The disclosure of the following application claiming priority is incorporated by reference herein: Japanese Patent Application No. 2015-226619 filed on Nov. 19, 2015.
The present invention relates to a granular material in which powder is attached to droplets and a method of producing the granular material.
Conventionally, a technique of producing a granular material by mixing liquid and powder has been known. However, since it is difficult to uniformly mix liquid and powder, various mixing apparatuses and mixing methods have been proposed (see, for example, Patent Literature 1).
However, with the aforementioned mixing apparatus, for example, when liquid and a material having a property that repels the liquid (hereinafter, the liquid repellent property) are mixed like a combination of water and waxy material, there is a problem that the liquid is detached from the material or the material lumps after mixing, preventing uniform mixing of liquid and powder.
It is an object of the present invention to provide a granular material in which liquid and powder are uniformly mixed, and a method of producing the granular material.
A granular material according to the present invention includes: a droplet; and powder having a liquid repellent property with respect to the droplet, the powder being attached to a surface of the droplet.
Furthermore, in the granular material according to the present invention, an angle of contact of the powder relative to the droplet is 90 degrees or more.
Furthermore, in the granular material according to the present invention, the droplet is a water drop formed of water and the powder is magnesium stearate powder.
Furthermore, in the granular material according to the present invention, the water drop has a median diameter D50 of 10 to 50 μm and the magnesium stearate powder has a median diameter D50 of 1 to 10 μm.
Furthermore, in the granular material according to the present invention, the droplet is an oil drop formed of oil and the powder is mica powder.
Furthermore, in the granular material according to the present invention, the oil drop has a median diameter D50 of 10 to 50 μm and the mica powder has a median diameter D50 of 1 to 10 μm.
Furthermore, a method of producing a granular material according to the present invention is a method of producing a granular material, the granular material including a droplet and powder having a liquid repellent property with respect to the droplet, the powder being mixed with the droplet, with a mixing apparatus for mixing the droplet and the powder, and the method includes: dispersing the powder from a powder dispersing portion arranged above an apparatus main body having an internal space into the internal space; spraying the droplet from a liquid spraying portion arranged in a vicinity of the powder dispersing portion into the internal space; and attaching the powder dispersed in the dispersing to a surface of the droplet sprayed in the spraying.
Furthermore, in the method of producing a granular material according to the present invention, the droplet has a median diameter D50 of 10 to 50 μm and the powder has a median diameter D50 of 1 to 10 μm.
Furthermore, in the method of producing a granular material according to the present invention, the droplet is a water drop famed of water and the powder is magnesium stearate powder.
Furthermore, in the method of producing a granular material according to the present invention, the droplet is an oil drop formed of oil and the powder is mica powder.
According to the present invention, a granular material in which liquid and powder are uniformly mixed and a method of producing the granular material are provided.
In the following, a granular material according to an embodiment of the present invention is described with reference to the drawings.
When the droplet A is a water drop formed of water, magnesium stearate powder is used as the powder B. In this case, the water drop has a median diameter D50 of 10 to 50 μm, and the magnesium stearate powder has a median diameter D50 of 1 to 10 μm. Furthermore, an angle of contact of the magnesium stearate powder relative to the water drop is 90 degrees or more. The water described in the present embodiment includes an aqueous solution, e.g., salt water and scented water. The powder B may be powder other than the magnesium stearate powder insofar as the powder has a liquid repellent property with respect to water (hereinafter the water repellent property).
When the droplet A is an oil drop formed of oil, mica powder is used as the powder B. In this case, the oil drop has a median diameter D50 of 10 to 50 μm, and the mica powder has a median diameter D50 of 1 to 10 μm. Furthermore, an angle of contact of the mica powder relative to the oil drop is 90 degrees or more. The powder B may be powder other than the mica powder insofar as the powder has a liquid repellent property with respect to oil (hereinafter the oil repellent property).
Next, the liquid repellent property of the powder is described.
The liquid repellent property of the powder is increased as the angle of contact θ illustrated in
The angle of contact θ of the magnesium stearate powder relative to the water drop is 90 degrees or more, and the magnesium stearate powder has a high water repellent property. Furthermore, the angle of contact θ of the mica powder relative to the oil drop is 90 degrees or more, and the mica powder has a high oil repellent property. Therefore, both when the magnesium stearate powder is attached to the surface of the water drop and when the mica powder is attached to the surface of the oil drop, the powder B does not get wet and is attached to the surface of the droplet A.
Next, a mixing apparatus according to an embodiment of the present invention is described with reference to the drawings.
The upper lid 4 is a lid for closing an upper end of the introduction pipe 6. In the upper lid 4, a powder disperser 4a for supplying powders in a dispersing manner into the apparatus main body 8 and liquid atomizing nozzles 4b for spraying atomized liquid into the apparatus main body 8 are arranged.
The introduction pipe 6 is a cylindrical pipe for introducing the powders supplied from the powder disperser 4a and the liquid sprayed from the liquid atomizing nozzles 4b, into the apparatus main body 8. The introduction pipe 6 has an outside diameter D of about 300 mm. The introduction pipe 6 has a length L6 of about 300 mm.
The apparatus main body 8 includes three cylindrical shell portions: an upper cylindrical shell portion 8a having a truncated square pyramidal shape, an intermediate cylindrical shell portion 8b having a rectangular cylindrical shape, and a lower cylindrical shell portion 8c having an inverted truncated square pyramidal shape. A top of the upper cylindrical shell portion 8a is famed with an opening 8d for introducing the powders and the liquid in the introduction pipe 6 into the apparatus main body 8. A lower end of the lower cylindrical shell portion 8c is famed with an opening 8e for discharging mixed powders to be collected by the collection container 12.
Furthermore, in the apparatus main body 8, a cylindrical member 14 for preventing the droplets A, the powders B, and the granular materials C from being dispersed into an internal space 20 of the apparatus main body 8, and bag filters 16 through which a discharge flow passes are arranged. The cylindrical member 14 is formed of a non-woven fabric having a bore diameter almost equivalent to that of the introduction pipe 6. The cylindrical member 14 is arranged in the internal space 20 with one end facing upward and the other end facing downward. The one end and the other end are opened to allow the droplets A, the powders B, and the granular materials C to flow. Furthermore, two bag filters 16 are arranged at positions across the cylindrical member 14 of the internal space 20 where a distance X with respect to the cylindrical member 14 is 100 mm in actual measurement (X/D=0.33). The cylindrical member 14 is arranged so that the one end is connected to the introduction pipe 6 and the other end is positioned between the lower end of the bag filters 16 and the collection container 12. The bag filters 16 are arranged at positions where a distance Y between the lower end of the bag filters 16 and the other end of the cylindrical member 14 is 50 mm in actual measurement. The cylindrical member 14 has a length L14 of about 700 mm. However, the length is not limited to the above, but may be selected from a length of L44/D>1.
The discharge portion 9 is provided on an outer wall portion of the intemediate cylindrical shell portion 8b of the apparatus main body 8. An accumulator 9a is arranged on a lower part of the discharge portion 9, and a discharge pipe 9c for discharging air in the internal space 20 is arranged on an upper part of the discharge portion 9. Furthermore, inside the discharge portion 9, an air pipe 9b for supplying pulsed compressed air, which is introduced from the accumulator 9a, to the bag filters 16 is arranged.
The collection container 12 is arranged below the lower cylindrical shell portion 8c and collects the granular materials C mixed in the introduction pipe 6 and the cylindrical member 14.
An upper part of the powder disperser 4a is formed with a powder supply port 22 having an inverted conical shape. At a roughly central part of the interior of the powder disperser 4a, a powder passage 24 through which the powder supply port 22 is communicated with the interior of the introduction pipe 6 is formed. Furthermore, inside the powder disperser 4a, an air chamber 26, which is an air reservoir for ejecting air at a uniform pressure, an air inlet port 28 for introducing air into the air chamber 26, and a slit 30 through which the air chamber 26 is communicated with the powder passage 24 are famed. The slit 30 is famed in an annular shape around the powder passage 24 and is communicated with the powder passage 24 and the air chamber 26 roughly circumferentially. The air chamber 26 is also famed in an annular shape around the powder passage 24. The air chamber 26 ejects the air introduced from the air inlet port 28 at a uniform pressure across the entire circumference of the slit 30.
The liquid atomizing nozzle 4b is a two-fluid type nozzle including a liquid passage 32 through which the liquid introduced from a liquid supply pipe 53 (see
As illustrated in
Furthermore, pulsed compressed air is introduced into the air pipe 9b from the accumulator 9a at predetermined time intervals. The pulsed compressed air introduced into the air pipe 9b is ejected into the space 16h through holes 9f famed through the air pipe 9b and is delivered into the space between the fabric 16a and the frame 16c via the space 16h. Thus, the fabric 16a is temporarily expanded and the powders adhered to the fabric 16a are removed by the oscillation of the fabric 16a. Thus, the air permeability of the fabric 16a is maintained. Therefore, clogging of the fabric 16a of the bag filter 16 is suppressed during discharge to the outside via the fabric 16a of the bag filter 16, the space between the fabric 16a and the frame 16c, the space 16h, the internal space of the discharge portion 9, and the discharge pipe 9c, thereby enabling suppression of a reduction in discharge force of the blower 56.
A process of generating a granular material with the mixing apparatus 2 according to the embodiment is described with reference to the schematic views of the mixing system illustrated in
First, when the operation of a mixing system 1 is started, both a compressed air supply portion 54 and the blower 56 are driven. When the compressed air supply portion 54 is driven, compressed air is introduced into the air passages 34 of the liquid atomizing nozzles 4b from the air pipe 55, and compressed air is introduced into the air inlet port 28 of the powder disperser 4a from the air pipe 55.
The compressed air introduced into the air inlet port 28 is ejected through the slit 30 at uniform ejection pressure by the air chamber 26 and is discharged into the introduction pipe 6 via the powder passage 24.
Furthermore, when the blower 56 is driven, the air in the internal space 20 of the apparatus main body 8 is discharged to the outside. The air in the internal space 20 passes through the fabric 16a put on the bag filter 16 and is then discharged to the outside via the space between the fabric 16a and the frame 16c, the space 16h, the internal space of the discharge portion 9, and the discharge pipe 9c. As illustrated in
Next, when the magnesium stearate powders are supplied to the powder supply port 22 from a feeder 70, as illustrated in
Next, when a pump 52 is driven, water is supplied from the liquid supply pipe 53 to the liquid passages 32 (see
The water passing through the liquid passages 32 of the liquid atomizing nozzles 4b is atomized by the compressed air injected from the air passages 34 at high speed, and, as illustrated in
The supply rate of the powders supplied from the feeder 70 is 1.5 kg/h and the supply rate of the water supplied from the pump 52 is 3.6 kg/h. Thus, a ratio of the supply rate of the powders to the supply rate of the water is roughly 1:2.
The droplets A sprayed into the introduction pipe 6 from the liquid atomizing nozzles 4b and the powders B dispersed into the introduction pipe 6 from the powder disperser 4a are mixed in the introduction pipe 6 or in the cylindrical member 14, and the powders B are attached to the surfaces of the droplets A. Since the magnesium stearate powders have a water repellent property, the powders B do not get wet. As illustrated in
According to the production method of the present embodiment, the droplet A and the powder B having the liquid repellent property with respect to the droplet A are uniformly mixed with the mixing apparatus 2 so that the powder B is attached to the surface of the droplet A. Thus, the granular material C retaining the nature as powder is produced while the powder B is not detached from the droplet A or the powder B does not lump.
In the experiments, the magnesium stearate powder used as indicated in (a) had a median diameter D50 of 5.9 μm, and the mica powder used as indicated in (e) had a median diameter D50 of 7.0 μm. Furthermore, the droplet famed of water indicated in (a) and (b) had a median diameter D50 of 35 μm, and the oil droplet of salad oil indicated in (c) to (e) had a median diameter D50 of 30 μm.
According to the experimental results, when the magnesium stearate powder was used as powder and water was used as liquid as in the present embodiment, as indicated in (a), an angle of contact of the magnesium stearate powder relative to the water drop was 109 to 125 degrees, enabling the production of a granular material in which the powder is attached to the surface of the droplet. Meanwhile, when an experiment was conducted using the powder-liquid combinations indicated in (b) to (d), an angle of contact of the powder relative to the droplet was zero degree, and a granular material could not be produced.
Specifically, as in (b), when wheat flour was used as powder and water was used as liquid, the water was soaked into the wheat flour and the wheat flour lumped. Thus, unlike the present embodiment, a granular material could not be produced. Similarly, as in (c), when wheat flour was used as powder and salad oil was used as liquid, the salad oil was soaked into the wheat flour and the wheat flour lumped. Thus, unlike the present embodiment, a granular material could not be produced.
Furthermore, as in (d), when sugar was used as powder and salad oil was used as liquid, the salad oil was soaked into the sugar and the sugar was not powdered. Thus, unlike the present embodiment, a granular material could not be produced.
When mica powder is used as powder and salad oil is used as liquid, as indicated in (e), an angle of contact of the mica powder relative to the oil drop is 95 to 123 degrees, enabling the production of a granular material in which the powder is attached to the surface of the droplet.
Furthermore, in the aforementioned embodiment, as indicated in
Furthermore, also in cases where an aqueous solution such as salt water and scented water is used instead of water, a granular material can be similarly produced insofar as an angle of contact between the magnesium stearate powder and the aqueous solution exceeds 90 degrees.
Furthermore, also in cases where oil is used as liquid in the same experiment as the aforementioned experiment of the embodiment, a granular material can be similarly produced insofar as an angle of contact between the oil and the powder exceeds 90 degrees.
Furthermore, in the aforementioned embodiment, an example of a case is described in which the droplet A (water drop) famed of water or aqueous solution has a median diameter D50 of 10 to 50 μm. However, the granular material C can be produced even when the nozzle pressure of the liquid atomizing nozzle 4b is reduced and the droplet A (water drop) has a median diameter D50 of 50 μm or more.
Furthermore, in the aforementioned embodiment, the bag filters 16 do not necessarily have to be arranged at positions where the distance X with respect to the cylindrical member 14 is 100 mm in actual measurement. It is sufficient that the bag filters 16 are arranged at positions where a ratio (X/D) of the diameter D of the cylindrical member 14 to the distance X with respect to the cylindrical member 14 is 0.1 or more.
Furthermore, in the aforementioned embodiment, it is sufficient that the bag filters 16 are arranged at positions where a ratio (Y/D) of the distance Y between the lower end of the bag filter 16 and the other end of the cylindrical member 14 to the diameter D of the cylindrical member is zero or more. However, the bag filters 16 are preferably arranged at positions where Y/D is 0.1 or more, more preferably arranged at positions where Y/D is 0.3 or more.
Furthermore, in the aforementioned embodiment, an example of a case is described in which the cylindrical member 14 has a cylindrical shape. However, the cylindrical member 14 may not necessarily have a cylindrical shape.
The embodiment described heretofore is described for the sake of easy understanding of the present invention, but is not described to limit the present invention. Therefore, the elements disclosed in the aforementioned embodiment include every design variation and equivalent falling within the technical scope of the present invention.
Number | Date | Country | Kind |
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2015-226619 | Nov 2015 | JP | national |