draft tube and a stirrer for stirring water in which sludge floats, which is detachably attached to the upper end of the draft tube,
An agitator loading / unloading mechanism for loading / unloading the agitator into / from the digestion tank through the through hole and the water sealing pipe and attaching / detaching to / from the upper end of the draft tube.
A gas vent pipe for penetrating the wall of the upper protruding portion and connected to the gap between the water sealing pipe and the inner wall of the through hole, for venting digestive gas generated in the digestion tank, It is characterized by being equipped with.

According to a second aspect of the present invention, there is provided a safety valve pipe which penetrates the wall of the upper protruding portion and is connected to the gap between the water sealing pipe and the inner wall of the through hole, and the safety valve pipe. It further comprises a safety valve, which is provided in the above, and which opens when the digestion gas accumulated in the upper portion of the digestion tank reaches a predetermined pressure or more.

An upper protrusion is provided on the ceiling of the anaerobic digestion tank, a through hole is provided inside the upper protrusion to connect the inside and outside of the digestion tank, and the inner wall of the through hole and a predetermined gap are provided inside the digestion tank. Open and install a pipe for water sealing. Gas is vented by penetrating the wall of the upper protruding portion and connecting a gas vent pipe to the gap between the through hole and the water sealing pipe. The water level of the sludge does not rise to the degassing pipe, and gas does not accumulate at the upper part of the digestion tank when sealing water in the digestion tank. Also, by connecting the safety valve piping and safety valve, it is possible to deal with the rise in gas pressure due to clogging of the gas vent pipe, etc., and the gas pressure does not rise abnormally in the digestion tank, and the degassing of the digestion gas is stabilized. You can do it.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing an upper structure of a stirring apparatus for a digestion tank according to an embodiment of the present invention, and FIG. 2 is a front view showing an overall configuration of a stirring apparatus for a digestion tank according to an embodiment of the present invention. In FIGS. 1 and 2, portions substantially the same as or corresponding to those in FIGS. 3 and 4 showing a conventional example are denoted by the same reference numerals as those in FIGS. 3 and 4.

As shown in FIGS. 1 and 2, sludge 4 floats on the surface of the water contained in the sludge anaerobic digestion tank 1. 4a is the water surface of the sludge at the time of water sealing. Less than,
Similar to the description of the prior art, water in which sludge floats will be described with sludge.

At the ceiling of the digestion tank 1, there is provided a center dome 57 which is an upper protruding portion provided so as to project upward from the ceiling. A through hole 5 is provided inside the center dome 57 to connect the inside and outside of the digestion tank 1. A blind flange 36 is provided at the inspection port 32, which is the upper opening of the through hole 5. Blind flange 36
Is a removable lid. A tubular water sealing pipe 34 is vertically provided in the through hole 5 and the digestion tank 1. The upper end of the water sealing pipe 34 is connected to the inspection port 32. The lower end of the water sealing pipe 34 can be submerged in the sludge 4, and the digestion tank 1 can be sealed by submerging the water sealing pipe 34 in the sludge 4.

In the digestion tank 1, there is a draft tube 2
To provide a plurality of (3 in the present embodiment shown in FIG.
The leg 6 of the book) is arranged with its lower end fixed to the tank bottom of the digestion tank 1. The upper ends of the legs 6 are grouped together, and the upper ends of the legs 6 thus grouped together are fixed with the upper ends of the draft tubes 2 via an annular ring plate 27 arranged around them. . On the upper surface of the ring plate 27, a plurality of guide rods 22, four in the present embodiment, are vertically provided around the draft tube 2. 1 and 2, the guide rods on the front side and the other side are not shown. Between the left and right guide rods 22a, 22b, the guide rods 22a,
An elevating guide 21 having a sliding mechanism 21a slidable with 22b is horizontally provided so as to be slidable with the guide rods 22a and 22b.

An arm 23 is vertically provided at the center of the elevating guide 21 from the center downward. An underwater stirrer 3 is provided at the lower end of the arm 23, and the stirrer 3 is installed on the top of the draft tube 2 by a holder 25. The stirrer 3 is vertically movable inside and below the water sealing pipe 34 by the action of the stirrer loading / unloading mechanism including the lifting guide 21, the arm 23, the holder 25, and the guide rod 22. By operating the stirrer 3, sludge enters the draft tube 2 from its upper end and is discharged from its lower end, as indicated by an arrow A in FIG.

A predetermined gap 51 is provided between the concrete slab 8a and the wall 8b constituting the center dome 57 of the digestion tank 1 and the water sealing pipe 34. A gas vent piping port 52 is provided penetrating one side (left side in FIG. 1) of the wall 8b forming the upper part of the center dome 57, and the gas vent piping 5 is provided in the gas vent piping port 52.
3 is connected and connected to a gas holder (not shown). A safety valve piping port 55 is provided through the other side (right side in FIG. 1) of the wall 8b, and a safety valve piping 56 is connected to the safety valve piping port 55. Furthermore, safety valve piping 56
A safety valve 54 is provided midway. Safety valve 54
Is designed to open when the digestion gas accumulated in the upper portion of the digestion tank 1 reaches a predetermined pressure or higher.

When the water level of the sludge is raised up to the water level 4a of the sludge at the time of water sealing by inspecting or replacing the submerged agitator 3, the generated gas is directly connected to the gas release pipe port 52 at the upper part after rising the sludge. Since it flows from the extraction pipe 53 to the gas holder, it does not stay in the upper part of the digestion tank. Further, when the digestion gas accumulates in the upper part of the digestion tank due to clogging of the gas release pipe port 52 or the like, and the pressure exceeds a predetermined pressure, the safety valve 54 automatically opens and the accumulated gas is released from the safety valve pipe 56 into the atmosphere. It has become so.

In this way, the degassing pipe provided at the upper part of the digestion tank always stabilizes the degassing of the generated digestive gas, even while the digestion tank is operating, or while the submersible agitator is inspected or replaced. Since it is performed, the gas does not stay in the digestion tank and the high-pressure gas does not spout.

[0020]

As described above, according to the present invention, the degassing pipe is provided at the upper protruding portion above the water surface, so that the degassing is not performed and the degassing is sufficiently performed.
The gas does not accumulate in the upper part of the digestion tank, the gas pressure does not increase, and the digestion tank can be safely operated, and the submersible agitator can be inspected and replaced, thus providing industrially useful effects.

[Brief description of drawings]

FIG. 1 is a front view showing an upper structure of a stirring device for a digestion tank according to an embodiment of the present invention.

FIG. 2 is a front view showing the overall configuration of a stirring device for a digestion tank according to an embodiment of the present invention.

FIG. 3 is a front view showing an example of a conventional stirring device for a digestion tank.

FIG. 4 is a front view showing an overall configuration of an example of a conventional stirring device for a digestion tank.

[Explanation of symbols]

1 Anaerobic digestion tank 2 Draft tube 3 underwater stirrer 4 sludge 4a Sludge water sealing surface 5 through holes 6 legs 8 tank outer wall 8a concrete slab 8b wall 10 Degassing pipe 21 Lifting guide 21a Sliding mechanism 22, 22a, 22b Guide rod 23 arms 24 Wire mounting hole 25 Holder 26 Trumpet part of holder 27 ring plate 28, 29 Connection ring 31 jig 32 inspection port 34 Water sealing pipe 36 blind flange 37 motor 38 Lifting wire 39 screw 51 Gap 52 Gas vent pipe port 53 Degassing pipe 54 Safety valve 55 Safety valve piping port 56 Safety valve piping 57 Center Dome Direction of A sludge

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shunichi Kamezaki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihonkokankan Co., Ltd. (56) References JP-A-8-10798 (JP, A) (58) Survey Areas (Int.Cl. ⁷ , DB name) C02F 11/04

Claims (2)

(57) [Claims] 1. A stirrer for an anaerobic digestion tank for sludge, which is provided in a ceiling portion of the digestion tank so as to project upward from the ceiling portion, and has a penetrating passage that communicates the inside and outside of the digestion tank. Inside the through-hole and inside the digestion tank, a predetermined gap is formed between the upper projecting portion having a hole and the inside wall of the through-hole, and sludge floats at the lower end in the digestion tank. A water-sealing pipe that is submerged in water to seal the digestion tank, and an upper end and a lower end of the water-sealing pipe that are erected under the water-sealing pipe and are submerged in the water in which sludge floats. A draft tube that is open, a stirrer that is detachably attached to the upper end of the draft tube and that stirs water in which sludge floats, and the stirrer is connected to the front through the through hole and the water sealing pipe. An agitator loading / unloading mechanism for loading / unloading into / from the digestion tank and for attaching to / detaching from the upper end of the draft tube, and penetrating the wall of the upper protruding portion, and between the water sealing pipe and the inner wall of the through hole. And a gas venting pipe connected to the gap for venting digestive gas generated in the digestion tank. 2. A safety valve pipe that penetrates the wall of the upper protrusion and is connected to the gap between the water sealing pipe and the inner wall of the through hole, and the safety valve pipe, The apparatus according to claim 1, further comprising a safety valve that opens when the digestion gas accumulated in the upper portion of the digestion tank reaches a predetermined pressure or higher.