Backqround Art When sealing receptacles which contain pharmaceuti- cals, for instance test tubes, it is important that the sealing object does not pollute the contents of the test tube. Such objects, for example rubber stoppers or alu- minium caps, are therefore thoroughly washed and steril- ised before use. The cleanness has to be maintained also when packing the objects, which demands specific proper- ties of the packing devices.

When small objects are to be dosed in packages, they are usually made to flow from a receptacle of some kind into the package through a duct which is provided with a valve, which can be opened and closed to regulate the flow of objects.

A risk in this method is that easily deformed ob- jects will be compressed and thus damaged during the dos- age. This is especially the case with the type of thin aluminium caps which is used for the sealing of tubes containing medicine for, for instance, injection into the body. If the cap is deformed, it does no longer fit on the test tube and has to be discarded. Thus, such caps are dosed and packed manually, which is time-consuming

and difficult since the presence of particles is not al- lowed in the handling operation.

SummarY of the Invention An object of the present invention is to provide a dosage device, which is designed for a sterile environ- ment in which there is no risk of easily deformed prod- ucts being damaged during the dosage.

This object is achieved by means of a device for dosing of objects in a sterile environment, comprising a duct through which a flow of the objects is intended to pass, the through-flow area of the duct being variable for controlling the flow at a regulating location along the duct. The device is characterised in that at least one means is movably arranged at the regulating location in order to provide, by moving relative to the walls of the duct, a variable stopping element in the duct, the stopping element causing an arch formation of objects up- stream of the regulating location, thus preventing damage to the objects during the dosage.

The means is movably arranged in the duct so that the through-flow area of the duct can be varied. When the means is positioned in the duct, it constitutes a stop- ping element for the flow of objects, allowing the ob- jects to form an arch formation upstream of the stopping element. Thanks to this arch formation, the distribution of the pressure on the objects is such that not even eas- ily deformed objects are compressed or damaged.

The obtained stopping element in the duct at the regulating location is variable between a fully open po- sition, at least one partially stopping position and a completely stopping position. The flow of objects can thus be regulated between a free flow, a partially stopped flow, and substantially no flow at all through the duct. In a partially stopping position, an arch for- mation of the objects arises above the stopping element and covers a part of the cross-sectional area of the

duct. In a completely stopping position, the arch forma- tion covers the whole cross-sectional area of the duct, so that no objects can pass.

Advantageously, the stopping element consists of at least two members arranged at a predetermined distance from each other at the regulating location, the distance being adapted in such a manner that the stopping element causes an arch formation of the objects.

The members preferably consist of elongated means which form a grating. Such a grating can take several partially stopping positions and, thus, provides a good possibility of regulating the flow of objects. Besides, the grating is advantageous for arch formation.

Preferably, each member is extendable and retract- able through an opening in the wall of the duct at the regulating location. This facilitates cleaning of the de vice since there are no movable parts for displacing the member in the duct.

A sealing element is conveniently arranged between the opening and the member. It seals so that the risk of foreign particles penetrating into the duct through the opening is eliminated.

In order to facilitate the arch formation each mem- ber conveniently has such an exterior design that an ob- ject which hits the member easily falls off. The member is preferably rounded in cross-section.

Brief Description of the Drawincts Fig. 1 is a schematic view of an embodiment of a de vice according to the invention.

Fig. 2 is a cross-sectional view of a part of the device in Fig. 1 along the line II-II.

Fig. 3 is a view of a detail of Fig. 2 on a larger scale.

Description of Preferred Embodiments Fig. 1 shows an embodiment of a dosage device ac- cording to the invention. A receptacle 1 containing ob- jects, which are to be packed in predetermined amounts of dosage, is supported by a hoisting device 2. In this case, the objects are sterilised in said receptacle 1, which by means of the hoisting device 2 has been trans- ferred from a sterilising device to the dosage device ac- cording to the invention.

The dosage device comprises a vertically arranged duct 3 through which the objects are intended to pass.

The upper end portion of the duct 3 is designed to con- stitute a contact means 4 against the opening 5 of the receptacle 1, the opening being arranged in abutment against the end portion. Along the duct 3, there is a regulating location 6, where the through-flow area of the duct 3 is variable for controlling the flow of objects from the receptacle 1. The duct 3 then tapers off to dis- charge the objects.

At the regulating location 6, a plurality of members 10 (see Fig. 2) are movably arranged. Each member 10 is connected with a displacing means 11 for displacing the member 10 in relation to the walls of the duct 3.

Furthermore, a valve 7 is arranged downstream of the regulating location 6 to enable a complete sealing of the duct 3.

A package 16, in this case a bag, in which the ob- jects are to be dosed in a predetermined amount, is ar- ranged at the outlet end of the duct 3. A measuring means 9, in this case a weighing machine, for reading the amount of objects which so far has been dosed in the package 16 is located downstream of the duct 3, seen in the direction of flow of the objects, and is connected to a control unit 8. The control unit 8 controls the dis- placing means 11 and, thus, the movement of each one of the members 10. The measuring signal from the measuring

means 9 thus provides the control unit 8 with a feed-back coupling for the regulation of the flow of objects.

Fig. 2 is a cross-sectional view of the duct 3 at the regulating location 6. The movable members here con- sist of piston rods 10, and the displacing means consist of corresponding piston-cylinder assemblies 11. The pis- ton rods 10 are extensible and retractable through open- ings 12 in the wall of the duct 3.

The cross-section of the duct 3 is in this case rec- tangular at the regulating location 6 and tapers off in a circular shape downstream thereof. The rectangular shape facilitates the arrangement of the piston-cylinder assem- blies 11. Four piston-cylinder assemblies 11 are arranged in parallel at the one side of the duct 3, and five at the opposite side of the duct 3. The piston-cylinder as- semblies 11 are alternatingly equidistantly spaced from one another, so that the piston rods 10, when extended, form a grating in the duct 3. The grating constitutes a stopping element for objects in the duct 3, which causes an arch formation of objects upstream of the regulating location 6. The stopping element is variable between a completely open position, a completely stopping position, and several partially stopping positions. The free ends of the piston rods 10 are round, thus preventing them from damaging fragile objects.

Fig. 2 shows a partially stopping position where the three middle piston rods 10 are retracted, and the others are extended. The extended members 10 form a grating over parts of the cross-section of the duct 3, at two sides of the same. The grating constitutes a stopping element, which stops the flow by causing an arch formation at the two sides of the duct 3, and only a small flow is allowed to pass in the middle of the duct 3. In another partially stopping position, for example, only the middle piston rod 10 is retracted. In a completely stopping position, all the piston rods 10 are extended, and the grating then covers the entire cross-section of the duct 3.

The distance between the piston rods 10 is such that the smallest imaginable object to be dosed can pass through the grating. When a flow of objects hits the grating, an arch will, however, form, and the flow will be stopped. The distance between the piston rods 10, as well as the diameter of the piston rods 10, is therefore adapted to the size of the objects to be dosed.

At each opening 12, a seal 13 between the opening 12 and the piston rod 10 is arranged (see Fig. 3). The seal 13 here consists of an O-ring supported by a holder 14, which is arranged at the opening 12. The seal 13 is pref- erably made of an elastic material, which is resistant to strong detergents, such as ethanol, e. g. EPDM rubber.

When using the device in Fig. 1, the receptacle 1 is first transferred from the sterilisation device to the dosage device by means of the hoisting device 2. The opening of the receptacle 1 is fitted in the end portion of the duct 3 while filtered air is blown over the con- tact surfaces in order to prevent foreign particles from passing into the duct 3 as it opens. All the piston rods 10 of the dosage device are now completely extended, i. e. in a completely stopping position. For additional safety, also the valve 7 is closed. The safety stop 15 of the re- ceptacle 1 may thus be released, the objects flowing down to the regulating location 6 where they are stopped by the stopping element in the form of the grating of piston rods 10, and causing an arch formation. If a few stray objects should pass the grating, they will be prevented from passing through the duct by the downstream valve 7.

Subsequently, a package 16, such as a bag, is placed on the weighing machine 9 and the control unit 8 is set at the desired programme. The weighing machine 9 measures the amount of dosed objects downstream of the dosage lo- cation and emits a measuring signal to the control unit 8. The control unit 8 regulates the piston-cylinder as- semblies 11, and thus, the movements of the piston rods 10 in relation to the so far dosed amount in the package

by means of the input signal from the measuring device 9 and pre-programmed parameters. The parameters are deter- mined depending on the required dosage amount, the re- quired flow rate, and the size and shape of the objects to be dosed.

The dosage is started by opening the valve 7. A pre- determined number of piston rods 10 are then retracted so that the desired flow of objects is achieved. The weigh- ing machine 9 continuously detects the dosed amount, i. e. the amount of objects in the bag 16. When the desired weight corrected in consideration of a certain after- flowing effect has been measured, the control unit con- trols all the piston rods 10 so that they are extended to their completely stopping position, and the flow of ob- jects is discontinued. The after-flowing effect which is taken into consideration mainly depends on the amount of objects which is positioned downstream of the regulating location 6, but which has not yet fallen into the bag 16 when the regulation occurs. The valve 7 is closed, the package 16 is removed and is replaced by a new one, and the method is repeated until the receptacle 1 is empty.

In connection with the dosage of fragile objects, for instance aluminium caps, it is important that arch formation takes place adjacent to the stopping element.

It goes without saying that the device may also be used for larger objects.

Many embodiments are possible within the scope of the invention. For instance, the construction can be sim- plified by several members 10 being connected to the same displacing means 11. The exterior design of the members 10, as well as their position in the duct 3, may be var- ied. For example, the members 10 may be arranged at dif- ferent levels along the duct 3 in the direction of flow of the objects. The cross-section of the members 10 may instead of being circular be, for instance, oval or roundedly triangular. The cross-section of the duct 3 at

the regulating location 6 may, for example, be circular instead of rectangular.

The device according to the invention is suitable for dosing of objects for medical aims, but also for other articles where good cleanness is desirable, for in- stance, within the electronics industry.