JP2015208696A - Coagulation agitation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coagulation agitation device ensuring the long life of a seal unit sealing the housing and bearing chamber of a high-speed agitator.SOLUTION: A coagulation agitation device is provided with a high-speed agitator 1 agitating a stock solution being injected with a coagulant and containing suspended matter at a high speed and a low-speed agitator 20 agitating the stock solution flown out from the high-speed agitator 1 after high-speed agitation at a low-speed agitation in a coagulation mixing tank 21. The high-speed agitator 1 is provided with agitation blades 5 agitating the stock solution, a housing 6 housing the agitation blades 5, a rotary shaft 4 penetrating the wall part of the housing 6 and extending to the agitation blades 5 and a seal unit 10 sealing a clearance between the housing 6 and the rotary shaft 4. The height of the seal unit 10 from the bottom of the coagulation mixing tank 21 is 1/2 or more of the height of the liquid surface of the stock solution from the bottom in the coagulation mixing tank 21.

Description

  The present invention relates to a coagulation stirrer for forming and growing a coagulation floc by agitating a stock solution containing a suspended substance into which a coagulant is injected. In particular, the present invention relates to a coagulation stirrer that performs two-stage stirring in which a stock solution into which a flocculant is injected is stirred at a high speed and then stirred at a low speed. 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 a suspended substance from a stock solution containing the suspended substance. ing. Examples of undiluted solutions containing suspended substances include sludge and wastewater, but other industrial raw material liquids such as food raw material liquids, cosmetic raw material liquids, papermaking raw material liquids, or slurries can also be used as suspension materials. Contained in stock solution containing. 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 this aggregation floc, an agitation stirrer is used.

  As a flocculating stirrer, there is known a flocculating stirrer in which a stock solution containing a suspended substance, into which a flocculant is injected, is stirred at a high speed and then stirred at a low speed. By stirring the stock solution into which the flocculant has been injected at a high speed, the flocculant is uniformly dispersed in the stock solution and comes into contact with the suspended substance. And the aggregation floc is formed and grows by carrying out low speed stirring of the undiluted | stock solution after high speed stirring. By growing the flocs in this way, the dewatering efficiency in the dehydrator can be increased.

  FIG. 5 shows a schematic side view of a conventional agglomeration stirring apparatus that performs such two-stage stirring. The flocculation agitation apparatus shown in FIG. 5 includes a high-speed stirrer 101 for high-speed stirring of a stock solution containing suspended solids in which a flocculant is injected, and a low-speed stirrer for low-speed stirring of the stock solution stirred by the high-speed stirrer 101. 120. The high-speed stirrer 101 includes a rotating shaft 104 rotatably supported by a bearing 102, a stirring blade 105 connected to the rotating shaft 104, a housing 106 that houses the stirring blade 105, and a rotating shaft 104. A motor 108. The bearing 102 is disposed in the bearing chamber 107. A through hole through which the rotation shaft 104 passes is formed in the upper wall of the housing 106. A seal device 110 that seals the gap between the rotary shaft 104 and the housing 106 is provided in the bearing chamber 107 so that the stock solution flowing in the housing 106 does not leak into the bearing chamber 107 through the through hole. The seal device 110 is a shaft seal device that prevents the stock solution from leaking from the housing 106 while allowing the rotation shaft 104 to rotate. As the sealing device 110, for example, a mechanical seal or a gland packing is used.

  An inlet pipe 114 is connected to the inlet of the housing 106 of the high-speed stirrer 101, and an outlet pipe 115 connected to the lower part of the coagulation mixing tank 121 of the low-speed stirrer 120 is connected to the outlet of the housing 106. The stock solution that has flowed into the high-speed stirrer 101 through the inlet pipe 114 is efficiently mixed with the flocculant by the action of the stirring blade 105 that rotates at high speed, and as a result, the flocculant is uniformly dispersed in the stock solution. The stock solution exiting the high speed stirrer 101 flows into the coagulation mixing tank 121 of the low speed stirrer 120 through the outlet pipe 115. The stock solution ascends slowly in the agglomeration mixing tank 121 while being slowly agitated by the agitating blade 123 rotating at a low speed of the low-speed agitator 120, and in this process, agglomeration flocs are formed and grow. A discharge port 128 is provided in the upper part of the coagulation / mixing tank 121, and the stock solution in the coagulation / mixing tank 121 is overflowed to the discharge port 128, so that the stock solution is dehydrated at the subsequent stage of the coagulation stirrer. Sent to.

  In the coagulation stirrer shown in FIG. 5, the high speed stirrer 101 is disposed near the lower part of the low speed stirrer 120. In such an arrangement, the pressure head H corresponding to the distance between the position of the seal device 110 and the level of the stock solution stored in the coagulation mixing tank 121 is applied to the seal device 110 of the high-speed stirrer 101. End up. The pressure head H is, for example, about 3 m, and the pressure of the stock solution to be sealed by the sealing device 110 is high. As a result, the sealing device 110 is damaged relatively quickly, and the maintenance frequency due to the replacement of the sealing device 110 is increased. During maintenance, it is not possible to perform processing with a coagulation stirrer, and the replacement cost of the seal device is also high, so that it is desired to extend the life of the seal device 110.

Japanese Patent No. 4761216 Japanese Patent No. 4623431 JP 2004-130297 A

  The present invention has been made in view of the above-described conventional problems, and provides a coagulation agitation apparatus that can realize a long life of a sealing device that seals a gap between a housing and a rotary shaft of a high-speed agitator. The purpose is to do.

  In order to achieve the above-described object, one aspect of the present invention includes a high-speed stirrer in which a flocculant is injected and stirs a stock solution containing a suspended substance at high speed, and a stock solution after high-speed stirring that exits the high-speed stirrer, A low-speed stirrer that stirs at a low speed in a coagulation mixing tank, and the high-speed stirrer includes a stirring blade that stirs the stock solution, a housing that houses the stirring blade, and a wall portion of the housing to reach the stirring blade. A rotating shaft that extends, and a sealing device that seals a gap between the housing and the rotating shaft, and the height of the sealing device from the bottom surface of the coagulation mixing tank is that of the stock solution in the coagulation mixing tank The coagulation agitation apparatus is characterized in that the liquid level is ½ or more of the height from the bottom surface.

In a preferred aspect of the present invention, the sealing device is arranged at a height equal to or higher than the liquid level of the stock solution in the aggregation and mixing tank.
In a preferred aspect of the present invention, the high-speed stirrer and the low-speed stirrer are integrated with each other by attaching the high-speed stirrer to the low-speed stirrer.
A preferred embodiment of the present invention is further characterized by further comprising a drain line for transferring the stock solution leaked from the sealing device into the coagulation mixing tank.

  ADVANTAGE OF THE INVENTION According to this invention, the pressure concerning a sealing device from the undiluted | stock solution stored in the aggregation mixing tank can be reduced. As a result, it is possible to extend the life of the sealing device. In particular, if the sealing device is placed at a level higher than the liquid level of the stock solution stored in the coagulation and mixing tank, the seal device will not be subjected to high pressure from the stock solution stored in the coagulation and mixing tank. Is more promoted.

It is a schematic side view of the aggregation stirring apparatus which concerns on one Embodiment of this invention. It is a schematic side view of the aggregation stirring apparatus which concerns on another embodiment of this invention. It is a schematic side view of the aggregation stirring apparatus which concerns on another embodiment of this invention. It is a schematic side view of the aggregation stirring apparatus which concerns on another embodiment of this invention. It is a schematic side view of the conventional aggregation stirring apparatus which performs two-stage stirring.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic side view of a coagulation stirrer according to an embodiment of the present invention. The flocculating stirrer shown in FIG. 1 includes a high-speed stirrer 1 that stirs a stock solution containing suspended solids into which a flocculant is injected, and a low-speed stirrer 20 that stirs the stock solution that has exited the high-speed stirrer 1 at a low speed. Prepare. That is, this agglomeration stirrer is a flocculent agitation device that performs two-stage agitation in which a stock solution containing a suspended substance is stirred at a high speed and then the stock solution is stirred at a low speed. In this specification, the stock solution refers to the liquid to be treated. Examples of undiluted solutions containing suspended substances include sludge, wastewater, etc. In addition, industrial raw material liquids such as food raw material liquids, cosmetic raw material liquids, papermaking raw material liquids, or slurries may be suspended substances. Contained in stock solution containing.

The high-speed stirrer 1 includes a first rotating shaft 4 that is rotatably supported by the bearing 2, a first stirring blade 5 that is connected to the first rotating shaft 4, a housing 6 that houses the first stirring blade 5, A first motor 8 for rotating the first rotating shaft 4. The first stirring blade 5 is fixed to the first rotating shaft 4, and when the first rotating shaft 4 is rotated by the first motor 8, the first stirring blade 5 also rotates together with the first rotating shaft 4. The first stirring blade 5 is rotated at a high speed. For example, the rotational speed of the first stirring blades 5 are 500～3000Min ^-1, preferably, a 1000~3000min ^-1. In this way, the stock solution containing suspended solids into which the flocculant has been injected is stirred at high speed with the high-speed stirrer 1 so that the flocculant is uniformly dispersed in the stock solution, and the flocculant is evenly dispersed in the suspended solids. Can be contacted.

  An inlet pipe 14 is connected to the inlet of the housing 6 of the high-speed stirrer 1, and an outlet pipe 15 connected to the lower part of the coagulation mixing tank 21 in the low-speed stirrer 20 is connected to the outlet of the housing 6. The housing 6 is sealed except for the inlet to which the inlet pipe 14 is connected, the outlet to which the outlet pipe 15 is connected, and the through hole through which the rotary shaft 2 passes. The stock solution containing suspended solids introduced into the high-speed stirrer 1 through the inlet pipe 14 is efficiently mixed with the flocculant by the action of the first stirring blade 5 rotating at high speed, so that the flocculant is uniformly contained in the stock solution. Be distributed. The flocculant is injected into the stock solution immediately before flowing into the high-speed stirrer 1. The flocculant may be injected into the stock solution in the high speed stirrer 1.

  The bearing 2 is disposed in the bearing chamber 7. The first rotating shaft 4 extends through the wall portion of the housing 6 to the first stirring blade 5. That is, a through-hole through which the first rotation shaft 4 passes is formed in the wall portion (the upper wall in the present embodiment) of the housing 6. A seal device 10 that seals the gap between the first rotating shaft 4 and the housing 6 is provided in the bearing chamber 7 so that the stock solution flowing in the housing 6 does not leak into the bearing chamber 7 through the through hole. The seal device 10 is a shaft seal device that prevents leakage of the stock solution from the housing 6 while allowing the rotation of the first rotation shaft 4. As the sealing device 10, for example, a mechanical seal or a gland packing is used.

  As the high-speed stirrer 1, an in-line mixer can be employed. An in-line mixer refers to a mixer incorporated in a pipe. When an in-line mixer is employed as the high-speed stirrer 1, only two pumps are prepared: a pump (not shown) for feeding the stock solution to the high-speed stirrer 1 and a pump (not shown) for injecting the flocculant into the stock solution. Can be sent from the high speed stirrer 1 to the low speed stirrer 20.

The stock solution stirred at high speed by the high-speed stirrer 1 flows into the bottom of the agglomeration mixing tank 21 of the low-speed stirrer 20 through the outlet pipe 15. The low-speed stirring device 20 accommodates therein a second rotating shaft 22 rotatably supported by a bearing (not shown), a second stirring blade 23 connected to the second rotating shaft 22, and a second stirring blade 23. And a second motor 25 for rotating the second rotating shaft 22. The second stirring blade 23 is fixed to the second rotating shaft 22. When the second rotating shaft 22 is rotated by the second motor 25, the second stirring blade 23 also rotates together with the second rotating shaft 22. The second stirring blade 23 is rotated at a lower speed than the first stirring blade 5. For example, the rotation speed of the second stirring blade 23 is 10 to 500 min ⁻¹ .

  The stock solution that has flowed into the agglomeration mixing tank 21 rises up in the agglomeration mixing tank 21 while being slowly stirred by the second stirring blade 23 that rotates at a low speed. In this process, agglomeration flocs are formed and grow. A discharge port 28 is provided in the upper part of the flocculation mixing tank 21, and the stock solution containing the flocculation floc is provided in the subsequent stage of the flocculation stirrer by overflowing the stock solution in the flocculation mixing tank 21 to the discharge port 28. Sent to the dehydrator. Note that the flocculant may be further injected into the flocculent mixing tank 21. This flocculant can be the same as or different from the flocculant injected into the stock solution before flowing into the high-speed stirrer 1 or in the high-speed stirrer 1.

  The outlet pipe 15 is provided with an air vent line 16. Since the first stirring blade 5 of the high-speed stirrer 1 is rotated at a high speed, the flow rate of the stock solution passing through the housing 6 of the high-speed stirrer 1 is increased. In this case, air in the bearing chamber 7 may be sucked from the seal device 10 due to the ejector effect of the stock solution passing through the housing 6. The air vent line 16 is provided for extracting the sucked air from the outlet pipe 15. Therefore, the air vent line 16 communicates with the outlet pipe 15 and is connected to the upper surface of the outlet pipe 15.

  In the present embodiment, as shown in FIG. 1, the sealing device 10 has a height of ½ or more of the height L from the bottom surface of the aggregation liquid mixing tank 21 of the liquid level of the stock solution stored in the aggregation mixing tank 21. Arranged. That is, when the height of the liquid level of the stock solution from the bottom surface of the agglomeration mixing tank 21 is L, the height of the sealing device 10 from the bottom surface of the aggregation mixing tank 21 is ½ L or more. In addition, the liquid level of the aggregation mixing tank 21 when determining the height L is the liquid level of the aggregation mixing tank 21 when the second stirring blade 23 is stopped. In other words, the liquid level of the flocculation / mixing tank 21 formed into a mortar shape by the rotation of the second stirring blade 23 is not used as the liquid level of the flocculation / mixing tank 21 when the height L is determined.

  As described above, when the sealing device 10 is disposed at a height of ½ or more of the height L from the bottom surface of the agglomeration mixing tank 21 of the liquid level of the stock solution stored in the agglomeration mixing tank 21, the aggregation mixing tank 21. The pressure applied to the sealing device 10 from the stock solution inside can be reduced. As a result, the load on the sealing device 10 can be reduced, and the life of the sealing device 10 can be extended.

  The reason why the sealing device 10 is arranged at a position higher than the conventional arrangement position shown in FIG. 5 is to reduce the pressure applied to the sealing device 10 from the stock solution in the coagulation mixing tank 21. Therefore, the higher the arrangement position of the sealing device 10, the lower the pressure applied to the sealing device 10. Therefore, the seal member 10 is preferably disposed at a height of 1/2 L or more from the bottom surface of the agglomeration mixing tank 21, more preferably at a height of 2/3 L or more from the bottom surface of the aggregation mixing tank 21, Most preferably, it is arranged at a height higher than the liquid level of the stock solution stored in the coagulation / mixing tank 21.

  FIG. 2 is a schematic side view of a coagulation stirrer according to another embodiment of the present invention. In the embodiment shown in FIG. 2, the sealing device 10 is disposed at a height equal to or higher than the liquid level of the stock solution stored in the aggregation and mixing tank 21. Since the other configuration is the same as that of the embodiment shown in FIG. 1, the corresponding components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 2, if the sealing device 10 is disposed at a height higher than the liquid level of the stock solution stored in the coagulation / mixing tank 21, the pressure of the stock solution in the coagulation / mixing tank 21 is not applied to the seal device 10. As a result, the lifetime of the sealing device 10 can be increased.

  FIG. 3 is a schematic side view of an agglomeration stirring apparatus according to still another embodiment of the present invention. In the embodiment shown in FIG. 3, the high speed stirrer 1 and the low speed stirrer 20 are integrated with each other by attaching the high speed stirrer 1 to the low speed stirrer 20. Since the other configuration is the same as that of the embodiment shown in FIG. 2, the corresponding components are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the flocculation stirrer shown in FIG. 3, the high speed stirrer 1 is attached to the outer wall of the flocculation mixing tank 21 of the low speed stirrer 20. A stepped portion in which a part of the outer wall of the coagulation mixing tank 21 is recessed inward may be provided, and the high-speed stirrer 1 may be accommodated in the stepped portion. Thus, if the high-speed stirrer 1 and the low-speed stirrer 20 are made into an integral structure, a compact coagulation stirrer can be provided. In the present embodiment, the air vent line 16 extends from the upper surface of the housing 6 to a position above the agglomeration mixing tank 21. If the end of the air vent line 16 is opened at the upper position of the coagulation mixing tank 21 in this way, even if the stock solution leaks from the air vent line 16, other equipment is not adversely affected.

  FIG. 4 is a schematic side view of an agglomeration stirring apparatus according to still another embodiment of the present invention. In the embodiment shown in FIG. 4, a drain line 17 is attached to the bearing chamber 7 of the high-speed stirrer 1. Since the other configuration is the same as that of the embodiment shown in FIG. 2, the corresponding components are denoted by the same reference numerals, and detailed description thereof is omitted.

  One end of the drain line 17 communicates with the inside of the bearing chamber 7 from the side surface of the bearing chamber 7, and the other end of the drain line 17 opens at a position above the agglomeration mixing tank 21. If a drain line 17 communicating with the bearing chamber 7 is provided, even if the stock solution in the housing 6 leaks the sealing device 10 and flows into the bearing chamber 7, the fed stock solution is transferred to the agglomeration mixing tank 21. Because it can, other equipment will not be adversely affected.

  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 stirrer 2 Bearing 4 1st rotating shaft 5 1st stirring blade 6 Housing 7 Bearing chamber 8 1st motor 10 Sealing device 14 Inlet piping 15 Outlet piping 16 Air vent line 17 Drain line 20 Low speed stirrer 21 Coagulation mixing tank 22 2nd rotation Shaft 23 Second stirring blade 25 Second motor 28 Discharge port

Claims (4)

A high-speed stirrer that stirs the stock solution containing suspended solids, into which the flocculant is injected, and
A low-speed stirrer that stirs the stock solution after high-speed stirring that has exited the high-speed stirrer at a low speed in a coagulation mixing tank,
The high-speed stirrer
A stirring blade for stirring the stock solution;
A housing for housing the stirring blade;
A rotating shaft extending through the wall of the housing to the stirring blade;
A sealing device that seals a gap between the housing and the rotating shaft,
The height of the sealing device from the bottom surface of the coagulation / mixing tank is ½ or more of the height from the bottom surface of the liquid surface of the stock solution in the coagulation / mixing tank.   The coagulation agitation apparatus according to claim 1, wherein the sealing device is disposed at a height equal to or higher than a liquid level of the stock solution in the coagulation mixing tank.   The aggregation stirring apparatus according to claim 1 or 2, wherein the high-speed stirrer and the low-speed stirrer are integrated with each other by attaching the high-speed stirrer to the low-speed stirrer.   The coagulation stirring apparatus according to any one of claims 1 to 3, further comprising a drain line for transferring the stock solution leaked from the sealing device into the coagulation mixing tank.

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