JPH0440052B2 - - Google Patents

Description

Detailed Description of the Invention <Technical Field> The present invention involves sucking and filling powder from a supply source into the holes of a supply drum, and then applying back pressure with compressed gas to discharge and fill the powder from the holes of the drum into a container. This invention relates to a solid-gas separator in a powder filling machine.

<Prior art> As a powder filling machine that continuously divides and measures a predetermined amount of powder at high speed and fills it into containers,
As shown in Figure 3, there is a hopper 1 for supplying powder, a rotary drum 2 adjacent to the lower part thereof and having a plurality of isolated measuring chambers 8, and a rotary drum 2 located within the rotary drum 2 and further centrally than the measuring chambers 8. A solid-gas separator 3, a vacuum source 4 and a compressed air source 5 for suctioning powder under reduced pressure and discharging powder through the solid-gas separator 3 under pressure, respectively, and a compressed air source 5 located at the bottom of the rotating drum, and a container 6 located at the bottom of the drum. There is known a container transport device 7 for transporting containers in synchronization with rotation.

In this type of powder filling method, the powder sucked into the measuring chamber 8 under reduced pressure is captured and held in the filter part of the solid-gas separator 3 so that the powder does not reach the vacuum source and remains in the measuring chamber 8. After moving to a predetermined position, the powder is repeatedly discharged into the container 6 by applying a counter pressure such as compressed air through this filter section. In order to accurately fill the container with the solid-gas separator 3, it is extremely important to appropriately select the solid-gas separator 3 including the filter section.

Traditionally, the filters for solid-gas separators used in such powder filling machines are: (a) Solid-gas separation wire formed by bundling thin metal fibers (wires) (b) Stainless steel mesh plate A filter made of sintered metal shaped into a plate shape (c) A filter made of sintered metal shaped into a plate shape (d) A filter made of resin such as Teflon or synthetic fiber material shaped into a membrane or plate shape (e) A cylindrical shaped filter made of sintered metal etc. There are filters etc. molded into the same shape, all of which are well known.

However, if a solid-gas separator equipped with these filters is used to fill fine powder with poor fluidity, which is often found in pharmaceuticals, agricultural chemicals, etc., in (a) above, the pore diameter of the filter section will be non-uniform. Moreover, since the holes are formed in the same direction as the airflow, fine powder can penetrate deep into the wire bundle.
Repeated filling operations tend to cause clogging over time, which in turn tends to reduce the filling weight or increase variation.

Furthermore, when the wire bundle is installed in a rotating drum, the surface of the wire bundle is difficult to be smooth, so that powder tends to remain in the measuring chamber. (B), (C), and (D) are molded into a membrane or plate shape, so the thickness of the filter part is usually thinner than in (A), so clogging over time is relatively rare, but there is a problem with the shape. have. That is, filter 1
1 is the movement adjustment member 1 which is the main body of the solid-gas separator 3;
Conventionally, the methods shown in FIGS. 14 to 17 have been adopted as a method for fixing to 2. Fig. 14 shows the filter 11 fixed to the opening 14 of the movement adjustment member 12 by welding, Fig. 15 shows the filter 11 fitted into the movement adjustment member so as not to escape, and Figs. 16 and 17 show the filter 11 fixed to the opening 14 of the movement adjustment member 12 by welding. A filter 11 is fixed with a ring-shaped member 13. However, in either case, the area around the filter 11, that is, the area around the top surface of the movement adjustment member 12 becomes a dead space D with respect to the circulation of air etc. through the opening 14 of the movement adjustment member 12, and as a result, the powder by compressed air etc. When discharging, peripheral dead space D
The powder adhering to the measuring chamber may not be discharged due to the lack of air flow, or the powder remaining in the peripheral dead space D may fall loosely after most of the powder has been discharged from the measuring chamber. There are many drawbacks such as loss of weight accuracy and powder scattering on the outer surface and surrounding areas of the container, contaminating the filling environment.

To overcome this drawback, the cylindrical filter described in (e) above may be considered, but as shown in FIG. Not suitable for inhalation at high speeds.

In addition, although the dead space D around the surface (top surface) where the filter 11 contacts the powder is eliminated, air is also sucked in and discharged from the filter side surface 11a, so there is a gap S between the filter side surface 11a and the wall surface of the measuring chamber 8. When powder enters the filter and is discharged by compressed air, the powder falls out from behind, similar to the filter described above.

<Objective of the Invention> The purpose of the present invention is to provide a solid-gas separator which solves the problems of dead space and the like in the conventional apparatus, reduces pressure loss as much as possible, and is less susceptible to changes over time, and thereby improves fluidity. The purpose is to quickly and stably supply an accurate amount over a long period of time even if the powder is of poor quality.

<Structure of the Invention> The present invention provides a solid-gas separation device for a powder filling machine, in which powder from a supply source is once sucked and filled into holes in a supply drum, and then the powder is discharged and filled into a container from the holes using compressed gas. The hole has a solid-gas separation filter forming a bottom surface of the hole and a movement adjustment member, and the filter is attached to the top surface of the movement adjustment member at a distance through a breathable material. A solid-gas separator for a powder filling machine is characterized by the following features.

<Example> FIGS. 1 to 4 each show a vertical cross section of a solid-gas separator according to an example.

In these embodiments, the filter 21 is not attached directly to the top surface 22a of the movement adjustment member 22, but is attached at an appropriate distance from the top surface 22a by interposing the breathable material 23. There is. That is, the rotating drum 2 (first
The filter 21 forming the bottom surface of the hole 24, which is the measuring chamber 8 of the device (see Figure 3), is moved within the hole 24 appropriately depending on the amount of powder supplied, and the depth of the hole 24 is adjusted.
It is necessary to adjust the amount of powder packed into the container. For this reason, it is necessary to attach the filter 21 to the movement adjusting member 22 which can be moved within the hole 24 to adjust the depth of the hole 24. Further, it is necessary to provide the movement adjusting member 22 with a ventilation passage 25 for sucking and discharging the powder. Therefore, in addition to the opening of the ventilation passage 25, the top surface of the movement adjustment member 22 must have:
The top surface 22a of the movement adjustment member 22, on which the filter 21 is to be attached between the opening and the inner wall of the hole 24, has a width. Therefore, the top surface 2
If the filter is placed directly on the filter 2a, a dead space D (see FIGS. 14 to 17) with poor ventilation will be created around the filter periphery. In this case, if the filter 11 is formed to have a considerable thickness,
Although the influence of dead space can be eliminated to some extent, an increase in the thickness of the filter 11 that performs solid-gas separation of fine powder will cause a large pressure loss. becomes impossible. Therefore, in the present invention, by installing the filter 21 with the breathable material 23 interposed,
This solved the dead space problem and pressure drop problem mentioned above all at once.

FIG. 1 shows a ring-shaped air permeable material 23 on which a filter 21 is attached. In this case, the better the air permeability of the air permeable material 23 is. Further, when attaching the breathable material and the filter or the breathable material and the movement adjustment member, any method may be used as long as the flow of air at the attachment part (joint part) is not impaired, but diffusion bonding is preferred, for example. Since the breathable material 23 is formed into a ring shape, air can freely pass through the internal space 26. FIG. 2 shows an example in which the ring-shaped breathable material 23 and the filter 21 are integrally molded from the same material. Even in this case, since the portion of the breathable material 23 is formed in a ring shape, no increase in pressure loss occurs. In the example shown in FIG. 3, by reducing the thickness of the filter 21, the filter 21 may be deformed or damaged depending on the intensity of suction or discharge, so the filter 21 is reinforced. It is something that That is, a reinforcing member 27 made of a material with good air permeability is arranged in a space 26 formed by the filter 21 and the ring-shaped air permeable member 23. If a material with sufficient air permeability is used for the reinforcing material 27, the filter 21 can be reinforced without causing an increase in pressure loss. Figure 4 shows the breathable material 23.
The reinforcing material 2 in FIG.
7, it is placed in the entire area between the movement adjustment member 22 and the filter 21. In this case, the filter 21 is fixed to the upper surface of the breathable material 23. The breathable material 23 is preferably one with high breathability.

Note that, as shown in FIG. 5, the ratio H ₁ /W ₁ of the height H ₁ to the width W ₁ is preferably 1 or more. To give an example of the dimensions in the example, W ₁ = 1.7 mm, H ₁ = 5.5 mm,
In that case, the thickness of the filter 21 should be 1.0mm, and the diameter should be 9.4mm.
mm.

By interposing the breathable material 23 as described above, dead space during suction and discharge is eliminated. However, there is one problem that arises from providing the breathable material 23. This is because some air enters and exits from the sides of the breathable material 23, so that the powder that has entered between the breathable material 23 and the inner wall of the holes 24 of the rotating drum passes through the filter when the powder is discharged from the holes 24. There is a delay in the discharge of the powder that has been properly filled onto the surface of the powder 21, and the powder falls down. The present inventors solved this problem by closing the side circumferential surface 23b of the breathable material 23, which faces the inner wall of the hole 24. Occlusion can be accomplished in a variety of ways. For example, if the breathable material 23 is made of a metal material, it is possible to grind the sides and crush the openings, or in other cases, it is possible to glue a non-breathable thin film or apply a coding agent, etc. May be applied. In short, it is sufficient if the surface is treated to prevent air from entering and exiting from the sides, or if it has such a structure.
Note that since the filter 21 is thin, there is no need to close the side circumferential surface of the filter 21, but the side circumferential surface of the filter 21 may also be closed.

Next, various tests conducted on the present invention and their results will be explained.

<Test 1> As shown in Figures 6 to 9, filter A
(present invention), filter B, filter C, filter D
(B, C, and D are conventional examples) were attached to the rotating drum of a powder filling machine, and the discharge state of the powder was investigated with a high-speed video camera (VTR), and after discharge, the presence or absence of powder remaining in the measuring chamber was visually observed. The powder used was a pharmaceutical powder finely pulverized to an average particle size of 3 to 5 μm. This powder has a bulk specific gravity of approximately 4.0 and an angle of repose of approximately 70.
~80° and has very poor fluidity.

Filling speed is 120 bottles/min, suction vacuum -760mmHg,
The test was carried out under the condition of a discharge pressure of 1.0 Kg/cm ² . Table 1 shows the results.
Shown below.

As shown in Table 1, in solid-gas separator A of the present invention, the discharge condition is good and there is no powder scattering, but in B and C, after most of the powder lumps have been discharged, a small amount of powder pieces are discharged around the container. This causes the product to scatter to other parts of the body. The discharge condition of D was also not good, and the powder adhering to the wire surface and between the wire and the inner wall of the rotating drum was easily discharged, and powder scattering was observed. In addition, the 6th
The circles and crosshatching shown at the bottom in FIGS. 9 to 9 indicate the area of the hole 24 and a portion (crosshatching) where good ventilation is achieved.

<Test 2> Under the same conditions as in Example 1, it was investigated whether or not there was an effect when the side surface of the filter was closed. The targeted filters are those with side surfaces polished and closed as shown in A in Figure 6...A, those with unclosed sides as shown in A in Figure 6...A ₁ , and circular filters as shown in Figure 18. There are four types: one with columnar filters blocking the sides...F, and one without blockage... _F1 . The results are shown in Table 2.

The results in Table 2 show that for filters A ₁ and F ₁ that do not block the side surfaces of the filters, powder is easily sucked into the gap between the rotating drum wall and most of the powder lumps transfer to the container when the powder is discharged, and then fall in pieces. Accompanied by powder scattering.

On the other hand, in filters A and F whose sides are closed, it is difficult for powder to be sucked into the above-mentioned voids, and even if powder does enter, air does not flow to the side surfaces during discharge, so it is presumed that good discharge can be achieved.

<Test 3> The five types of filters shown in Table 3 were installed in the filling machine, and the filling operation was repeated 10,000 times for each filter, and changes in filling weight, variation in filling weight, and changes in filter ventilation amount over time were observed. investigated.

A precision electronic balance was used to measure the filling weight.
The air flow rate of the filter was measured by using a rotameter 28, as shown in FIG.

The variation in the filled weight was evaluated by measuring the weight 10 times at each time point and calculating the coefficient of variation of these values.

The discharge state was observed using a VTR as described above, and it was determined whether stable discharge was being exhibited.

The powder used was the same as in the example, and the measuring chamber (inner diameter 9.5 mm) was 30 mm deep to adjust the filling amount.
The suction vacuum was -760 mmHg, the discharge pressure was 1.0 Kg/cm ² , the air pressure was 4 Kg/cm ² for backwashing the filter after discharge, and the filling speed was 120 bottles/min.

The results are shown in Table 4 and FIGS. 11 and 12.

Filters A and E of the solid-gas separator having foot portions show little decrease in filling weight and ventilation amount over time. However, in the case of filter _A1, which does not have its sidewalls closed, the weight variation between samples at each time of investigation is somewhat large. Filters D and F
When the number of fillings approaches 10,000, the suction force for the powder becomes weak due to the small amount of ventilation, and as a result, the powder in the measuring chamber is not compacted and the powder falls loose during dispensing, a so-called discharge failure occurs. Also, the filling weight has decreased significantly.

Both D and F have large average opening diameters, so it is easy for fine powder to penetrate deep into the filter, and after the powder is discharged, it is difficult to return to its original state even if reverse pressure is applied with high-pressure compressed air and backwashing is performed. This has led to a decrease in quantity.

On the other hand, in filter E, the average opening diameter is very small like the filter, but the pressure loss is also large because it is thick. Therefore, the amount of air passing through is also very small from the beginning. As a result, the filling weight was insufficient, and discharge failures occurred immediately after the test started.

As mentioned above, in order to repeat the filling operation of fine powder used in pharmaceuticals, etc. at high speed, over a long period of time, with high precision and stability, it is necessary to select a thin filter material with a small opening diameter. Dead space should be eliminated as much as possible.

From this point of view, it has been found that the structure of the solid-gas separator of the present invention is very useful as it eliminates dead space and allows even a thin filter material to be connected to the movement adjustment member.

<Effects> The present invention has the above configuration, and the solid/gas separation filter is attached to the movement adjustment member with a gap between them via the breathable material, so the generation of dead space that conventionally occurs is eliminated. Air is circulated throughout the entire cross-sectional area of the holes in the rotary drum, eliminating the problem of powder remaining in the holes during discharge. Moreover, in the present invention, there is no need to increase the thickness of the filter itself, so the pressure loss is small, and the increase in pressure loss over time due to clogging is small. Therefore, over a long period of time, accurate amounts of powder can be obtained quickly.
Can be stably supplied. In addition, if the side circumferential surface of the breathable material is closed, air can be prevented from entering and exiting from the side circumferential surface, and the powder may enter the gap between the side circumferential surface and the inner wall of the hole, causing it to scatter during discharge. This solves the inconvenience of the product falling later.

[Brief explanation of drawings]

1 to 4 are longitudinal sectional views of a solid-gas separator according to an embodiment of the present invention, FIG. 5 is an enlarged sectional view of a part of the solid-gas separator of the embodiment, and FIGS. FIG. 9 is a cross-sectional view of each solid-gas separator used in Test 1, FIG. 10 is a diagram showing measurement of air flow rate of filter 21 by rotameter 28, and FIGS. 11 and 12 are diagrams showing the results of Test 3. , FIG. 13 is a cross-sectional view schematically showing a conventional powder feeder, and FIGS. 14 to 18 are longitudinal cross-sectional views showing a conventional solid-gas separator, respectively. 21...Filter, 22...Movement adjustment member, 2
2a...Top surface of movement adjustment member, 23...Breathable material, 24...Rotating drum hole, 25...Vent passage,
26...Space part, 27...Reinforcement material.

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Claims (1)

[Scope of Claims] 1. A solid-gas separation device for a powder filling machine, in which powder from a supply source is once filled by suction into holes in a supply drum, and then the powder is discharged and filled into a container from the holes using compressed gas. and a solid-gas separation filter forming a bottom surface of the hole and a movement adjusting member are provided in the hole, and the filter is attached to the upper surface of the movement adjusting member with a gap therebetween via a breathable material. A solid-gas separator for powder filling machines featuring: 2. The solid-gas separation device for a powder filling machine according to claim 1, wherein the breathable material is formed in a ring shape along the inner wall of the hole. 3. A solid-gas separator for a powder filling machine according to claim 2, wherein the breathable material is integrally molded from the same material as the filter. 4. The solid-gas separation device for a powder filling machine according to claim 1, wherein the breathable material fills the entire space between the filter and the movement adjustment member. 5. The solid air of the powder filling machine according to any one of claims 1 to 4, wherein the breathable material closes the side surface facing the inner wall of the hole to prevent ventilation to the inner wall surface of the hole. Separation device.