JPH0340479Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is used to supply powder from a hopper to a feedstock that fills the powder into the mortar hole of a rotary disk according to instructions from a powder level sensor. The present invention relates to the structure of a powder level sensor of a powder feeder in a rotary tablet machine.

(Prior art) Generally, in order to manufacture tablets by compression molding powder using a rotary tablet manufacturing machine, the powder filled in the mortar hole of a rotating rotary disk is compressed when upper and lower punches pass between compression rolls. This is done by

If the manufactured tablet is a pharmaceutical, its weight is controlled according to the Japanese Pharmacopoeia Law.
In the case of catalysts, electrical parts, etc., weight control is carried out in the same way as for pharmaceuticals, as this affects the shape and hardness after firing.

In order to keep the weight of the above-mentioned tablet within the limit, it is sufficient to keep the weight of the powder filled into the mortar hole within a certain limit. Since it is determined by volume, if the density of the powder changes, the weight will change, and it is difficult to keep the weight of the tablet constant just by keeping the volume of powder in the mortar constant. It is what it is.

This change in powder density is mainly due to the amount of powder in the feedstock.
It is necessary to detect the amount of powder in the feed-shuttle, control the amount of powder falling from the hopper based on the detection signal, and supply the powder into the feed-shuttle.

Therefore, in the past, Japanese Patent Application Laid-Open No. 48-37371 (Patent Application No. 46-37371)
72347) and Japanese Patent Application Laid-Open No. 139759 (1983)
As disclosed in Japanese Patent Application No. 55-43103, there is a technique in which a powder level sensor is disposed in a feed stock to detect the amount of powder in the feed stock.

Also, Utility Application No. 175241 (1983)
As disclosed in the above publication, there is a technique in which a powder level sensor is disposed in a holding cylinder at the top of an open feed shuttle to detect the amount of powder in the feed shuttle.

(Problems to be solved by the invention) Although such conventional technology can meet the above-mentioned requirements, the former two types of sensors installed in the feedstock are In addition to being directly affected by the stirring blade, the amount of powder in the feedstock also fluctuates.

In other words, the rotation of the stirring blade causes the powder in the feedstock to pulsate (the powder has peaks and troughs), so if you try to detect the powder, the sensor will fail even though the powder is decreasing. The presence of powder is detected every time the stirring blade passes underneath, which not only makes the detection accuracy unstable, but also causes the problem that the amount of powder in the feedstock is not constant, and therefore the powder density is not constant. It was hot.

Also, in the case of the latter open feed system,
After all, the level sensor is installed directly in the feedstock, and the level sensor attempts to directly detect the powder in the feedstock, which is inconvenient when cleaning the feedstock or replacing the level sensor. There was a problem with low level detection accuracy.

That is, the present invention comprehensively improves the powder level sensor in the conventional powder feeder in terms of its installation location, installation method, installation structure, sensor type, etc.
To provide a structure of a powder level sensor that keeps the powder in a feed stock constant, detects the powder level more precisely, keeps the powder density in the feed stock constant, and is easy to handle. It is something.

(Means for Solving the Problems) In order to solve these problems, according to this invention, powder is supplied from a hopper 4 to a feed shaft 3 that fills the powder into the mortar hole of the mortar 2 of the rotary disk 1. In a powder feeder in a rotary tablet machine that feeds according to instructions from a powder level sensor 5 when feeding,
The hopper 4 is arranged so that the powder made of a synthetic resin having a dielectric constant higher than that of the detected powder is formed in a vertical portion 6 where the powder made of synthetic resin has a higher dielectric constant than the detected powder at least near the upper part of the feedstock 3.
A capacitance type powder level sensor 5 is disposed outside the vertical portion 6 to detect changes in dielectric constant due to changes in the object between the electrodes, and the level sensor 5 is connected to the vertical portion 6. There is provided a structure of a powder level sensor of a powder feeder in a rotary tablet making machine, characterized in that the powder level in the vertical part 6 is detected without directly contacting the powder through the outer wall of the rotary tablet making machine. Ru.

In the above configuration, the vertical portion 6 can be formed transparent.

In this case, the powder level can be visually confirmed.

(effect) The above technical means works as follows.

At least near the upper part of the feed stock 3, the powder made of synthetic resin having a higher dielectric constant than the detection powder is formed with a vertical part 6 through which it is easy to flow, so that the feed stock 3, the hopper 4, and the level sensor 5 can be easily separated. At the same time, when the amount of powder in the feed tray 3 decreases, it is immediately replenished by the powder in the vertical portion 6, so that the amount of powder in the feed tray 3 always remains constant.

By disposing a capacitive powder level sensor 5 outside the vertical portion 6 made of synthetic resin to detect changes in dielectric constant due to changes in the object between the electrodes, the detection portion of the level sensor 5 is 7. There is no contact with the powder at all, which means that even if the powder level is low, there is no possibility of detecting the presence of powder due to powder adhering to the detection part, and the detection is always highly accurate. This makes it possible to keep the powder weight in the feed-shut 3 constant, so that the powder density in the feed-shut 3 can be kept constant at all times.

The level sensor 5 also operates in such a way that it can be replaced or adjusted without removing powder from the feedstock 3, vertical section 6 and hopper 4.

(Example) An example of this invention will be explained with reference to the drawings.
FIG. 1 is a vertical sectional view of the main part showing an embodiment of the present invention.
FIG. 2 is an enlarged longitudinal sectional view of the main part of FIG. 1.

Reference numeral 1 denotes a rotary disk in which a large number of dies 2 are arranged on the periphery, and an upper punch 11 is slidably fitted into the upper part of the rotary disk 1, and is supported above the mortars 2 by an upper punch guide rail 23. ing.

12 is a lower punch fitted into the lower part of the rotary disk 1, and the upper end of the lower punch 12 fits into the hole of the mortar 2, and its head rests on the upper end of the weight rail 24. The weight rail 24 moves up and down, thereby changing the volume inside the hole of the mortar 2.

Reference numeral 4 denotes a hopper with a built-in powder transfer disk 13, and the hopper 4 is centered on the transfer disk 13, and a hopper flange 30 provided at the lower end is attached to the upper surface of the hopper stand 17. The hopper stand 17 is attached to the upper surface of the ceiling plate 21.

The powder transfer disk 13 is provided with pockets 14 intermittently on its periphery, and is fitted onto a shaft 22 which is rotated at a reduced speed by a motor 18 and a speed reducer 19, and is fixed with a nut 31.

Reference numeral 3 denotes a feed shaker disposed so as to be in contact with the surface of the rotary disk 1 and fixed to the feed shake stand 16, and the feed shaker 3 has stirring blades 10 inside.
is rotatably arranged.

Reference numeral 6 denotes a vertical part that communicates and connects the feeder 3 and the powder falling port 15 of the hopper 4. The vertical part 6 is formed into a pipe shape from transparent synthetic resin, and the lower part is connected to the lower flange 26 and the upper part is connected to the upper part. They are slidably and hermetically attached to the flanges 27 via O-rings 28, respectively.

5 is a powder level sensor disposed outside the vertical portion 6 slightly above the feedstock 3;
The level sensor 5 is a capacitance type proximity switch having a detection part 7 at the tip and a sensitivity adjustment bolt 29 at the rear. The detection section 7 detects the powder inside the vertical section 6 through the synthetic resin outer wall of the vertical section 6.

A control device 20 controls the rotation of the motor 18 by amplifying the detection signal of the level sensor 5, and the control device 20 stops the motor 18 when the level sensor 5 detects that powder is present. , when it is detected that there is no powder, the motor 18 is rotated.

In operation, the powder in the hopper 4 falls inside the pocket 14 of the powder transfer disk 13;
When this transfer disk 13 is rotated by the motor 18, the powder that has entered the pot 14 at the position A is moved horizontally as it is, due to the fact that the center of the transfer disk 13 and the center of the hopper 4 are oscillated. The powder is scraped off by the lower opening edge 25 of the hopper 4, and the powder falling from above is blocked by the flange 30 of the hopper 4, and the powder in the pocket 14 is eventually sent to position B, that is, above the powder drop port 15. It turns out.

Then, the powder is dropped and supplied from the powder drop port 15 to the vertical part 6, sequentially supplied to the feeder 3, sent to the upper surface of the mortar 2 by the stirring blade 10, and filled into the mortar 2.

In this case, the level sensor 5 detects the powder supplied to the vertical portion 6, that is, near the upper part of the feed shaft 3, as a powder level. For example, when this powder level is at position C, the motor 18 to stop powder supply from the hopper 4, and when the powder level is at position D, the motor 18 is instructed to drive to supply powder from the hopper 4 as the powder level is at the lower limit, and the powder level reaches C again.
When it returns to the position, it instructs the motor 18 to stop,
Control the powder level so that it is always between C and D.

In addition, in disassembly and cleaning that may occur on a daily basis, the second
In the figure, if the vertical part 6 is slid downward, it will be disengaged from the upper upper flange 27, and the feedstock 3 and hopper 4 can be easily disassembled, and the level sensor 5 will remove the powder in the vertical part 6. It can be removed by loosening the bolt 9 without removing it.

FIG. 3 is a longitudinal cross-sectional view of a main part showing another embodiment of the present invention.

32 is a rotary disk, 33 is a feeder, 34 is a hopper, 40 is a stirring blade, 41 is a control device, 42
is a motor, and 43 is a powder transfer disk.

Reference numeral 36 denotes a vertical part formed in the shape of a short rectangular pipe near the upper part of the feedstock 33. The outer vertical part 36 is made of transparent synthetic resin, and the lower part is connected to the lower flange 45, and the upper part is connected to the lower part of the inclined cylinder 44. are slidably and hermetically connected to each other via a sealing material.

Reference numeral 35 denotes a powder level sensor inserted into a holding portion 38 integrally formed with the vertical portion 36, and the level sensor 35 is a capacitance type proximity switch.

37 is a detection unit, and 39 is a bolt.

The present invention is not limited to the above-mentioned embodiments. For example, the vertical portion is preferably vertical, but may be approximately vertical. Only a portion of the vertical portion may be transparent. The powder level may be adjusted up and down to make the powder level variable, or an open feed system may be used as desired.

(Effects of the invention) As explained above, the present invention detects the powder level near the top of the feedstock without being affected by the rotation of the stirring blade, and moreover, detects the powder level vertically as the powder in the feedstock decreases. The powder in the shaped part is first fed into the feed shaker, and since the amount of powder in the feed shaker can always be kept constant, the powder density in the feed shaker can be kept constant.

Furthermore, by arranging the powder level sensor in a vertical section separate from the feed stock, cleaning and inspection of the feed stock and hopper can be facilitated.

Furthermore, the level sensor is of a capacitance type and indirectly detects the powder through the outer wall of the vertical part of the synthetic resin, so the detection accuracy is high and the powder level can be precisely controlled. This has effects such as being able to maintain a constant powder density in the feed shed with little influence from powder weight, etc., and allowing the level sensor to be replaced or adjusted without removing any powder in the feed shed.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of the main part showing one embodiment of the present invention, FIG. 2 is an enlarged vertical sectional view of the main part of FIG. 1, and FIG. 3 is a main part showing another embodiment of the invention. FIG. In the drawing, 1 and 32 are rotary disks, 2 is a mortar,
3 and 33 are feedshu, 4 and 34 are hoppers,
5, 35 are powder level sensors, 6, 36 are vertical parts, 7, 37 are detection parts, 8, 38 are holding parts, 9,
39 is a bolt, 10 and 40 are stirring blades, 11 is an upper punch, 12 is a lower punch, 13 and 43 are powder transfer disks, 1
4 is a pocket, 15 is a powder drop port, 16 is a feed stand, 17 is a hopper stand, 18 and 42 are motors, 19 is a speed reducer, 20 and 41 are control devices, 21
is the ceiling plate, 22 is the shaft, 23 is the upper punch guide rail,
24 is a weight rail, 25 is a lower end opening edge, 26, 4
5 is a lower flange, 27 is an upper flange, 28 is an O-ring, 29 is a sensitivity adjustment bolt, 30 is a hopper flange, and 31 is a nut.

Claims (1)

[Claims for Utility Model Registration] 1. A rotary tablet machine that supplies powder from a hopper 4 to a feedstock 3 that fills the powder into a mortar hole of a mortar 2 of a rotary disk 1 with the support of a powder level sensor 5. In the powder feeder in
At least near the upper part of the feedstock 3, the powder made of a synthetic resin having a higher dielectric constant than the detection powder is connected to the hopper 4 so as to be formed in a vertical part 6 where it is easy to flow, and an object between the electrodes is placed outside the vertical part 6. A capacitance-type powder level sensor 5 that detects changes in dielectric constant due to changes is disposed, and the level sensor 5 detects the inside of the vertical portion 6 without directly contacting the powder through the outer wall of the vertical portion 6. A structure of a powder level sensor of a powder feeder in a rotary tablet manufacturing machine, characterized in that the powder level sensor is configured to detect the powder level of a rotary tablet manufacturing machine. 2 Utility model registration claim 1 characterized in that the vertical portion 6 is formed transparently
Structure of a powder level sensor of a powder feeder in a rotary tablet making machine as described in 2.