JP3518751B2 - Airflow classifier - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air stream classifier for centrifuging powder particles in a swirling air stream.

[0002]

2. Description of the Related Art The structure of a conventional airflow diverter 01 is shown in FIGS. The air flow diverter 01 is a small diameter cylindrical exhaust chamber 02, a medium diameter flat cylindrical dispersion chamber 03, a lower wide conical guide chamber 04, and a large diameter cylindrical classification chamber in order from the top with a common vertical center axis. 05, secondary air intake chamber 06 with the same diameter, and recovery hopper 07 with an upper wide cone shape.

In the exhaust chamber 02, a blower suction path is provided in a horizontal tangential direction.
02a extends to the dispersion chamber 03 in the horizontal tangential direction to supply fluid.
03a extends, a communication passage 03b that connects the classification chamber 05 and the exhaust chamber 02 is provided in the center of the inside, the guide chamber 04 is provided with a conical guide cone 04a, and the classification chamber 05 is provided with an inside. Is provided with a lower wide cone-shaped classification cone 05a, the secondary air intake chamber 06 is provided with a secondary air supply passage 06a extending in the horizontal tangential direction, and a lower wide cone body 06b is provided in the center of the inside.

When a solid-gas mixture fluid of powder and primary air is introduced into the dispersion chamber 03 from the fluid supply passage 03a, the primary air is swirled along the inner peripheral wall of the dispersion chamber 03 to generate powder particles. The particles collide with the inner peripheral wall, or the particles collide with each other and disperse, and are guided by the guide cone 04a to descend while swirling and enter the classification chamber 05 from the peripheral portion.

Secondary air is supplied to the classifying chamber 05 from the lower secondary air supply passage 06a and is formed as a swirling airflow in the secondary air intake chamber 06 to increase the swirling speed of the dispersed solid-gas mixture fluid. In the classification chamber 05, the particles are distributed in the centrifugal direction in the order of particle size by utilizing centrifugal force.

That is, the powdery particles are distributed such that the particle size increases with increasing distance from the center. Communication passage 03b opened in the center
The fine powder in the vicinity of the center is sucked into the exhaust chamber 02 through the exhaust chamber 02 and discharged from the blower suction passage 02a, and the remaining coarse powder on the peripheral edge descends along the peripheral edge and is guided and dropped by the recovery hopper 07 to be recovered. Classified into powder.

When extracting a component having an active ingredient particle size from a raw material granular material, it is recovered from the recovery hopper 07 such that the coarse powder contains a large amount of the active ingredient particle size granular material. The classification point can be reduced by increasing the swirling speed of the swirling air flow, and the guide cone 04a and the classification cone 05a
It is possible to change the classification point of the granular material and the recovery rate of each of the coarse powder and the fine powder by adjusting the interval (cone interval ΔH) between and.

[0008]

Such an air stream classifier has been usually used in many cases for powder particles which are relatively difficult to be crushed, such as inorganic powder particles such as carbon powder and metal powder. However, when classifying powders that are relatively easily crushed, such as pharmaceuticals, pesticides, and foods, the dispersibility is generally too strong, and the powders that are the raw materials are worn away, and the properties of the powders change due to wear. In particular, the amount of fine powder and ultrafine powder smaller than fine powder increases.

In the case of extracting a component having an active ingredient particle size from a raw material granular material, a powder granule having a larger active ingredient particle diameter may be used again as a raw material in an air flow classifier to extract a component having an active ingredient particle diameter. It is possible, however, it is impossible to extract a component having the particle size of the active ingredient from the crushed product which is smaller than the particle size of the active ingredient.

Therefore, when a large amount of fine powder and ultrafine powder smaller than the particle size of the active ingredient is generated due to abrasion, the component having the particle size of the active ingredient cannot be extracted with good yield.
Therefore, it is conceivable to reduce the amount of air supply (air flow) in the air flow classifier to reduce wear and tear. However, if the air flow is decreased, the amount of the active ingredient particle size contained in the fine powder to be discarded increases and is recovered. The amount of the active ingredient particle size component contained in the coarse powder is reduced.

The above situation can be shown from the result of the test using the conventional air flow classifier. Table 2 in FIG. 7 shows the test results and classification conditions, where the former is the case where the air volume of the former is large and the conventional case is the case where the air volume of the latter is smaller.

In the test, a sweetener (erythritol), which is widely used in the food industry, is used as a raw material, and the powder has a maximum particle size of 834.27 μm and an average particle size of 119.78 μm. The component particle size is 45 to 106 μm and it is recovered as a coarse powder.

The particle size distribution as a raw material before classification is 2 if the particle size is smaller than the active ingredient particle size (<45 μm).
0.21%, effective ingredient particle size (45 ~ 106μm) is 24.54
%, Particles having a particle size larger than the particle size of the active ingredient (> 106 μm) are 55.25%.

The total air flow (blower air flow) under the test conditions is 1.80 m ³ / min in the conventional case, whereas it is 1.45 m ³ / min in the conventional case, and the other guide cone 04a and classification cone 05a Has a cone spacing ΔH of 15 mm, a secondary air flow rate of 1.00 m ³ / min, a raw material supply rate of 2000 g, and a classification time of 4
The test conditions are the same, such as 0 min and the throughput of 3 kg / hr.

The respective amounts and particle size distributions of the coarse powder recovered from the recovery hopper 07 and the fine powder discharged from the blower suction passage 02a, which are the test results, are as shown in the table. Note that the total powder is a case where the coarse powder and the fine powder are summed up, and the active ingredient particle size recovery rate is the effective ingredient particle size contained in the recovered coarse powder with respect to the amount of the active ingredient particle size of the raw material before classification. Amount ratio.

In the conventional case of classifying with a large total air volume, the proportion of components having a particle size (<45 μm) smaller than the particle size of the non-reusable active ingredient is as large as 33.40% in total powder, and the yield is extremely poor.

Further, in the conventional case of classifying with a small total air volume, the particle size of the active ingredient in the fine powder to be discarded (45 to 106 μm)
The ratio of the component is as large as 21.77%, so the particle size recovery rate of the active component is too low as 45.7%. As described above, when classifying a powder or granular material that is easily crushed by the conventional airflow classifier 01,
It is difficult to extract the component of the active ingredient particle size with good yield.

In the airflow classifier as described above, a fluid supply passage (03a) extending horizontally tangentially to the dispersion chamber (03).
An example in which only the air is supplied from above and the solid-gas mixture fluid is introduced vertically downward from above with respect to this horizontal air supply direction.
2000-202367), which is disturbed by the air flow supplied from the horizontal direction in the flow of the solid-gas mixture fluid introduced vertically downward, causing turbulence, and is strong against powdery particles in the mixture fluid. It gives shock and vibration to actively perform crushing.

Therefore, it is applied to inorganic powders such as carbon powders and metal powders, and in order to extract a component having an effective particle diameter from powders that are relatively easily crushed such as pharmaceuticals, agricultural chemicals, foods, etc. Not suitable.

The present invention has been made in view of the above point, and the object thereof is to reduce the wear during dispersion even if the powder particles that are easily crushed are classified, and to reduce the component of the effective component particle size. The point is to provide an airflow classifier that can extract with good yield at low cost.

[0021]

In order to achieve the above-mentioned object, the invention according to the first aspect of the present invention provides
A cylindrical dispersion chamber in which a solid-air mixed fluid of secondary air is introduced to form a swirling air flow and dispersed, and a classification chamber in which secondary air is introduced below the dispersion chamber to centrifuge into coarse powder and fine powder. In the equipped air flow classifier, the solid-gas mixture fluid is flowed into the dispersion chamber.
Separately from the mixed fluid inflow path to enter, only air in the dispersion chamber
The inflowing air inflow path has a horizontal tangent to the cylindrical dispersion chamber.
And the mixed fluid inflow path is formed in the circle.
In the cylindrical dispersion chamber, point from the upper side to the lower diagonal tangential direction.
An airflow that is formed so as to intersect the air inflow path at an acute angle, and the solid-gas mixture fluid and the air fluid that have flowed in from the mixed fluid inflow path and the air inflow path merge at an acute angle immediately before the classification start point in the dispersion chamber. It was a classifier.

Since the solid-gas mixture fluid and the air fluid merge at an acute angle immediately before the classification start point, the flow of the solid-gas mixture fluid naturally joins without disturbing the air fluid without causing turbulence. Therefore, without giving an excessive dispersion force to the particles in the solid-gas mixture fluid, the collision force of the particles on the inner wall of the dispersion chamber and the mutual collision force between the particles are mitigated, and the particles that are easily crushed Even if the particles are classified, the particles can be appropriately dispersed to reduce the wear and the components having the effective particle diameter can be extracted with a high yield.

In addition to the mixed fluid inflow passage, the air inflow passage for introducing only air in the dispersion chamber of the conventional airflow classifier is provided separately from the mixed fluid inflow passage.

[0024]

The air fluid introduced into the air inflow passage and fed in the horizontal direction is merged at an acute angle with respect to the solid-gas mixture fluid introduced into the dispersion chamber in the obliquely downward tangential direction from above into the dispersion chamber. Therefore, a smooth swirling airflow without turbulence can be formed in the cylindrical dispersion chamber to reduce the abrasion of the powder and granules and realize proper dispersion. Since the mixed fluid inflow passage is located above the air inflow passage, it is easy to supply the granular material to the mixed fluid inflow passage.

According to a second aspect of the present invention, in the air stream classifier according to the first aspect , the powdery or granular material is a powdery or granular material which is relatively easily crushed for pharmaceuticals, agricultural chemicals, foods and the like. .

By applying to powders or granules such as pharmaceuticals, pesticides and foods which are relatively easily crushed, it is possible to extract components having an effective particle diameter with good yield by proper dispersion with reduced wear and tear.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. The airflow classifier 1 according to the present embodiment has the same basic structure as the above-described conventional airflow classifier 01, and has an exhaust chamber in a small-diameter cylindrical exhaust chamber case 2a in order from the top with a common vertical center axis. 2, a dispersion chamber in a medium-diameter flat cylindrical dispersion chamber case 3a, a guide chamber in a lower wide cone-shaped guide chamber case 4a 4, a large-diameter cylindrical classification chamber case 5a, a classification chamber 5, the same diameter The secondary air intake chamber 6 is formed by the secondary air intake chamber 6 and the recovery hopper 7 having an upper wide cone shape.

In this embodiment, a dry type sieve 8 is arranged below the lower end opening of the recovery hopper 7 of the airflow classifier 1, and the sieve 8 has a sieve size of 106 μm.

The exhaust pipe 12 extends in the horizontal tangential direction from the cylindrical exhaust chamber case 2a to form a blower suction passage 12a, and an upper wide cone 2b is inserted in the central portion of the exhaust chamber 2 around it. In FIG. 2, the clockwise swirling airflow is discharged tangentially from the blower suction passage 12a.

From the dispersion chamber case 3a of the dispersion chamber 3 located below the exhaust chamber 2, the primary air supply pipe 13 is arranged in the horizontal tangential direction.
To extend to form a primary air supply passage 13a, and a cylindrical communication pipe 23 is provided in the center to connect the lower classification chamber 5 and the upper exhaust chamber 2 to each other.

As shown in FIG. 3, a fluid supply pipe 33 extending obliquely downward from above with respect to the primary air supply pipe 13 oriented horizontally is coupled to the primary air supply pipe 13 at an acute angle of about 45 degrees. is doing. Good results can be obtained if the coupling angle between the fluid supply pipe 33 and the primary air supply pipe 13 is an acute angle in the range of 15 to 75 degrees.

The fluid supplied from the fluid supply passage 33a of the fluid supply pipe 33 and the primary air supplied from the primary air supply passage 13a merge at an acute angle and are drawn along the inner peripheral surface of the dispersion chamber 3. At 2, a clockwise swirling air flow is formed.

A funnel 33b is formed so as to project vertically upward from a part of the fluid supply pipe 33, and the granular material is put into the funnel 33b and passes through the fluid supply passage 33a together with the entrained air to form a solid-gas mixture fluid. Is supplied to the dispersion chamber 3.

In the guide chamber 4 below the dispersion chamber 3, a conical guide cone 14 extending downward from the communication pipe 23 is provided. The recessed inside of the guide cone 14 communicates with the exhaust chamber 2 via a communication pipe 23.

A support rod 2c hanging vertically downward from the upper wide cone 2b in the exhaust chamber 2 penetrates the communication pipe 23 to reach from the guide chamber 4 to the classification chamber 5 therebelow. At the lower end of the rod 2, there is a lower wide cone-shaped classification cone 15 in the classification chamber 5.
It is suspended inside.

A lower wide cone 6b is provided at the center of the secondary air intake chamber 6 below the classification chamber 5, and a spiral inner plate is formed around the lower wide cone 6b along the inner peripheral surface of the secondary air intake chamber case 6a. 6c is installed.

The secondary air supply pipe 16 extends in the horizontal tangential direction from the secondary air intake chamber case 6a to form a secondary air supply passage 16a. The secondary air supply passage 16a supplies the secondary air. In the secondary air intake chamber 6, the air is a spiral inner plate 6
The spiral swirling airflow in FIG. 2 is formed by being guided by c.

The airflow classifier 1 has the above-mentioned structure and sucks from the blower suction passage 12a to supply the fluid to the fluid supply pipe.
When the powder or granules as a raw material is charged into the funnel 33b of 33, the primary air is supplied from the primary air supply passage 13a to the dispersion chamber 3 in the horizontal tangential direction, and the fluid supply path 33a into which the powder or granules are charged is supplied. Along with the entrained air, as a solid-gas mixture fluid, the primary air that is horizontally supplied from diagonally above is merged at an acute angle of about 45 degrees just before the classification start point of the dispersion chamber 3 and introduced into the dispersion chamber 3 (FIG. 3).
reference).

Therefore, the flow of the solid-gas mixture fluid naturally joins without disturbing the primary air without causing turbulence, and the solid-gas mixture fluid introduced into the dispersion chamber 3 flows along the inner peripheral wall of the dispersion chamber 3. The particles are appropriately dispersed by the swirling airflow generated as a result, and are guided by the guide cone 14 to descend while swirling and enter the classification chamber 5 from the peripheral portion.

On the other hand, the secondary air is sucked into the secondary air intake chamber 6 from the secondary air supply passage 16a to form a swirling airflow to increase the swirling speed of the solid-gas mixture fluid in the classifying chamber 5 to increase the swirling speed. 5
Using the centrifugal force, the particles are distributed in the centrifugal direction in the order of particle size. That is, the particles are distributed such that the particle size increases as the distance from the center increases.

Fine powder in the vicinity of the center of the classification chamber 5 is sucked into the exhaust chamber 2 through the communication pipe 23 opened in the center of the classification chamber 5 and discharged from the blower suction passage 12a. And is dropped and collected from the collection hopper 7.

Thus, the granular material is classified into fine powder and coarse powder. The discharged fine powder has a relatively small particle size distribution, and the recovered coarse powder has a relatively large particle size distribution.

In the present air flow classifier 1, the solid-gas mixture fluid and the primary air merge at an acute angle, so that the flow of the solid-gas mixture fluid is naturally merged without disturbing the primary air without causing turbulence. It does not give an excessive dispersion force to the powder particles in the solid-gas mixture fluid, reduces the collision force of the particles on the inner wall of the dispersion chamber and the mutual collision force between the particles, and the particles are easily crushed. Even if the body is classified, the particles can be dispersed appropriately to reduce the wear and the components having the particle diameter of the active ingredient can be extracted with good yield.

Table 1 in FIG. 4 shows the results of a classification test conducted by the present air flow classifier 1 using a sweetener (erythritol) as a raw material under substantially the same classification conditions as in the conventional air flow classifier. The present case is a case where classification is performed by the above-mentioned method, and the present invention exchanges the roles of the primary air supply pipe 13 and the fluid supply pipe 33, and supplies the solid-gas mixture fluid from the primary air supply pipe 13 to supply the fluid supply pipe 33. This is the case where the primary air is supplied from the above to perform classification.

The raw material sweetener (erythritol) used is the same as in the conventional case, and the test conditions are exactly the same as in the conventional case. Looking at the test results in the case of this plan, the ratio of the coarse powder containing the extracted active ingredient particle size (45 to 106 μm) was as large as 82.5%, and the ratio of the active ingredient particle size (45 to 106 μm) Is 21.56%, and the active ingredient particle size recovery rate, which is the ratio of the amount of the active ingredient particle size contained in the recovered coarse powder to the amount of the active ingredient particle size of the raw material before classification, is as high as 72.5%. Shows good yield.

Of the large proportion of coarse powder of 82.5%,
Particle size larger than reusable active ingredient particle size (> 106μ)
The component ratio of m) occupies a large ratio of 76.00%, and this large particle size component is obtained by sieving the coarse powder recovered from the recovery hopper 7 through the sieve 8 with a sieve size of 106 μm, which is effective for classification again. Since the component having the component particle size can be extracted, the yield is further improved.

In this case and in the case of the present case, the present case shows a better result in terms of the recovery rate of the particle diameter of the active ingredient.
The airflow classifier 1 may be constructed by a simple process and at a low cost as long as a fluid supply path that is newly connected to the fluid supply path of the conventional airflow classifier is connected to form an acute angle.

A classification test was carried out using a sweetener (erythritol), which is a powder that is relatively easily crushed, as a raw material. The airflow classifier 1 is a powder that is relatively easily crushed such as pharmaceuticals, pesticides or foods. It is suitable for classifying granules and extracting active ingredient particle size components.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an airflow classifier according to an embodiment of the present invention.

FIG. 2 is a top view of the same.

FIG. 3 is a side sectional view of a main part.

FIG. 4 is a table 1 showing test results and classification conditions by the airflow classifier.

FIG. 5 is a vertical sectional view of a conventional airflow classifier.

FIG. 6 is a top view of the same.

FIG. 7 is a table 2 showing test results and classification conditions by the conventional airflow classifier.

[Explanation of symbols]

1 ... Air flow classifier, 2 ... Exhaust chamber, 3 ... Dispersion chamber, 4 ... Guide chamber, 5 ... Classifying chamber, 6 ... Secondary air intake chamber, 7 ... Recovery hopper, 8 ... Sieve, 12 ... Exhaust pipe, 13 ... Primary air supply pipe, 14
… Guide cone, 15… Classification cone, 16… Secondary air supply pipe, 23… Communication pipe, 33… Fluid supply pipe.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI // A23L 1/236 A23L 1/236 A (72) Inventor Shinichi Tanaka 5-27-7 Sendagaya, Shibuya-ku, Tokyo Japan Brunswick Building Stocks Company In-house company (72) Inventor Morinoyuki Okuma Gensuke Fujieda-shi, Shizuoka 301 Kaken Pharmaceutical Co., Ltd. Research Institute (72) Inventor Yasutomi Kato Fujieda-shi Gensuke 301 Kaken Pharmaceutical Co., Ltd. Research Institute (56 ) References JP-A-60-38072 (JP, A) Actual Kaihei 5-39687 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B07B 1/00-15/00

Claims (2)

(57) [Claims] 1. A cylindrical dispersion chamber in which a solid-gas mixture fluid of powder and granules and primary air is introduced to form a swirling air flow and to be dispersed.
An air flow classifier equipped with a classifying chamber for injecting secondary air into the lower part of the dispersion chamber to centrifuge it into coarse powder and fine powder, separately from a mixed fluid inflow path for flowing the solid-gas mixed fluid into the dispersion chamber. An air inflow path through which only air flows into the dispersion chamber
Formed in the cylindrical dispersion chamber in the horizontal tangential direction
The mixed fluid inflow passage is inserted into the cylindrical dispersion chamber from above.
Point in a diagonally downward tangential direction and intersect the air inlet channel at an acute angle.
The air-flow classifier, characterized in that the solid-gas mixture fluid and the air fluid, which are formed to have different shapes and flow in from the mixed fluid inflow path and the air inflow path, merge at an acute angle immediately before the classification start point in the dispersion chamber. . 2. The airflow classifier according to claim 1, wherein the powder or granule is a powder or granule that is relatively easily crushed such as pharmaceuticals, agricultural chemicals, and foods.