JP3961084B2 - Digestive function maintenance device of digester - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a digester tank for maintaining a sludge digestion function of a digester tank when a normally used mechanical stirrer of a digester tank is temporarily removed for inspection and repair in a digester tank such as sewage sludge. The present invention relates to a function maintaining device.
[0002]
[Prior art]
In sewage treatment plants, sludge is often digested to reduce sludge, prevent malodors, improve dewatering efficiency, and the like. In the sludge digestion treatment, the sludge in the digestion tank is agitated to promote sludge digestion. There are several means for stirring the sludge, but there are many cases of using a mechanical stirring device that can freely change the direction of the liquid flow either vertically.
[0003]
When using a mechanical stirring apparatus, as shown in FIG. The stirrer 2 includes a vertical stirring pump 4 and a drive motor 3. A draft tube 5 is installed at the center of the digester 1. The draft tube 5 is supported in a vertical state by a lower pedestal 6 and an upper tie rod 7.
[0004]
The stirring pump 4 is provided with a rectifying disk 14, an upper stage impeller 15, and a lower stage impeller 16 on a shaft 13. The lower stage impeller 16 is disposed above the draft tube 5, and has an inner diameter of the draft tube 5 and an outer diameter of the lower stage impeller 16. The cores are inserted so that a uniform gap is formed between them.
[0005]
The agitation pump 4 can generate both the downward flow and the upward flow by the upper impeller 15 and the lower impeller 16 by changing the rotation direction of the shaft 13.
[0006]
When the agitation pump 4 is operated so as to suck the liquid in the digestion tank 2 from the upper end of the draft tube 5 and discharge it from the lower end to generate a downward flow in the draft tube 5, the digester tank outside the draft tube 5 is operated. An upward flow is generated in 5.
[0007]
When the agitation pump 4 is operated so that the liquid in the digestion tank 2 is sucked from the lower end of the draft tube 5 and discharged from the upper end and an upward flow is generated in the draft tube 5, the digester tank outside the draft tube 5 is operated. 5 has a downward flow.
[0008]
Thus, the digestion process of sludge is performed by generating a circulating flow in the digestion tank 5 and controlling the direction of the flow as necessary.
[0009]
[Problems to be solved by the invention]
One stirrer 2 is installed for one digester 1 and usually has no equipment due to equipment cost constraints. The agitator 2 must be removed from the digestion tank 1 when performing periodic repairs such as overhaul, so that the agitation in the digestion tank 1 becomes impossible during the repair period and the sludge digestion process is stopped. In the sewage treatment plant, digestion treatment must be bypassed during this period, so the quality of the treated water deteriorates and the sludge in the digestion tank 1 decays. Is required.
[0010]
The present invention solves the above problems in a digester equipped with a mechanical stirrer, and when the stirrer is temporarily removed for inspection and repair, etc., by replacing it with a sludge digestion function of the digester. It aims at providing the digestive function maintenance apparatus of the simple digester which can be maintained.
[0011]
[Means for Solving the Problems]
In the present invention, in a digestion tank equipped with a mechanical stirrer, as a digestive function maintenance apparatus for a digester tank that is installed as an alternative when the stirrer is removed, digestion gas is sucked from the digestion tank through the gas suction pipe to the required pressure. The above-mentioned problem is solved by providing a gas pressure generating device for increasing the pressure and a gas supply pipe for introducing the digestion gas increased by the gas pressure generating device into the draft tube.
[0012]
The digestion function maintaining device installed as an alternative sucks digestion gas from the digestion tank into the gas pressure generation device via the gas intake pipe by operating the gas pressure generation device. The inhaled digestion gas is boosted to a required pressure and discharged from the gas pressure generator to the supply gas pipe. The discharged digestion gas is guided into the draft tube by the supply gas pipe, and is discharged from the discharge port of the supply gas pipe into the draft tube.
[0013]
The sludge liquid in the vicinity of the discharge port of the gas supply pipe contains digestion gas and has a lower specific gravity than the surrounding sludge liquid and rises in the draft tube. When digestion gas is continuously discharged from the discharge port, an upward flow is generated in the draft tube, and a circulating flow is induced in the digestion tank, and the sludge is stirred, so the sludge digestion function is maintained. Is done.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an overall configuration diagram of a digestion tank provided with a digestive function maintaining apparatus according to an embodiment of the present invention.
[0015]
A draft tube 5 is installed in the center of the digester 1. The draft tube 5 is supported in a vertical state by a support device including a lower pedestal 6 and an upper tie rod 7.
[0016]
The digestive function maintaining device is installed in the digestion tank 1 equipped with a mechanical stirrer when the stirrer 2 in FIG. 2 is removed for inspection and repair. A generator 8 is installed. A gas suction pipe 9 is laid from the upper part in the digestion tank 1 to the gas pressure generator 8, and a gas supply pipe 10 is laid from the gas pressure generator 8 to the inside of the draft tube. A discharge port 11 is opened at the lower end of the gas supply pipe 10.
[0017]
Since this digestive function maintaining apparatus has a simple configuration as described above, it can be easily installed after the agitator 2 is removed.
When the gas pressure generating device 8 is operated, the digested gas generated in the digesting tank 1 and staying in the upper part is sucked into the gas pressure generating device 8 through the gas intake pipe 9. The inhaled digestion gas is boosted to a required pressure by the gas pressure generator 8 and discharged from the gas pressure generator 8 to the supply gas pipe 10. The digestion gas is guided into the draft tube 5 by the gas supply pipe 10 and is released into the draft tube 5 from the discharge port 11 of the gas supply pipe 10.
[0018]
The sludge liquid in the vicinity of the discharge port 11 of the gas supply pipe 10 contains digestion gas and has a specific gravity smaller than that of the surrounding sludge liquid and rises in the draft tube 5. When digestion gas is continuously discharged from the discharge port 11, a continuous upward flow is generated in the draft tube 5, and a circulating flow is induced in the digestion tank 1 so that sludge is stirred. , Sludge digestion function is maintained. Therefore, the digester 1 can carry out repair work on the stirrer of the mechanical stirrer while maintaining the sludge digestion function.
[0019]
When the repair work of the stirrer is completed, the digestive function maintaining device is removed and the mechanical stirrer is returned to the state before repair by installing the stirrer 2 again.
The removal work of the digestive function maintaining apparatus at this time can also be performed very easily.
[0020]
【The invention's effect】
As described above, the digestive function maintaining device for digester according to the present invention is installed in place of a stirrer in a digester equipped with a mechanical stirrer when the stirrer is temporarily removed for inspection and repair. By this, the sludge digestion function of the digester can be maintained.
[0021]
Therefore, the agitator can be repaired without stopping the sludge digestion process in the digester.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a digestion tank provided with a digestive function maintaining apparatus according to an embodiment of the present invention.
FIG. 2 is an overall configuration diagram of a digester equipped with a conventional mechanical stirring device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Digestion tank 2 Stirrer 3 Drive motor 4 Stirring pump 5 Draft tube 6 Mounting leg 7 Tie rod 8 Gas pressure generator 9 Gas absorption piping 10 Gas supply piping 11 Release port

Claims (1)

A digester with a mechanical stirrer, which is replaced by a digester function when the stirrer is removed. The digester is maintained from the digester through the gas suction pipe and the pressure is increased to the required pressure. A digestion tank digestion function maintaining device, comprising: a gas pressure generator; and a gas supply pipe for guiding digestion gas boosted by the gas pressure generator into a draft tube.

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