WO2011051740A2

WO2011051740A2 - Low-pressure dispensing apparatus for liquids and method for sterile dispensing of liquids at low pressure

Info

Publication number: WO2011051740A2
Application number: PCT/HU2010/000113
Authority: WO
Inventors: István LINDMAYER S.
Original assignee: Lindmayer S Istvan
Priority date: 2009-10-30
Filing date: 2010-10-26
Publication date: 2011-05-05
Also published as: HUP0900683A2; WO2011051740A3; EP2493808A2; HU0900683D0

Abstract

The present invention relates to an apparatus for a sterile dispensing of liquids at low pressure. The apparatus comprises a liquid container (2) having a substantially rigid wall and an upper filling aperture, the liquid container further comprising a liquid space (15) having a predetermined volume and a gas space (16) having a predetermined volume; a deformable gas container (21) arranged externally to the liquid container (2); a container closure unit (1 ) sealingly coupled to said upper filling aperture of the liquid container (2) and said external gas container (21), said a container closure unit comprising a first means for dispensing the liquid from the liquid container (2), and a second means for establishing a fluid communication between the gas space (16) of the liquid container (2) and the external gas container (21), said second means comprising a two-position valve assembly (7) allowing the gas, in a first position, to flow from the gas container (21) into the liquid container (2), and in a second position, to flow from the liquid container (2) into the gas container (21); and an operating unit (25) removably coupled to said container closure unit (1), said operating unit comprising operating members for operating said first and second means of the container closure unit (1) from outside.

Description

Low-pressure dispensing apparatus for liquids and method for sterile dispensing of liquids at low pressure

The present invention relates to an apparatus and a method for a sterile dispensing of liquids at low pressure.

Carbonated or still, non-alcoholic or alcoholic drinks and beverages are sold in glass or plastic bottles. The dispensing aperture of these bottles is closed by an unthreaded plastic cap or a pressed-on metal cap. At removing the cap, the ambient gases, for example oxygen and nitrogen, immediately ingress into the bottle through the dispensing aperture and thus oxidation and deterioration of the liquid in the bottle will start. This is particularly characteristic to bio-products that are bottled under aseptic conditions without the addition of any preservative.

One possible way to reduce quality loss is to add various preservatives to the beverages. Another common way of preserving quality, which is primarily used at dispensing carbonated liquids, is that the bottle is provided with an appropriate dispensing head that prevents the ambient air, e.g. oxygen, from entering into the bottle, thus the shelf-life of the liquid stored in the bottle is long enough and the liquid can be dispensed without oxidation.

Such a dispensing head device is disclosed in the international patent applications WO 2004/092033 A3 and WO 95/31398. The main drawback of these solutions is that the liquid in the bottle should be dispensed through a dip tube, which requires an overpressure of at least 6-7 bars. Such an overpressure, however, results in a high speed outflow and intensive turbulences in the dispensing head system that cause a significant loss of the carbon-dioxide content and thereby lead to excessive frothing, in particular in sugar-containing products, but also in other kinds of product, e.g. in beers, which substantially reduces the deliciousness of the drink. Thus a portion of the carbon-dioxide gas, which has been absorbed (saturated) in the liquid by an expensive technology, egresses (gets shaken out) from the liquid flowing out at a high speed, and only a significantly reduced portion of the carbon-dioxide gas remains in the dispensed liquid. The loss of carbon-dioxide content may, in many cases, reach an extent that makes consuming of the dispensed drink unenjoyable.

It is therefore an object of the present invention to provide a dispensing apparatus that can be manufactured with a reduced cost and can be used conveniently, that allows to dispense a liquid from the bottle without oxidation (in a sterile way) and at low pressure, i.e. at a pressure close to the ambient air pressure. Dispensing at low pressure is particularly advantageous for carbonated beverages as due to the low-rate outflow of the liquid, the extent of turbulences developing in the liquid under dispensing are reduced significantly, which results in a substantial reduction in the carbon-dioxide loss and frothing of the dispensed beverage.

It is another object of the invention to provide a liquid container or bottle with a container closure unit that can be mounted onto the upper dispensing aperture of a common beverage bottle by a conventional technology.

Yet another object of the invention is to provide a modular dispensing apparatus that is adapted for using any number of liquid containers successively.

The invention is based on the inventive idea that a gas space is to be provided inside the liquid container, e.g. in a beverage bottle, in which the gas is stored to permanently maintain a gas pressure substantially equal to the ambient air pressure within the gas space of the beverage container, even after opening said beverage container. The pressure prevailing in the gas space of the liquid container preferably always exceeds the ambient air pressure to a minimal extent so that a slight overpressure is maintained inside the beverage container to make the liquid dispensing easier.

Before opening the beverage container, the high-pressure gas that has been filled in to the beverage container at the bottling is removed into an external deformable (inflatable) gas container, the maximum volume of which is dimensioned so that the pressure of the gas filled into the liquid container can decrease to a pressure substantially equal to the ambient air pressure.

As a result, the space portion defined by the dispensed amount of the liquid will be occupied by the gas flowing back from the deformable gas container of the dispensing apparatus, while the volume of the deformable gas container decreases gradually, and thus the development of vacuum in the liquid container is prevented, which otherwise would cause the ambient air to flow in. Additionally, due to the relatively low gas pressure prevailing in the liquid container, the liquid flows out from the liquid container at a relatively low rate when being dispensed. Because of the low pressure maintained in the liquid container, the liquid may preferably be dispensed by free flow. The apparatus according to the invention is adapted not only for a sterile dispensing of carbonated liquids without quality loss at a low rate, but also for any other kind of non-carbonated, i.e. so-called still beverages, such as tea, milk, fruit juices, tomato juice, etc.

Although the liquid dispensing apparatus according to the invention is particularly suitable for dispensing beverages, in particular for carbonated beverages, its application is not limited to foods, and may also be utilized in the field of chemical industry or health care, or in other fields.

In a first aspect, the above objects are achieved by providing an apparatus for a sterile dispensing of liquids at low pressure, wherein the apparatus comprises

- a liquid container having a substantially rigid wall and an upper filling aperture, the liquid container further comprising a liquid space having a predetermined volume and a gas space having a predetermined volume,

- a deformable gas container arranged externally to the liquid container,

- a container closure unit sealingly coupled to said upper filling aperture of the liquid container and said external gas container, said a container closure unit comprising

- a first means for dispensing the liquid from the liquid container, and

- a second means for establishing a fluid communication between the gas space of the liquid container and the external gas container, said second means comprising a two-position valve assembly allowing the gas, in a first position, to flow from the gas container into the liquid container, and in a second position, to flow from the liquid container into the gas container; and

- an operating unit removably coupled to said container closure unit, said operating unit comprising operating members for operating said first and second means of the container closure unit from outside.

Preferably, the deformable gas container is an initially collapsed, inflatable bag.

The inflatable bag may have an elastic wall or a rigid wall. In the latter case, the inflatable bag is preferably provided with a weight externally exerting a pressure to the wall of the bag.

In a preferred embodiment of the dispensing apparatus according to the invention, said first means comprises a liquid discharging channel and an associated movable blocking member. The liquid discharging channel may be formed, for example, by a tube having an elastic wall, and in such a case, said movable blocking member is preferably formed by a restriction element adapted to restrict said tube.

It is particularly preferred that the operating unit comprises a multiple function operating lever that is adapted in a first position, to close the liquid discharging channel while keeping the two-position valve assembly in its first position; in a second position, to open the liquid discharging channel while keeping the two-position valve assembly in its first position; and in a third position, to closed the liquid discharging channel while keeping the two-position valve assembly in its second position.

Preferably, the operating unit and the external gas container are secured to a rigid supporting equipment.

The gas space of the liquid container preferably contains a protective gas, for example nitrogen. It is preferred that the initial pressure of the gas in the gas space is about 5 bars.

In a second aspect, the above objects are achieved by providing a method for the sterile dispensing of liquids at low rate, the method comprising the steps of

- filling a predetermined amount of liquid and a predetermined amount of high- pressure gas into a liquid container having a substantially rigid wall through an upper filling aperture of said liquid container,

- sealingly closing the upper filling aperture of the liquid container by a container closure unit,

- coupling an operating unit and a deformable external gas container to the container closure unit of said liquid container, wherein said gas container have a predetermined maximum volume,

- before the first opening of the liquid container, removing, by means of said operating unit, a portion of the high-pressure gas from the liquid container into said deformable gas container so that the gas space of the liquid container have a gas pressure substantially equal to the ambient air pressure, and

- by means of said operating unit, dispensing the liquid from the liquid container while allowing the gas to return from the deformable gas container into the liquid container so that the gas space of the liquid container permanently have a gas pressure substantially equal to the ambient air pressure.

Preferably, a protective gas, e.g. nitrogen, is filled into the liquid container. Preferably, the deformable gas container is initially maintained in a state with a minimum volume and upon the reduction of the pressure of initially high- pressure gas of the liquid container, the gas container is expanded to a state with said maximum volume.

The liquid is preferably dispensed from the liquid container by free flow. As further steps of the method according to the invention, when the liquid container has become empty, the liquid container may be removed from the operating unit and the external gas container, and a further unopened liquid container may be coupled to the operating unit and to the external gas container.

The liquid dispensing apparatus according to the invention has the advantage that into the place of the dispensed liquid, a cleaned, food quality, oxygen-free gas, normally nitrogen or carbon dioxide, flows back from the external gas container into the liquid container instead of the ambient, usually contaminated air that in case of foods, might cause deterioration of the food. Due to this backflow of the gas, a pressure substantially equal to the ambient pressure is permanently maintained in the liquid container. Thereby contamination and oxidation of the liquid is prevented, thus the quality of the liquid stored in the liquid container may be preserved within the period guaranteed by the manufacturer without opening the liquid container.

Another advantage of the invention is that due to the low pressure, i.e. a pressure substantially equal to the ambient pressure, the liquid can be dispensed from the liquid container at a low velocity and therefore frothing of the liquid, and in particular for carbonated beverages, the loss of carbon dioxide is reduced significantly, which, in case of drinks, makes consumption of the liquid much more enjoyable.

Yet another advantage of the invention is that the liquid discharging channel and the filling gas compensation passages are all formed within the container closure unit, which therefore may be mounted onto a conventional beverage bottle, providing even wider applicability of the invention.

The invention also has the advantage that it is of modular design, which allows to couple a new, unopened liquid container to the operating unit and to the external gas container after the used liquid container has become empty. Thereby the operating unit and the external gas container may be re-used several times.

The low-pressure dispensing apparatus according to the invention will now be described through its preferred embodiments with reference to the accompanying drawings, without limiting either the practical applicability or the scope of the invention to the preferred embodiments described hereinafter. In the drawings:

Figure 1 is an enlarged cross-sectional view of the upper end portion of the liquid container forming a part of the liquid dispensing apparatus according to the invention;

Figures 2a and 2b illustrate a universal inset of the container closure unit in a longitudinal cross-sectional view and in a top plan view, respectively;

Figure 3 is a side cross-sectional view of the bottle supporting equipment and its associated operating unit;

Figures 4a to 4c illustrate various embodiments of a rigid wall gas container in an elevation view, a side view and a perspective view, respectively;

Figure 5 is a perspective view of the liquid container and the bottle supporting equipment before inserting the liquid container into the bottle supporting equipment;

Figure 6 is an enlarged cross-sectional view of the upper part of an assembled liquid dispensing apparatus with its operating lever being in a gas releasing position;

Figure 7 illustrates the cross-sectional view of a whole assembled liquid dispensing apparatus with its operating lever being in the gas releasing position;

Figure 8 illustrates the upper part of an assembled liquid dispensing apparatus in an enlarged cross-sectional view with its operating lever being in a liquid dispensing position;

Figure 9 is a cross-sectional view of another preferred embodiment of the apparatus according to the invention; and

Figure 10 is a flow diagram illustrating the basic steps of the method according to the invention.

Figure 1 illustrates an enlarged cross-sectional view of the upper part of a liquid container forming a part of a first preferred embodiment of the liquid dispensing apparatus according to the invention. The liquid container 2, which is typically a beverage bottle, comprises an upper filling aperture adapted for filling the liquid to be stored and a technological gas into the container. The liquid container 2 has a liquid space 15 for receiving the liquid and a gas space 16. A container closure unit 1 is sealingly mounted onto the upper filling aperture of the liquid container 2. The container closure unit 1 and the upper filling aperture of the liquid container 2 may be coupled to each other by means of corresponding threaded portions, in which case the container closure unit 1 can be tightly screwed onto the top of the liquid container 2. As shown in Figure 1 , it is preferred that the container closure unit 1 is secured to the upper filling aperture of the liquid container 2 by snap fitting so that when the container closure unit 1 is pressed on the liquid container 2, a fixing shoulder 4 formed on the envelope 3 of the container closure unit 1 snaps underneath a fixing ring 5 formed on the liquid container 2.

Between the liquid container 2 and the container closure unit 1 , a tube 6 made of an elastic material and a universal inset 8 is arranged, said inset 8 comprising a two-position valve assembly 7. The inset 8 is adapted to release the gas from the gas space 16 of the liquid container 2 and also to allow the gas to flow back thereto.

In the initial state of the container closure unit 1 , the liquid dispensing outlet, which is preferably formed by the tube 6, may be closed or opened by means of a movable blocking member, for example a movable restriction element 9. The outer end 10 of the tube 6 is closed by said restriction element 9 in a way, for example, that it forces the end portion 10 against an upper flange of a closing rib 1 1. Upon displacement of the restriction element 9, the tube 6 becomes open and the liquid can be dispensed from the liquid container 2. On the upper surface 12 of the restriction element 9, a plurality of teeth 13 is formed to project therefrom, said teeth 13 allowing a displacement of the restriction element 9 by means of an external operating lever (which will be described later), thereby also allowing the tube 6 to be opened or closed, wherein said tube 6 forms the liquid dispensing channel of the liquid container 2. The teeth 13 are made inaccessible from outside by means of a tear-off cover member 14. Integrity of the cover member 14, which is typically made of a tear-off paper, plastic or metal foil, indicates the unopened state of the liquid container 2.

In Figures 2a and 2b, the universal inset 8 made of an elastic material can be seen in a longitudinal cross-sectional view and in a top plan view, respectively, said universal inset 8 comprising the tube 6 and the two-position valve assembly 7 as integrated parts. On the front surface 37 of the universal inset 8, two recesses 38 are formed, said recesses 38 being adapted to release a portion of the technological gas from the liquid container 2 into the environment upon an overpressure exceeding the allowed pressure range. It means that said recesses 38 serve as safety valves. The valve assembly 7 of the universal inset 8 comprises passages 31 through which a portion of the gas contained in the gas space 16 of the liquid container 2 flows into the external gas container (through an operating unit that will be described below), and the universal inset 8 further comprises a unidirectional plate valve 32 through which the gas can flow back from the external gas container into the liquid container 2 upon dispensing the liquid.

Figure 3 illustrates a side cross-sectional view of a supporting equipment 20, and an operating unit 18 and an external deformable gas container 23, both coupled to said supporting equipment 20, according to a preferred embodiment of the dispensing apparatus according to the invention. The supporting equipment 20 has a fixing tab 34 adapted to secure the supporting equipment 20 to a shelf or other sheet-like supporting surfaces during the use of the dispensing apparatus.

The deformable gas container 21 , which is made of a gas-tight material and has a predetermined maximum volume, is arranged inside the supporting equipment 20. Preferably, the gas container 21 has an elastic wall, that is after an initial filling and inflation thereof with the gas, it is capable of contracting by itself as the gas contained therein flows back into the gas space 16 of the liquid container 2 upon discharging the liquid container 2. The gas container 21 is connected to the liquid container through a gas conduit 22.

An alternative embodiment of the gas container 21 , the various views of which are illustrated in Figures 4a to 4c, comprises a rigid wall. In this case, the rigid wall gas container 21 may comprise a polyethylene bag 23, for example, into one half of which an appropriately dimensioned weight 24 is placed so that the necessary contraction of the gas container 21 can be achieved upon dispensing the liquid, and thereby a desired gas pressure (substantially equal to the ambient pressure) can be maintained in the gas space 16 of the liquid container 2.

In Figure 5, the liquid container 2 and an operating unit 25 integrated into the supporting equipment 20 are illustrated in a perspective view before inserting the liquid container into said supporting equipment 20. On the container closure unit 1 of the liquid container 2, the intact cover member 14 can be clearly seen, wherein said cover member 14 is to be removed from the container closer unit 1 immediately before insertion of the liquid container 2 into the supporting equipment 20. The operating unit 25 is firmly secured to the supporting equipment 20, said operating unit 25 having a multifunctional operating lever 27, in this example. The operating unit 25 is set into a highest position by means of fixing tabs 26, thereby providing the liquid container 2 and the container closure unit 1 arranged thereon with enough place.

Figure 6 illustrates an enlarged cross-sectional view of the upper part of an assembled liquid dispensing apparatus, wherein elements of the operating unit 25 are illustrated in detail. As shown in Figure 6, the operating lever 27 of the operating unit 25 is in a gas releasing position. The operating lever 27 is operatively coupled to a pushing arm 28 that exerts a force to a valve stem 29 at the release of the initially high-pressure gas from the gas space 16 of the liquid container 2. The lower end of the valve stem 29 leans on the upper surface of the valve assembly 7. In Figure 6, the valve assembly 7 can be seen in a second position, wherein it is slightly shifted towards the liquid container 2, whereby the high-pressure gas flows out from the gas space 16 through the passage 31 of the valve assembly 7 and passages 30c and 30b of the operating unit 25, and finally through a passage 30a of the supporting equipment 20 into the gas container 21. The plate valve 32 is designed so that it allows the gas to flow only in one direction, i.e. the gas can traverse this plate valve 32 only when the pressure in the gas container 21 is higher than the pressure prevailing in the gas space 16 of the liquid container 2.

Figure 7 illustrates the assembled liquid dispensing apparatus as a whole in a cross-sectional view, wherein the operating lever 27 is in its gas releasing position as shown in Figure 6, and the major portion of the gas of the gas space 16 has already flown into the gas container 21 , which is shown almost entirely expanded or inflated in Figure 7.

In Figure 8, an enlarged cross-sectional view of the upper part of the assembled liquid dispensing apparatus can be seen, wherein the operating lever 27 is in a liquid dispensing position. By pivoting the operating lever 27 in an opposite direction with respect to the liquid container 2, the restriction element 9 displaces in response to the rotation of a cog-wheel 36 engaged with the teeth 13 and thus co-rotating with the operating lever 27, whereby the tube 6 within the container closure unit 1 opens and thus allows to dispense the liquid contained in the liquid container 2. At dispensing of the liquid, the technological gas 19 can flow from the gas container 21 through the plate valve 32 into the evacuated space volume of the liquid container 2, thus no vacuum can develop in the liquid container 2.

Figure 9 shows and alternative embodiment of the dispensing apparatus according to the invention in a cross-sectional view, wherein instead of the operating lever used in the first embodiment, another operating lever 40 is rather applied that can be moved by a glass used for receiving the liquid, and thus the liquid can be dispensed even by one hand conveniently.

Operation of the liquid dispensing apparatus according to the invention is described below with reference to the flow diagram of Figure 10, as well as Figures 6 and 8 described above.

In step S100, a predetermined amount of liquid and a predetermined amount of high-pressure technological gas are filled into a substantially rigid wall liquid container 2 through its upper filling aperture. The gas, for example nitrogen or carbon-dioxide, is preferably filled into the liquid container 2 only after filling of the liquid (or in special case, before filling the liquid) by means of a well-known gas filling machine arranged along the production line.

Next, in step S102, within the shortest possible time (yet before the transition of the fluid or solid state gas 19 into a gaseous state would take place), the liquid container 2 is sealingly closed by the container closure unit 1. The added fluid or solid state gas 19 changes into a gaseous state within a short time (i.e. within a few seconds), thus the gas space 16 of the liquid container 2 becomes filled up with a high-pressure gas. At this stage, the pressure of the gas 19 is preferably about 4 to 5 bars.

At the first use of the liquid container 2, in step S 04, the liquid container 2 is coupled to the operating unit 25 and to the external gas container 21 , said gas container 21 having a predetermined maximum volume. Next, in step S106, the high pressure prevailing in the gas space 16 of the liquid container 2 is reduced to substantially the ambient pressures in a way that a (major) portion of the high- pressure gas 19 is removed from the gas space 16 into the deformable external gas container 21. Due to the appropriate design of the gas container 21 , a (low) gas pressure substantially equal to the ambient air pressure will develop in the gas space 19, and accordingly, in the gas container 21 as well.

As shown in Figure 5, in a preferred embodiment of the apparatus according to the invention, before the first use of the liquid container 2, the cover member 14 is removed from the container closure unit 1 and the liquid container 2 is inserted into the supporting equipment 20 so that the operating unit 25 gets into its highest position due to the fixing tabs 26, as mentioned above. Subsequently, when the liquid container 2 has already been put in place, the fixing tabs 26 are released and the operating unit 25 is pressed onto the container closure unit 1. Thereby a gas-tight connection is established between the gas space 16 of the liquid container 2 and the gas container 21 by pivoting the operating lever 27 towards the liquid container 2. Together with the operating lever 27, the push arm 28 also displaces, which pushes the valve stem 29 before itself, and thus said valve stem 29 opens the valve assembly 7, thereby providing a free path for the high-pressure gas 19 of the gas space 16, which then flows into the gas container 21 through the passages 31 , 30a, 30b and 30c. In response to the expansion of the gas container 21 , the pressure in the liquid container 2 decreases. After the reduction of the high gas pressure prevailing in the liquid container 2, the operating lever 27 is returned to its initial position, thereby the fluid communication between the passage 30c and the passage 31 of the valve assembly 7 is blocked, and therefore the low- pressure gas 19 of the gas container 21 will be able to flow only through the plate valve 32 in one direction, i.e. through the passages 30a and 30b into the liquid container.

After the above operations, liquid dispensing can be started, which is carried out in step S108 in a way that the supporting equipment 20 steadily holding the liquid container 2 is laid into a horizontal position. If needed, the supporting equipment 20 may be secured to a shelf of a refrigerator by means of a fixing tab 34 designed for this purpose. In this position, the liquid container 2 is tilted ahead and the liquid stored therein entered into the tube 6 of the container closure unit 1 , whereas the gas 19 occupied the highest space portion of the liquid container 2.

To dispense the liquid, the operating lever 27 is rotated in a direction opposite to the liquid container 2, thereby due to the rotation of the cog-wheel 36 engaged with the teeth 13, the restriction element 9 displaces and opens the tube 6, through which the liquid may be dispensed from the liquid container 2, preferably by free flow. Because of the low pressure prevailing in the liquid container 2, the liquid flows out at a low rate, which results in a minimum extent of frothing and in case of carbonated beverages, the loss of carbon-dioxide in the dispensed beverage reduces to a minimum level. During dispensing of the liquid, the gas flowing back from the gas container 21 into the liquid container 2 can enter into the gas space 16 through the liquid. Due to a pressure compensation between the gas container 21 and the gas space 16, the gas container 21 gradually collapses while the liquid is being dispensed. It is preferred for the apparatus according to the invention that the pressure prevailing in the gas space 16, which is substantially equal to the ambient pressure, exceeds the ambient pressure to a minimum extent, which guarantees that no ambient air enters into the gas space 16 through the liquid that is flowing out from the liquid container 2.

Although in the foregoing, dispensing of the liquid by free flow has been mentioned as a preferred way of dispensing the liquid, it is obvious for a skilled person that the liquid may be dispensed from the liquid container 2 in many other ways as well, for example by using a suitable pump.

Due to the unidirectional plate valve 32 and the substantially ambient pressure prevailing in the gas space 16, at dispensing of the liquid, no ambient air can enter into the liquid container 2 until it becomes entirely empty. When the liquid container 2 gets entirely empty, the pressure of the gas container 21 is compensated by the ambient air pressure through the plate valve 32 and although at this time, some ambient air could enter into the empty liquid container 2, the unidirectional plate valve 32 still prevents the ambient air from entering into the gas container 21 . After the liquid container 2 has become empty, it can be removed from the operation unit 25 and the external gas container 21 , and another unopened liquid container 2 can be coupled to the operating unit 21 and the external gas container 21. Since the initially flat gas container 21 , which contains only a minimum amount of technological gas after the first use, never gets into contact with the external environment, the liquid can be dispensed from the next liquid containers 2 also in a sterile way.

In the present specification the liquid dispensing apparatus and method according to the invention was described through particular preferred embodiments. It is obvious for a person skilled in the art that the apparatus and the method according to the invention have many modifications within the scope of the invention as defined by the claims.

Claims

1 . An apparatus for a sterile dispensing of liquids at low pressure, wherein the apparatus comprises

- a liquid container (2) having a substantially rigid wall and an upper filling aperture, the liquid container further comprising a liquid space (15) having a predetermined volume and a gas space (16) having a predetermined volume,

- a deformable gas container (21) arranged externally to the liquid container (2),

- a container closure unit (1 ) sealingly coupled to said upper filling aperture of the liquid container (2) and said external gas container (21), said container closure unit comprising

- a first means for dispensing the liquid from the liquid container (2), and

- a second means for establishing a fluid communication between the gas space (16) of the liquid container (2) and the external gas container (21 ), said second means comprising a two-position valve assembly (7) allowing the gas, in a first position, to flow from the gas container (21) into the liquid container (2), and in a second position, to flow from the liquid container (2) into the gas container (21 ); and

- an operating unit (25) removably coupled to said container closure unit (1 ), said operating unit comprising operating members for operating said first and second means of the container closure unit (1 ) from outside.

2. The dispensing apparatus according to claim 1 , wherein the deformable gas container (21 ) is an initially collapsed, inflatable bag.

3. The dispensing apparatus according to claim 2, wherein the inflatable bag has an elastic wall.

4. The dispensing apparatus according to claim 2, wherein the inflatable bag (23) has a rigid wall and said bag is provided with a weight (24) externally exerting a pressure to the wall of the bag.

5. The dispensing apparatus according to claim 4, wherein said first means comprises a liquid discharging channel and an associated movable blocking member.

6. The dispensing apparatus according to claim 5, wherein said liquid discharging channel is formed by a tube (6) having a flexible wall, and said movable blocking member is formed by a restriction element (9) adapted to restrict said tube (6).

7. The dispensing apparatus according to claims 1 to 6, wherein said operating unit (25) comprises a multiple function operating lever (27) that is adapted

- in a first position, to close the liquid discharging channel while keeping the two- position valve assembly (7) in its first position,

- in a second position, to open the liquid discharging channel while keeping the two-position valve assembly (7) in its first position, and

- in a third position, to closed the liquid discharging channel while keeping the two- position valve assembly (7) in its second position.

8. The dispensing apparatus according to any one of claims 1 to 7, wherein said operating unit (25) and said external gas container (21) are secured to a rigid supporting equipment (20).

9. The dispensing apparatus according to any one of claims 1 to 8, wherein the gas space (16) of the liquid container (2) contains a protective gas, preferably nitrogen.

10. The dispensing apparatus according to any one of claims 1 to 9, wherein the initial pressure of the gas in the gas space (16) is about 5 bars.

1 1. A method for the sterile dispensing of liquids at low rate, the method comprising the steps of

- filling (S 00) a predetermined amount of liquid (15) and a predetermined amount of high-pressure gas (19) into a liquid container (2) having a substantially rigid wall through an upper filling aperture of said liquid container (2), - sealingly closing (S102) the upper filling aperture of the liquid container (2) by a container closure unit (1 ),

- coupling (S104) an operating unit (25) and a deformable external gas container (21 ) to the container closure unit (1 ) of said liquid container (2), wherein said gas container (21 ) have a predetermined maximum volume,

- before the first opening of the liquid container (2), removing (S106), by means of said operating unit (25), a portion of the high-pressure gas (19) from the liquid container (2) into said deformable gas container (21 ) so that the gas space (16) of the liquid container (2) have a gas pressure substantially equal to the ambient air pressure, and

- by means of said operating unit (25), dispensing (S108) the liquid from the liquid container (2) while allowing the gas (19) to return from the deformable gas container (21 ) into the liquid container (2) so that the gas space (16) of the liquid container (2) permanently have a gas pressure substantially equal to the ambient air pressure.

12. The method according to claim 1 1 , wherein a protective gas, preferably nitrogen, is filled into the liquid container (2).

13. The method according to claim 1 1 or 12, wherein the deformable gas container (21 ) is initially maintained in a state with a minimum volume and upon the reduction of the pressure of initially high-pressure gas (19) of the liquid container (2), the gas container (21 ) is expanded to a state with said maximum volume.

14. The method according to any one of claims 11 to 13, wherein the liquid is dispensed from the liquid container (2) by free flow.

15. The method according to any one of claims 1 1 to 14, wherein the method further comprises the steps of

- when the liquid container (2) has become empty, removing the liquid container (2) from the operating unit (25) and the external gas container (21), and

- a further unopened liquid container (2) is coupled to the operating unit (25) and to the external gas container (21 ).