Method and system for removing a liquid from a container for accommodating an ophthalmic lens

Abstract

A method of removing a liquid from a container (1) for accommodating an ophthalmic contact lens, in particular a soft contact lens, during transporting the container (1) from a liquid bath (13) to a subsequent processing station (14), the method including the steps of: transporting the container (1) from the liquid bath to the subsequent processing station, generating suction (20), and applying the suction (20) to a bottom (11) of the container (1) during the step of transporting the container (1) from the liquid bath to the subsequent processing station, thereby removing the liquid from the container (1).

Claims

1. A method of removing a liquid from a container (1) for accommodating an ophthalmic lens, during transporting the container (1) from a liquid bath (13) to a subsequent processing station (14), the method comprising the steps of: transporting the container containing the ophthalmic lens (1) from the liquid bath (13) to the subsequent processing station (14), generating suction (20), applying the suction (20) to a bottom (11) of the container (1) during the step of transporting the container (1) from the liquid bath to the subsequent processing station, thereby removing the liquid from the container, wherein the step of applying suction (20) comprises: providing an aspirator (2) comprising a suction cup (21) having a concave wall (22) with at least one suction orifice (24) arranged in the concave wall (22), applying the suction (20) through the at least one suction orifice (24) arranged in the concave wall (22) of the suction cup (21), and moving the suction cup (21) towards the bottom (11) of the container (1) with the concave wall (22) of the suction cup (21) facing the bottom (11) of the container (1).

2. The method according to claim 1, wherein the bottom (11) of the container (1) has a convex shape, and wherein the concave wall (22) of the suction cup (21) has a shape which corresponds to the convex shape of the bottom (11) of the container.

3. The method according to claim 1, wherein applying the suction (20) to the bottom (11) of the container (1) allows a leakage stream of the liquid from the container to flow between the bottom (11) of the container (1) and the concave wall (22) of the suction cup (21) towards the at least one suction orifice (24) in the concave wall (22) of the suction cup (21).

4. The method according to claim 1, wherein the suction cup (21) is moved towards the bottom (11) of the container (1) only to an extent that the suction cup (21) does not contact the bottom (11) of the container (1).

5. The method according to claim 1, wherein the suction (20) is applied to the bottom (11) of the container (1) during a time period in a range of 0.5 seconds to 2 seconds.

6. The method according to claim 1, wherein an air flow of the suction (20) is in a range of 2 m.sup.3 to 8 m.sup.3.

7. The method according to claim 1, wherein the suction (20) is in a range of up to 900 hPa.

8. The method according to claim 1, wherein transporting the container (1) from the liquid bath (21) to the subsequent processing station is accomplished intermittently, and wherein suction is applied to the bottom (11) of the container (1) while the container (1) is intermitted.

9. The method according to claim 3, wherein the suction (20) is applied to the bottom (11) of the container (1) during a time period in a range of 0.5 seconds to 2 seconds.

10. The method according to claim 3, wherein transporting the container (1) from the liquid bath (21) to the subsequent processing station is accomplished intermittently, and wherein suction is applied to the bottom (11) of the container (1) while the container (1) is intermitted.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous aspects of the invention become apparent from the following description of embodiments of the invention with the aid of the drawings, in which:

(2) FIG. 1 is a cross-sectional perspective view of some essential components of an embodiment of the system according to the invention;

(3) FIG. 2 is a cross-sectional view of some details of the system of FIG. 1;

(4) FIG. 3 is a detailed view of an arrangement of aspirators and suction cups in a position spaced apart from one another (before or after liquid removal);

(5) FIG. 4 is a detailed view of the arrangement of aspirators and suction cups of FIG. 3 in the operating position (during liquid removal);

(6) FIG. 5 is an enlarged cross-sectional side view of the aspirator with the suction cup in the spaced-apart position; and

(7) FIG. 6 is an enlarged cross-sectional side view of the aspirator of FIG. 5 with the suction cup in the operating position.

DETAILED DESCRIPTION OF EMBODIMENTS

(8) As used in this specification, the term liquid or treatment liquid comprises any type of liquid to which the ophthalmic lens, in particular a contact lens such as a soft contact lens, may be exposed during a contact lens manufacturing process, and include in particular liquids influencing the physical or chemical properties of the lens. Without being exhaustive, such treatment liquids may comprise extraction liquids, rinsing liquids, coating liquids or any other type of liquid and in particular also may comprise water.

(9) FIG. 1 shows in cross-sectional perspective view some essential components of a system according to one embodiment of the invention. As can be seen from FIG. 1, the system comprises a plurality of containers 1 each for accommodating a contact lens (not shown). The container 1 enables a flow of a treatment liquid into and out of the container 1, and a plurality of transport carriers 12 holding the containers 1 during conveyance through liquid baths 13, 14 (indicated by respective arrows) and during transfer from one liquid bath 13 (the preceding liquid bath) to another liquid bath 14 (the subsequent liquid bath), with the direction of transport generally being from left to right in the embodiment shown in FIG. 1. The contact lenses (not shown) are individually accommodated in the tube-like containers 1 which are held side-by-side in the respective transport carriers 12 (see also FIG. 2). The transport carriers 12 are conveyed along a travel path through the liquid baths 13, 14 by a conveyor 3 including a conveyor chain. For transferring the transport carriers 12 from the preceding liquid bath 13 to the subsequent liquid bath 14, the transport carriers 12 are lifted out of liquid bath 13 by conveyor 3 as shown in FIG. 1, are transported horizontally, and are then lowered again so that the containers 1 carried by the respective carrier 12 are immersed in the liquid of liquid bath 14 through which the carriers 12 are then transported. That portion of the respective container 1 (including at least a bottom 11 of the container 1) in which the contact lens is accommodated is completely immersed in the treatment liquid so that the contact lenses are exposed to the treatment liquid during the travel of the containers 1 through the respective liquid bath. Of course, instead of transporting the containers 1 from the preceding liquid bath 13 to the subsequent liquid bath 14, the containers could also be transported to a subsequent processing station other than a liquid bath. Thus, it is evident that the subsequent liquid bath 14 is one embodiment of a subsequent processing station.

(10) The embodiment of the system shown in FIG. 1 further comprises a plurality of aspirators 2 (one for each individual container 1) having a suction cup 21 connected to a vacuum supply line 23 for applying suction 20 (see FIG. 6) to the bottom 11 of the container 1. Suction cup 21 may be formed by a solid, noncorrosive material like stainless steel or an adequate synthetic material. Also, the system comprises a positioner 4 (see again FIG. 1) for moving the respective suction cup 21 towards the bottom 11 of the respective container 1 such that the bottom 11 of the container 1 can be exposed to the suction 20 applied through the suction cup 21 during operation (see FIG. 4), however, the respective suction cup 21 is moved towards the respective container 1 only to an extent such that the suction cup 21 does not come into mechanical contact with the bottom 11 of the container 1.

(11) As discussed already further above, during transfer from the preceding liquid bath 13 to the subsequent liquid bath 14, a carry-over of liquid from the preceding liquid bath 13 to the subsequent liquid bath 14 may result either in a change in concentration of the liquid of the subsequent liquid bath 14 (in case the subsequent liquid bath 14 is of the same kind), or may result in contamination of the liquid of the subsequent liquid bath 14 (in case the subsequent bath is of a different kind). In case of transportation of the containers 1 to a processing station other than a subsequent liquid bath 14, the liquid carried over from the liquid bath 13 may get spilled in the manufacturing line which is also unwanted.

(12) To avoid such carry-over or spillage of liquid during the transport of the transport carrier 12 and the respective containers 1 from the preceding liquid bath 13 to the subsequent liquid bath 14 (or other processing station), the transport carrier 12 with the containers 1 is first arranged in a position relative to the aspirator 2 as is shown in FIG. 2 and FIG. 3, so that the bottom 11 of each individual container 1 is arranged above a corresponding suction cup 21 of the respective aspirator 2. The suction cup 21 of the respective aspirator 2 is then lifted towards the bottom 11 of the respective container 1 into a position which is shown in FIG. 4,

(13) As can be seen in FIG. 3 and FIG. 4, the aspirator 2 comprises a suction cup 21 having a central suction orifice 24 in the center of a concave wall 22 of the suction cup 21 allowing to apply suction to the convex bottom 11 of the container 1. The concave wall 22 of the suction cup 21 has a shape which corresponds to the convex shape of the bottom 11 of the container 1, so that the convexly shaped bottom 11 of the container 1 is accommodated in a cavity bounded by the concave wall 22 of the suction cup 21.

(14) The positioner 4 comprises an actuator for linearly moving the suction cup 21 from a retracted position (FIG. 3) towards the bottom 11 of the container 1 until reaching a suction position (FIG. 4). This movement may be performed with the aid of a pneumatic linear drive, which is comprised by the positioner 4 shown in FIG. 1. This upward movement of the suction cup 21 is also indicated by the arrow shown in FIG. 5.

(15) Once the suction cup 21 has been moved into the suction position, the concave wall 22 of the suction cup 21 is arranged in the closed vicinity of the convex bottom 11 of the container 1 but does not contact the bottom 11 of the container 1. Rather, there is a small gap between the concave wall 22 of the suction cup 21 and the convexly shaped bottom 11 of the container 1 in order to allow for air to flow through that small gap formed between the concave wall 22 of the suction cup 21 and the convexly shaped bottom 11 of the container 1.

(16) The small gap allows for a leakage stream of air to enter between the concave wall 22 of the suction cup 21 and the convex bottom 11 of the container 1. This leakage stream flows towards the central suction orifice 24 in the concave wall 22 of the suction cup 21 and helps to transport liquid remaining on the surface of the bottom 11 of the container 1 and on the contact lens away through the vacuum supply line 23 through which the suction 20 is applied. However, the leakage stream and the suction applied are such that the remaining liquid is efficiently removed without affecting the contact lens accommodated in the container 1.

(17) In operation, the conveyor 3 conveys the transport carrier 12 from the preceding liquid bath 13 to the subsequent liquid bath 14 (see FIG. 1). For that purpose, the transport carrier 12 with the containers 1 is lifted out of the first liquid bath 13 and is conveyed to position above the aspirators 2. Once the transport carrier 12 has reached the position above the aspirators 2 (see FIG. 2 and FIG. 3), the transport of the carrier 12 is intermitted (stopped), and the suction cups 21 are moved vertically towards the bottom 11 of the container 1 (see FIG. 5) into the suction position, however, without contacting the bottom 11 of the container 1 (see FIG. 4). Suction 20 is applied with the aid of a vacuum supply line 23 through the suction orifice 24 arranged in the concave wall 22 of the suction cup 21, as this is shown in FIG. 6. Through the application of suction 20, an air stream air is drawn through the small gap formed between the concave wall 22 of the suction cup 21 and the convexly shaped bottom 11 of the container 1 into the suction orifice 24.

(18) By way of example only, the suction 20 may be applied to the bottom 11 of the container 1 through the suction orifice 24 in the concave wall 22 of the suction cup 21 during a time period in the range of 0.5 seconds to 2 seconds, at an air flow in the range of 2 m.sup.3 to 8 m.sup.3, and at a suction (underpressure) in the range of up to 900 hPa (corresponding to 900 millibars), in particular in the range of 350 hPa to 750 hPa (corresponding to 350 millibars to 750 millibars).

(19) Once removal of the liquid has been completed, the suction cups 21 are lowered again, and movement of the transport carrier 12 with the containers 1 accommodating the contact lenses towards and into the subsequent liquid bath 14 is resumed. Through the afore-described removal of the liquid, any liquid adhering to the bottom 11 of the container or to the contact lenses is reliably drawn in through the suction orifice 24 together with the air stream, so that there is no liquid anymore that can be carried-over to the subsequent bath 14 or that can be spilled.

(20) It has already been mentioned above, that in the treatment process for contact lenses a major contamination may arise during the conveyance of the container accommodating the contact lens between two liquid baths of different kinds. Therefore, it is advantageous to provide for a liquid removal in accordance with the invention between a water bath and a liquid bath containing an extraction liquid, or between a liquid bath containing a coating liquid and the subsequent rinsing bath, or even at the end of the liquid treatment of the contact lenses before the contact lenses are transported to the next processing station, for example to an inspection station.

(21) The invention has been described with a reference to the particular embodiments shown in FIG. 1 to FIG. 6. However, for the skilled person it is evident that many changes and modifications can be made without departing from the general concept underlying the invention. Therefore, the scope of protection is not intended to be limited to the embodiments described but rather is defined by the appended claims.