JPH0732960B2 - Rotary powder molding machine for vacuum tableting - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary powder molding machine for vacuum tableting, in which powder is compressed under reduced pressure to form tablets.

[0002]

2. Description of the Related Art Conventionally, as a rotary powder molding machine for vacuum tableting of this kind, a valve such as a rotary valve for intermittently and continuously introducing a powder or granular material, and an intermittent powder are also used. And a machine with a tableting function is housed in a closed box equipped with a valve for continuously discharging tablets, and the introduction valve and the discharge valve are connected to a machine with a tableting function and hermetically sealed. There is known a powder molding machine characterized in that tableting is performed in a state where the presence of air and moisture in the box is reduced (see Japanese Patent Publication No. 42-21489).

[0003]

However, the rotary valve is difficult to seal between the rotor and the casing, and
The shaft for driving the rotor must be penetrated through the side wall of the casing, and it is difficult to effectively reduce the pressure inside the closed box.

The present invention has been made in view of such circumstances, and it is possible to effectively depressurize the inside of a sealed box with a simple structure, and to prevent capping, laminating, etc. during molding. An object of the present invention is to provide a rotary powder molding machine for vacuum tableting that can effectively eliminate the conditions.

[0005]

The present invention adopts the following constitution in order to achieve the above object. That is, the rotary powder molding machine for vacuum tableting according to the present invention is capable of moving up and down from the lower side into a rotary disc that holds a plurality of dies at a predetermined pitch in the rotation direction, and a mortar hole of each mortar from below. The lower punch inserted into the die, the feedstock that sequentially fills the mortar hole with the powder supplied on the surface of the turret through the constant quantity feeder, and the upper part inside the mortar hole filled with the powder. The upper punch inserted from, the compression punch that compresses the powder in the die by pressing the upper punch and the lower punch from above and below, and the upper punch that has passed through the compression roll is pulled out from the die hole and the lower punch is pressed. It is equipped with a punch guide mechanism that pushes up and molded tablets from the die hole onto the surface of the rotary disk, and a damper that guides the tablets extruded onto the surface of the rotary disk to the base end of the cylindrical chute for tablet extraction. The airframe is housed in a closed box. Further, the powder receiving port of the constant quantity feeder is connected to a hopper for powder storage arranged outside the hermetically sealed box via a first airtight valve, and the tip of the cylindrical chute is connected to a second airtight valve. It faces the tablet receiving can arranged outside the sealed box. And, each of the airtight valves is provided with a piston cylinder having an inlet and an outlet at different positions in the axial direction on the peripheral wall, and an airtight fit to the inner circumference of the piston cylinder so as to be able to advance and retreat in the axial direction. A piston having an annular groove having a width dimension that cannot simultaneously communicate with the inlet and the outlet,
The piston is provided with a piston urging means for advancing and retracting the piston from an introduction position where the annular groove matches the inlet to a discharge position where the annular groove matches the outlet, and It is characterized in that the pressure can be reduced by a vacuum pump.

As a preferred mode of the piston biasing means,
An example is one in which a closed air chamber is provided between both end faces of the piston and both end walls of the piston cylinder, and compressed air can be selectively introduced into these air chambers.

[0007]

When the piston of the first airtight valve is stopped at the introduction position, part of the powder in the powder storage hopper is introduced from the inlet of the piston cylinder into the annular groove of the piston. In that state, when the piston is moved to the discharge position, the powder in the annular groove is discharged from the outlet to the outside of the cylinder piston and is supplied to the powder receiving port of the fixed quantity feeder. By advancing and retracting the piston between the introduction position and the extraction position in this way, the powder in the popper can be sequentially supplied to the constant quantity feeder, but the aforementioned inlet and outlet communicate with each other through the annular groove. None, either one will always be blocked by the piston. Therefore, it is possible to prevent the outside air from leaking into the fixed quantity feeder from the popper side, and it is possible to introduce only the powder into the closed box.

The powder introduced into the closed box is sequentially supplied onto the surface of the rotating disk and is filled in the die holes of the die by the feed shoe. The powder filled in the mortar is guided to the position where the compression roll is placed while being held by the lower and upper punches, and when passing through the compression roll, the powder is pressed by the lower and upper punches to form a tablet having a predetermined shape. Is molded into. After passing through the compression roll, the upper punch is pulled out from the die and the lower punch rises, so the tablets in the die holes are pushed up onto the surface of the rotating disc, and the damper guides the base end of the cylindrical chute for tablet ejection. Be thrown into.

When the piston of the second hermetic valve is stopped at the introduction position, the tablets discharged through the cylindrical chute are introduced into the annular groove of this piston. When this piston is moved to the lead-out position in that state, the tablets in the annular groove are discharged from the outlet to the tablet receiving can. By advancing and retracting the piston between the introduction position and the derivation position in this manner, the tablets in the cylindrical chute can be sequentially discharged to the tablet receiving can, but the aforementioned inlet and outlet are provided via the annular groove. There is no communication, and either one will always be closed by the piston. Therefore, outside air can be prevented from leaking into the cylindrical chute from the outlet of the second airtight valve, and only the tablet can be led out of the closed box.

[0010]

EXAMPLES Examples will be described with reference to the drawings.

This rotary powder compression molding machine for vacuum tableting is a machine in which a machine body 100 having a tableting function is housed in a closed box 21, and a hopper 1 for storing powder and a tablet can 18 are provided.
Are arranged in the atmosphere outside the closed box 21.

The machine body 100 includes a turntable 25 which holds a plurality of mortars 26 at a predetermined pitch in the rotating direction, and the mortars 2 described above.
Lower punch 27 inserted in the die hole of No. 6 so as to be able to move up and down from below
And a feedstock 11 for sequentially filling the powder supplied to the disk surface 25a of the rotary disk 25 through the constant quantity feeder 8 into the die holes by the guiding action of the stirring blades 30, and from the upper side into the powder-filled die holes. An upper punch (not shown) to be inserted, a compression roll (not shown) for compressing and molding the powder in the die 26 by pressing the upper punch and the lower punch 27 from above and below, and the upper punch passing through the compression roll from the die hole. A punch guide mechanism (not shown) for pushing out the tablet formed by raising and lowering the lower punch 27 from the die hole onto the rotary disc surface 25a, and the tablet extruded on the rotary disc surface 25a of the cylindrical chute 12 for tablet extraction. And a damper 31 for guiding the base end. Since the machine body 100 has substantially the same structure as a machine body of a known ordinary rotary compression molding machine having no closed box, the detailed description of the compression roll and the punch guide mechanism will be omitted.

One end of a vacuum pipe 24 is connected to the closed box 21, and the inside of the closed box 21 is decompressed by a vacuum pump connected to the other end. Reference numeral 33 is a closed window for inspection or the like.

The fixed quantity feeder 8 has a rotary vane 28 rotatably housed in a casing 8c having a powder receiving port 8a and a powder discharging port 8b. The rotary vane 28 is rotated by a motor 29. The powder receiving port 8a of the constant quantity feeder 8 is located outside the closed box 21, and the powder discharge port 8b is opened inside the closed box 21. The powder receiving port 8a of the constant quantity feeder 8 is connected to the first airtight valve 36.
The powder discharge port 8b is connected to the feedstock 11 via the intermediate pipe 10 while being connected to the hopper 1 arranged outside the closed box 21 via the.

The first airtight valve 36 has a horizontal piston cylinder 2 formed by opening an upward inlet 2a and a downward outlet 2b at axially different positions on a peripheral wall, and an inner circumference of the piston cylinder 2. A piston 6 having an annular groove 5 having a width dimension that is airtightly fitted in the shaft 2 so as to be able to move back and forth in the axial direction and cannot communicate with the inlet 2a and the outlet 2b at the same time.
And a piston urging means 37 for advancing and retracting the piston 6 between an introduction position where the annular groove 5 coincides with the inlet 2a and a discharge position where the annular groove 5 coincides with the outlet 2b.
And. The piston urging means 37 includes both end surfaces of the piston 6 and both end walls 3, 4 of the piston cylinder 2.
Air chambers 37a and 37b sealed between are provided,
The compressed air can be selectively introduced into the air chambers 37a and 37b. That is, both ends of the piston cylinder 2 are sealed by end walls 3 and 4, and compressed air pipes 19 and 20 for sending compressed air to these end walls 3 and 4 are connected.

A powder sensor 9 is provided on the intermediate pipe 10. The powder sensor 9 detects the amount of powder in the intermediate pipe 10 and emits a signal when the amount of powder decreases. When this signal is issued, the compressed air pipe 1 is added to the air chamber 37a of the piston cylinder 2.
Compressed air is fed from 9 to operate the piston 6 to supply the powder to the powder receiving port 8a of the constant quantity feeder 8, and at the same time, to operate the motor 29 of the constant quantity feeder 8 to rotate the powder. The blades 28 are rotated so as to drop into the intermediate pipe 10 in a fixed amount.

On the other hand, the cylindrical chute 12 has a base end opened in the vicinity of the damper 31 and is provided through the closed box 21.
The leading end of the tablet canister 18 is disposed outside the closed box 21 via the second airtight valve 38.

As shown in FIG. 2, the second airtight valve 38 has an inlet 13a facing upward and an outlet 13 facing downward on the peripheral wall.
The horizontal piston cylinder 13 is formed by opening b at different positions in the axial direction, and the inner circumference of the piston cylinder 13 is airtightly fitted so as to be able to advance and retreat in the axial direction. At the same time, a piston 17 having an annular groove 16 having a width dimension that cannot communicate with each other, and a lead-out position at which the annular groove 16 coincides with the inlet 13a to the outlet 13b. And a piston urging means 39 for advancing and retracting between the two. The piston urging means 39 is the piston 17
Both end faces of the piston cylinder 13 and both end walls 14 and 15 of the piston cylinder 13.
Air chambers 39a and 39b sealed between are provided,
The compressed air can be selectively introduced into the air chambers 39a and 39b. That is, both ends of the piston cylinder 13 are sealed by end walls 14 and 15, and compressed air pipes 22 and 23 for sending compressed air to these end walls 14 and 15 are connected. When the amount of tablets flowing from the chute 12 into the annular groove 16 of the piston 17 reaches an appropriate amount, compressed air is sent from the compressed air pipe 22 into the air chamber 13a, and the piston 1 is compressed.
7 is moved laterally, and the tablet is discharged from the outlet 13b of the piston cylinder 13 to the tablet receiving can 18 in the atmosphere. Incidentally, 34 and 35 are piston contacts for stopping the piston 17 at the aforementioned introduction position and extraction position.

Next, the operation of this embodiment will be described.

Air chamber 37 in the first airtight valve 36
When compressed air is introduced into b to move the piston 6 to the left in FIG. 1 and stopped at the illustrated introduction position, part of the powder in the powder storage hopper 1 is discharged from the inlet 2a of the piston cylinder 2. It is introduced into the annular groove 5 of the piston 6. From that state, the air chamber 37b is opened to open the air chamber 37b.
When compressed air is introduced into a and the piston 6 is moved to the extraction position, the powder in the annular groove 5 is extracted from the outlet 2b to the outside of the cylinder piston 2 and is supplied to the powder receiving port 8a of the constant amount feeder 8. It will be. Piston 6
The powder in the popper 1 can be sequentially supplied to the constant quantity feeder 8 by advancing and retracting between the introduction position and the discharge position. However, the inlet 2a and the outlet 2b described above communicate with each other via the annular groove 5. One of them is always closed by the piston 6. Therefore, it is possible to prevent outside air from leaking into the casing 8c of the constant quantity feeder 8 from the popper 1 side, and only the powder is blown into the body 10
It is possible to appropriately introduce it into the closed box 21 in which 0 is stored. The reciprocating operation of the piston 6 is performed, for example, each time the powder sensor 9 detects that the powder in the intermediate pipe 10 has dropped below a certain level.

As is well known, the powder introduced into the closed box 21 is sequentially supplied onto the rotary disk surface 25a through the intermediate pipe 10 and is filled in the die hole of the die 26 by the feed shoe 11. The powder filled in the die hole is held by the lower punch 27 and the upper punch (not shown) and guided to the position where the compression roll is arranged. When passing through the compression roll, the powder is pressed by the lower punch 27 and the upper punch. It is molded into tablets of a predetermined shape. After passing through the compression roll, the upper punch is pulled out from the die 26 and the lower punch 27 is raised, so that the tablet in the die hole is pushed up onto the rotary plate surface 25a, and the damper 31 guides the tablet to take out the cylindrical shape. It is thrown into the base end of the chute 12.

Air chamber 39 in the second airtight valve 38
When compressed air is introduced into b to move the piston 17 to the left in FIG. 2 and stop at the introduction position as shown, the tablets discharged through the cylindrical chute 12 are It is introduced into the annular groove 16.
In that state, the air chamber 39b is opened and the air chamber 3 is opened.
When compressed air is introduced into 9a and this piston 17 is moved to the lead-out position, the tablets in the annular groove 16 will exit from the outlet 13.
It is discharged from the b to the tablet receiving can 18. By advancing and retracting the piston 17 between the introduction position and the extraction position in this manner, the tablets in the cylindrical chute 12 can be sequentially discharged to the tablet receiving can 18.
The a and the outlet 13b do not communicate with each other through the annular groove 16, and one of them is always closed by the piston 17. Therefore, it is possible to prevent the outside air from leaking into the cylindrical chute 12 from the outlet 13b of the second airtight valve 38, and it is possible to draw only the tablet out of the closed box 24.

As described above, according to the present rotary compression molding machine, the powder can be compression molded in the decompressed closed box 24 to successively manufacture tablets, but the powder disposed in the atmosphere is used. A first airtight valve 36 for preventing outside air leakage between the storage hopper 1 and the inside of the sealed box 24, and an atmospheric leak between the tablet can 18 arranged in the atmosphere and the inside of the sealed box 24. Since the second airtight valve 38 for prevention uses the pistons 6 and 17 that reciprocate so that a high sealing property can be easily ensured by an O-ring, a piston ring, etc. The tableting work can be performed by efficiently depressurizing. Therefore, the capping phenomenon can be reduced and the tablet hardness can be reasonably improved.

An experiment was conducted to specifically show such an effect. In this experiment, 100 mesh lactose 40%, Avicel 9.5% and Neusilin 50 were used in the powder mixing ratio.
%, Then added and mixed with 0.5% of magnesium stearate, once crushed and then crushed into slag granules 16
-30 mesh 50%, 40-80 mesh 40%, 1
Using powder of coarse granule tablets of 10% through 00 mesh,
The average of 20 tablets sampled by compression molding under the conditions of a punch diameter of 8 mm, a punch surface of 12 R and a rotation speed of 40 RPM was repeated 5 times and the experimental data thereof are shown in Table 1 below.

[0025]

[Table 1] In Table 1 above, Experimental Example No. In the case of No. 1, although the tablet breaks when dropped by 1 m, the experimental example no. 2 and No.
In the case of 3, the tablet does not break when dropped by 1 m.

As is clear from the experimental data shown in Table 1 above, when the lower punch height in the die hole was kept constant and the decompression force was increased, the tablet weight increased and the capping phenomenon decreased, resulting in The thickness changes more greatly than that in the atmosphere, but it does not change much with respect to the difference in decompression force,
It can be seen that the tablet hardness increases and cracking becomes difficult.

According to the rotary powder molding machine for vacuum tableting according to the present invention, the airtightness in the closed box 21 can be enhanced. Tableting under conditions such as No. 3 can be easily performed, and it is possible to produce tablets with high hardness without capping.

[0028]

As described in detail above, according to the present invention, a space between a closed box containing a machine having a tableting function and a powder storage hopper and a tablet receiving can arranged in the atmosphere. Further, since the airtight valves utilizing the reciprocating piston capable of ensuring high sealing property are respectively interposed, it becomes easy to maintain the tableting atmosphere in the closed box in a favorable reduced pressure state. Therefore, it is possible to eliminate adverse conditions such as capping and laminating during molding, and it is possible to produce excellent tablets having high hardness.

When the piston urging mechanism is set forth in claim 2, the structure for operating the pistons of the first and second hermetic valves can be made particularly simple.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a rotary powder molding machine for vacuum tableting according to the present invention.

FIG. 2 is an enlarged central vertical sectional view showing a second airtight valve shown in FIG.

[Explanation of Codes] 1 ... Hopper 2 ... Piston Cylinder 2a ... Inlet 2b ... Outlet 3 ... End wall 4 ... End wall 5 ... Annular groove 6 ... Piston 7 ... Pipe 8 ... Fixed amount feeder 8a ... Powder inlet 8b ... Powder discharge Outlet 8c ... Casing 9 ... Powder sensor 10 ... Intermediate pipe 11 ... Feedstock 12 ... Cylindrical chute 13 ... Piston cylinder 13a ... Inlet 13b ... Outlet 14 ... End wall 15 ... End wall 16 ... Annular groove 17 ... Piston 18 ... Tablet holder Can 19 ... compressed air pipe 20 ... compressed air pipe 21 ... closed box 22 ... compressed air pipe 23 ... compressed air pipe 24 ... vacuum pipe 25 ... turntable 25a ... turntable surface 26 ... mortar 27 ... lower punch 28 ... rotary blade 29 ... Motor 30 ... Stirring blade 31 ... Damper 33 ... Sealing window 34 ... Per piston 35 ... Per piston 36 ... First airtight valve 37 ... Pist Biasing means 37a ... air chamber 37b ... air chamber 38 ... second hermetic valve 39 ... urging means 39a ... air chamber 39 b ... air chamber 100 ... aircraft with piston

Claims (2)

[Claims] 1. A rotary disk which holds a plurality of dies at a predetermined pitch in the rotating direction, a lower punch which is vertically movable from the lower side into a mortar hole of each mortar, and a rotary feed through a constant quantity feeder. A feed shoe that sequentially fills the die holes with the powder supplied onto the plate surface by using the rotation of the rotary disc, an upper punch that is inserted into the die holes filled with the powder from above, and the upper punch and the above-mentioned A compression roll that compresses the lower punch from above and below to compress and mold the powder in the die, and the upper punch that has passed through the compression roll is pulled out from the die hole, and the lower punch is raised to rotate the formed tablet from the die hole. A punch guide mechanism that pushes out onto the platen surface and a damper that guides the tablets pushed out onto the rotary platen surface to the base end of a cylindrical chute for tablet extraction are housed in a sealed box, and the quantitative supply is performed. The powder inlet of the container was arranged outside the closed box via the first airtight valve. It is connected to a hopper for powder storage and the tip of the cylindrical chute is exposed to a tablet receiving can arranged outside the sealed box via a second airtight valve, and each airtight valve is provided with an inlet and an outlet on the peripheral wall. And a piston cylinder opened at different positions in the axial direction, and an annular shape with a width dimension that is airtightly fitted to the inner circumference of the piston cylinder so as to move forward and backward in the axial direction and cannot communicate with the inlet and the outlet at the same time. A piston having a groove, and a piston urging means for moving the piston back and forth between an introduction position where the annular groove matches the inlet and a discharge position where the annular groove matches the outlet. The rotary powder molding machine for vacuum tableting, characterized in that the inside of the closed box can be decompressed by a vacuum pump. 2. A piston urging means is provided with air chambers sealed between both end faces of the piston and both end walls of a piston cylinder, and compressed air can be selectively introduced into these air chambers. The rotary powder molding machine for vacuum tableting according to claim 1.