JP2010201290A - Flour milling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a planetary ball milling device oversized in a flour milling method using a planetary ball milling device equipped with a synthetic resin pot and a synthetic resin ball. <P>SOLUTION: (1) The planetary ball milling device includes at least one synthetic resin pot 10 with a volume of 500 to 20,000 cc and a plurality of synthetic resin balls 15 enclosed in the pot 10. Further, the inside diameter of the pot 10 is 2.5 to 4 times the diameter of the ball 15. (2) A raw material for flour milling and the ball 15 are enclosed in the pot 10, and the pot 10 is actuated to revolve or revolve and rotate for one to 720 minutes within the range of a number of revolutions of 10 to 750 rpm. Thus the grinding of the raw material for flour milling can be achieved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a milling method, and more particularly to a milling method using a planetary ball mill apparatus suitable for producing fine powders such as foods and herbal medicines.

  Prepare a synthetic resin pot and a planetary ball mill equipped with a synthetic resin ball, enclose tea leaves, dried food, etc. as raw materials and a synthetic resin ball in the synthetic resin pot, and rotate and rotate it. Thus, a method for pulverizing raw materials to produce powdered tea, fine powder of dried food, and the like has been proposed so far (see Patent Document 1).

  According to this method, compared with the conventional milling method using a planetary ball mill apparatus provided with a metal pot and a hard ball formed of chromium steel, ceramics, etc., it becomes possible to make the raw material uniform and fine powder, For example, when powdered tea is produced from raw tea leaves, a pulverized product that is inferior to powdered tea by a conventional pulverization method is obtained.

  However, in this method, when the planetary ball mill apparatus is enlarged, (1) the optimum correlation between the pot size and the ball diameter is not clear, and (2) the pot and the ball need to be rotated at high speed. At that time, the temperature in the pot suddenly increased due to friction between the resins, and the pot and the ball were easily worn, and it was considered that they were not suitable for the production of foods, herbal medicines, etc. (3 ) It was thought that this high-speed rotation increased the noise caused by the collision between the balls in the pot and between the balls and the pot, and (4) the milling time was expected to increase because the weight of the milling raw material increased. For this reason, it is difficult to increase the size of the planetary ball mill device. For this reason, only pots with a capacity of up to 400 cc can be used. Powder there is a problem that can not be mass-produced at a time.

International Publication WO2006 / 106964 Pamphlet

  Accordingly, an object of the present invention is to realize an increase in size of a planetary ball mill device in a milling method using a planetary ball mill device including a synthetic resin pot and a synthetic resin ball.

  In order to solve the above problems, the present invention includes (1) at least one synthetic resin pot having a volume of 500 to 20000 cc, and a plurality of synthetic resin balls enclosed in the pot, A planetary ball mill device having an inner diameter of 2.5 to 4 times the diameter of the ball is prepared. (2) The milling raw material and the ball are enclosed in the pot, and the pot is rotated at a rotational speed of 10 The milling method is characterized in that the milling raw material is pulverized by revolving, or revolving and rotating for 1 to 720 minutes within a range of ˜750 rpm.

  In this milling method, it is preferable to set the rotational speed of the rotating motion of the pot to be 1 to 3 times the rotational speed of the revolving motion.

  Further, in a state where the plurality of balls are enclosed in the pot, one or both of the transition portion from the peripheral wall surface to the bottom wall surface and the transition portion from the peripheral wall surface to the top wall surface in the internal space of the pot have a predetermined curvature. It is preferable that the radius of curvature of the transition portion is equal to or larger than the radius of the ball, and the plurality of balls are enclosed in the pot, The pot is preferably formed so that the height of the internal space is about 1.1 to 1.9 times the diameter of the ball.

  If necessary, the ball may have a two-layer structure including a spherical core formed of a first synthetic resin and a skin layer formed of a second synthetic resin surrounding the core, or A core made of a metal sphere may be incorporated in the ball, or the ball may be hollow.

Further, the synthetic resin is any one of polyetheretherketone and polyamideimide and polybenzimidazole, or a mixture thereof, or a copolymer composed of a constituent monomer of polyetheretherketone or polyamideimide or polybenzimidazole. Is preferred.
Further, it is preferable that the rotation speed and the rotation duration time are set so that the temperature in the pot becomes equal to or lower than a predetermined temperature, and the potting material is pulverized by revolving, or revolving and rotating.

According to the present invention, in a milling method using a planetary ball mill apparatus equipped with balls and pots made of a synthetic resin, it is predicted in the case of a large pot based on a simple scaling law from the milling conditions in the case of a conventional small pot. According to the milling conditions that are completely different from the milling conditions, the large pot is revolved, or revolved and rotated to grind the milling raw material. Thus, a large amount of fine powder can be produced at one time.
According to the present invention, various milling raw materials can be made into fine powders. In particular, various foods such as tea leaves and dried foods (such as bonito, kelp, mushrooms, and dried abalone), and various herbal medicines (Chinese medicines) ) As well as chitosan, pearls and chemicals can be pulverized to produce high-quality fine powders in large quantities at a low cost.

It is a sectional side view of the planetary ball mill apparatus used in the milling method by one Example of this invention. It is a figure which shows one Example of the pot of a planetary ball mill apparatus, (A) is a perspective view, (B) is a longitudinal cross-sectional view. It is a figure which shows the state in which the ball | bowl was accommodated in the pot, (A) is a top view, (B) is a longitudinal cross-sectional view. It is a figure which shows another Example of the pot of a planetary ball mill apparatus, (A) is a top view of the state in which the ball was accommodated in the pot, (B) is the longitudinal cross-sectional view. It is a figure explaining the movement state of the ball | bowl in the pot in the grinding | pulverization process by the Example of FIG. It is the table | surface which put together the experimental result at the time of grind | pulverizing the raw tea leaf of tencha using the milling method of this invention. 7 is a graph corresponding to the table of FIG. It is the table | surface which put together the experimental result which compared the case where the raw tea leaves of Tencha were pulverized with the large pot according to the milling method of this invention, and the case where it pulverized with the small pot according to the conventional method.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The milling method of the present invention is particularly suitable for pulverizing foods and herbal medicines to produce fine powders thereof.
According to the milling method of the present invention, first, at least one synthetic resin pot with a volume of 500 to 20000 cc and a plurality of synthetic resin balls enclosed in the pot are provided, and the pot has an inner diameter of the ball. A planetary ball mill apparatus having a size 2.5 to 4 times the diameter is prepared.

  FIG. 1 is a side sectional view of the planetary ball mill device. The planetary ball mill apparatus used in the milling method of the present invention has the same configuration as a known planetary ball mill apparatus except for pots and balls. Therefore, in the following, components other than pots and balls of the planetary ball mill apparatus will be described. Just a brief explanation. Further, the configuration of the pot and ball rotation drive mechanism in the planetary ball mill apparatus is not limited to that described below, and a planetary ball mill apparatus provided with any appropriate known rotation drive mechanism can be used.

  Referring to FIG. 1, the planetary ball mill apparatus includes a vertical main shaft 2 that is rotationally driven by a motor 1, and a disk-shaped rotary table 3 is fixed to the main shaft 2. Further, on the turntable 1, four pot turntables 5 are arranged so as to be rotationally symmetric with respect to the main shaft 2, and can be rotated around the rotation shaft 4 with respect to the turntable 1. The main shaft 2 and each rotation shaft 4 are connected by a planetary gear mechanism 6.

Further, a flat upper support member 7 is fixed to the upper portion of the main shaft 2. The upper support member 7 has a plurality of arm portions that extend radially from the main shaft 2 and reach above the pot turntables 5. Each arm portion 5 has a pressing rod 8 that can move up and down in the axial direction. It is rotatably mounted around its axis.
Then, after the pot 3 in which a plurality of balls and a milling raw material are enclosed is placed on the pot turntable 2, the pressing rod 8 is moved downward so that the tip of the pressing rod 8 is moved. The pot 10 is fixed to the pot turntable 5 by being pressed against the upper surface of the pot 10.

Thus, the rotary table 1 is driven to rotate around the main shaft 2 by the motor 1, and the pot turntable 5 is rotated around the rotation shaft 4 by the motor 1 via the planetary gear mechanism 6. , So that the pot 10 is revolved around the main shaft 2 and is rotated around the rotation shaft 4.
In order to prevent danger during operation of the planetary ball mill device, an openable and closable protective cover 9 that covers the motion space of the pot turntable 5 is provided on the upper portion of the planetary ball mill device.

  2A and 2B are diagrams showing an embodiment of the pot, where FIG. 2A is a perspective view and FIG. 2B is a longitudinal sectional view. As shown in FIG. 2, the pot 10 includes a cylindrical pot body 11 with one end closed, and a lid body 12 that can seal the other end opening of the pot body 11 with a ring-shaped packing 14. Yes. Further, the transition portion 11c from the peripheral wall surface 11a to the bottom wall surface 11b of the inner cavity portion 13 of the pot body 11 is curved with a predetermined radius of curvature r.

  The pot 10 and the ball 15 are made of synthetic resin. Any synthetic resin can be used as long as it is not toxic to the human body and has high wear resistance, high self-lubrication property and high impact resistance. Particularly, polyether ether ketone and polyamideimide (for example, Torlon (registered trademark)) and polybenzimidazole, or a mixture thereof, or a polyether ether ketone or polyamideimide (for example, Torlon (registered trademark)) or a copolymer of polybenzimidazole. It may be.

The pot 10 and the ball 15 formed from the same type of synthetic resin need not always be used in combination, and the pot 10 and the ball 15 formed from different types of synthetic resin may be used in combination.
The pot 10 only needs to have an inner wall surface made of a synthetic resin, and may be a pot having an outer skin made of a metal such as stainless steel or iron outside the synthetic resin layer forming the inner wall surface in order to prevent deformation.

  In order to achieve good pulverization, the specific gravity of the balls 15 may be appropriately changed according to the dimensions of the balls 15 and the pot 10 and the type of the milling raw material. As a method of changing the specific gravity of the ball 15, two types of synthetic resins having different specific gravities are prepared, and the ball 15 is surrounded by a spherical nucleus formed from the first synthetic resin and the outside of the nucleus. A method of changing the specific gravity as a two-layer structure comprising an outer skin layer formed of a synthetic resin, a method of increasing the specific gravity by incorporating a core made of a metal sphere into the ball 15, or a hollow inside of the ball 15 To reduce the specific gravity.

FIGS. 3A and 3B are views showing a state in which the ball is accommodated in the pot, where FIG. 3A is a plan view and FIG. 3B is a longitudinal sectional view. Referring to FIG. 3, the radius of curvature r of the transition portion 11 c from the peripheral wall surface 11 a to the bottom wall surface 11 b of the inner cavity portion 13 of the pot 10 is equal to or larger than the radius of the ball 15.
Further, the diameter s of the inner cavity portion 13 of the pot 10 is 2.5 to 4 times the diameter R of the ball 15, and 5 to 8 identical balls 15 are provided per pot. Be contained.

  4A and 4B are diagrams showing another embodiment of the pot, in which FIG. 4A is a plan view of a state where a ball is accommodated in the pot, and FIG. 4B is a longitudinal sectional view thereof. The embodiment of FIG. 4 differs from the embodiment of FIG. 3 only in the internal structure of the pot. Therefore, in FIG. 4, the same components as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

With reference to FIG. 4, in this embodiment, in a state where the upper end opening of the pot body 11 is sealed by the lid body 12, the transition portion 11 c from the peripheral wall surface 11 a to the bottom wall surface 11 b in the internal space 13 of the pot 10, and A transition portion 11d from the peripheral wall surface 11a to the upper wall surface is curved with a predetermined radius of curvature r. In this case, the radius of curvature r of the transition portions 11c, 11d is equal to or larger than the radius of the ball 15.
In this embodiment, the height d of the internal space 13 of the pot 10 is about 1.1 to 1.9 times the diameter R of the ball 15 with the upper end opening of the pot body 11 sealed by the lid 12. It has become. Therefore, in this embodiment, the balls 15 are not arranged in two stages in the pot 10.

  Also in this embodiment, as in the embodiment of FIG. 3, the diameter s of the inner cavity portion of the pot 10 is 2.5 to 4 times the diameter of the ball 15 and one pot is used. 5 to 8 identical balls 15 are enclosed.

  Then, according to the milling method of the present invention, the milling raw material and the ball 15 are enclosed in the pot 10, and the pot 10 is fixed to the pot turntable 5 of the planetary ball mill device, and the rotation speed is within the range of 10 to 750 rpm. Rotate for 1 to 720 minutes, or revolve and rotate. In this case, it is preferable to set the rotation speed of the pot's rotation movement to be 1 to 3 times the rotation speed of the revolution movement. Moreover, when making a revolution and a rotation motion, both the direction of rotation of a revolution motion and a rotation motion may be the same, and may be mutually opposite directions.

  Thus, in the initial stage of the pulverization process, when the pulverization does not proceed, when the ball 15 moves in the planetary pot 10, the movement of the ball 15 becomes disordered because the viscosity of the milling raw material is large. The collision between 15 and the collision between the ball 15 and the inner wall of the pot 10 frequently occur (see FIG. 5A), and the resulting collision sound is generated. During this collision, the milling raw material enters between the balls 15 and between the balls 15 and the inner wall of the pot 10 and is pulverized.

  When the milling raw material is pulverized to a certain degree due to the collision between the balls 15 and between the ball 15 and the inner wall of the pot 10, the viscosity of the milling raw material decreases, and the force that gives disorder to the movement of the balls 15 is weakened. Then, the entire ball 15 starts to move in an orderly manner, the collision as described above does not occur (see FIG. 5B), and the collision sound disappears. After that, the milling raw material is pulverized and pulverized mainly by a shearing force generated by the relative movement of the assembly of balls 15 and the inner wall of the pot 10.

  The time until the collision sound disappears after the operation of the ball mill device starts depends on the revolution speed, rotation speed, kind of milling raw material of the pot 10, the amount of fine powder produced and the average particle size. If the revolution speed, rotation speed, type of milling raw material, and amount of fine powder produced are all the same, the longer the viscosity of the powder, the longer the revolution speed, rotation speed, and the same type of milling raw material. If so, it increases as the amount of fine powder produced increases.

  As a result, the pulverization process while the collision sound is generated is a coarse pulverization process, and the pulverization process after the collision sound disappears is a pulverization process to a finer particle size. In order to make the milling raw material finer, the pulverization process after the collision sound disappears may be continued.

According to the milling method of the present invention, the temperature in the pot increases as the speed of the revolution or rotation of the pot increases and as the duration of the rotation and rotation increases. This temperature rise is due to both impact and shear forces.
By the way, when the temperature in the pot is sharply increased when the milling raw material is pulverized, the produced fine powder may be discolored by the action of heat, and the quality such as aroma and flavor may be deteriorated. In such a case, it is desirable to perform pulverization at a temperature equal to or lower than the temperature at which quality deterioration occurs in the fine powder to be produced. For this reason, it is desirable to set the rotation speed and rotation duration time of the planetary ball mill device so that the temperature rise in the pot during pulverization can be suppressed to a predetermined temperature or less.

  The setting of the number of rotations and the rotation duration is, for example, by repeating trial pulverization in advance, measuring the temperature in the pot immediately after pulverization with an infrared radiation thermometer or the like, based on the data acquired at that time, For each size of pot and ball, type of milling raw material, amount of fine powder to be produced, etc., determine the range of rotation speed and rotation duration where the temperature rise during pulverization is below the predetermined temperature and make a table. In actual operation, it may be performed each time according to the table.

Next, a pot and a ball were actually made, and a verification experiment was conducted to see whether the desired result was obtained. The contents of the demonstration experiment are as follows.
Two types of the example of FIG. 4 were prepared as pots for the planetary ball mill device.
(A) Pot No. 1 (pot with a volume of 2000 cc): polyetheretherketone (PEEK) having an inner diameter s = 163 mm, a depth d = 96.6 mm, and a radius of curvature r = 29.6 mm at the transition from the peripheral wall surface to the bottom wall surface and the upper wall surface Pot (b) Pot No. 2 (pot having a volume of 500 cc): Pot made of polyether ether ketone (PEEK) having an inner diameter s = 110 mm, a depth d = 65 mm, and a radius of curvature r = 20 mm of the transition portion from the peripheral wall surface to the bottom wall surface and the upper wall surface Pot No. As a ball for 1,
(C) Ball No. 1: Polyetheretherketone (PEEK) ball (specific gravity approximately 1.3, diameter R = 59.2 mm)
And pot no. As a ball for 2,
(D) Ball No. 2: Polyetheretherketone (PEEK) ball (specific gravity about 1.3, diameter R = 36.5 mm)
It was created.

[Experiment 1]
Example 1
Tencha, which is the raw material for Matcha, is used as the milling material. No. 1 with an equal amount of tea leaves and five ball Nos. 1 and 4 pot Nos. 1 is fixed on the pot turntable of the planetary ball mill apparatus of FIG. 1, and rotates and revolves in two directions at two different rotation speeds of 140 rpm and 190 rpm in opposite directions for three different times of 20 minutes, 40 minutes and 60 minutes, respectively. It was exercised to produce powdered tea. And the temperature of the powdered tea in the pot immediately after a rotation stop was measured, and also the particle size distribution of the powdered tea was measured using the particle size distribution measuring apparatus.
(Example 2)
The same tea leaves as in Example 1 were used, and four pot Nos. 1, each of the same amount of tea leaves as in Example 1 and six ball Nos. 1 and 4 pot Nos. 1 is fixed on the pot rotating table of the same planetary ball mill apparatus as in Example 1 and rotated in the reverse direction at two different rotational speeds of 140 rpm and 190 rpm, respectively, for three different times of 20 minutes, 40 minutes and 60 minutes, respectively. The powder tea was produced by revolving. And the temperature of the powdered tea in the pot immediately after a rotation stop was measured, and also the particle size distribution of the powdered tea was measured using the particle size distribution measuring apparatus.

The measurement results are shown in the table of FIG. 6 and the graph of FIG. In the table of FIG. 6 and the graph of FIG. 7, the definitions of MV (μm), MN (μm), MA (μm), CS and SD (μm) are as follows.
MV: Average diameter weighted by volume MA: Average diameter weighted by area MN: Average diameter obtained from virtual number distribution SD: Standard deviation serving as a guide for particle size distribution width CS: When particles are assumed to be spherical From the table of FIG. 6 and the graph of FIG. 7, according to the milling method of the present invention, when the pot volume is increased from 500 cc to 2000 cc, at a low rotation speed of 140 to 190 rpm for a short time (20 It can be seen that a powdered tea with a relatively small particle size can be obtained only by crushing (about 60 minutes).

[Experiment 2]
Example 3
As the raw material for milling, the same tea leaves as in Examples 1 and 2 were used. 2, each of the same amount of tea leaves as in Examples 1 and 2 was added to five ball Nos. 2 and then fixed on the pot rotating table of the same planetary ball mill apparatus as in Examples 1 and 2, and rotated in reverse at 320 rpm for different times of 90 minutes, 150 minutes, 210 minutes and 360 minutes, respectively. The powder tea was produced by revolving. And the particle size distribution of the obtained powder tea was measured using the particle size distribution measuring apparatus.

  Furthermore, for the powdered tea obtained in Example 2 and the powdered tea obtained in Example 3, the color difference (a value) was measured using a spectroscopic color difference meter (SE-6000 manufactured by Nippon Denshoku Industries Co., Ltd.). The sensory test was conducted. The sensory test is a test method for evaluating and judging quality based on human sensory organs, and is currently the test most commonly used for tea quality evaluation. And in this experiment, paying attention to the inspection items, two points of color (powder color) and flavor (scent and taste when included in the mouth), stone mill ground matcha as a reference (10 points), 0.5 Comparison was made with each powdered tea obtained in Example 2 and Example 3 by the point increment / decrement method and evaluated.

  The results are shown in the table of FIG. From the table of FIG. 8, in Example 3 (500 cc pot), the average particle size could be pulverized to 31.7 μm at a rotation speed of 320 rpm and 90 minutes, whereas Example 2 (2000 cc pot). It can be seen that, in order to pulverize to approximately the same average particle diameter of 31.25 μm, the rotational speed is 190 rpm, the pulverization time is 60 minutes, and the rotational speed is lower than that of Example 3, and the time is shorter. In addition, the color of the powdered tea obtained in Example 2 is better than that obtained by pulverizing for 90 minutes in Example 3, and the flavor is somewhat inferior, so the quality of the powdered tea obtained in Example 2 is It is about the same as or higher than the powdered tea obtained in the comparative example.

  Thus, according to the milling method of the present invention, the milling conditions predicted in the case of a large pot having a volume of 500 cc or more based on a simple scale rule from the milling conditions in the case of a conventional small pot (capacity of about 400 cc at most). The milling material is pulverized by rotating and rotating the large pot according to completely different milling conditions, so that a large amount of fine powder can be obtained at a lower speed and in a shorter time than the conventional small pot. Can be manufactured, and noise during manufacturing can be reduced.

DESCRIPTION OF SYMBOLS 1 Motor 2 Main axis | shaft 3 Rotary table 4 Autorotation shaft 5 Pot rotation base 6 Planetary gear mechanism 7 Upper support member 8 Press rod 9 Protective cover 10 Pot 11 Pot main body 11a Peripheral wall surface 11b Bottom wall surface 11c Transition part 12 Cover body 13 Inner cavity part 14 Ring packing 15 balls

Claims (8)

(1) It includes at least one synthetic resin pot having a volume of 500 to 20000 cc and a plurality of synthetic resin balls enclosed in the pot, and the inner diameter of the pot is 2.5 of the diameter of the ball. Prepare a planetary ball mill device with a size of ~ 4 times,
(2) The milling raw material and the ball are enclosed in the pot, and the pot is made to revolve, or revolve and rotate for 1 to 720 minutes within a rotation speed range of 10 to 750 rpm. A milling method characterized by crushing raw materials.   The milling method according to claim 1, wherein the rotation speed of the rotation motion of the pot is set to be 1 to 3 times the rotation speed of the revolution motion.   With the plurality of balls enclosed in the pot, one or both of the transition portion from the peripheral wall surface to the bottom wall surface and the transition portion from the peripheral wall surface to the upper wall surface in the internal space of the pot have a predetermined radius of curvature. The milling method according to claim 1, wherein the milling method is formed by bending, and a radius of curvature of the transition portion is equal to or larger than a radius of the ball.   The pot is formed so that the height of the internal space of the pot is about 1.1 to 1.9 times the diameter of the ball in a state where the plurality of balls are enclosed in the pot. The milling method according to any one of claims 1 to 3.   The ball has a two-layer structure including a spherical core formed of a first synthetic resin and an outer skin layer formed of a second synthetic resin surrounding the outer side of the core. The milling method according to any one of claims 1 to 4.   The milling method according to any one of claims 1 to 5, wherein a core made of a metal sphere is incorporated inside the ball, or the inside of the ball is hollow.   The synthetic resin is any one of polyetheretherketone and polyamideimide and polybenzimidazole, or a mixture thereof, or a copolymer composed of a constituent monomer of polyetheretherketone or polyamideimide or polybenzimidazole. The milling method according to any one of claims 1 to 6.   The rotational speed and rotation duration time are set so that the temperature in the pot becomes equal to or lower than a predetermined temperature, and the milling raw material is pulverized by revolving, or revolving and rotating. The milling method in any one of Claims 1-7.

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