The present invention relates to an equipment for filling a medical substance essentially in powder form into cap¬ sules. The capsules are intended to be implanted under the skin, and from which the medical substance diffuses to the blood circulation through the capsule wall. In¬ tended uses are for instance dosing of contraceptive hor- mones, as well as in dosing antabus agents.

In capsule production the starting point is a tube for forming the casing of the capsule, and for which a suit¬ able material is a silicone plastic. The diameter of the tube under the manufacturing of hormone capsules is 1.5 mm. The tube is fed to the capsule manufacturing line as continuous lengths from a suitable apparatus. At the starting point of the capsule manufacturing line, the tube is cut into capsule blanks of a suitable length, e.g. to lengths of about 34 mm.

The said capsule blanks are then arranged into rows for¬ med by several blanks. One row may comprise e.g. 12 blanks. One of such rows is advantageously joined toget- her and it forms a handling unit for the next stages of the process. In order to join this handling unit row it is possible to use a means to keep the blanks in their prescribed positions and with the help of which the handling unit row is transferred from one stage to another in the process, as well as positioned for each process stage. The said means can advantageously be a cassette of a clamping claw structure where the claws are in a mutual spring loaded clamping contact and where mutually co-operating indentation slots have been formed on the contact faces of the claws in order to form through holes for receiving the capsule blanks.

In the following process stages, the dosed quantity of

the material is dropped from each dosing means to its respective transportation groove made in the surface of a disc, operating as a vibrating conveyor. The dosed mate¬ rial quantities proceed in the grooves of the vibrating conveyor further to feeding funnels, below which the capsule blanks to be filled have been transferred, car¬ ried by the clamping claw cassette. In order to promote the flow of the material into the capsule blanks, a spe¬ cial spiral feeder is used. The said feeder comprises a spiral spring that has a diameter less than the inner diameter of the capsule blank, and a straight guiding wire therein. This spring is rotatable in the forward di¬ rection of its spiral.

As far as the feeding process itself is concerned, the procedure is carried out so that the spiral spring is inserted into the capsule blank and made to rotate. Si¬ multaneously with the activation of the rotative movement raising of the spiral spring from the capsule blank is initiated. When the rotation direction is as said above the spring acts as a feeder screw. When the filling of the capsule blank advances, the spiral spring is extract¬ ed, still in rotation, from the capsule blank. During the saiύ operational stages, the feeding funnels are kept under vibration. When the head of the spiral spring has risen to the desired material filling level, its rising movement is stopped but vibration and rotation of the spring are continued. Thus, the spiral spring determines the height of the material column fed to the capsule.

After the filling stage, it is advisable to clean the inner surfaces of the open ends of the capsule blanks to remove any adhered filling material to ensure the sealing of the ends of the capsule blanks without problems. The cleaning may be carried out on the inside of the mouth area of the capsule blank by using a scraping rotating mandrel or a corresponding brush. The ends of the capsule

blanks are sealed by using similar procedures as in con¬ nection with the sealing of the first ends of the capsule blanks described above. After the glue used in the seal¬ ing process has hardened, the capsule ends may be simi- larly finished by cutting parts away from their sealed portions.

After these stages the completed capsules are conveyed through as such known process stages, whereby the capsul- es are washed, dried, inspected, packaged and sterilized to ready-to-use products.

In the following, the invention will be described refer¬ ring to the annexed drawing where:

Fig. 1 shows a dosing and filling apparatus axonomet- rically;

Fig. 2 shows a magnified detail from the area of the feeding funnels.

The material batches dosed on the groove disc 21 are transferred to filling funnels 23 placed in a transverse row below the tail edge of the groove disc 21. Beneath these filling funnels, a row of capsule blanks 7 carried by a clamping claw cassettes 6 has been conveyed the lower ends of which capsules have been sealed and advan¬ tageously trimmed.

A filling device 24 comprises feeding devices, the number of which corresponds to the number of the filling funnels 23. Each feeding device comprises a rotating motor 25, a spindle 26, and a feeder screw 27 attached to the the lower end of the spindle. To operate the feeder screw 27 within the conditions determined by the small dimensions of the capsules to be filled, the filling screw is formed by a thin spiral spring. For better control of the move-

ments of the spiral spring, another thin straight guiding wire is placed inside the spring, extending substantially along the whole length of the spiral spring.

The feeder screw 27 formed by the spiral spring is direc¬ ted through each feeding funnel 23 to the capsule blank below it and is made to rotate. The rotative movement is naturally chosen in the feeding direction of the spiral spring. The feeder screw rotating in the capsule blank feeds the material fed into the feeder funnel efficiently into the capsule blank. In order to avoid unnecessary compacting of the material in the capsule blank, the feeder screw is raised as filling is advancing. After the dosed batch has been completely fed, the feeder screw is removed completely from the capsule blank and the blanks are transferred to be sealed. Before sealing it is pos¬ sible to clean the inside of their mouth areas to remove any remaining filling material. The sealing is carried out by glueing in the same way as sealing of the opposite end of the blanks before the filling stage.

After sealing, the ends of the filled capsules can be trimmed by cutting. After trimming, the completed capsu¬ les will be removed from their respective clamping claw cassettes after which operation they will be processed individually according to prior technology discussed briefly above.