JP4387038B2 - Sludge digester agitator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stirring device for an anaerobic digester of sludge.
[0002]
[Prior art]
As a conventional digester used for anaerobic treatment of sludge, for example, a sludge digester having a turtle shell shape or an abacus shape and an egg-shaped sludge digester shown in FIG. 4 are used.
Among them, a gas stirring method has been adopted in a turtle shell-shaped or abacus-shaped sludge digester to stir sludge. However, with this gas stirring method, the stirring power is weak, and there are problems such as sand and sludge accumulating in the lower part of the sludge digestion tank, and more recently, reduction (high concentration) by mechanical concentration of sewage sludge has progressed. However, the gas agitation method is becoming increasingly insufficient. For this reason, it is desired to adopt a mechanical stirring system with excellent stirring power in a turtle shell-shaped or abacus-shaped sludge digester.
[0003]
On the other hand, the egg-shaped sludge digestion tank 101 shown in FIG. 4 employs a mechanical stirring system with excellent stirring power. Specifically, the draft tube 102 is provided in an upright state inside the sludge digestion tank 101, the screw 105 of the stirrer 103 is inserted from the upper end opening of the draft tube 102, and the screw 105 rotates downward into the draft tube 102. Alternatively, an upward flow is generated, whereby a circulating flow by forced convection is generated in the sludge digestion tank 101 to agitate the sludge 106 as a whole.
[0004]
Here, as shown in FIG. 4, the lower portion of the draft tube 102 is fixed to the lower portion of the inner wall of the sludge digestion tank 101 by a plurality of support legs 107, and is erected and disposed in the sludge 106. The sludge is sucked and the sucked sludge is discharged from the other end opening.
The agitator 103 includes a bearing box embedded in the concrete slab 101a immediately above the draft tube 102 of the sludge digestion tank 101, and a motor disposed on the upper side of the bearing box. The shaft 104 is connected to the shaft 104 via a bearing box.
[0005]
[Problems to be solved by the invention]
However, the sludge digestion tank 101 shown in FIG. 4 has the following problems.
That is, the egg-shaped sludge digestion tank 101 shown in FIG. 4 is developed on the assumption that it is applied to a digestion tank designed in advance so as to be able to install the agitator 103 on the concrete slab at the top of the sludge digestion tank 101. Therefore, there is a problem that the agitator 103 cannot be installed due to a problem in strength in a digestion tank that has already been operated without consideration of such design strength.
[0006]
That is, in the existing sludge digestion tank of the above-mentioned turtle shell shape or abacus type, the strength of the concrete slab at the top of the sludge digestion tank is insufficient, and the mechanical stirring type agitator 103 used for the egg-shaped digestion tank 101 is installed. Can not do it.
In the egg-shaped sludge digestion tank 101 shown in FIG. 4, when the agitator 103 is pulled out of the sludge digestion tank 101 for maintenance, the tank sludge 106 is emptied or the sludge 106 is put in the state. must implement security measures previously purged with nitrogen or the like in order to prevent leakage of harmful digestion gas, maintainer Nsu working agitator 103 has been a cumbersome.
[0007]
Accordingly, the present invention has been made to solve the above-described problems, and its purpose is to provide a mechanical stirring system without placing a burden on the top slab even in an existing digester having a turtle shell shape or an abacus shape. It is providing the stirring apparatus of the sludge digestion tank which enabled installation of the stirrer of this.
Moreover, the other object of this invention is to provide the stirring apparatus of the sludge digestion tank which can implement the maintenance operation | work of a stirrer easily.
[0008]
[Means for Solving the Problems]
In order to solve the above object, a sludge digesting tank agitator according to claim 1 of the present invention comprises a draft tube erected on a lower portion of an inner wall of the sludge digesting tank via a support leg, and the sludge digesting tank inside And a stirring device for a sludge digesting tank equipped with a stirrer for stirring sludge, and extending the upper end of the draft tube to at least the lid of the inspection port provided at the top of the sludge digesting tank. The stirrer is detachably installed in the draft tube, and the motor holding part of the stirrer has a main body part having an inclined outer shape corresponding to the inclined surface part of the draft tube, and an arm extending upward from the main body part The stirrer is held by the draft tube by fitting the main body portion and the arm portion to the inclined surface portion .
[0009]
According to this stirrer, the stirrer is installed so as to be able to be inserted into and removed from the upper end portion of the draft tube, and the load of the draft tube and the stirrer is supported by the lower portion of the inner wall in the sludge digestion tank via the support legs. This eliminates the burden on the top slab of the sludge digester, and even in existing digesters with a turtle shell or abacus shape, a mechanical stirrer is installed without placing a burden on the top slab. Can do. Since the upper end of the draft tube extends at least to the lid of the inspection port provided at the top of the sludge digestion tank, the draft can be lifted from the upper end of the draft tube by a free lifting device. It can be easily installed in the tube. In addition, since the upper end of the draft tube extends to the lid of the inspection port, when the agitator is pulled up with sludge in the sludge digestion tank, the draft tube itself is in the sludge digestion tank. The digestive gas remaining in can be shut off.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view of an embodiment of a stirring apparatus for a sludge digestion tank according to the present invention. FIG. 2 is an enlarged view showing details of the vicinity of the stirrer of the stirrer shown in FIG. 3A and 3B are explanatory views when the stirrer is pulled up from the time when the stirrer is operated. FIG. 3A is a partial vertical cross-sectional view when the stirrer is operated, and FIG.
[0011]
As shown in FIG. 1, the sludge digestion tank 1 has a turtle shell shape or an abacus shape in cross section, and about half of the tank is embedded below the ground surface GL. The top slab 3 of the sludge digestion tank 1 is provided with an inspection port 4 that communicates the inside and the outside of the sludge digestion tank 1. The inspection port 4 is provided with a lid 5 having a through hole through which a large-diameter pipe portion 12 of a draft tube 10 described later passes.
[0012]
In the sludge digestion tank 1, a draft tube 10 is erected on the inner wall lower part 2 in the sludge digestion tank 1 via support legs 20. The draft tube 10 has a relatively thin inner / outer diameter small-diameter pipe portion 11 having openings at upper and lower ends, a large-diameter pipe portion 12 having an inner / outer diameter larger than that of the small-diameter pipe portion 11 and openings at upper and lower ends, and a small diameter. It consists of an intermediate pipe part 13 that connects both the pipe part 11 and the large diameter pipe part 12. The small-diameter pipe portion 11 of the draft tube 10 is disposed below the sludge digestion tank 1 and is fixed to the lower portion 2 of the inner wall in the sludge digestion tank 1 by support legs 20. The large-diameter pipe portion 12 is disposed above the sludge digestion tank 1, and the upper end portion of the large-diameter pipe portion 12 projects upward through the through-hole of the lid 5 on the upper surface of the inspection port 4. Has been established. In the present embodiment, the upper end portion of the large-diameter pipe portion 12 penetrates the through hole of the lid body 5 and protrudes upward. However, if it extends at least to the through hole of the lid body 5 Good. In addition, the upper end part of the large diameter pipe part 12 penetrates the through-hole of the cover body 5 and protrudes upwards, so that the lid member 14 that can be removably attached to the upper end opening of the large diameter pipe part 12 can be easily provided. Can be installed. Airtightness is maintained between the through hole of the lid 5 and the large-diameter pipe portion 12 so that the inside of the sludge digestion tank 1 and the outside air are blocked. The upper end opening of the large-diameter pipe portion 12 can be closed by a removable lid member 14. Further, the intermediate tube portion 13 is disposed between the large diameter tube portion 12 and the small diameter tube portion 11, and as shown in FIG. 2, the intermediate tube portion 13 extends from the inner diameter of the large diameter tube portion 12 to the inner diameter of the small diameter tube portion 11. It has the inclined surface part 13a which reduces an internal diameter gradually. A sludge inflow / outlet opening 15 is formed on the lower side surface of the inclined surface portion 13 a of the intermediate pipe portion 13. Further, the support leg 20 extends obliquely with respect to the small-diameter pipe part 11 and tilted leg part 21 that fixes the small-diameter pipe part 11 to the inner wall lower part 2, and extends perpendicularly to the small-diameter pipe part 11 and extends into the small-diameter pipe part. 11 and an orthogonal leg 22 that connects the inclined leg 21.
[0013]
Further, an agitator 30 for agitating the sludge 40 in the sludge digestion tank 1 is installed in the draft tube 10 so as to be insertable / removable. Agitator 30, as best shown in FIG. 2, comprises a motor 31, a screw 32 rotatable attached to the rotating shaft of the motor 31, a motor holding member 33 for holding the motor 31 on the inside is doing. The motor holding member 33 has a main body part 33 a having an inclined outer shape corresponding to the inclined surface part 13 a of the intermediate pipe part 13 and an arm part 33 b extending upward from the main body part 33 a. In the state installed inside, the main body portion 33a and the arm portion 33b are held by being fitted to the inclined surface portion 13a. In the installed state of the stirrer 30, the screw 32 is located in the small diameter pipe portion 11 of the draft tube 10 and below the sludge inflow / outflow opening 15. Further, the sludge 40 in the sludge digestion tank 1 flows into the draft tube 10 from the lower end opening of the small-diameter pipe portion 11 of the draft tube 10 and the sludge inflow / outflow opening 15 of the intermediate pipe portion 13, and the agitator 30 is installed. Then, the sludge 40 is filled around the stirrer 30, and the stirrer 30 is submerged. In addition, in FIG.1, FIG.2 and FIG.3 (A), the code | symbol 34 is a cabtire cable.
[0014]
Next, the installation method of the stirrer 30 is demonstrated with reference to FIG.1 and FIG.2.
First, after the sludge 40 in the existing sludge digesting tank 1 is discharged, the lid member 14 at the upper end opening of the draft tube 10 is removed, and the stirrer 30 is lifted by a lifting device such as a crane through a suspension wire (not shown). Is inserted into the inside of the draft tube 10 through the upper end opening. When the stirrer 30 is inserted into the draft tube 10, the arm portion 33 b serves as a guide, so that the stirrer 30 is positioned substantially at the center in the draft tube 10. Further, the agitator 30 is lowered until the main body portion 33a and the arm portion 33b are fitted to the inclined surface portion 13a of the draft tube 10, and the agitator 30 is separated from the crane, so that the agitator 30 can be inserted into and removed from the draft tube 10. Installed. When the agitator 30 is installed in the draft tube 10, the loads of the draft tube 10 and the agitator 30 are supported by the lower portion 2 of the inner wall in the sludge digestion tank 1 through the support legs 20. For this reason, there is no load on the top slab 3 of the sludge digestion tank 1, and even the existing sludge digestion tank 1 in the shape of a turtle shell or an abacus is agitated by a mechanical stirring method without burdening the top slab 3. Machine 30 can be installed. And since the upper end part of the draft tube 10 extends at least to the cover body 5 of the inspection port 4 provided in the top slab 3 of the sludge digestion tank 1, the arm part 33b is positioned by the inclined surface part 13a. The agitator 30 can be easily installed in the draft tube 10 from the upper end of the draft tube 10 by a crane that can be raised and lowered freely. Incidentally, agitator 30, since the water of its installed state, agitator 30 weight itself is Tsu a lighter, be installed in draft Chi Yubu 10, sludge digestion tank 1 via the support legs 20 The inner wall lower part 2 is supported without problems.
[0015]
After the stirrer 30 is installed in the draft tube 10, the sludge 40 is filled in the sludge digestion tank 1 and the operation of the stirrer 30 can be started. When the screw 32 is rotated in accordance with the operation of the stirrer 30, a downward or upward flow as indicated by an arrow in FIG. 1 is generated inside the small-diameter pipe portion 11 of the draft tube 10, thereby forcibly entering the sludge digester 1. A circulating flow by convection is generated to stir the sludge 40 as a whole. When the sludge 40 is stirred, the sludge inflow / outlet opening 15 formed in the intermediate pipe portion 13 of the draft tube 10 functions as an inlet of the sludge 40 when a downward flow is generated in the draft tube 10. When an upward flow is generated in the draft tube 10, it functions as an outlet for the sludge 40. For this reason, the circulating flow of the sludge 40 can be reliably generated in the sludge digestion tank 1. As shown in FIG. 2, the height position of the inflow / outlet opening 15 is below the liquid level WL of the sludge 40 and is a position where air (gas) is not involved when the sludge 40 flows downward. is there. For this reason, air does not get involved in the inflow / outflow opening 15 when the sludge 40 flows downward.
[0016]
Next, when the agitator 30 is pulled up for maintenance, it is not necessary to empty the sludge 40 in the sludge digester 1, and the sludge 40 is removed from the sludge digester as shown in FIGS. 3 (A) and 3 (B). 1, the lid member 14 at the upper end opening of the draft tube 10 is removed, and the agitator 30 may be lifted from the upper end opening of the draft tube 10 via a suspension wire by a lifting device such as a crane. In the operation state of the agitator 30 shown in FIG. 3A, the digestion gas is filled in the sludge digestion tank 1, and when this agitation gas flows out when the agitator 30 is pulled out, It is harmful to However, since the upper end portion of the large-diameter pipe portion 12 of the draft tube 10 extends to reach the lid 5 of the inspection port 4, the draft tube 10 itself becomes the sludge digester when the stirrer 30 is pulled up. The digestive gas remaining in 1 can be shut off. For this reason, the outflow of the digestion gas to the outside of the tank can be surely prevented, and safety measures associated with the outflow of the digestion gas are not required. Therefore, the maintenance work of the stirrer 30 is compared with the stirrer shown in FIG. It can be done easily.
[0017]
【The invention's effect】
As explained above, according to the sludge digestion tank agitator according to claim 1 of the present invention, the agitator is installed so as to be able to be inserted into and removed from the upper end of the draft tube, and the load of the draft tube and the agitator Is supported by the lower part of the inner wall of the sludge digestion tank via the support legs, so even in existing digesters with a turtle shell or abacus shape, a mechanical stirrer is installed without placing a burden on the top slab. be able to. Since the upper end of the draft tube extends at least to the lid of the inspection port provided at the top of the sludge digestion tank, the draft can be lifted from the upper end of the draft tube by a free lifting device. It can be easily installed in the tube. In addition, since the upper end of the draft tube extends to the lid of the inspection port, when the agitator is pulled up with sludge in the sludge digestion tank, the draft tube itself is in the sludge digestion tank. It is possible to shut off the digestion gas remaining in the slag, and to easily carry out the maintenance work of the stirrer.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an embodiment of a stirring apparatus for a sludge digestion tank according to the present invention.
FIG. 2 is an enlarged view showing details in the vicinity of the stirrer of the stirrer shown in FIG. 1;
FIGS. 3A and 3B are explanatory views when the stirrer is pulled up from the time when the stirrer is operated; FIG. 3A is a partial vertical cross-sectional view when the stirrer is operated; and FIG.
FIG. 4 is a longitudinal sectional view of a conventional egg-shaped sludge digester.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sludge digestion tank 2 Inner wall lower part 3 Top slab 4 Inspection port 5 Cover body 10 Draft tube 11 Small diameter pipe part 12 Large diameter pipe part 13 Intermediate pipe part 13a Inclined surface part 14 Lid member 15 Sludge inflow / outflow opening 20 Support leg 21 Inclined leg Section 22 Right leg section 30 Stirrer 31 Motor 32 Screw 33 Motor holding section 33a Main body section 33b Arm section 34 Cabtire cable 40 Sludge GL Ground surface WL Sludge liquid level

Claims (1)

In a stirring apparatus for a sludge digestion tank, comprising a draft tube erected on a lower portion of the inner wall in the sludge digestion tank, and a stirrer for stirring the sludge in the sludge digestion tank,
The upper end of the draft tube extends to at least the lid of the inspection port provided at the top of the sludge digestion tank, and the stirrer is installed so as to be insertable into and removed from the draft tube .
The motor holding portion of the stirrer has a main body portion having an inclined outer shape corresponding to the inclined surface portion of the draft tube, and an arm portion extending upward from the main body portion, and the main body portion and the arm portion are inclined. The stirrer for a sludge digestion tank , wherein the stirrer is held by the draft tube by being fitted to a surface portion .

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