JP6267594B2 - High speed stirring device and coagulation stirring method - Google Patents

Description

  The present invention relates to a high-speed stirring device that uniformly mixes a flocculant and the stock solution by stirring the stock solution containing suspended solids into which the flocculant has been injected. The present invention also relates to an agglomeration stirring method in which a stock solution containing a suspended substance into which a flocculant is injected is stirred at high speed with a high speed stirring apparatus and then stirred at low speed with a low speed stirring apparatus. In this specification, the stock solution refers to the liquid to be treated.

  Conventionally, various types of dehydrators such as a screw press type, a belt press type, a centrifugal type, a vacuum type, a filter press type, or a multi-disc type are used to separate the suspended substance from the stock solution containing the suspended substance. It has been. Stock solutions containing suspended solids include human waste sludge, sewage sludge, or private industrial wastewater sludge, but also raw water from water purification plants, food raw material liquid, cosmetic raw material liquid, paper raw material liquid, or industrial use. The raw material solution is included in the stock solution containing suspended solids. As a pretreatment for dehydrating the stock solution containing the suspended solids with a dehydrator, the flocculant is injected into the stock solution, and the stock solution into which the flocculant has been injected is stirred, thereby aggregating flocs of the suspended material in the stock solution. Forming is performed.

  In order to form an agglomeration floc, it is known to perform a two-stage agitation in which a stock solution containing a suspended substance into which a flocculant has been injected is agitated at high speed with a high-speed agitator and then at a low-speed agitator. . The stock solution containing suspended solids into which the flocculant has been injected is stirred at high speed with a high-speed stirrer, so that the flocculant is uniformly mixed with the stock solution containing suspended solids. Aggregated flocs are granulated by stirring the undiluted solution after high-speed stirring at a low speed with a low-speed stirring device. Thus, the dewatering efficiency in a dehydrator is improved by granulating the aggregation floc.

  A side view of a conventional high-speed stirring device is shown in FIG. The conventional high-speed stirring device 101 includes an upstream pipe 130 and a downstream pipe 133 connected to a first opening end and a second opening end of a T-shaped pipe (so-called cheese pipe) 160, and a T-shaped pipe. And a stirring blade 105 attached to the rotary shaft 103 inserted from the third opening end of 160. The rotating shaft 103 is connected to a drive source 102 such as a motor.

  When the rotating shaft 103 is rotated by the drive source 102, the stirring blade 105 rotates together with the rotating shaft 103. A flange 126 is provided at the third opening end of the T-shaped pipe 160, and a lid plate 125 provided with a through hole through which the rotation shaft 103 passes is fixed to the flange 126. A sealing device 116 is provided in the through hole provided in the lid plate 125. The seal device 116 is a shaft seal device that prevents the undiluted solution from leaking while allowing the rotation shaft 103 to rotate. As the sealing device 116, for example, a mechanical seal or a gland packing is used.

  With such a configuration, by rotating the stirring blade 105 at a high speed, the stock solution flowing from the upstream pipe 130 is stirred at a high speed in the T-shaped pipe 160. The stock solution into which the flocculant is injected is stirred by the high-speed rotation of the stirring blade 105 in the T-shaped pipe 160. As a result, the stock solution containing the suspended substance is uniformly mixed with the flocculant.

  However, the gap between the inner peripheral surface of the T-shaped pipe 160 and the stirring blade 105 is not uniform. That is, there are places where the gap between the inner peripheral surface of the T-shaped pipe 160 and the stirring blade 105 is large, and there are also places where the gap is small. Therefore, it is difficult to uniformly mix the flocculant in the stock solution. Although the flocculant can be uniformly mixed with the stock solution by rotating the stirring blade 105 at a higher speed, the life of the sealing device 116 is shortened due to the high-speed rotation of the stirring blade 105.

International Publication No. 2012/108312 Pamphlet JP 2010-437 A JP 2008-149256 A JP 2008-1000014 A

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a high-speed stirring device capable of efficiently and uniformly mixing a flocculant with a stock solution containing a suspended substance. . It is another object of the present invention to provide a coagulation stirring method in which high-speed stirring is performed with this high-speed stirring apparatus and then low-speed stirring is performed with a low-speed stirring apparatus.

In order to achieve the above-described object, one aspect of the present invention is a high-speed stirring device that stirs a stock solution containing suspended solids into which a flocculant is injected, the rotating shaft rotated by a driving source, A stirring blade connected to a rotating shaft; a cylindrical member disposed coaxially with the rotating shaft; housing the stirring blade; a plurality of baffles fixed to an inner peripheral surface of the cylindrical member ; A front-end disk and a rear-end disk arranged along the longitudinal direction so as to sandwich the stirring blade, and the plurality of baffles are disposed around the stirring blade. Features.

In a preferred aspect of the present invention, each of the plurality of baffles has a polygonal cross section.
One reference example of the present invention is characterized in that each of the plurality of baffles is composed of divided bodies arranged along the longitudinal direction of the rotating shaft.

One reference example of the present invention further includes a lid member that closes an opening end of the cylindrical member, and the lid member is detachably attached to the cylindrical member. Thereby, opening inspection of a high-speed stirring device becomes easy.
One reference example of the present invention further includes a lid member that closes an open end of the cylindrical member, and the distal-end disk is attached to the lid member.
In one reference example of the present invention, an inflow pipe for introducing the stock solution containing the suspended substance into the cylindrical member and a discharge pipe for discharging the stock solution from the cylindrical member are connected to a side surface of the cylindrical member, and the inflow An angle of a direction in which the discharge pipe extends with respect to a direction in which the pipe extends is 90 ° or more and 270 ° or less.
In a preferred aspect of the present invention, an inflow pipe for introducing the stock solution containing the suspended substance into the cylindrical member and a discharge pipe for discharging the stock solution from the cylindrical member are connected to a side surface of the cylindrical member, and the cylindrical member The flow direction of the stock solution passing through the inside is perpendicular to the rotation axis.

  Another aspect of the present invention is to supply a stock solution containing suspended solids into which the flocculant is injected, and stir the stock solution and the flocculant with the high-speed stirrer. The stock solution and the flocculant are mixed, the stock solution in which the flocculant is mixed is supplied to the flocculent mixing tank, the flocculant is added again in the flocculent mixing tank, and the flocculant floc is stirred. Is a method of agglomerating and stirring, characterized in that.

  According to this invention, a stirring blade is accommodated in the cylindrical member provided coaxially with the rotating shaft to which a stirring blade is fixed. Therefore, the gap between the cylindrical member and the stirring blade is uniform over the entire circumference in the rotation direction of the stirring blade, so that the stock solution containing suspended solids into which the flocculant has been injected can be uniformly stirred. As a result, the flocculant can be uniformly mixed with the stock solution. A baffle is provided on the inner peripheral surface of the cylindrical member. The stock solution stirred by the stirring blade can collide with the baffle to form a turbulent flow and generate a vortex, so that the flocculant can be efficiently mixed with the stock solution in a short time. Furthermore, since the flocculant and the stock solution can be sufficiently stirred even if the stirring blade is rotated at a medium speed, the power consumption of a driving source such as an electric motor can be reduced as a result, and the life of the shaft seal device can be extended.

It is a side view of the high-speed stirring apparatus which concerns on one Embodiment of this invention. It is sectional drawing in the AA of FIG. It is sectional drawing in the BB line of FIG. It is sectional drawing corresponding to FIG. 2 of the high-speed stirring apparatus which concerns on another embodiment of this invention. It is sectional drawing corresponding to FIG. 3 of the high-speed stirring apparatus which concerns on another embodiment of this invention. It is sectional drawing corresponding to FIG. 2 of the high-speed stirring apparatus which concerns on another embodiment of this invention. It is a schematic flowchart which shows an example of the aggregation stirring apparatus with which the high-speed stirring apparatus which concerns on embodiment of this invention was integrated. It is a side view of the conventional high-speed stirring apparatus.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a side view of a high-speed stirring device according to an embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. 3 is a cross-sectional view taken along line BB in FIG. A high-speed stirring device 1 shown in FIGS. 1, 2, and 3 is a device that stirs a stock solution containing suspended solids into which a flocculant is injected at high speed. Stock solutions containing suspended solids include human waste sludge, sewage sludge, private industrial wastewater sludge, etc. The raw material solution is included in the stock solution containing suspended solids. The undiluted solution in this specification is a general term for liquids processed by the high-speed stirring device 1.

  The high-speed stirring device 1 includes a drive source 2 such as a motor, a rotary shaft 3 connected to the drive source 2 and rotated by the drive source 2, a stirring blade 5 connected to the rotary shaft 3, and a rotary shaft 3. A cylindrical member 7 disposed on the same axis. The stirring blade 5 is accommodated in the cylindrical member 7. Thus, since the cylindrical member 7 is arranged coaxially with the rotary shaft 3, the gap between the stirring blade 5 and the cylindrical member 7 is uniform over the entire circumference in the rotation direction of the stirring blade 5. As a result, the stock solution stirred by the high-speed stirrer 1 can be uniformly stirred, so that the flocculant and the stock solution containing the suspended substance can be mixed uniformly.

  A flange 26 is provided at the upper end of the cylindrical member 7, and a companion flange 25 is fixed to the flange 26. The companion flange 25 has a through hole 25a through which the rotary shaft 3 passes. The gap between the through hole 25a and the rotary shaft 3 is sealed by the sealing device 16 so that the stock solution flowing through the high speed stirring device 1 does not leak from the through hole 25a. The sealing device 16 is a shaft sealing device that prevents the stock solution from leaking while allowing the rotation shaft 3 to rotate. As the sealing device 16, for example, a mechanical seal or a gland packing is used.

  The high-speed stirring apparatus 1 in the illustrated example is configured as an inline mixer. An in-line mixer refers to a mixer incorporated in a pipe. As shown in FIGS. 1 and 2, on the side surface of the cylindrical member 7, there are an inflow pipe 20 for introducing a stock solution containing suspended solids into the cylindrical member 7, and a discharge pipe 21 for discharging the stock solution from the cylindrical member 7. It is connected. The inflow pipe 20 and the discharge pipe 21 constitute a part of the high-speed stirring device 1. The inflow pipe 20 and the discharge pipe 21 are arranged on a straight line. Therefore, the undiluted solution flowing in from the inflow pipe 20 flows linearly through the cylindrical member 7 to the discharge pipe 21. Moreover, since the inflow piping 20 and the discharge piping 21 are each connected perpendicularly to the side surface of the cylindrical member 7, the direction in which the inflow piping 20 extends and the direction in which the discharge piping 21 extends are rotation axes to which the stirring blades 5 are connected. 3 is perpendicular. Therefore, the flow direction of the stock solution passing through the cylindrical member 7 is perpendicular to the rotation axis 3.

  A flange 23 is attached to the end of the inflow pipe 20 opposite to the end connected to the cylindrical member 7. Similarly, the end of the discharge pipe 21 connected to the cylindrical member 7 is opposite. A flange 24 is attached to the end portion on the side. The flange 23 is connected to a flange 31 provided in an upstream pipe 30 disposed on the upstream side of the high-speed stirring apparatus 1, and similarly, the flange 24 is a downstream pipe 33 disposed on the downstream side of the high-speed stirring apparatus 1. It is connected to the flange 34 provided in. Thus, the high speed stirring apparatus 1 is configured as an in-line mixer by connecting the upstream pipe 30 and the downstream pipe 33 via the high speed stirring apparatus 1.

  The stirring blade 5 includes a cylindrical shaft member 17 that is detachable from the rotary shaft 3 and a plurality of blades 18 that are arranged at equal intervals along the circumferential direction of the shaft member 17. In the present embodiment, four blades 18 are fixed to the outer peripheral surface of the shaft member 17. As shown in FIG. 2, when the stirring blade 5 is viewed from above, the blades 18 extend radially outward from the outer peripheral surface of the shaft member 17. The blades 18 extend radially outward from the outer peripheral surface of the shaft member 17 and also extend in a direction parallel to the longitudinal direction of the rotating shaft 3 as shown in FIG. The number of blades 18 is not limited to four. For example, the number of wings 18 may be 5 or more, or 3 or less.

A through hole into which the rotary shaft 3 is fitted is formed at the center of the shaft member 17 of the stirring blade 5, and a key (not shown) provided on the rotary shaft 3 is inserted into the through hole. A key groove (not shown) is provided. The agitating blade 5 is fixed to the rotating shaft 3 by engaging the key of the rotating shaft 3 with the key groove of the stirring blade 5 and attaching the fastening member 10 to the end of the rotating shaft 3 and tightening the fastening member 10. . The fastening member 10 is, for example, a nut that is screwed into a thread groove formed at the end of the rotating shaft 3. When the rotating shaft 3 is rotated by the drive source 2, the stirring blade 5 rotates together with the rotating shaft 3. The stirring blade 5 has a rotational speed of about 1000 to 3600 min ^{−1 and} is rotated at a high speed such that the outer peripheral speed of the blade 18 (the peripheral speed at the tip of the blade) is 4 m / s or more and 20 m / s or less. It is done. The optimum rotation speed varies depending on the amount and properties of the stock solution.

  A plurality of baffles 15 adjacent to the stirring blade 5 are provided on the inner peripheral surface of the cylindrical member 7. In the present embodiment, four baffles 15 are provided. These baffles 15 are arranged so as to surround the stirring blade 5, and a gap is formed between the stirring blade 5 and the baffle 15 so that the rotating stirring blade 5 does not contact the baffle 15. Each baffle 15 extends in a direction parallel to the longitudinal direction of the rotary shaft 3. Since the rotating shaft 3 extends in a direction perpendicular to the flow direction of the stock solution flowing into the cylindrical member 7 of the high-speed stirring device 1, the baffle 15 also extends in a direction perpendicular to the flow direction of the stock solution.

  As shown in FIG. 2, the baffle 15 of the present embodiment is made of a plate material and has a rectangular cross section. The baffle 15 is installed on the inner peripheral surface of the cylindrical member 7. In the embodiment shown in FIG. 2, the baffle 15 is a surface perpendicular to the flow direction of the stock solution and passes from the surface passing through the center of the cylindrical member 7 to the upstream side and the downstream side in the rotation direction of the stirring blade 5. It is provided at positions in four directions separated by 35 °. Further, as shown in FIG. 3, each baffle 15 is composed of divided bodies 15 a and 15 b arranged along the longitudinal direction of the rotating shaft 3. A gap 15c along the longitudinal direction of the rotating shaft 3 is formed between the divided bodies 15a and 15b.

  The arrangement position and the number of the baffles 15 are not limited to the illustrated example. For example, the baffle 15 may be provided at four positions that are perpendicular to the flow direction of the stock solution and are separated from the plane passing through the center of the cylindrical member 7 at an angle different from 35 °. In addition, a baffle configured as a single body (that is, a baffle that is not configured from a plurality of divided bodies) can be used, or the baffle is configured from three or more divided bodies and the three or more divided sections are used. The body may be spaced apart along the longitudinal direction of the rotating shaft 3.

  The stock solution stirred by the stirring blade 5 collides with a baffle 15 provided on the inner peripheral surface of the cylindrical member 7 to form a turbulent flow and generate a vortex in the cylindrical member 7. As a result, the stock solution containing the suspended substance and the flocculant can be efficiently mixed in a short time. In particular, each baffle 15 is composed of a plurality of (two in the illustrated example) divided bodies 15a and 15b arranged along the rotation axis 3, so that the stock solution flowing in the gap 15c between the divided bodies 15a and 15b. And a flow rate difference between the flow rate of the undiluted solution colliding with the baffle 15 and impeding the flow. And since a vortex arises in the cylindrical member 7 resulting from this speed difference, the undiluted | stock solution in which the coagulant | flocculant was inject | poured can be stirred more efficiently.

  According to the high-speed stirring device 1 of the present embodiment, since the stock solution containing suspended solids into which the flocculant has been injected can be efficiently stirred, the rotational speed of the stirring blade 5 can be increased compared to the conventional high-speed stirring device. Can be lowered. If the rotational speed of the stirring blade 5 can be lowered, the load applied to the sealing device 16 that prevents the leakage of the stock solution from the high-speed stirring device 1 can be reduced. As a result, the maintenance frequency of the high-speed stirring device 1 can be reduced.

  A lid member 28 is detachably attached to the opening end of the cylindrical member 7. The lid member 28 is, for example, a closing flange connected to a flange 29 fixed to the outer peripheral end of the cylindrical member 7. The lid member 28 includes a columnar plug 39 disposed in the cylindrical member 7. A plurality of through holes are provided in the outer peripheral portion of the lid member 28, and the through holes are also provided in the flange 29 at positions corresponding to the through holes. The through hole of the lid member 28 and the through hole of the flange 29 are aligned, the bolt 35 is inserted into both the through holes, and the bolt 35 is fastened with the nut 36, so that the lid member 28 is attached to the flange 29. Fixed. If the nut 36 is removed from the bolt 35, the lid member 28 can be removed from the flange 29. The operator can easily maintain the stirring blade 5 simply by removing the lid member 28 from the cylindrical member 7 during maintenance of the high-speed stirring device 1.

  As shown in FIG. 3, the front end side disk 30 and the rear end side disk 31 are arranged along the longitudinal direction of the rotary shaft 3 so as to sandwich the stirring blade 5. The front end side disc 30 and the rear end side disc 31 are arranged in the vicinity of the stirring blade 5. The front end side disk 30 and the rear end side disk 31 are configured by a disk perpendicular to the longitudinal direction of the rotation shaft 3, and the centers of the front end side disk 30 and the rear end side disk 31 are the rotation axes. It coincides with the center of 3. Moreover, the front end side disk 30 and the rear end side disk 31 have a diameter smaller than the inner diameter of the cylindrical member 7 and larger than the diameter of the stirring blade 5.

  The rear end side disk 31 is fixed to the rotating shaft 3 and rotates together with the rotating shaft 3. The distal end side disk 30 is fixed to the plug 39 of the lid member 28, and the distal end side disk 30 does not rotate even when the stirring blade 5 rotates. A uniform narrow gap is formed between the front end side disc 30 and the stirring blade 5 and between the rear end side disc 31 and the stirring blade 5. As shown in FIG. 3, the gap between the disks 30 and 31 and the stirring blade 5 is almost the same size as the gap between the baffle 15 and the stirring blade 5. Thus, since the uniform clearance gap is formed in the whole stirring blade 5, the stirring blade 5 can stir stock solution efficiently. As a result, the flocculant and the stock solution containing the suspended substance can be efficiently mixed.

  FIG. 4 is a cross-sectional view corresponding to FIG. 2 of a high-speed stirring device according to another embodiment of the present invention. As shown in FIG. 4, the baffle 15 of this embodiment has a triangular cross section. That is, the cross section perpendicular to the longitudinal direction of the baffle 15 is triangular. The stock solution stirred by the stirring blade 5 can collide with the baffle 15 to form a turbulent flow and generate a vortex in the cylindrical member 7. As a result, the stock solution containing suspended solids into which the flocculant has been injected is efficiently stirred, and the flocculant and the stock solution can be efficiently mixed in a short time. Furthermore, when the baffle 15 having such a triangular cross section is used, it is possible to prevent entangled dust such as residue contained in the stock solution from being entangled with the baffle 15 when the stirring blade 5 rotates. Therefore, the maintenance frequency of the high-speed stirring device 1 can be reduced while maintaining efficient stirring of the stock solution. The shape of the cross section of the baffle 15 is not limited to a triangular shape. For example, the baffle 15 may have a polygonal cross section such as a quadrangle or a pentagon. Further, the baffle 15 may have a circular or circular cross section.

  FIG. 5 is a cross-sectional view corresponding to FIG. 3 of a high-speed stirring device according to still another embodiment of the present invention. In the high-speed stirring apparatus 1 shown in FIG. 5, a plurality of baffles 40 are fixed to the surface of the tip side disk 30 that faces the stirring blade 5. These baffles 40 are erected vertically from the distal end side disk 30. Each baffle 40 extends in the radial direction of the distal end side disk 30 and is disposed close to the stirring blade 5. The plurality of baffles 40 are arranged at equal intervals along the circumferential direction of the distal end side disk 30. For example, when two baffles 40 are provided, the baffles 40 are arranged at intervals of 180 °. Similarly, when three baffles 40 are provided, the baffles 40 are arranged at intervals of 120 °, and when four baffles 40 are provided, the baffles 40 are arranged at intervals of 90 °. The number of baffles 40 is not limited to four. The number of baffles 40 may be 5 or more, or 3 or less. For example, it is possible to provide only one baffle 40.

  In this way, when another baffle (second baffle) 40 is provided in addition to the baffle (first baffle) 15 attached to the inner peripheral surface of the cylindrical member 7, the stock solution stirred by the stirring blade 5 Therefore, the stock solution containing suspended solids into which the flocculant has been injected can be more efficiently stirred.

  FIG. 6 is a cross-sectional view corresponding to FIG. 2 of a high-speed stirring device according to still another embodiment of the present invention. In the high-speed stirring apparatus 1 shown in FIG. 6, on the side surface of the cylindrical member 7, there are an inflow pipe 20 into which a stock solution containing suspended solids infused with a flocculant and a discharge pipe 21 through which the stock solution is discharged. Although it is the same as the embodiment shown in FIG. 2 in that it is connected, the direction in which the discharge pipe 21 extends is different in that it is perpendicular to the direction in which the inflow pipe 20 extends. That is, the stock solution flowing in from the inflow pipe 20 flows through the cylindrical member 7 to the discharge pipe 21 while changing the flow direction to 90 °. In this case, the baffles 15 are arranged at intervals of 90 ° along the circumferential direction of the cylindrical member 7 so that the baffle 15 provided on the inner peripheral surface of the cylindrical member 7 does not interfere with the inflow pipe 20 and the discharge pipe 21. Is done.

  The baffle 15 shown in FIG. 6 has a triangular cross section, but the shape of the cross section of the baffle 15 is not limited to the triangular shape as described above. For example, the baffle 15 may have a polygonal cross section such as a quadrangle or a pentagon. Further, the baffle 15 may have a circular or circular cross section. If the angle in the direction in which the discharge pipe 21 extends with respect to the direction in which the inflow pipe 20 extends is θ, the angle θ may be an angle other than a right angle. The range of the angle θ is preferably 90 ° or more and 270 ° or less. For example, the angle θ can be 120 °. The case where the angle θ is 180 ° is the case where the inflow pipe 20 and the exhaust pipe 21 shown in FIG. 2 are arranged on a straight line.

  FIG. 7 is a schematic flow diagram showing an example of a coagulation agitation apparatus incorporating a high-speed agitation apparatus according to an embodiment of the present invention. 7 includes the high-speed stirring device 1 described above and a low-speed stirring device 70 disposed on the downstream side of the high-speed stirring device 1. That is, this agglomeration agitation apparatus is an agglomeration agitation apparatus that performs two-stage agitation in which a stock solution containing a suspended substance is agitated at high speed and then at low speed.

The low-speed stirring device 70 includes a driving source 72 such as a motor, a rotating shaft 73 rotated by the driving source 72, a stirring blade 75 connected to the rotating shaft 73, and an agglomeration mixing tank 71 that houses the stirring blade 75 therein. And comprising. The stirring blade 75 is fixed to the rotating shaft 73, and when the rotating shaft 73 is rotated by the drive source 72, the stirring blade 75 also rotates together with the rotating shaft 73. The stirring blade 75 is rotated at a lower speed than the stirring blade 5 of the high-speed stirring device 1. The stirring blade 75 of the low-speed stirring device 70 is, for example, a rotational speed of about 30 to 300 min ⁻¹ and a low speed such that the peripheral speed of the outermost periphery of the stirring blade 75 is 1 m / s or more and less than 4 m / s. Rotated.

  As described above, the flocculant and the stock solution containing the suspended substance can be uniformly mixed by stirring the stock solution containing the suspended substance into which the flocculant has been injected with the high-speed stirring device 1. . The flocculant is injected into the stock solution immediately before flowing into the high-speed stirring device 1. The flocculant may be injected into the stock solution in the high-speed stirring device 1.

  The stock solution mixed with the flocculant leaving the high-speed stirring device 1 flows into the lower part of the coagulation mixing tank 71 of the low-speed stirring device 70. The undiluted solution flowing from the lower part of the agglomeration mixing tank 71 rises in the agglomeration mixing tank 71 while being slowly agitated by the agitating blade 75 rotating at a low speed of the low-speed agitator 70, and in this process agglomeration flocs are granulated. And grow. A discharge port is provided in the upper part of the agglomeration mixing tank 71. The stock solution in the flocculation / mixing tank 71 overflows and flows into this discharge port, and is further sent to a dehydrator provided on the downstream side of the low-speed stirring device 70. In the dehydrator, the stock solution is separated into a dehydrated cake that is an aggregate of aggregated flocs and a dehydrated filtrate, and as a result, the aggregated flocs can be recovered as a dehydrated cake.

  A flocculant may be further injected into the flocculent mixing tank 71. This flocculant can be the same as or different from the flocculant injected into the stock solution before flowing into the high-speed stirring device 1 or in the high-speed stirring device 1.

  An experiment was conducted to compare the mixing state of the flocculant in the conventional high-speed stirring device and the high-speed stirring device according to one embodiment of the present invention. In the experiment, the solution of the polymer flocculant was poured into the sludge, and the sludge was further agitated by a high-speed agitator to agglomerate the sludge, and the particle diameters of the obtained agglomerated flocs were compared. In the experiment, the high-speed stirring device 1 shown in FIG. 4 was used. As a comparative example, a conventional high-speed stirring apparatus 101 shown in FIG. 8 was used.

  In the experiment, anaerobic digested sludge collected from a wastewater treatment facility was used. The sludge has a TS (Total Solids) of 22.5 g / L. TS is an evaporation residue and is a concentration of a substance remaining when sludge is evaporated to dryness at 105 to 110 ° C. The measurement method conformed to the sewage test method. As the polymer flocculant, a cationic polymer flocculant was used. The polymer flocculant solution was an aqueous solution obtained by dissolving the polymer flocculant in water, and was prepared at a concentration of 2.5 g / L. The concentration of the polymer flocculant means the concentration of the polymer flocculant in the aqueous solution.

The experimental procedure is as follows.
First, a polymer flocculant solution having a predetermined flow rate is injected into a sludge having a predetermined flow rate. Next, the sludge into which the polymer flocculant solution has been injected is supplied to a high-speed stirring device. In the high-speed stirring device, the sludge and the polymer flocculant solution are mixed by high-speed stirring at a rotational speed of 1000 min ⁻¹ (peripheral speed of about 4.2 m / s). When the sludge and the polymer flocculant solution are mixed with a high-speed stirrer, the sludge is aggregated and flocs are formed. Next, the formed floc was collected, and the particle size of the floc was measured. The experimental results are shown in Table 1.

When the sludge flow rate was 1.0 m ³ / h, the high-speed stirring device according to one embodiment of the present invention was able to make the floc particle size smaller than that of the conventional high-speed stirring device. Even when the sludge flow rate was 2.0 m ³ / h, the floc particle size could be reduced by the high-speed stirring device according to one embodiment of the present invention. From these things, it turned out that the high-speed stirring apparatus 1 concerning one Embodiment of this invention has high stirring efficiency.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible.

DESCRIPTION OF SYMBOLS 1 High-speed stirring apparatus 2 Drive source 3 Rotating shaft 5 Stirring blade 7 Cylindrical member 10 Fastening member 15 Baffle 15a, 15b Divided body 15c Clearance 16 Sealing device 17 Shaft member 18 Blade 20 Inflow piping 21 Discharge piping 23 Flange 24 Flange 25 Flange 26 Flange 28 Lid Member 29 Flange 30 Upstream Piping 31 Flange 33 Downstream Piping 34 Flange 35 Bolt 36 Nut 39 Plug 40 Baffle 70 Low Speed Stirrer 71 Aggregation Mixing Tank 72 Drive Source 73 Rotating Shaft 75 Stirring Blade 75

Claims (4)

A high-speed stirring device that stirs a stock solution containing suspended solids into which a flocculant is injected,
A rotating shaft rotated by a driving source;
A stirring blade connected to the rotating shaft;
A cylindrical member disposed coaxially with the rotating shaft and containing the stirring blade;
A plurality of baffles fixed to the inner peripheral surface of the cylindrical member;
A front-end-side disk and a rear-end-side disk that are arranged along the longitudinal direction of the rotation shaft and arranged to sandwich the stirring blade ,
The high-speed stirring device, wherein the plurality of baffles are arranged around the stirring blade. The high-speed stirring device according to claim 1, wherein each of the plurality of baffles has a polygonal cross section. An inflow pipe for introducing the stock solution containing the suspended solids into the cylindrical member and a discharge pipe for discharging the stock solution from the cylindrical member are connected to the side surface of the cylindrical member,
The high-speed stirring device according to claim 1 or 2 , wherein a flow direction of the stock solution passing through the cylindrical member is perpendicular to the rotation axis. A stock solution containing suspended solids, into which a flocculant is injected, is supplied to the high-speed stirring device according to any one of claims 1 to 3 .
By stirring the stock solution and the flocculant with the high-speed stirring device, the stock solution and the flocculant are mixed,
Supply the stock solution mixed with the flocculant to the flocculent mixing tank,
In the coagulation mixing tank, a coagulation floc is formed by re-adding the coagulant and stirring the stock solution.

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