Powder scattering prevention device and powder scattering prevention method

Abstract

To provide a powder scattering prevention device and a powder scattering prevention method capable of preventing powder scattering.SOLUTION: The powder scattering prevention device 10 is equipped with a nozzle 3 arranged with a gap G provided against the upper end outer surface 1a of the container 1, and is configured to generate a downward drawing airflow F2 above the container 1 by spraying air from the nozzle outlet 4 of the nozzle 3 toward the gap G. This serves to send powder that is about to scatter into the container 1, thereby preventing the powder from scattering.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to an apparatus and a method for preventing scattering of powder put into a container.

Background Art

[0002] FIG. 8 schematically shows a step of putting powder P into a container 90 to be mixed with a liquid L in the process of manufacturing pharmaceuticals, cosmetics, etc. In pharmaceuticals, cosmetics, etc., powder P with high fluidity (jetability) is often used, and the put powder P may scatter as shown in FIG. 8(B) to generate dust. Such dust has an adverse effect on the health and safety of workers and leads to pollution of the working environment. Therefore, a method for preventing scattering of powder is strongly desired.

[0003] As one countermeasure, it is conceivable to install a dust collector 91 near the container 90 to collect the powder P that is about to scatter. However, since the scattered powder P diffuses in various directions and floats for a long time, it is difficult to efficiently collect the powder P with the locally installed dust collector 91. In addition, the installation of the dust collector 91 may reduce the working space. On the other hand, large dust collection devices such as isolators and safety booths (registered trademarks) have a high introduction hurdle because the equipment is large-scale.

[0004] As another countermeasure, it is conceivable to put a small amount of powder P into the container 90 little by little so that no dust is generated. However, since the production efficiency inevitably decreases due to the long powder P input time, it is not practical.

[0005] In Patent Document 1, an apparatus for preventing and collecting scattering of powder has been proposed. However, the apparatus is intended to suck and collect the scattered powder together with air.

[0006] Patent Document 2 discloses a blower assembly without blades that generates an air flow, but does not suggest a solution for the scattering of powder as described above.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a powder scattering prevention device and a powder scattering prevention method capable of preventing powder from scattering.

Means for Solving the Problems

[0009] The powder scattering prevention device of the present disclosure includes a nozzle disposed with a gap with respect to the outer surface of the upper end portion of the container, and is configured to generate a downward drawing air flow above the container by ejecting air from the ejection port of the nozzle toward the gap.

[0010] The powder scattering prevention method of the present disclosure is to dispose a nozzle with a gap with respect to the outer surface of the upper end portion of a container into which powder is charged, and generate a downward drawing air flow above the container by ejecting air from the ejection port of the nozzle toward the gap, and send the powder about to scatter into the container.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0012] An embodiment of the present disclosure will be described with reference to the drawings.

[0013] [Powder Scattering Prevention Device] FIG. 1 is a perspective view showing a powder scattering prevention device according to an embodiment of the present disclosure. FIG. 2 is a longitudinal sectional view schematically showing the powder scattering prevention device. The powder scattering prevention device 10 of the present embodiment is used in the step of charging powder into the container 1 for mixing with the liquid L in the process of manufacturing pharmaceuticals, cosmetics, detergents, foods, etc.

[0014] The container 1 into which the powder is charged is an unsealed container with an open upper end. In the present embodiment, the container 1 is formed in a circular shape in plan view, but is not limited thereto. The container 1 stores the liquid L for mixing the charged powder. Although not shown in FIG. 1, a stirrer 2 for stirring the liquid L is installed, and the container 1 is used as a stirring tank. The stirrer 2 has a stirring blade 21 disposed in the container 1 and a motor 22 as a driving unit for rotating the stirring blade 21. The diameter d, the immersion amount h, and the eccentricity e from the center of the container 1 of the stirring blade 21 are appropriately set respectively.

[0015] As will be described in detail later, the powder scattering prevention device 10 includes a nozzle 3 disposed with a gap G provided with respect to the outer surface 1a of the upper end portion of the container 1, and by ejecting air from the ejection port 4 of the nozzle 3 toward the gap G, it is configured to generate a downward drawing airflow F2 (see FIG. 6) above the container 1. Thereby, it has the effect of sending the powder about to scatter into the container 1, and the scattering of the powder can be prevented.

[0016] The powder scattering prevention device 10 includes a blower 5 that sends out air toward the nozzle 3 and a support member 6 that supports the nozzle 3. The blower 5 has a built-in fan or blower in a housing connected and fixed to the nozzle 3. The support member 6 supports the nozzle 3 via the blower 5. The support member 6 may have a mechanism that expands and contracts in the vertical direction, such as a jack, so that the vertical position of the nozzle 3 can be adjusted. Note that the structure for supporting the nozzle 3 is not particularly limited. For example, a structure in which the nozzle 3 is supported by the container 1 or a structure in which the nozzle 3 is supported by a blower 5 that stands on its own with a housing extended downward may be used.

[0017] FIG. 3 is a (A) front view and (B) plan view of the nozzle 3. FIG. 4 is a cross-sectional view taken along the line X-X of FIG. 3(B). FIG. 5 is an enlarged view of the Y portion of FIG. 4. The nozzle 3 extends annularly in plan view, and a cavity 7 is formed at its center. The upper end portion of the container 1 is fitted into the cavity 7, and the nozzle 3 is disposed so as to surround the upper end portion of the container 1. By externally fitting the nozzle 3 with a play in the upper end portion of the container 1, an annular gap G is formed between the nozzle 3 and the outer surface 1a of the upper end portion. In the present embodiment, the gap G having a substantially constant width extends annularly.

[0018] FIG. 6 is a longitudinal sectional view schematically showing the periphery of the upper end portion of the container 1. The jet airflow F1 is the flow of air ejected from the jet outlet 4 of the nozzle 3. The jet airflow F1 is directed toward the gap G and not into the container 1. By generating the jet airflow F1, an intake airflow F2 is generated upstream (i.e., upward) in the jet direction. The intake airflow F2 is the flow of air drawn in by the Coandă effect and becomes a downward airflow above the container 1. The jet airflow F1 is a flow of air ejected vigorously from the jet outlet 4, while the intake airflow F2 is a relatively gentle flow of air.

[0019] In the gap G between the nozzle 3 and the outer surface 1a of the upper end portion, particularly in the vicinity of the jet outlet 4, a region of pressure lower than the atmospheric pressure is formed due to the jet airflow F1. As a result, the air floating above is drawn toward the low-pressure region, and it is considered that such an intake airflow F2 is generated. The region where the intake airflow F2 is generated extends not only above the gap G but also to its periphery and reaches a range overlapping the inner region of the container 1 in plan view.

[0020] By generating a downward intake airflow F2 above the container 1, a downward inertial force is imparted to the powder about to scatter. Thereby, the powder progresses downward due to the inertial effect, collides with the liquid L, and is adsorbed to the liquid surface. Also, since a weak airflow, the intake airflow F2, is generated above the container 1 instead of a strong airflow like the jet airflow F1, there is little concern that the airflow rebounding from the liquid surface will lift the powder and generate dust. Thus, according to the powder scattering prevention device 10 of the present embodiment, it is possible to promote the adsorption of the powder to the liquid surface and prevent scattering.

[0021] By preventing the scattering of powder as described above, the health and safety of workers and the soundness of the working environment can be achieved. In addition, since it is not necessary to adjust the powder input speed and the powder can be input in the same manner as before, it is practical without causing a decrease in production efficiency. Furthermore, even if the device 10 is installed, a sufficient working space is secured above the container 1, so there is no concern about hindering workability. Moreover, since it does not require large-scale equipment and can be easily incorporated into an existing manufacturing site, the hurdle for introduction is low.

[0022] Although not adopted in this embodiment, it is possible to install a capturing member such as a filter in the powder scattering prevention device 10 that does not allow the passage of powder but allows the passage of air. Such a capturing member is disposed below the ejection port 4 and is attached, for example, to the side or bottom of the nozzle 3. Thereby, even if there is powder that has entered the gap G without being adsorbed to the liquid surface, it can be steadily recovered, so that the scattering prevention effect can be enhanced and the health and safety of workers and the soundness of the working environment can be achieved well.

[0023] The device 10 of this embodiment is configured to generate an ejection air flow F1 over the entire circumference of the annularly formed gap G. Thereby, an intake air flow F2 can be generated over the entire circumferential direction of the container 1, and the scattering of powder can be more effectively prevented. In this embodiment, the nozzle 3 is formed by a single annularly shaped part, but it is not limited thereto. Therefore, for example, a plurality of arc-shaped nozzles may be connected to each other to extend annularly in a plan view, and even in such a case, it is possible to generate an intake air flow F2 over the entire circumferential direction of the container 1.

[0024] As shown in FIGS. 4 to 6, the jet outlet 4 is formed by a slit (an elongated cut). According to such a configuration, air can be vigorously discharged from the jet outlet 4, which is convenient for generating the induced air flow F2. In the present embodiment, since the slit forming the jet outlet 4 extends annularly, the jet air flow F1 can be generated over the entire circumference of the gap G, and thus the induced air flow F2 can be generated over the entire circumferential direction of the container 1. Note that the jet outlet 4 may have a form other than a slit as long as it can generate the jet air flow F1 that causes the induced air flow F2. For example, it may be constituted by an array of a large number of minute holes.

[0025] In the present embodiment, the nozzle 3 has an internal space 30 filled with air sent out from the blower 5, and compresses the air in the internal space 30 and discharges it from the jet outlet 4. Thereby, the compressed air is accelerated and discharged at the jet outlet 4 (a slit in the present embodiment), becoming a strong jet air flow F1, which is convenient for generating the induced air flow F2. The internal space 30 is a passage extending annularly along the nozzle 3, and a part of its circumferential direction communicates with the inside of the blower 5. Therefore, the air sent out from the blower 5 evenly spreads into the internal space 30.

[0026] The nozzle 3 has a vertical cross-sectional shape extending in the vertical direction and is formed to taper downward. The jet outlet 4 is set at an intermediate position in the vertical direction of the nozzle 3. The jet outlet 4 opens downward. The nozzle 3 has an inner piece portion 31 facing the gap G and extending along the vertical direction, and air is discharged downward from the jet outlet 4 along the outer surface of the inner piece portion 31. Therefore, the outer surface of the inner piece portion 31 extends along the air discharge direction. The inner piece portion 31 is disposed opposite to the outer surface 1a of the upper end portion of the container 1 with the gap G interposed therebetween.

[0027] The nozzle 3 has an inner piece portion 31 facing the outer piece portion 32 that extends along the vertical direction with the internal space 30 interposed therebetween. In the present embodiment, the outer surface of the inner piece portion 31 is inclined downward away from the container 1, and the outer surface of the outer piece portion 32 extends substantially parallel to the vertical direction, but it is not limited thereto. The nozzle 3 is formed in a cylindrical shape by the inner piece portion 31 and the outer piece portion 32 connected to the inner piece portion 31. The inner piece portion 31 and the outer piece portion 32 are each formed of a plate-like member. In the present embodiment, the annularly extending inner piece portion 31 is disposed relatively on the inner peripheral side, and the annularly extending outer piece portion 32 is disposed relatively on the outer peripheral side.

[0028] The internal space 30 is surrounded by the inner surface of the inner piece portion 31 and the inner surface of the outer piece portion 32. At the upper end portion of the nozzle 3, the outer piece portion 32 is bent toward the inner piece portion 31, whereby an overlapping portion 33 is formed in which the inner surface of the outer piece portion 32 overlaps so as to face the outer surface of the inner piece portion 31. In the overlapping portion 33, a gap is provided between the outer surface of the inner piece portion 31 and the inner surface of the outer piece portion 32 facing it, and the gap forms a slit that serves as the jet outlet 4. Note that the shape of the nozzle 3 and the inner piece portion 31 and the outer piece portion 32 forming the same are not particularly limited.

[0029] As described above, the nozzle 3 has the inner piece portion 31 facing the gap G. The inner piece portion 31 is preferably curved along the contour of an airfoil in a longitudinal sectional view, whereby it is easy to increase the blowing efficiency and smoothly generate the induced air flow F2. FIG. 7 shows the shape of an airfoil E473 (EPPLER 473 AIRFOIL) as an example of an airfoil. This airfoil is a symmetric airfoil having a symmetric shape with respect to the center line CL. In the present embodiment, an example is shown in which the inner piece portion 31 is curved along the contour of the airfoil E473 (the contour on one side with respect to the center line CL) in a longitudinal sectional view, and the jet outlet 4 is set at the portion farthest from the center line CL.

[0030] The distance D1 shown in Fig. 6 is the horizontal separation distance between the outer surface 1a of the upper end of the container 1 and the jet outlet 4. The separation distance D1 corresponds to half of the difference between the inner diameter of the nozzle 3 at the jet outlet 4 and the outer diameter at the outer surface 1a of the upper end of the container 1 (which may be the outer diameter at the upper edge 1E of the container 1). The separation distance D1 is not particularly limited as long as the desired effect can be obtained, but from the viewpoint of appropriately ensuring the gap G, it is preferably 10 mm or more, and more preferably 20 mm or more. Also, from the viewpoint of appropriately acting the attracting air flow F2 on the powder floating above the container 1, the separation distance D1 is preferably 40 mm or less, and more preferably 30 mm or less.

[0031] In the present embodiment, the upper end of the nozzle 3 is disposed above the upper edge 1E of the container 1, and the lower end of the nozzle 3 is disposed below the upper edge 1E of the container 1. Also, the jet outlet 4 is disposed above the upper edge 1E of the container 1. The positional relationship between the upper edge 1E and the jet outlet 4 in the vertical direction is not particularly limited as long as the desired effect can be obtained, and the jet outlet 4 may be disposed below the upper edge 1E. However, from the viewpoint of appropriately acting the attracting air flow F2 on the powder floating above the container 1, it is preferable that the jet outlet 4 is disposed at the same position as the upper edge 1E or above it.

[0032] The distance D2 shown in Fig. 6 is the vertical separation distance between the upper edge 1E of the container 1 and the jet outlet 4. The separation distance D2 is not particularly limited as long as the desired effect can be obtained. However, from the viewpoint of suppressing the powder from entering the gap G, the separation distance D2 between the upper edge 1E and the jet outlet 4 located above it is preferably 30 mm or less, more preferably 15 mm or less, and still more preferably 5 mm or less. Also, from the viewpoint of appropriately acting the attracting air flow F2 on the powder floating above the container 1, the separation distance D2 between the upper edge 1E and the jet outlet 4 located below it is preferably 30 mm or less, more preferably 15 mm or less, and still more preferably 5 mm or less.

[0033] The angle θ shown in Fig. 5 is the inclination angle of the outer surface of the inner piece portion 31 extending downward from the jet outlet 4 with respect to the vertical direction. From the viewpoint of appropriately acting the drawing airflow F2 on the powder floating above the container 1, it is preferable that the outer surface of the inner piece portion 31 is inclined in a direction away from the container 1 downward as in the present embodiment, and examples of the inclination angle θ are 5 to 15 degrees. However, the inclination angle θ is not particularly limited as long as a desired effect can be obtained, and it may be zero. Also, the outer surface of the inner piece portion 31 may be inclined in a direction approaching the container 1 downward.

[0034] [Powder scattering prevention method] A method for preventing powder scattering using the above-described apparatus 10 will be briefly described. First, as shown in Figs. 1 and 2, a nozzle 3 is arranged with a gap G provided with respect to the outer surface 1a of the upper end portion of the container 1 into which the powder is charged. Then, while stirring the liquid L with the stirrer 2, the powder is charged into the container 1. At this time, as shown in Fig. 6, the blower 5 is operated to send air into the nozzle 3, and air is ejected from the jet outlet 4 toward the gap G to generate an ejection airflow F1, thereby generating a downward drawing airflow F2 above the container 1 and sending the powder about to scatter into the container 1. Thereby, powder scattering can be prevented.

[0035] [Examples] The effect of the above-described powder scattering prevention apparatus was verified by an actual test. In the test, the case of charging powder using the powder scattering prevention apparatus was taken as an example, and the case of charging powder without using such an apparatus was taken as a comparative example, and they were compared. The powder scattering prevention apparatus used in the example has the above-described configuration described with reference to Figs. 1 to 7. The specifications of the apparatus are shown in Table 1.

[0036] [Table 1]

[0037] When manufacturing the device, the shape was designed to improve the air blowing efficiency according to the size of the container used. This is because it is considered that the larger the air blowing efficiency is increased to increase the flow velocity of the induced air flow, the larger the inertial parameter of the powder becomes, and the better the anti-scattering effect is. CFD (Computational Fluid Dynamics) analysis was used for the shape design, and the separation distances D1, D2 and the inclination angle θ were used as design variables.

[0038] In the examples and comparative examples, while stirring the liquid (1,3-butylene glycol) in the container under the conditions shown in Table 2, powder (powder of an acrylic acid methacrylic acid alkyl copolymer) was put into the container.

[0039]

Table 2

[0040] To verify the anti-scattering effect, the difference (increase) in the amount of dust before and immediately after the powder was put in was measured. The amount of dust was evaluated by the average pixel value of a color different from that of the background on the back of the container, where a background of a color different from that of the powder (black) was provided and the upper part of the container was photographed from the front. The smaller the difference (increase) in the average pixel value before and immediately after the input, the less dust was generated by the input of the powder, indicating that the scattering of the powder was prevented. The results are shown in Table 3.

[0041]

Table 3

[0042] As shown in Table 3, in the examples, the result was obtained that less dust was generated by the input of the powder compared with the comparative examples. Therefore, it can be said that the scattering of the powder was prevented in the examples, and its significance could be confirmed. In the examples, when a filter as a capturing member was installed on the side of the nozzle, 0.51 g of powder was captured, and a small amount of powder leaked from the container could be recovered.

[0043] It is understood by those skilled in the art that the above-described embodiments are specific examples of the following aspects.

[0044] [1] The powder scattering prevention device of the present disclosure includes a nozzle disposed with a gap with respect to the outer surface of the upper end portion of the container, and is configured to generate a downward drawing air flow above the container by ejecting air from the ejection port of the nozzle toward the gap. According to such a configuration, it is possible to prevent the scattering of the powder by serving to send the powder about to scatter into the container.

[0045] [2] In the powder scattering prevention device of the above [1], the nozzle may extend annularly in a plan view. According to such a configuration, the nozzle can be arranged so as to surround the upper end portion of the container, and a drawing air flow can be generated over the entire circumferential direction of the container.

[0046] [3] In the powder scattering prevention device of the above [1] or [2], the ejection port may be formed by a slit. According to this, air can be ejected vigorously from the ejection port, which is convenient for generating a drawing air flow.

[0047] [4] In the powder scattering prevention device of any one of the above [1] to [3], the nozzle may have an internal space filled with air sent out from a blower, and eject the air compressed in the internal space from the ejection port. According to such a configuration, the compressed air is accelerated and ejected at the ejection port to become a strong ejection air flow, which is convenient for generating a drawing air flow.

[0048] [5] In any of the powder scattering prevention devices of [1] to [4] above, the nozzle may have an inner piece portion facing the gap and extending along the vertical direction, and air may be ejected downward along the outer surface of the inner piece portion from the ejection port. According to such a configuration, an ejection air flow can be generated along the outer surface of the inner piece portion, and thereby an induced air flow can be generated.

[0049] [6] In any of the powder scattering prevention devices of [1] to [5] above, the nozzle may have an inner piece portion facing the gap, and the inner piece portion may be curved along the contour of an airfoil in a longitudinal sectional view. According to such a configuration, it is easy to increase the blowing efficiency and smoothly generate an induced air flow.

[0050] [7] Further, in the powder scattering prevention method of the present disclosure, a gap is provided on the outer surface of the upper end portion of the container into which the powder is charged, and a nozzle is arranged. By ejecting air from the ejection port of the nozzle toward the gap, a downward induced air flow is generated above the container, and the powder about to scatter is sent into the container. According to such a method, it is possible to prevent the powder from scattering by exerting the action of sending the powder about to scatter into the container.

[0051] Although the embodiments of the powder scattering prevention device and the powder scattering prevention method according to the present disclosure have been described with reference to the drawings, the specific configuration should not be considered to be limited to this embodiment. The scope of the present invention is shown not only by the description of the above-described embodiment but also by the claims, and further includes all changes within the meaning and scope equivalent to the claims.

[0052] The powder scattering prevention device and the powder scattering prevention method according to the present disclosure are not limited to the above-described embodiments at all, nor are they limited to the above-described effects. The powder scattering prevention device and the powder scattering prevention method according to the present disclosure can be variously improved and modified without departing from the gist thereof. Also, each configuration employed in the above-described embodiments can be arbitrarily combined and employed.

Description of Signs

[0053] 1 Container, 1a Outer surface of upper end, 2 Stirrer, 3 Nozzle, 4 Jet outlet, 5 Blower, 6 Support member, 10 Powder scattering prevention device, 30 Internal space, 31 Inner piece part, 32 Outer piece part, 33 Overlapping part, F1 Jet airflow, F2 Suction airflow, G Gap

Claims

1. A powder scattering prevention device comprising a nozzle disposed with a gap with respect to the outer surface of the upper end portion of a container, and configured to generate a downward drawing airflow above the container by ejecting air from an ejection port of the nozzle toward the gap.

2. The powder scattering prevention device according to claim 1, wherein the nozzle extends annularly in a plan view.

3. The powder scattering prevention device according to claim 1, wherein the ejection port is formed by a slit.

4. The powder scattering prevention device according to claim 1, wherein the nozzle has an internal space filled with air sent out from a blower, and ejects the air compressed in the internal space from the ejection port.

5. The powder scattering prevention device according to claim 1, wherein the nozzle has an inner piece portion facing the gap and extending along the vertical direction, and ejects air downward along the outer surface of the inner piece portion from the ejection port.

6. The nozzle has an inner piece portion facing the gap, The powder scattering prevention device according to claim 1, wherein the inner piece portion is curved along a profile of an airfoil in a longitudinal sectional view.

7. A powder scattering prevention method, wherein a nozzle is disposed with a gap with respect to the outer surface of the upper end portion of a container into which powder is charged, and a downward drawing airflow is generated above the container by ejecting air from an ejection port of the nozzle toward the gap, so as to send the powder about to scatter into the container.

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