METHOD FOR FREEZING A LIQUID

Abstract

In a method for freezing a liquid located in a container, in particular a liquid drug, the container is exposed to a cold gas in order to freeze the liquid. The cold gas preferably flows around the container, and/or is cooled in another way in order to freeze the liquid. The container is insulated at a surface of at least one first volume portion of the container, and the container is cooled nearly immediately at a surface of a second volume portion of the container by the cold gas such that the liquid freezes through later in the at least one first volume portion than in the second volume portion.

Claims

1. A method of freezing a liquid disposed in a container, in particular a liquid drug, wherein the container for freezing the liquid is exposed to a cold gas, preferably having the cold gas flowing around same, and/or is cooled in another way for freezing the liquid, the container is insulated at a surface of at least a first volume portion of the container, and the container is cooled substantially directly by the cold gas and/or the other way at a surface of a second volume portion of the container, so that the liquid freezes therethrough in the at least one first volume portion later than in the second volume portion.

2. The method according to claim 1, wherein the second volume portion is a centre of the container and the at least one first volume portion extends from the centre of the container to the edges of the container.

3. The method according to claim 1, wherein a substantially cuboidal container is used, wherein a height of the container is preferably less than a quarter of a width and/or a length of the container.

4. The method according to claim 1, wherein at least one insulation body is used for insulating the surface of the at least one first volume portion.

5. The method according to claim 4, wherein an insulation body of substantially U-shaped cross-section is used.

6. The method according to claim 3, wherein the at least one insulation body is fitted laterally on to the cuboidal container.

7. The method according to claim 1, wherein an arrangement of a flexible inner container holding the liquid and a substantially rigid outer container is used as the container.

8. The method according to claim 7, wherein a foampreferably an elastic foamis used between the inner container and the outer container, by means of which foam an expansion in the volume of the liquid upon freezing is at least partiallypreferably completelycompensated.

9. The method according to claim 8, wherein a foam is used, that has a decreasing elasticity with decreasing temperature below the freezing point.

10. The method according to claim 8, wherein a foam is used, which substantially hardens at a temperature between 0 C. to 30 C., preferably between 5 C. and 25 C. and particularly preferably between 10 C. and 20 C.

11. The method according to claim 8, wherein a foam is used, the process of hardening being reversible.

12. The method according to claim 8, wherein the outer container is lined with the foam in such a way that the inner containerpreferably together with any attachmentsis completely surrounded by the foam when the inner container is arranged in the outer container.

13. The method according to claim 12, wherein a foam block for receiving the attachments is provided in the outer container.

14. The method according to claim 8, wherein at least one additional layer of foam is arranged in the outer container when the inner container is filled only to a part of the its capacity.

15. The method according to claim 1, wherein a container is used, wherein a top side and/or an underside of the container is/are respectively formed by a metal plate.

16. A method of freezing liquids disposed in a plurality of containers, in particular liquid drugs, wherein the liquids disposed in the containers are frozen at the same timepreferably arranged in mutually superposed relationship in a freezing apparatusin the method according to claim 1.

17. An arrangement comprising a container filled with a liquid, in particular a liquid drug, and at least one insulation body arranged at a surface at least of a first volume portion of the container, in particular for carrying out the method according to claim 1, wherein a surface of a second volume portion of the container is insulation-free.

18. A freezing apparatus comprising one or more arrangements according to claim 17, which are arranged within the freezing apparatuspreferably in mutually superposed relationshipwherein the freezing apparatus is adapted to freeze the liquid within the container or the liquids in the containers by means of cold gas and/or other means.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0037] Further details and advantages of the invention will be apparent from the Figures and the related specific description. In the Figures:

[0038] FIGS. 1a to 1c show steps in a method of freezing a liquid according to the state of the art,

[0039] FIGS. 2a to 2d show steps in a method according to the invention of freezing a liquid,

[0040] FIGS. 3a and 3b show diagrammatic views of an arrangement according to the invention, FIG. 4 shows a diagrammatic view of an arrangement according to the invention with a plurality of containers,

[0041] FIG. 5a shows a further but more detailed view of an arrangement according to the invention,

[0042] FIGS. 5b and 5c show views of an arrangement comprising an inner container and an outer container using a foam,

[0043] FIGS. 6a and 6b show views of an arrangement according to the invention with a plurality of mutually superposed containers, and

[0044] FIGS. 7a and 7b show photographs of the arrangement according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0045] FIGS. 1a to 1c show a method according to the state of the art of freezing a liquid, in particular a drug. At the beginning the liquid 3 is arranged in the container 2. Cooling from the exterior causes a partial volume 13 of the liquid 3 to freeze, more specifically in such a way that the partial volume 13 encloses the volume of the liquid 3 which is still liquid, as is shown in FIG. 1b (therefore from edge layers). As that process progresses the expansion in volume upon freezing of the part of the liquid, that is not yet frozen, leads to relatively great stresses in the partial volume 13 which is already frozen. Those stresses are firstly transmitted to the container 2 and secondly can result in rupture of the frozen partial volume 13. The invention seeks to avoid that effect which is shown in FIG. 1c.

[0046] FIGS. 2a to 2d show an embodiment according to the invention.

[0047] The arrangement 1 which is shown in FIGS. 2a to 2d is expanded in relation to the state of the art by the two U-shaped insulation bodies 4, those insulation bodies 4 being fitted over edge regions of the cuboidal container 2. As can be seen from FIG. 2b the insulation bodies prevent that partial volume 13 of the liquid 3, which freezes first, enclosing that partial volume of the liquid 3, which is not yet frozen. Rather, two freezing fronts meet from the upper and lower central region. Admittedly here too the increase in volume upon freezing of the liquid 3 takes place. In this case however that is no problem as the additional volume can be pushed out to the side. In other words, there is no enclosed region of liquid 3 which has not yet frozen, which could exert greater stresses on the partial volume 3 which has already frozen.

[0048] It can also be clearly seen from FIG. 2b that a relatively shallow cuboidal container can be advantageous because in that way the non-insulated region can freeze therethrough, before the further regions freeze to significant proportions.

[0049] FIG. 2c shows further freezing of the liquid 3 after the freezing fronts of FIG. 2b have met and further freezing throughout the liquid slowly takes place to the sides. Here too there are no enclosed regions of unfrozen liquid 3.

[0050] FIG. 2c also shows a foam 8 which has a compensation function for the normal expansion in volume of the liquid 3 upon freezing.

[0051] That will be clear in comparison with FIG. 2d, FIG. 2d showing the state of the arrangement 1, in which the liquid has completely frozen through, that is to say the frozen-through partial volume 13 almost completely fills out the container 2. The foam 8 has reduced its volume for compensation and can only still be seen in the corners of the view in FIG. 2d.

[0052] It will be clear from the comparison of FIGS. 1a to 1c on the one hand and FIGS. 2a to 2d on the other hand how an insulation, in particular insulation bodies 4, can prevent damage due to the expansion in volume of the liquid upon freezing.

[0053] FIGS. 3a and 3b show diagrammatic views of the arrangement 1 according to the invention. That would again be FIG. 3a showing a side view. Besides the container 2 it is also possible to see the two U-shaped insulation bodies 4.

[0054] FIG. 3b shows a plan view of the same structure.

[0055] FIG. 4 shows an arrangement 10 comprising a plurality of mutually superposed containers 2 which are respectively provided with insulation bodies 4. In this case the insulation bodies 4 are of such a configuration that they respectively accommodate a plurality of the containers 2. The containers 2 can thus for example also be really easily transported. Naturally they can also be arranged completely as an arrangement 10 in a freezing apparatus 7 and frozen in a single freezing process.

[0056] FIG. 5a shows a more detailed sectional view of the arrangement 1, wherein the container 2 is made up of an inner container 5 and an outer container 6. That inner structure of the container 2 can also be used in the other illustrated embodiments. The flexible inner container 5 holds the liquid 3 and the outer container 6 is mechanically stable. In addition there is a certain excess volume between the inner container 5 and the outer container 6, that can also be filled with a foam 8.

[0057] FIGS. 5b and 5c show an example of an arrangement of a rigid outer container 6 and a flexible inner container 5 (single use bag) using a foam 8. The foam 8 compensates for the expansion in volume of the liquid 3 upon freezing. In addition the foam 8 can be of such a nature that it also sets at low temperatures so that after freezing the inner container 5 is enclosed in a close fit in the foam 8 and in the outer container 6.

[0058] The foam 8 includes a foam block 9, by means of which attachments 12 like tubes and connecting elements can also be enclosed. The foam block 9 naturally also serves to compensate for the expansion in volume upon freezing of the liquid 3.

[0059] The outer container 6 can comprise plastic and/or metal. In the present embodiment the cover layers are respectively made from (relatively thin) stainless steel and the side walls from a polyethylene.

[0060] For example so-called visco-elastic foam 8 can be used as the foam 8, which hardens at certain negative temperatures.

[0061] FIGS. 6a and 6b are a perspective and a sectional view of an arrangement 10 according to the invention with a plurality of containers 2 arranged in mutually superposed relationship. FIG. 6b also indicates how the containers 2 also have an internal structure comprising an inner container 5 and an outer container 6. (Not all containers 2 are denoted by reference numerals in order not to make the views less clear).

[0062] To illustrate the real aspects FIGS. 7a and 7b show photographs. FIG. 7a shows an arrangement according to the invention in a freezing apparatus 7 after it was cooled to 85 Celsius. It can be clearly seen that the container 2 has not experienced any outward buckling, therefore it can be assumed that a desired freezing of the liquid therethrough has occurred, that is to say the liquid 3 was frozen without damage (to the surrounding items of equipment).

[0063] FIG. 7b shows how the inner container 5 looks after it has been removed from the outer container 6 in the frozen state. It can also be seen here that there are no major deformations.