JPH0145562B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for metering fine powder materials such as pharmaceuticals, and more particularly, each metering chamber is defined by a filter member or screen, and a vacuum is applied to the metering chamber through the filter member or screen. Applying a suction action, the powdered material flows in to completely fill the chamber to the desired degree of compaction, and then air pressure is applied to the chamber through the filter member to transfer the metered material from the metering chamber into a suitable container. The present invention relates to a suction type volumetric measuring device that discharges water.

The metering device of the invention consists of a metering drum mounted for rotation about a horizontal axis, which closes a downwardly directed bottom opening of a powder material supply hopper by a portion of its cylindrical outer circumferential surface. It is done like this. The metering drum has a plurality of radial metering chambers arranged at equal intervals in the circumferential direction of the outer peripheral surface. Each metering chamber can be connected to a source of vacuum suction and air pressure through a filter screen forming its bottom. The vacuum suction source is for sucking the powder material from the supply hopper and filling it into the metering chamber, and the air pressure is for discharging the filled powder material from the metering chamber into the container. A feature of this metering device is that at least two metering chambers of the metering drum are positioned simultaneously in the bottom open zone of the feed hopper, and that each metering chamber moves across the bottom open zone of the feed hopper. The chamber was intermittently connected to a source of vacuum suction. This first feature increases the time each metering chamber remains in the bottom open or filling zone of the feed hopper. Alternatively, each metering chamber can be moved at a faster speed across a longer filling zone, thereby allowing each metering chamber to be filled more evenly and more completely. Therefore, the depth of each measuring chamber can be made deeper than conventional ones.
The number of metering chambers can be increased without having to increase the diameter of the drum. This is because the diameter of the metering chamber can be reduced by increasing the depth of the metering chamber. According to a second feature, the vacuum suction action is applied in a pulsating manner and the powder material is filled into the metering chamber without a "bridging" phenomenon.

According to another feature of the invention, each metering chamber is intermittently connected to a source of vacuum suction as it moves across the bottom open zone of the feed hopper, whereby the vacuum suction action is applied in a pulsating manner. to ensure that the powder material is filled into the metering chamber without creating a "bridging" phenomenon.

According to a further feature of the invention, after the filled powder material has been discharged from each metering chamber at the discharge station, the metering chamber is intermittently connected to a source of air pressure to pass intermittent jets of air. Ensure the room is thoroughly cleaned.

These and other features and advantages of the invention will become more apparent from the following description, taken in conjunction with the accompanying drawings.

The present invention will be described in connection with a case where it is applied to a measuring device for filling a container L with a predetermined amount of fine powder such as a medicine. This weighing device has a large bottom opening 1
a supply hopper F containing powder C, comprising:
The measuring drum A rotates continuously or intermittently in the direction of arrow B about a horizontal axis. The bottom opening 10 of the hopper F is adapted to be closed by the drum A.

The metering drum A has a plurality of radial metering chambers C.
are placed at equal intervals. Each weighing room is
Preferably, it is configured as a cylindrical hole with an open end opening in the outer circumferential surface of the drum. Within each chamber C is a filter screen E defining the bottom wall of the chamber.
A hollow plunger D is attached to the outer end in the radial direction. By adjusting the position of the plunger D within the metering chamber C, the volume of the chamber can be changed as desired. The depth of each measuring chamber C is the distance from the opening of the measuring chamber open to the outer peripheral surface of the measuring drum A to the filter screen E, and is preferably 2 to 3 times the diameter of the chamber. . Filter screen E
is preferably formed of a fabric woven from monofilament of a synthetic resin such as polytetrafluoroethylene, and is fixed to the end of the plunger D by a fixing ring Q as shown in FIG. Make yourself appropriately tense. Such a screen is described in Japanese Patent Application No. 55-153710 of the present applicant.

According to the invention, the bottom opening 10 of the supply hopper F
There are always two or three successive weighing chambers C within the zone of
The diameter of each chamber C, the interval between each chamber, and the width of the bottom opening 10 of the hopper (the width along the circumferential direction of the drum A) are selected so that While the metering chamber C moves within the zone of the bottom opening 10 of the feed hopper F, it is connected to a source of vacuum suction. Thereby, powder G
is sucked from the hopper F and is completely and uniformly filled into the measuring chamber C up to the bottom screen E.
Since, as mentioned above, there is always more than one metering chamber C located within the opening zone of the hopper, the path through which each individual metering chamber moves across the opening 10 of the hopper is relatively long and Since the powder remains in communication with the hopper opening for a relatively long time, the filling operation of the powder material into the metering chamber can be accomplished using a relatively weak vacuum suction. The use of a relatively weak vacuum suction action ensures that, despite the relatively deep depth of each metering chamber C, without the formation of undesirable condensates or bridges (concave top surfaces) of highly compacted powder. Enables uniform compressed filling into the measuring chamber.

The operation of connecting each metering chamber C to a vacuum suction source (not shown) in the bottom open zone of the supply hopper F is as follows:
This can be carried out in a known manner via an arcuate suction groove 11 formed in a fixed member disposed adjacent to and coaxially with the metering drum A. The inner end of each measuring chamber C is open by contacting the fixed member,
A radial conduit is provided which is adapted to communicate with the suction groove 11 as the drum A rotates.

Each measuring chamber C within the zone of the bottom opening 10 of the hopper F
The vacuum suction applied to the chamber can be maintained at a uniform level throughout the passage of the chamber across the aperture zone. In this case, it is preferable to connect the suction groove 11 to a suction source (not shown) at several locations in the longitudinal direction of the groove. Alternatively, the vacuum suction may increase or decrease along the direction of rotation of the metering drum A.
In that case, the suction groove 1 is
1 is connected to a suction source at the front or rear end.

FIG. 4 shows an embodiment of the invention.
In this embodiment, instead of a single arcuate suction groove 11, a plurality of individual suction grooves 111, 211, 31 are provided.
1 are arranged along concentric arcs of drum A, each groove being connected by a separate conduit to a suction source (not shown). According to this configuration, the suction action exerted on each measuring chamber C while moving across the zone of the bottom opening 10 of the hopper F is different from that during the movement from the suction groove 111 to the suction groove 211.
It is interrupted intermittently for a short time while moving from to 311. Intermittent connection with such a suction source
As mentioned above, this is advantageous in uniformly compressing and filling the powder material G into each metering chamber of the drum without producing powder material agglomerates and bridging. Furthermore,
According to the embodiment of FIG. 4, the vacuum suction force exerted through each different suction groove can be varied. Specifically, the vacuum suction force can be gradually increased or decreased in the direction of rotation of the drum A. For this purpose, simply each suction groove 111, 211, 3
11 may be connected to a suction source via a suitable pressure regulating valve (not shown).

After each metering chamber C filled with powder passes through the bottom opening zone of the supply hopper F due to the rotation of the drum, it is vacuum-suctioned through a suction groove 12 extending along an arc concentric with the drum. maintained in communication with the source. The suction force exerted through the suction groove 12 is intended to prevent the filling powder from being accidentally released from the metering chamber due to centrifugal force or gravity. Furthermore, a fixed arc-shaped suction hood M that surrounds the outer peripheral surface of the drum A is disposed in the zone of this suction groove 12. The suction hood M is used to suction and remove particles of the powder material G adhering to the outer peripheral surface of the drum, thereby completely cleaning the drum surface. Of course, the suction force exerted by the hood M must be lower than the suction force exerted by the suction groove 12.

Each measuring chamber C is rotated approximately 180 degrees from the supply hopper F, that is, at the lowest position of the drum.
is briefly connected to a source of air pressure (not shown).
This connection takes place through air injection holes 15 provided in a stationary member arranged coaxially with the rotary metering drum A. That is, the measured powder filled in the measuring chamber C is discharged into the container L placed below by the air injected from the injection hole 15. Of course, this dispensing operation is assisted by gravity.

Discharge station H when viewed from the rotational direction of drum A
There are two cleaning stations N
and 13 are provided. Measuring chamber C into which the filling powder was discharged at the previous discharge station H
Immediately thereafter, a further jet of air is blown into this cleaning station N, 13, so that the particles of powder material adhering to the filter screen E and the walls of the metering chamber are completely cleaned. The injection air in these two cleaning stations N, 13 is obtained by successively connecting the conduit of each metering chamber C to two successively arranged air injection holes 16, 17. These intermittent blasts of air cause the filter screen E to vibrate, as shown by the dashed lines in FIG. 3, thereby effectively shaking out particles of powder material. The metering chamber C thus cleaned moves towards the bottom opening 10 of the supply hopper F, ready to be filled with powder material again.

Although the embodiments of the present invention have been described above, various changes can be made to the detailed structure without departing from the spirit and scope of the present invention.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of the measuring device of the present invention;
The figure is an enlarged sectional view of the measuring chamber during filling of powder material.
The figure is a partial sectional view of the metering chamber during a cleaning operation, and FIG. 4 is a partial sectional view of the metering device of the present invention. In the figure, A is a measuring drum, C is a measuring chamber, E is a filter screen, F is a supply hopper, H is a discharge station, L is a container, N and 13 are cleaning stations, 10 is a bottom opening, and 11 and 12 are suction grooves. ,1
5, 16, 17 are air injection holes.

Claims (1)

[Scope of Claims] 1. A device for weighing powder material, the meter being mounted so as to be rotatable about a horizontal axis so as to close the downward bottom opening 10 of the powder material supply hopper F. It consists of a drum A having a plurality of radial metering chambers C arranged at equal intervals in the circumferential direction of the drum, each metering chamber having a filter screen E provided at its bottom. It was connected sequentially to a vacuum suction source and an air pressure source, thereby sucking the powder material from the supply hopper and filling it into the metering chamber, and then discharging the filled powder material from the metering chamber into the container L. The metering device is configured such that at least two metering chambers of the metering drum are simultaneously located in the bottom open zone of the supply hopper at all times during rotation of the metering drum; A conduit is provided, each metering chamber having at least two separate fixed suction grooves 11 arranged along an arc concentric with the drum due to the rotation of the drum.
1,211,311, the metering device being adapted to be connected to a vacuum suction source in the zone of the bottom opening of the feed hopper via said respective conduits communicating with said feed hopper. 2. The measuring device according to claim 1, wherein the depth of each measuring chamber C is 2 to 3 times its diameter. 3 Each of the separate suction grooves 111, 211, 311
are each connected to the vacuum suction source via a pressure regulating valve, thereby making it possible to change the strength of the suction force exerted on each suction groove. Weighing device as described. 4 A conduit connected to each of the metering chambers is provided in the drum, and each metering chamber is communicated with a fixed suction groove 12 disposed along an arc concentric with the drum as the drum rotates. via said respective conduits, which are adapted to be connected to a source of vacuum suction from immediately after said feed hopper, viewed in the direction of rotation of said drum, up to a zone where said powder material is discharged into said container. A measuring device according to claim 1. 5. Each metering chamber is connected to at least two successively arranged separate air injection holes which communicate with a source of air pressure immediately after the zone in which the powder material is discharged into the container, viewed in the direction of rotation of the drum. A measuring device according to claim 1, wherein: