JP3551765B2 - Eddy prevention device for sludge digestion tank agitator - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for suppressing the generation of vortex when a stirrer in an anaerobic digestion tank for sludge draws sludge into a draft tube.
[0002]
[Prior art]
FIG. 7 is a longitudinal sectional view showing the entire configuration of a conventional sludge digestion tank stirrer.
[0003]
In FIG. 7, 1 is a draft tube, 2 is sludge, 2a is the highest level of sludge during normal operation, 2b is the level of sludge during water sealing, and 3 is a leg for fixing the draft tube 1 to the bottom in the digestion tank. , 4 is a concrete slab, 5 is an upper space, 6 is an inspection □, 7 is an inspection □ 6, a water sealing pipe having an upper end connected to 6, 8 is a blind flange, 9 is an underwater stirrer, 11 is a motor of an underwater stirrer 9, 12 is a screw of the underwater stirrer 9, 13 is a ring plate connected to the upper part of the draft tube 1, 14 is a guide rod having one end fixed to the ring plate 13 side and the other end extending vertically upward, in the circumferential direction of the draft tube. It is arranged in several places. The free ends (upper portions) of the guide rods 14 are connected to each other by connection rings 15a and 15b. Reference numeral 16 denotes a slider which is arranged horizontally and slides up and down by sliding on the guide rod 14, and 17 denotes an arm which connects the slider 16 and the underwater stirrer 9, and extends downward from the center of the slider 16. Reference numeral 18 denotes a holder for installing the underwater stirrer 9 directly above the draft tube 1, and 19 denotes a flapper connected to the holder 18, and the wrapper 19 is installed at the top of the draft tube 1. The underwater stirrer 9 is fixed. Reference numeral 21 denotes a hole for mounting a wire (or a chain) provided on the slider 16, reference numeral 22 denotes a hook provided on an upper portion of the inner surface of the water sealing pipe 7, and reference numeral 23 denotes a hoist connecting the mounting hole 21 and the hook 22. The wire (or chain) 24 is a reinforcing rib of the water seal pipe 7. The arrow in the figure indicates the direction in which sludge flows.
[0004]
In such a device, the digestion tank has a draft tube 1 whose upper and lower ends are open, which is erected inside sludge so as to be immersed in sludge. An underwater stirrer 9 inserted from the inspection port 6 is installed directly above the draft tube 1, and a downward or upward flow (here, downward) flows into the draft tube 1 by rotation of a screw 12 of the underwater stirrer 9. This generates a circulating flow by forced convection in the digestion tank, whereby the sludge 2 can be stirred as a whole. The generated gas is collected in a gas holder (not shown) from a gas vent pipe provided through the outer wall of the digestion tank.
[0005]
[Problems to be solved by the invention]
By the way, when the screw 12 of the underwater stirrer 9 rotates to generate a flow in the draft tube 1, a vortex is generated in the sludge drawn into the draft tube 1. In the case of downward flow, a strong suction vortex is formed depending on the sludge level due to the circumferential velocity component of this vortex, and the air (digestion gas) in the upper space is sucked, which causes noise and vibration, Invites erosion.
[0006]
To simply eliminate the flow velocity component in the circumferential direction of the vortex, it is sufficient to arrange the plate so as to block the flow of the vortex, but careless installation of protrusions may cause entanglement of the residue. turn into.
[0007]
The technical problem of the present invention is to pay attention to the above-described problem, and to suppress generation of vortex without causing sticking of residue when a submerged stirrer draws sludge into a draft tube. It is in.
[0008]
[Means for Solving the Problems]
Vortex prevention apparatus of the engagement Ru sludge digestion tank agitator to the onset Ming are those having the structure below. That is, in the sludge digestion tank stirrer that draws sludge into the draft tube in the digestion tank by rotation of the screw of the underwater stirrer and generates a circulating flow by forced convection in the digestion tank , around the casing of the motor of the underwater stirrer, A plurality of guide plates for guiding the sludge drawn into the draft tube by the screw in the vertical direction are radially mounted, and each guide plate holds an installation ring member surrounding the screw of the underwater stirrer, and the underwater stirrer is used. Is supported at the top of the draft tube by each guide plate via a ring member .
In the present invention , each guide plate arranged around the underwater stirrer eliminates the circumferential flow velocity component of the vortex generated when the sludge is drawn into the draft tube, and removes the sludge drawn into the draft tube. Guide vertically. Therefore, in the case of downward flow, it is not possible to suck air (biogas) in the head space is prevented vortex generated by noise and vibration is suppressed, with it no longer lead to erosion, the guide The flow rate of the sludge passing through the plate portion is increased, so that the residue does not cling to each guide plate.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the illustrated embodiments.
FIG. 1 is an overall configuration diagram including a partially transparent display of a vortex prevention device of a sludge digestion tank stirrer according to an embodiment of the present invention, FIG. 2 is a front view of a state in which a joint ring with the arm is removed, and FIG. 4 is a schematic bottom view, FIG. 4 is a plan view schematically showing the relationship between the motor casing of the underwater stirrer and each guide plate, FIG. 5 is a plan view corresponding to FIG. 4 showing a modification of the guide plate, and FIG. It is a front view which shows the other modification of a guide plate. In each figure, the same code | symbol is attached | subjected to the same part as the above-mentioned conventional example, and the description is abbreviate | omitted. In the description, reference will be made to the above-described conventional drawing (FIG. 7).
[0011]
The vortex prevention device of the sludge digestion tank stirrer according to the present embodiment includes a plurality of sludges that guide the sludge drawn into the draft tube 1 by the screw 12 of the underwater stirrer 9 around the casing 11a of the motor 11 of the underwater stirrer 9 in the vertical direction. (Four here) guide plates 31 are radially mounted, and each guide plate 31 holds an installation ring member 32 surrounding the screw 12 of the underwater stirrer 9. Are supported at the top of the draft tube 1 by the respective guide plates 31 through the fins .
[0012]
More specifically, each of the guide plates 31 is formed of a flat plate having a right-angled triangular shape (FIG. 6 (a)), and has a half-cylindrical cylindrical shape attached to the casing 11a of the motor 11 of the underwater stirrer 9. Are fixed to the covers 11b and 11c by welding so that their right-angled portions are downward and one side sandwiching the right-angled portions is along the central axis of the motor 11. That is, each of the guide plates 31 is set so that one side on the side to be welded is approximately the same as the axial length of the casing 11 a of the motor 11, and is arranged so that the lower portion is widened toward the bottom. Are mounted on the covers 11b and 11c so as to be radial with respect to the casing 11a. This ensures a sufficient area to eliminate the circumferential flow velocity component of the vortex generated when the sludge is drawn into the draft tube 1. The half-cylindrical covers 11b and 11c have fastening flanges (not shown) formed on both side edges thereof, and the flanges are fixed to each other by bolts. The casing 11a is fastened.
[0013]
Further, each guide plate 31 is formed with a hook portion 31a on the outer end side of the lower side thereof, and the hook portion 31a holds an installation ring member 32 surrounding the screw 12 of the underwater stirrer 9. I have.
[0014]
The ring member 32 is formed in a flared tube 32a whose upper end is divergent, and when inserted into an opening at the top of the draft tube 1, the ring member 32 is prevented from being sunk by a fitting plate 32b attached to the outer periphery of the ring member. It has become. That is, the ring member 32 functions as a joint when the underwater stirrer 9 is installed directly above the draft tube 1. The other peripheral configuration is the same as that of the above-described conventional example.
[0015]
As described above, in the vortex prevention device of the sludge digestion tank stirrer of the present embodiment, the circumferential flow velocity component of the vortex generated when the sludge is drawn into the draft tube 1 with respect to the casing 11a of the underwater stirrer 9. Since a plurality of guide plates 31 each having a sufficient area for eliminating the air are radially attached, the sludge drawn into the draft tube 1 is prevented from flowing in the circumferential direction by the respective guide plates 31, and the traveling direction thereof is reduced. Is deflected in the vertical direction and drawn into the draft tube 1. Therefore, in the case of a downward flow, the air (digestion gas) in the upper space in the digestion tank is not sucked, the generation of eddies is prevented, noise and vibration are suppressed, and erosion does not occur. .
[0016]
In addition, since each guide plate 31 is attached to the motor casing 11a near the screw 12 of the underwater stirrer 9, the flow rate of the sludge passing through each guide plate 31 is high, and the residue does not stick to each guide plate 31. .
[0017]
Here, the guide plate 31 has been described as an example in which each of the guide plates 31 is formed of a flat plate having a right triangle (FIG. 6A), but what is important about the guide plate 31 is the circumference of the vortex. The shape and the like are not so important to ensure a sufficient area to eliminate the flow velocity component in the direction, and for example, a flat plate in which the hypotenuse of a right triangle as shown in FIG. Alternatively, a trapezoidal plate as shown in FIG. 6 (c) can be employed, and furthermore, a guide in which these shaped plates are curved so as to take in the flow velocity component in the circumferential direction of the vortex as shown in FIG. The plate 41 may be used, and in any case, the same operation and effect as those of the above-described embodiment can be obtained.
[0018]
【The invention's effect】
As described above, according to the present invention , a plurality of guide plates for vertically guiding sludge drawn into a draft tube by a screw are radially mounted around a casing of a motor of a submersible stirrer , and each guide plate is The holding ring member surrounding the screw of the underwater stirrer was held, and the underwater stirrer was supported at the top of the draft tube by the respective guide plates via the ring member, so that the sludge was introduced into the draft tube. The circumferential flow velocity component of the vortex generated at the time of drawing is eliminated by each guide plate, and the sludge drawn into the draft tube can be guided in the vertical direction. Therefore, in the case of downward flow, it is not possible to suck air (biogas) in the head space is prevented vortex generated by noise and vibration is suppressed, with it no longer lead to erosion, the guide The flow rate of the sludge passing through the plate portion is increased, so that the residue does not cling to each guide plate.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram including a partially transparent display of a vortex prevention device of a sludge digestion tank stirrer according to an embodiment of the present invention.
FIG. 2 is a front view of a state in which a ring for joint with an arm of a vortex prevention device of a sludge digestion tank stirrer according to the present embodiment is removed.
FIG. 3 is a schematic bottom view of the eddy prevention device of the sludge digestion tank stirrer according to the present embodiment.
FIG. 4 is a plan view schematically showing a relationship between a motor casing of an underwater stirrer and each guide plate of the vortex prevention device of the sludge digestion tank stirrer according to the present embodiment.
FIG. 5 is a plan view corresponding to FIG. 4, showing a modification of the guide plate.
FIG. 6 is a front view showing another modification of the guide plate.
FIG. 7 is a longitudinal sectional view showing the entire configuration of a conventional sludge digestion tank stirrer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Draft tube 2 Sludge 9 Underwater stirrer 11 Motor 11a Motor casing 12 Screw 31, 41 Guide plate 32 Ring member

Claims (1)

In the sludge digestion tank stirrer that draws sludge into the draft tube in the digestion tank by rotation of the screw of the underwater stirrer and generates a circulating flow by forced convection in the digestion tank,
Around the casing of the motor of the underwater stirrer, a plurality of guide plates for vertically guiding sludge drawn into the draft tube by the screw are radially attached, and each guide plate is provided with a screw around the screw of the underwater stirrer. A vortex preventing device for a sludge digestion tank stirrer , wherein a surrounding ring member for installation is held, and the underwater stirrer is supported at the top of a draft tube by each guide plate via the ring member .

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