JP6312306B2 - Cleaning method for mixing equipment - Google Patents

Description

  The present invention relates to a cleaning method for a mixing apparatus.

In general, the dentifrice contains ingredients such as an abrasive, a foaming agent, a wetting agent, a binder, and a fragrance (see, for example, Patent Document 1).
In dentifrice, in order to obtain the design quality of flavor, kneaded shape (kneaded skin), shape retention, cleaning power, etc., when mixing the above ingredients, disperse them uniformly. Therefore, it is necessary for the production to surely swell sufficiently. Therefore, a mixing device having sufficient shearing force and kneading force is usually used for the production of dentifrice.

Japanese Patent Laid-Open No. 11-171743

By the way, in the dentifrice market, many types of dentifrices with different flavors and appeal points are commercially available in order to improve consumers' willingness to purchase. In the above-described dentifrice mixing apparatus, in the case of multi-product production, it is necessary to perform a cleaning operation or the like when the product is switched. In particular, when water-insoluble granular materials (particularly colored granular materials) are blended, sufficient washing is necessary to prevent mixing into the following different varieties.
However, in the conventional mixing apparatus cleaning method, residues such as water-insoluble granular materials and raw material mixtures are likely to remain in the clearance of a high-shear mixer such as a homogenizer, which is difficult to remove. In addition, there is a problem that a large amount of cleaning water is required to clean and remove the residue remaining in the clearance and the cleaning time is long.
This invention is made | formed in view of the said situation, and makes it a subject the washing | cleaning method of the mixing apparatus excellent in the washability.

As a result of intensive studies, the present inventors provide the following means in order to solve the above problems.
That is, the mixing device cleaning method of the present invention is a mixing device cleaning method having a mixing portion having a rotating rotor and a stator combined with the rotor, and the mixing portion is immersed in water while being 100 kPa or less. It is characterized by having a reduced-pressure washing process in which the rotor is rotated under an environment of

  According to the method for cleaning a mixing apparatus of the present invention, the cleaning property is excellent.

It is sectional drawing which shows one Embodiment of a mixing apparatus. It is sectional drawing to which the mixing part 20 was expanded. It is a perspective view which shows the state of the mixing part at the time of performing external circulation. It is a perspective view which shows the state of the mixing part which the stator and the rotor protruded upwards from the discharge port.

  A cleaning method for a mixing apparatus according to the present invention is a cleaning method for a mixing apparatus having a mixing section having a rotating rotor and a stator combined with the rotor, and has a specific vacuum cleaning step.

(Mixing device)
The mixing device according to the present invention includes a mixing unit having a rotor and a stator combined with the rotor.
FIG. 1 shows an embodiment of a mixing apparatus according to the present invention.
The mixing apparatus 100 in FIG. 1 includes a stirring tank 10 and a mixing unit 20.
The agitation tank 10 includes a tank body 12 and an anchor blade 30 disposed inside the tank body 12.
The tank body 12 has a content outlet 12a at its bottom. The tank body 12 is formed with a mixing portion storage chamber 12b protruding downward from the discharge port 12a.
The anchor wing 30 includes a center blade 32 and a U-shaped blade 34.
The central blade 32 has a central shaft 32 a that is arranged in parallel with the height direction of the tank body 12, and a plurality of flutes 32 b that protrude from the central shaft 32 a toward the side wall surface of the tank body 12.
The U-shaped blade 34 has a U-shaped shaft 34a disposed at the same rotation center axis position as the central shaft 32a, and a plurality of U-shaped blades 34 projecting from the portion along the side wall surface of the tank main body 12 to the inside of the tank main body 12. And a plurality of blades 34c that protrude from the U-shaped shaft 34a toward the side wall surface of the tank body 12 and scrape off the side wall surface.
The central blade 32 and the U-shaped blade 34 are provided individually or together and rotatably in the same direction or in the opposite direction.

FIG. 2 is an enlarged cross-sectional view of the mixing unit 20.
The mixing unit 20 is a high-shear mixer, and includes a stator 22, a rotor 24, and a bearing unit 26 (mechanical seal pressing plate). In the rotor / stator type mixing unit 20, the rotor 24 rotates in the stator 22. At that time, a fluid shearing action is generated by the effects of both the peripheral speed of the tip of the rotor 24 and the liquid flow through which the liquid passes through the stator 22 and is discharged out of the stator 22, and the liquid is dispersed and mixed. .
The stator 22 has a substantially disk shape in which a circular opening 22c is formed in the center thereof, and comb-shaped blades 22a are provided in two rows on a concentric circle on the periphery of the opening 22c.
The rotor 24 has a substantially disk shape, has a rotation shaft 24b at the center thereof, and a plurality of blades 24a are provided in three rows on concentric circles.
A hole 26a is formed in the center of the bearing portion 26 (mechanical seal pressing plate).
The stator 22 and the rotor 24 are combined so that the blade 22a is positioned between the blade 24a and the blade 24a. The clearance D (m) between the stator 22 and the rotor 24 is about 0.1 × 10 ⁻³ to 2 × 10 ⁻³ m.
The rotor 24 is disposed so as to be sandwiched between the stator 22 and the bearing portion 26, and the stator 22 is fixed to the bearing portion 26. The distance L (m) between the rotor 24 and the bearing portion 26 is about 1 × 10 ^{−3 to} 5 × 10 ⁻³ m.
The rotating shaft 24b of the rotor 24 is inserted into the hole 26a and connected to a motor 28 that is in contact with the surface of the bearing portion 26 opposite to the rotor 24 side.
In the mixing unit 20 of FIG. 2, the stator 22 is on the upper side, and the stator 22 and the rotor 24 protrude above the discharge port 12a. The mixing unit 20 is movable up and down in the mixing unit storage chamber 12b by a lifter (not shown).

Moreover, the mixing apparatus 100 of FIG. 1 has the circulation path 40 which connects the mixing part storage chamber 12b and the tank main body 12 upper part. In the middle of the circulation path 40, there is provided a valve 50 that can be switched in three directions: a mixing section storage chamber 12b, a tank body 12, and a pipe 60 that extends outside the system.
In FIG. 2, a communication hole 12 c communicating with the circulation path 40 is formed in the mixing unit storage chamber 12 b.

(How to use the mixing device)
A dentifrice, a conditioner, a treatment, a skin cream, etc. can be manufactured using the mixing apparatus 100 of FIG.
For example, when manufacturing a dentifrice, the raw material abrasive | polishing agent, a foaming agent, a wetting agent, a binder, a fragrance | flavor, etc. are thrown in in the tank main body 12, These raw materials are rotation of the anchor wing | blade 30, and the mixing part 20's. It is mixed by the rotation of the rotor 24. By moving the mixing unit 20 below the mixing unit storage chamber 12b to secure the communication hole 12c and switching the valve 50 in the direction of the tank body 12, the raw material is sent to the circulation path 40 and mixed while circulating. Can do.
Hereinafter, the manufacturing method of a dentifrice is demonstrated.

Dentifrice production method 1:
The dentifrice, for example, using the mixing device 100, throws the powder component into the liquid mixture in the tank body 12, and operates the anchor blade 30 (low-speed rotating stirrer) to perform preliminary mixing. It is manufactured by operating the mixing unit 20 (high shear mixer) to knead the liquid mixture and the powder component.
For the mixing apparatus 100, a VAKUMIX (VAKU), a universal mixer (HAAGEN & LINAU), Becomix (Berents), Flyma Mixer (Fryma), etc., equipped with a mixing unit 20 (high shear type mixer) and capable of degassing under reduced pressure may be used. it can.
Examples of the mixing unit 20 (high shear mixer) include a homogenizer (such as a homomixer and an ultramixer), a colloid mill, and the like.

The liquid mixture is, for example, a mixed liquid obtained by adding water, a part of an abrasive, a part of a wetting agent, and an optional water-soluble component in the tank body 12 and mixing them. It is prepared by adding and mixing a binder dispersion in which a binder is dispersed in a separately prepared wetting agent to obtain a swelling liquid, and adding and mixing a fragrance into the swelling liquid.
In addition, when a part of abrasive | polishing agent is contained in swelling liquid as mentioned above, content of abrasive | polishing agent becomes like this. Preferably it is 20 mass% or less with respect to swelling liquid, More preferably, it is 2-15 mass%. When the content of the abrasive in the swelling liquid exceeds 20% by mass, the binder is liable to swell due to the water absorbing action of the abrasive.
Thereafter, the powder component is charged into the liquid mixture. Examples of the powder component include the remaining abrasive and foaming agent. The foaming agent is preferably added and mixed after the abrasive is kneaded. By adding the foaming agent after kneading the abrasive, foaming of the foaming agent is less likely to occur when the foaming agent is added.

  After the introduction of the abrasive, the anchor blade 30 is first operated to perform preliminary mixing. The premixing conditions may be set as appropriate, and the rotational speed is preferably 10 to 200 rpm, more preferably 20 to 120 rpm; the mixing time is preferably 10 minutes or less, more preferably about 2 to 5 minutes. By this preliminary mixing, a paste without coarse particles can be obtained.

After the preliminary mixing, the mixing unit 20 is operated to sufficiently knead and finely disperse the paste. The kneading conditions in this case may be appropriately set. The shear rate of the rotor 24 is preferably 3000 sec ⁻¹ or more, more preferably 5000 to 50000 sec ⁻¹ ; the kneading time is preferably 5 to 50 minutes, more preferably 10 to 10 minutes. About 40 minutes.
The kneading of the powder component by the operation of the mixing unit 20 is preferably performed while depressurizing the tank body 12 and degassing. In this case, the pressure (absolute pressure) may be appropriately set, and is preferably 10 kPa or less, more preferably 1 to 7 kPa. It is preferable to perform deaeration under such reduced pressure from the viewpoint of sufficient kneading and defoaming.
Note that the mixing of the foaming agent is preferably performed by operating the mixing unit 20 with the anchor blades 30 under reduced pressure as in the case of kneading the abrasive.
When kneading the powder component, the input amount of the powder component is preferably 1/5 times or more, more preferably 1/5 to 1/1 times the mass of the input amount of the liquid mixture. preferable. By setting the input amount of the powder component in the above preferred range, a dentifrice having a viscosity at 25 ° C. of 30 mPa · s or more, particularly 30 to 150 mPa · s can be efficiently produced.

When the active ingredient is added, the active ingredient is preferably added after the abrasive is charged and mixed. This makes it possible to prevent an adverse effect due to excessive shearing force on an active ingredient that is particularly easily decomposed and, in addition, facilitates uniform mixing by vacuum mixing with a foaming agent.
Moreover, there is no restriction | limiting in particular in the mixing | blending order of arbitrary components, For example, another water-soluble component and an oil-soluble component can be mix | blended when preparing a liquid mixture.

Dentifrice production method 2:
In the manufacturing method 1 of dentifrice, you may add a fragrance | flavor, after adding a powder component to a liquid mixture (except a fragrance | flavor) instead of preparing a liquid mixture.
In such a case, after the abrasive is introduced into the swelling liquid, first, the anchor blade 30 is operated to perform preliminary mixing. The premixing conditions may be set as appropriate, and the rotational speed is preferably 10 to 200 rpm, more preferably 20 to 120 rpm; the mixing time is preferably 10 minutes or less, more preferably about 1 to 5 minutes. By this preliminary mixing, a paste without coarse particles can be obtained.
After the preliminary mixing, the foaming agent and the fragrance are added and mixed in this order, and then the mixing unit 20 is operated to sufficiently knead and finely disperse. The kneading conditions in this case may be appropriately set. The shear rate of the rotor 24 is preferably 3000 sec ⁻¹ or more, more preferably 5000 to 50000 sec ⁻¹ ; the kneading time is preferably 5 to 50 minutes, more preferably 10 to 10 minutes. About 40 minutes.
The kneading by the operation of the mixing unit 20 is preferably carried out while depressurizing the tank body 12 and degassing. In this case, the pressure (absolute pressure) may be appropriately set, and is preferably 10 kPa or less, more preferably 1 to 7 kPa. It is preferable to perform deaeration under such reduced pressure from the viewpoint of sufficient kneading and defoaming.

Dentifrice production method 3:
By effectively using a high-shear mixer, the powder component can be charged into the liquid mixture and kneaded and finely dispersed without preparing a swelling liquid as described above. At that time, the powder component can be added in a lump or dividedly, and the fragrance can be added after the powder component is added. In this case, the kneading conditions can be appropriately set, and the shear rate of the rotor 24 is preferably 3000 sec ⁻¹ or more, more preferably 5000 to 50000 sec ⁻¹ ; the kneading time is preferably 5 to 50 minutes, more preferably 10 About 40 minutes.
The kneading by the operation of the high shear mixer is preferably carried out while depressurizing the tank body 12 and degassing. In this case, the pressure (absolute pressure) may be appropriately set, and is preferably 10 kPa or less, more preferably 1 to 7 kPa. It is preferable to perform deaeration under such reduced pressure from the viewpoint of sufficient kneading and defoaming.

  In addition, when the high shear mixer is a homomixer in the above-described dentifrice production methods 1 to 3, when performing kneading and fine dispersion by the operation of the high shear mixer, under the above kneading conditions and reduced pressure conditions, The number of external circulations is preferably 1 to 10 times, and more preferably 1 to 6 times. By setting the number of times of external circulation to the above preferable range, it is easy to obtain a dentifrice excellent in skin mixing, shape retention and flavor.

After the manufactured dentifrice is discharged by switching the valve 50 in the direction of the pipe 60, a water-insoluble granular material and a water-insoluble raw material mixture (final preparation, poorly mixed material) are contained in the mixing tank 100. 12 wall surfaces, anchor blades 30 and mixing unit 20 remain.
As shown in FIG. 2, water-insoluble particulate matter 70 (residue) tends to remain in the clearance between the stator 22 and the rotor 24 and in the gap between the rotor 24 and the bearing portion 26.
As the water-insoluble granular material 70, granular zeolite (white granular material, colored granular material; particle size of about 212 to 425 μm), calcium bicarbonate (particle size of about 1400 μm), anhydrous silicic acid (particle size) White to bluish white powder; particle size of about 100 μm, about 63 to 198 μm, about 355 to 709 μm).
In addition, although the component mix | blended with dentifrice etc. was illustrated as a residue which remains easily in clearance etc., as other residue, it is an emulsion, such as a conditioner, a treatment, skin cream, or a liquid composition or a high viscosity composition. Also included are water-insoluble substances, capsules, polymers and the like.

(Mixing device cleaning method)
The mixing apparatus cleaning method according to the present invention includes a vacuum cleaning step.
Hereinafter, a method for cleaning the mixing apparatus will be described with reference to an embodiment. The cleaning method for the mixing apparatus of the present embodiment is a cleaning method that is performed by combining a normal pressure cleaning step and a reduced pressure cleaning step.

[Normal pressure cleaning process]
The normal pressure washing process is a process of putting water into the tank body 12 and draining it. For example, water may be drained while putting water into the tank body 12; water is put into the tank body 12, and at least one of the anchor blade 30 and the mixing unit 20 is operated under normal pressure (the mixing unit 20 is operated). In some cases, external circulation may be performed) and then drained.

When water is poured into the tank body 12, water is poured so that, for example, the uppermost end 34d of the U-shaped shaft 34a is immersed so that residues attached to the wall surface in the tank body 12 and the anchor blade 30 can be removed. Is preferred.
The anchor blade 30 may rotate only one of the central blade 32 and the U-shaped blade 34 (at this time, the other is fixed without rotating), or both may be rotated. Since both cleaning efficiency is good, it is preferable to rotate both, and it is more preferable to rotate in a certain direction (forward rotation) and then to rotate in the opposite direction (reverse rotation), or to rotate in opposite directions.
The rotational speeds of the center blade 32 and the U-shaped blade 34 are appropriately determined in consideration of the amount of water input to the tank body 12, the amount of residue attached, or the physical properties of the residue (hardness to peel off).
The shear rate of the mixing unit 20 is appropriately determined in consideration of the amount of residue attached or the physical properties of the residue (hardness to peel off).
The number of circulations (the number of passes) of the external circulation of the washing water (circulation in which the washing water is taken out from the discharge port 12a and returned to the tank body 12 through the circulation path 40) is not limited to one round, and may be circulated a plurality of times. It is determined appropriately in consideration of the amount of residue attached or the physical properties of the residue (hardness to peel off, etc.).
The operation in the normal pressure washing step is preferably performed by adjusting the water temperature to 90 ° C. or less, more preferably from 10 to 70 ° C.

[Vacuum washing process]
After draining in the normal pressure washing process, water is put into the tank body 12 so that the mixing unit 20 is immersed. For example, it is preferable to add water of about 8 to 20% of the capacity of the tank body 12.
At that time, it is preferable to add water from the upper surface of the tank body 12 so as to remove the residue attached to the wall surface in the tank body 12 and the anchor blades 30 that could not be removed in the previous atmospheric pressure washing step. .

Next, while the mixing unit 20 is immersed in water, the pressure inside the tank body 12 is reduced to 100 kPa or less, preferably 90 kPa or less, more preferably 50 kPa or less, further preferably 20 kPa or less, and particularly preferably 7 to 10 kPa. Is operated to rotate the rotor 24. In the present invention, the pressure (kPa) at the time of depressurization means absolute pressure.
At this time, water (washing water) that flows into the mixing unit 20 from the opening 22c passes between the blade 22a and the blade 24a while being accelerated by the rotation of the rotor 24, and flows out of the mixing unit 20.
The operating condition of the mixing unit 20 is not particularly limited, and the shear rate and the like may be adjusted so that the residue of the mixing unit 20 can be removed. Shear rate of the rotor 24 is preferably 7000Sec ^-1 or more, more preferably 10000～50000Sec ^-1, more preferably 12000~35000sec ^-1. If the shear rate of the rotor 24 is less than the preferred lower limit, the residue may not be sufficiently removed.
The shear rate of the rotor 24 is v / D (sec ⁻¹ ) when the tip speed of the blade 24 a of the rotor 24 is v (m / s) and the clearance between the stator 22 and the rotor 24 is D (m). This is a calculated value. The shear rate can be controlled by adjusting the rotational speed of the blade 24 a or the clearance D between the stator 22 and the rotor 24.

  The washing water may be circulated only in the tank body 12 (internal circulation), or may be circulated through the circulation path 40 (external circulation).

In the mixing apparatus 100, as shown in FIG. 3, the cleaning water is moved to the circulation path 40 by moving the mixing section 20 below the mixing section storage chamber 12 b and securing the communication hole 12 c communicating with the circulation path 40. Flow, external circulation can be performed.
In this case, the water-insoluble particulate matter 70 (residue) remaining in the vicinity of the circulation path 40 of the mixing unit 20 flows out from the mixing unit 20 and is easily removed, but the colored particulate matter 70 remaining on the side far from the circulation path 40. Tends to remain without flowing out of the side wall of the mixing unit storage chamber 12b.

As shown in FIG. 4, the mixing unit 20 is moved above the mixing unit storage chamber 12b, and the stator 22 and the rotor 24 are protruded upward from the discharge port 12a, whereby the cleaning water is circulated only in the tank body 12. (Internal circulation).
In this case, the water-insoluble granular material 70 (residue) remaining in the mixing unit 20 easily flows out into the tank body 12 and is easily removed because there is no obstacle around it. From the viewpoint of removing the water-insoluble particulate matter 70 (residue), it is preferable to perform the cleaning while rotating the rotor 24 with the stator 22 and the rotor 24 protruding above the discharge port 12a.

The number of circulations (pass number) of the external circulation of the cleaning water is not limited to one round, and a plurality of rounds may be circulated, and is determined as appropriate in consideration of the entire cleaning process or manufacturing efficiency. Preferably, external circulation of 2 to 5 laps is performed.
The washing operation by operating the mixing unit 20 is preferably performed by adjusting the water temperature to 90 ° C. or less, and more preferably by adjusting the water temperature to 10 to 70 ° C. The washing time is preferably 5 to 20 minutes.

  After the mixing unit 20 is actuated and the rotor 24 is rotated, the mixing unit 20 is moved below the mixing unit storage chamber 12b to secure the communication hole 12c, and the valve 50 is switched in the direction of the pipe 60 so that the washing water is supplied. Send to piping 60 and drain out of system. At that time, drainage may be performed while the mixing unit 20 is operated, or drainage may be performed without being operated, but in order to suppress water-insoluble matter remaining in the gap between the rotor 24 and the bearing unit 26. It is preferable to drain the water while operating the mixing unit 20.

  The cleaning method for the mixing apparatus of the present invention is not limited to the cleaning method performed by combining the above-described normal pressure cleaning step and the reduced pressure cleaning step, and may be only the reduced pressure cleaning step depending on the remaining residue. An atmospheric pressure washing process may be provided after the vacuum washing process. However, in order to perform cleaning efficiently, a cleaning method in which the normal pressure cleaning step and the reduced pressure cleaning step are combined is preferable.

Moreover, in the mixing apparatus 100 shown in FIG. 1, although the mixing part 20 was provided in the mixing part storage chamber 12b protruded below from the discharge port 12a of the tank main body 12, it is not limited to this, For example, circulation The mixing unit 20 may be provided in the middle of the path 40, and the mixing unit 20 may be provided in the tank body 12.
In addition, the mixing apparatus 100 may include a stirring blade other than the anchor blade 30 such as a turbine blade, or may not include the circulation path 40.

  As a mixing apparatus (apparatus name, manufacturer) suitable as an object to be cleaned by the cleaning method of the present invention, for example, a universal mixer (HAAGEN & LINAU), Becomix (Berents), DINEX-H (Fryma Koruma), Zoatec Mixer (Azo) ), Flyma Mixer (Fryma), VAKMIX (VAKU), New UNIMIX (EKATO), ALMIX (TETRA PAK), Ajihomo mixer (Primics), vacuum emulsifier (Mizuho Industry), and the like.

(Function and effect)
As described above, the cleaning method of the mixing apparatus of the present invention rotates the rotor in an environment of 100 kPa or less while immersing the mixing unit having the rotor and the stator combined with the rotor in water, By having a reduced-pressure washing step to drain, residues such as water-insoluble particulate matter and raw material mixture remaining in the mixing part can be sufficiently removed with a small amount of water and in a shorter washing time. Excellent.

  According to the cleaning method for a mixing apparatus of the present invention, since the cleaning performance is excellent, the efficiency of the product switching operation can be improved and the productivity is increased.

  Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples. In this example, “%” indicates “% by mass” unless otherwise specified.

Using a mixing apparatus similar to the mixing apparatus shown in FIG. 1, the dentifrice was manufactured by mixing the ingredients which are the raw materials of the dentifrice shown in Table 1 as follows (with external circulation).
In advance, using a stirring tank equipped with paddle blades, 180.0 parts by mass of propylene glycol and 90.0 parts by mass of carboxymethylcellulose were mixed to prepare dispersion (1).
A mixing apparatus similar to the mixing apparatus 100 shown in FIG. 1 is used, and 12.0 parts by mass of sodium saccharin is mixed and dissolved in 1908.0 parts by mass of water in the tank body 12, and then silicic anhydride (average particle size 14 μm) 300 is mixed therein. Add 0.0 parts by weight and mix, and further add 1800.0 parts by weight of 70% by weight sorbit liquid and mix. Add dispersion (1) to the resulting mixture to prepare a swelling liquid at a temperature of 25 ° C. did.
After adding 1200.0 parts by mass of calcium carbonate to this swelling liquid, the anchor blade 30 was first rotated at a rotation speed of 30 rpm for 3 minutes to mix the whole.
Subsequently, 180.0 parts by mass of granular zeolite (blue particle group), 180.0 parts by mass of granular zeolite (white particle group), and 90.0 parts by mass of sodium lauryl sulfate are sequentially added, and the anchor blade 30 is rotated. The whole was mixed by rotating at a speed of 30 rpm for 1 minute.
Subsequently, 60.0 mass parts of fragrance | flavor was added and mixed.
Next, the inside of the tank body 12 is depressurized to 5 kPa, the temperature is set to 25 ° C., the shear rate of the rotor 24 is set to 10000 sec ⁻¹ , and the circulation number of the external circulation is set to 3 times. A dentifrice was obtained.
Then, the manufactured dentifrice was taken out from the discharge port 12a of the tank body 12, sent to the pipe 60, and discharged out of the system.
Next, the mixing device used for the preparation of the dentifrice was cleaned.

<Washing method of mixing device>
Example 1
Normal pressure washing process:
First, 5t of water was put into the tank main body having a capacity of 6 t from the upper surface of the tank main body so as to remove the residue of the dentifrice adhering to the wall surface and the anchor blades in the tank main body (operation (1)).
Next, the mixing part is arranged so that the stator and the rotor protrude above the discharge port (the state shown in FIG. 4), and the anchor blade (center blade and U-shaped blade) and the mixing part are aligned for 6 minutes. (Operation (2)). At that time, the water temperature was adjusted to 45 ° C. Further, the rotation speed of the anchor blade was set to 30 rpm, and the shearing speed of the mixing unit rotor was set to 15000 sec ⁻¹ .
Subsequently, while reversing the anchor blades (both the center blade and the U-shaped blade), external circulation was performed for 7.5 minutes to allow the washing water to flow into the circulation path, and the water was drained (operation (3)). At that time, the rotation speed of the anchor blade was set to 30 rpm, the shearing speed of the mixing unit rotor was set to 15000 sec ⁻¹ , and the number of circulations of the external circulation was set to two.
Thereafter, for the purpose of eliminating bubbles, 200 kg of water was poured into the tank body from the upper surface of the tank body and drained three times (operation (4)).

  Subsequently, said operation (1)-(4) was performed again.

Vacuum cleaning process:
Next, 500 kg of water was introduced into the tank body from the upper surface of the tank body so as to remove residues adhering to the wall surfaces and anchor blades in the tank body.
Subsequently, the inside of a tank main body was pressure-reduced to 7 kPa, and the mixing part of the state immersed in water was operated under pressure reduction. At that time, the mixing unit was moved in the mixing unit storage chamber and operated for 20 minutes in the state shown in FIG. The shear rate of the mixing portion rotor was set to 15000 sec ⁻¹ .
Thereafter, the washing water was drained while operating the mixing section rotor at a shear rate of 1200 sec- ¹ .

  Subsequently, in order to remove the residue at the bottom in the tank body, 200 kg of water was poured from the top surface of the tank body and drained three times.

Next, 500 kg of water was put into the tank body from the top surface of the tank body (operation (5)).
Subsequently, the mixing part immersed in water was operated under normal pressure (operation (6)). At that time, the mixing unit was moved in the mixing unit storage chamber and operated for 1 minute in the state shown in FIG. The shear rate of the mixing portion rotor was set to 15000 sec ⁻¹ .
Thereafter, the washing water was drained while operating the mixing section rotor at a shear rate of 1200 sec ⁻¹ (operation (7)).
Next, in order to remove the residue at the bottom in the tank body, 200 kg of water was poured from the top surface of the tank body and drained three times (operation (8)).

  Next, the above operations (5) to (8) were further repeated 4 times.

(Example 2)
During the vacuum washing step, the inside of the tank body was decompressed to 90 kPa, and the mixing unit immersed in water was operated under reduced pressure, and the above operations (5) to (8) were repeated a total of 6 times. Except that, the same operation as in Example 1 was performed.

(Comparative Example 1)
The operations (1) to (4) in Example 1 were repeated twice.

(Comparative Example 2)
The operations (1) to (4) in Example 1 were repeated twice.
Next, operations (5) to (8) in Example 1 were repeated 15 times.

<Evaluation>
In the cleaning method of the mixing apparatus in each example, dentifrice residue (granular zeolite (blue particle group) which is a water-insoluble colored granular material) was evaluated. Moreover, the washing time required for washing the mixing device and the amount of water used were measured. These results are shown in Table 2.

Evaluation of the dentifrice residue was performed by sieving the waste liquid after predetermined drainage with a 75 μm filter, and ◯ when no residue was found on the filter, and × when the residue was found. .
In Example 1 and Example 2, the waste liquid after the last drainage in operation (8) in the first operation (5) to (8); in Comparative Example 1, the second operation (1) to (4) The waste liquid after the last drainage in the operation (8) in the second operation (5) to (8) in the comparative example 2 respectively, the waste liquid after the last drainage in the operation (8) in the second operation (4) did.

  From the results shown in Table 2, according to the cleaning methods of Example 1 and Example 2 to which the present invention is applied, the amount of water used can be reduced, the cleaning time can be shortened, and the cleaning property is excellent. I can confirm.

DESCRIPTION OF SYMBOLS 10 Stirring tank, 12 Tank main body, 20 Mixing part, 22 Stator, 24 Rotor, 26 Bearing part, 28 Motor, 30 Anchor blade, 32 Center blade, 34 U blade, 40 Circulation path, 50 Valve, 60 Piping, 70 Water Insoluble particulate matter, 100 mixing device.

Claims (2)

A stirring tank having a tank body, a mixing portion and a stator combined to the rotor and the rotor which rotates in the cleaning method of mixing apparatus having,
The mixing unit is a high shear mixer, and a clearance between the stator and the rotor is 0.1 × 10 ⁻³ to 2 × 10 ⁻³ m,
Under normal pressure, the normal pressure washing process of putting water into the tank body and draining it,
A vacuum washing step of rotating the rotor under an environment of 100 kPa or less while immersing the mixing unit in water, and flowing out the water flowing into the mixing unit out of the mixing unit by the rotation of the rotor, and then draining the water. And a cleaning method for a mixing device. The rotor is substantially disc-shaped and has a rotation shaft at the center thereof,
  The rotor has a plurality of blades;
  The plurality of blades form concentric rows centered on the rotation axis,
  The stator is substantially disk-shaped, has a blade,
  The cleaning method for a mixing apparatus according to claim 1, wherein the blades of the stator are located between an arbitrary row of the plurality of blades of the rotor and a row adjacent thereto.

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