CN102149627B - Bag-in-container with prepressurized space between inner bag and outer container - Google Patents

Abstract

Bag-in-container (2) comprising an inner layer (21) forming a bag filled with a fluid (10), said bag being separatable from an outer layer (22) forming the container, and further comprising a mouth (5) fluidly connecting the volume defined by the bag to the atmosphere and separated therefrom by sealing means (1), said container further comprising at least one space vent (3) fluidly connecting the space (24) between inner and outer layers (21) and (22) to the atmosphere, wherein said vent comprises closing means able to control the gas flow between the space (24) and the atmosphere and in that the space (24) contains an amount of gas (V S,i ) at a pressure (P i ) insufficient to compress the bag to drive out more than 80% of the fluid contained therein. The present invention also concerns a kit of parts comprising a bag-in-container as defined above and a dispensing appliance.

Description

Bag-in-inner container with pre-pressurized space between inner bag and outer container

field of invention

The present invention relates generally to new developments in dispensing bag-in-containers and, in particular, to bag-in-containers wherein the dispensing of the fluid contained therein is driven by the application of fluid compressive pressure to the inner bag .

Background of the invention

The inner bag container is also called the inner bag bottle or the inner bag box depending on the geometric size of the outer container. In this paper, all terms considered to be included in the meaning of the inner bag container are a type of liquid dispensing packaging (liquid dispensing packaging), the liquid The dispensing package comprises an outer container including an opening to the atmosphere, a spout, and an inner collapsible bag joined to the container. A fluid to be dispensed, such as a beverage, is contained within the bag and dispensing of the fluid may be driven by any of the following techniques.

(a) by injecting gas into the space between the inner bag and the outer container when dispensing (see US-A-3484011, US-A-3450254, US-A-4,330,066 and US-A-4892230; US-A-5301838 , US-A-5407629, JP-A-5213373, JP-A-8001761; EP-A-1356915; US-A-6649121; JP-A-10180853);

(b) by storing pressurized gas in the space between the inner bag and the outer container, said space being subsequently sealed (see GB-A-2184491; EP-A-741088; GB-A-1414329; US-A -4039103; WO2006087462; WO2007085051; WO2007128157; EP-A-105537; EP-A-776834; FR-A-2446128);

(c) by creating low air pressure in the inner bag, thus drawing fluid out of the bag (see EP-A-596142; EP-A-391817; WO9211187; WO9312013);

(d) by applying external mechanical pressure to the bag by means of elastic sleeves (see WO8200780; WO9314987) or moving members (see WO2006068586; WO2007105934);

(e) by injecting pressurized gas into the inner bag in contact with the fluid to be dispensed and using a dispensing conduit immersed in the fluid; this solution differs from the previous ones in that the collapsible bag is not used as a dispensing drive, but only As a disposable hygienic storage tool.

What techniques (a) and (b) defined above have in common is that an external compressed fluid pressure is applied to the inner bag, said fluid being confined in the space between the inner bag and the outer container. These solutions are advantageous because the pressurized gas never comes into contact with the fluid to be dispensed and they do not require a vacuum pump to depressurize the inner bag to suck out the liquid contained therein.

In technique (a) consisting of injecting gas into the space between the inner bag and the outer container when dispensing, there is no overpressure in the space until the dispensing of the beverage contained in the bag is initiated by injecting pressurized gas into the space , and in theory, when the dispensing operation is interrupted, the overpressure could/should drop to close to zero. The great advantages of this technology are:

the outer container need not be high pressure resistant, and it is usually sufficient that the outer container is substantially harder than the bag to be handled (which is very pliable), and

In the case of co-blow molding of the inner bag with the outer container in a single blowing operation, the initial (i.e., before use of the outer container) volume V _i of the space between the inner bag and the outer container can be very small, even zero.

However, the disadvantages of this technique are:

Injecting pressurized gas into the space, requiring bulky and noisy equipment such as pumps or compressors if compressed gas cartridges (eg liquefied _CO2 cartridges) are used, or if between the inner and outer containers It is more complicated to use a regulating valve in between;

- in case the fluid contained in the inner bag is sensitive to oxygen, the only protection against oxidation therein is the walls of the inner container and the outer container, which are designed to be as thin as possible for economical reasons; and

In the case of integrally blow molded bag-in-containers, the walls of the inner and outer containers are attached to each other, but are rough and may be during delamination when pressurized gas is injected through the interface cause problems.

On the other hand, the technique (b) of storing pressurized gas in the space between the inner bag and the outer container, which space is then sealed, solves most of the disadvantages of the preceding techniques, but creates others, in particular:

●The outer container must withstand high pressure;

• For a given bag volume, the outer container must be larger, because some initial volume V _i of the space between the inner bag and the outer container must be set to accommodate pressurized (propellant) gas;

• The pressure in the space decreases rapidly as the bag shrinks.

Most developments involving pressurized gas stored in spaces include "pressure enclosures" (as cited from WO9212912) which can resist high pressures. The pressure shell cannot be produced by integrally blow molding a two-layer preform. Some ingenious solutions have been proposed where _CO2 is formed in situ by fermentation (EP0314554) or by release of gas adsorbed on zeolite or activated carbon (EP0569590), but the application of these solutions is still limited .

Summary of the invention

The present invention proposes an ingenious solution that solves the problems of both techniques (a) and (b), while combining their respective advantages.

In particular, the present invention relates to bag-in-containers comprising an inner layer forming a fluid-filled bag separable from an outer layer forming the container, and further comprising fluidly connecting the volume bounded by the bag to atmosphere and The container also includes at least one space vent fluidly connecting the space between the inner and outer layers to the atmosphere by sealing the mouth of the means from the atmosphere. A bag-in-container including the vent is adapted to include a dispensing technique that injects pressurized gas through the vent to expel liquid from the bag. They can also be used in the technique of sucking liquid out of the bag to equalize the pressure in the space to the atmosphere as the bag volume decreases, but the vents are simple holes and do not include closure means and cannot be connected to a source of pressurized gas. In the present invention, only vents that can be connected to a source of pressurized gas are considered and must further include closure means capable of controlling the flow of gas between the space and the atmosphere. The space between the inner bag and the outer container of the bag-in-container of the present invention contains an amount V _{s,i of gas at a pressure P i insufficient} to compress the bag to drive out more than 80% of the fluid contained therein .

The invention also relates to a kit of parts comprising a bag-in-container as described above and a device for regulating the bag-in-container, and comprising a dispensing conduit and an external source of pressurized gas, the dispensing conduit having a device for adjusting the bag-in-container The connection means to connect it to the mouth of the inner bag container, the external source of pressurized gas has connecting and mating means, when additional pressure is required to expel the fluid out of the inner bag, the pressurized gas An external source of air is connected to the vent and cooperates with the closure tool.

In a preferred embodiment, the closing means are opened when the pressure in the space drops below a given value. Alternatively or concomitantly, the closing means are opened when the external pressure is higher than the pressure in the space by a given value. In a simpler embodiment, the closure means can be opened by piercing the vent when it is connected to an external source of pressurized gas.

Preferably, the gas stored in the space between the inner bag and the outer container is at an initial pressure _Pi (i.e. when the inner bag is full and the fluid it contains is not being _dispensed ) comprised between Between 0.1 bar and 6.0 bar, preferably between 0.1 bar and 4.0 bar, most preferably between 0.5 bar and 3.0 bar. The normalized volume of space V _s,i /V _c should be as low as possible, thereby minimizing the size of the outer container and should be less than 10%, preferably less than 5%, most preferably less than 0.1%, where V _s,i is the The initial volume of the space (or gas with pressure Pi ₎ and _Vc is the volume of the container. The starting volume V _s,i of the space can be close to zero, especially if the bag-in-container is produced by integrally blow molding two polymer preforms together, resulting in a container consisting of two polymer preforms joined by a weak interface. Composition of separable layers. The interface between the inner and outer layers of integrally blow molded bag-in-containers is typically split by the end user injecting gas therethrough through the vents when dispensing the fluid contained in the inner bag. However, the layer separation is not always as reproducible as desired, which can lead to uncontrolled bag shrinkage and the formation of fluid-filled pockets that seal off the mouth of the bag, and thus lead to incomplete dispensing of the fluid. By introducing a given amount of gas into the space between the pouch and container before the end user begins dispensing the contents of the inner pouch, the interface between the two layers splits in a controlled manner, ensuring that the pouch is inside when in use The container works smoothly and completely, allowing complete dispensing of the fluid contained therein. With the inner bag filled with fluid and the space pre-pressurized with gas, any leaks in the bag can be detected quickly. Therefore, any bag-in-container defective at the interface or in the bag can be quickly soiled and discarded when the amount of pressurized gas is introduced through the interface.

Bag-in-containers according to the present invention may be used in a variety of applications, including the dispensing of therapeutic fluids, chemicals, and the like. However, a preferred application is for dispensing beverages, carbonated or non-carbonated, in particular soft drinks and beer. In many applications, fluids may be sensitive to oxidation. The added benefit of extending the shelf life of the fluid can be obtained by prepressurizing the space between the inner bag and the outer container with a gas such as _CO2 or _N2 , as the gas forms a barrier for passing through the walls of the outer container and the walls of the inner bag. Cushion or barrier to oxygen diffusion.

Brief description of the drawings

Fig. 1 is a cross-sectional view of a bag-in-container according to the present invention.

Figure 2 is a graphical representation of the pressure drop in the space between the inner bag and the outer container of a pre-pressurized bag-in-container when in use.

Figure 3 is a pictorial representation of a bag-in-container installed on a dispensing appliance and ready for use in accordance with the present invention.

Detailed description of the invention

inner bag container

Referring now to Figure 1 , there is illustrated a bag-in-container 2 comprising an inner bag 21 filled with fluid 10 and an outer container 22 passing through an interface at least at the level of the neck region 6 (not at the level of the neck region 6). shown in the figure) to join. The space 24 of the volume V _s,i between the inner bag 21 and the outer container 22 is in fluid communication with at least one vent 3 and is filled with a certain amount of pre-pressurization stored in the starting space volume V _{s,i at} a pressure Pi Gas, which will be defined below. Said vent is separated from the atmosphere by closure means 4 adapted to control the flow of gas through the vent 3 . A closure means 4 is herein considered to control flow through a vent 3 if the closure means 4 can be alternated at least once from a closed position preventing any gas flow to an open position allowing gas to flow through the vent 3 . A simple barrier or lid, usually present in a pressurized bag-in-container, is not considered to control flow, since its sole function is to seal the pressurized space from the atmosphere. Similarly, a hole in a bag-in-container for compensating the pressure in the space by means of the atmosphere when the inner bag contracts due to the withdrawal of the fluid contained in the inner bag, cannot be considered to contain the fluid, since its purpose Yes keep it open.

The closing means 4 can be a valve which can be actuated manually or automatically depending on the pressure in the space 24 . Alternatively, the closure means 4 can be pierced open when the bag-in-container is installed in its corresponding dispensing device. In this embodiment, the closure means 4 may be a simple cap made of an elastomeric material such as rubber. The elastomeric cover or barrier may include a thinner portion to facilitate its puncturing or breaking open when the pressure differential between the space 24 and the gas source 103 reaches a predetermined value. Preferably, the vent 3 and the corresponding closing means 4 are positioned adjacent to the mouth 5 and oriented coaxially with the mouth 5, thereby simplifying the mounting of the bag-in-container onto the dispensing device (see Figure 3).

The bag-in-container according to the present invention may be manufactured by any method known in the art. However, a particularly preferred manufacturing technique is to integrally blow mold two layered preforms or two interconnected preforms in a single process step, resulting in a two-layer container in which an inner layer and an outer layer Separation by the interface creates an essentially zero (V _s =0) volume of space prior to the injection of pre-pressurization gas (see US 11/785748-Inbev). The injection of pre-pressurized gas at pressure _Pi through the vent 3 opens up the separation of the interface between the inner bag and the outer container, ensuring a smoother and more controlled shrinkage of the inner bag when in use and thus forming a more reliable The product. Integral blow molded bag-in-containers were produced that developed a laminar pressure of approximately 0.5 ± 0.1 bar overpressure and showed no cohesive failure between the inner and outer layers, indicating that the pre-pressurized gas was greater than 0.5 Injection of a pressure P _i in bar through the interface of the integrally blow molded bag-in-container can be effectively used to open the separation of the interface.

The interface can be further weakened by applying a release agent on either or both surfaces of the inner and outer preforms which will form the interface of the inner bag-in container. Any release agent available on the market that is most suitable for the material of the preform and resistant to the blowing temperature, for example silicon-based or PTFE-based release agents (eg Freekote) can be used. The release agent may be applied before loading the preforms into the blow molding unit, or the preforms may be pretreated.

Alternatively or additionally to the application of the release agent, when blow molding the bag-in-container, at the same time, when the preform is used without an air gap between the inner preform and the outer preform, by blowing the The portion of the pressurized fluid used between the two preforms to prevent intimate contact between the inner and outer layers and thus prevent the formation of a strong interface between the two layers, the interface can be weakened. The portion of pressurized fluid injected between the two preforms must be carefully measured so that enough fluid is injected to form a thin fluid cushion between the two layers, but blowing that would result in a lack of inner bag should be avoided any excess. Proper ratios can be determined simply by a series of adjustment tests.

Preferred materials for bag-in-containers of the present invention are polyesters such as PET, PEN, PTT, PTN; polyamides such as PA6, PA66, PA11, PA12; polyolefins such as PE, PP; EVOH; biodegradable polymers such as polyethylene glycol ester (PGAc) and polylactic acid (PLA); and copolymers and mixtures thereof. If different materials are used for the inner and outer layers, their optimal blow molding temperatures should differ from each other by no more than about 70°C, preferably 40°C, most preferably 10°C, and ideally should have the same blow molding temperature. The temperature of the layer can be determined by infrared measurements.

For integrally blow-molded bag-in-containers, the at least one vent opening 3 is preferably in the shape of a wedge with the wide side at the level of its opening, where the closing means 4 are positioned and as it goes deeper Penetrating into the vessel and getting thinner until the two layers touch to form an interface at least at the level of the neck region. The container may include one or more vents evenly distributed around the edge of the mouth of the bag-in-container. Some vents are advantageous because they allow the interface of the inner layer 21 and outer layer 22 of the bag-in-container 2 to detach more evenly when pressurized gas is blown through the vents. Preferably, the pre-form comprises two vents opening at diametrically opposite positions at the mouth edge of the vessel. More preferably three, and most preferably at least four vents open at even intervals around the edge of the mouth.

Initial gas pressure and space volume

Fluid compressive force can be applied to the inner bag of a bag-in-container, literally "squeezing" the fluid out of the bag, or:

(a) by injecting pressurized gas into the space between the inner bag and the outer container when dispensing; in this technique the initial pressure P _i in the space 24 is substantially zero and such that its initial volume V _{s ,i} is substantially zero; the source of pressurized gas may be a pump or compressor, or, particularly for domestic installations, a gas cartridge (such as a liquefied _CO cartridge); or

(b) by storing pressurized gas in the space between the inner bag and the outer container, said space is subsequently sealed; in this technique, the initial pressure P _i and the initial volume V _s,i must be sufficient Substantially all of the fluid contained therein is expelled from the bag.

As explained in the section entitled "Background of the Invention", cartridges of pressurized (or liquefied) gas are relatively expensive and extending their working life would certainly be of benefit to the end user. Similarly, a reduction in the size of the pump or compressor required to drive the distribution of the fluid is advantageous in terms of cost, noise and bulkiness of the device.

Technique (b) solves all these problems because neither a cartridge nor a compressor is required for its function. On the other hand, the initial pressure _Pi of the pressurized gas contained in the space 24 must be high to ensure that sufficient driving force is available for squeezing out substantially all of the fluid contained in the bag. It should be considered that when the pressure P in the bag is equal to or less than the pressure P0 required to deform the bag and raise the fluid to be dispensed to the highest point of the dispensing conduit, there is _no more driving force available to squeeze the fluid out of the bag .

It is clear that the pressure P in the pressurized bag-in-container space 24 decreases as the volume of the bag (V _B =V _c -V _s ) decreases as the bag shrinks. For an ideal gas, P=(P _i ×V _s,i )/V _s , where the subscript i refers to the pressure and volume of the space 24 before use, and B, C, S refer to the bag 21, container 22 and Space 24. Divide both terms of this expression by the container volume V _c and rearrange to form the expression:

P=(P _i ×(V _s,i /V _c ))/(V _s /V _c ) (1)

This is represented graphically in FIG. 2 as the pressure P as a function of the relative space volume V _s /V _c . The initial volume of the space before any beverage is dispensed is characterized by V _s,i /V _c ; and the minimum pressure required to compress the bag and expel fluid from the bag is denoted by P ₀ , and there is a corresponding volume of the space, V _s,0 /V _c . The volume of fluid that fails to be dispensed due to insufficient pressure in space 24 is simply 1-V _s,0 /V _c . According to the invention, in the example shown in FIG. 2 , the initial pressure P _i and the volume V _s,i of the pre-pressurized gas stored in the space 24 are sufficient to dispense only 40 of the fluid originally contained in the inner bag. %, so (1-V _s,0 /V _c ) = 60% of the liquid remaining in the bag. This result is unacceptable for any pressurized bag-in-container using technique (b) as defined above, wherein the pressurized gas is sealed in the space 24 . A manufacturer facing this situation should increase the initial volume V _{s,i of} the space 24, thus increasing the size of the container, or increase the initial pressure Pi of the gas stored in the space 24, thus requiring a substantially stronger outer container to resist deformation due to this pressurization.

The present invention exploits the advantageous benefits of each of techniques (a) and (b) as defined above, while it bypasses their respective drawbacks. In fact, the space 24 of the bag-in-container of the present invention is pre-pressurized by the gas stored therein at a volume V _{s,i and} a pressure Pi, which is not sufficient to expel from the inner bag all the fluid contained in it. According to the invention, the initial volume V _{s,i and} the pressure Pi of the pre-pressurized gas stored in the space 24 are such that no more than 80% of the fluid initially contained in the inner bag can be compressed out of the bag by its compression. (ie, ΔV _s /V _c =((V _s,i −V _s,0 )/V _c )≤0.8), preferably between 10% and 70% and more preferably at 25 Between % and 50%. The pressure not included to expel the remaining content of the inner bag (1-V _s,0 /V _c ) out of the bag is controlled by the gas flowing through the vent connected to the vent 3 and communicating with the closing means 4. An external source 103 of pressurized gas is provided. The external source 103 of pressurized gas may be a pump or compressor or a pressurized gas cartridge (eg, a liquefied _CO2 cartridge).

The advantages of this solution are surprisingly good. If the initial gas content, characterized by V _{s,i and} Pi, is sufficient to drive, say, 50% of the initial fluid content of the inner bag, and the remaining fluid is expelled from the bag by an external source of pressurized gas, such as a cartridge, then relative to no The same system for pre-pressurization of space 24 doubles the working life of the cartridge with corresponding savings for the end user. Compared to a fully pressurized bag-in-container, the mechanical resistance of the outer container is proportional to the cube of the initial pressure _Pi , resulting in a significantly cheaper container with corresponding savings for the end user.

Ideally, the initial volume V _s,i in which pre-pressurized gas is stored should be kept as small as possible, thereby reducing the overall size of the container for a given inner bag volume. Preferably, it should be limited to less than 10%, preferably less than 5%, most preferably less than 1% of the total container volume _Vc . The ideal initial pressure P _i depends on some parameters, such as the initial relative space volume V _s,i /V _c , the minimum driving pressure P ₀ of the system and the mechanical resistance of the outer container. Generally speaking, the initial pressure P _i is comprised between 0.1 bar and 6.0 bar above atmospheric, preferably between 0.5 bar and 4.0 bar, most preferably between 1.0 bar and 3.0 bar.

In order to produce a bag-in-container according to the present invention, an empty bag-in-container must first be produced by any method known in the art (for example, producing the container and bag separately and inserting the bag into the container, or more preferably, by inserting the inner bag and The outer container is co-blow molded in a single blow molding operation, as discussed above). The pre-pressurized gas and the fluid 10 to be dispensed must then be introduced into the inner bag 21 and the space 24, which are respectively sealed. These two operations can be done in any order: or,

The bag 21 is first filled with fluid 10 and then the space 24 is pressurized by injecting gas through the vent 3 until the desired starting pressure P _i and volume V _i are reached; each of the mouth 5 and the vent 3 respectively Sealing or sealing with sealing tool 1 and closing tool 4 at the appropriate time, or

The space is first filled with a given amount of gas, after which the inner bag 21 is filled with the fluid to be dispensed, thus compressing the gas in the space 24 until it reaches the desired starting pressure P _i and volume V _i , or

- Both inner bag 21 and space 24 together are filled with fluid to be dispensed and pre-pressurized gas respectively.

distribution device

In order to dispense the fluid 10 contained in the inner bag 21 , the bag-in-container of the present invention will be mounted on a dispensing device 100 as illustrated in FIG. 3 . In its installed position, the dispensing conduit 105 to the atmosphere at 107 is in fluid communication with the interior of the inner bag 21 through the mouth 5 of the inner bagged container, while the source 103 of pressurized gas cooperates with the closure means 4 through the vent 3. Into fluid communication with the space 24 (in Fig. 3 only one connection to the vent 3 is shown for the sake of clarity). Both connections are held tight with fastening means 109, which may advantageously be bolts. The pressurized gas source 103 may be a cartridge of pressurized or liquefied gas, such as _CO2 or _N2 , as represented in Figure 3, or it may be a pump or compressor (not shown). The dispensing conduit 105 may be provided with a tip capable of tearing the sealing means 1 separating the interior of the inner bag 21 from the atmosphere when the mouth 5 comes into contact with said end of the dispensing conduit 105 to create a fluid connection therebetween.

Similarly, the closure tool 4 can be pierced open by the sharpened end of the conduit 101 to create fluid communication between the space 24 and the gas source 103 . Alternatively, the closure means 4 may be a valve connectable to the end of the conduit 101 . Control valves 113, 115 may be provided to both the distribution conduit 105 and the gas conduit 101, respectively, to manually or automatically control the flow of fluid and gas, respectively, as required.

When in use, the initial pressure Pi of the pre-pressurized gas stored in the space 24 is sufficient to dispense a given amount of fluid 10 contained in the inner bag 21 (not more than 80% of the initial fluid content (= _Δ V _s /V _c )). As the pressure P in the space 24 decreases as shown in FIG. 2 , additional pressurized gas is injected into the space 24 from the gas source 103 through the conduit 101 and the vent 3 . The control of the flow of gas from the gas source to the space 24 may be provided by the closing means 4 itself, or alternatively, by control means such as a pressure valve 115 arranged between the gas source 103 and the closing means 4, which must then be provided, for example, by means of a thrust valve. Break it and be opened. In the former case, the closing means 4 may be adapted to open when the pressure in the space 24 drops below a given value, eg P/P ₀ <1.2. Alternatively, it may be adapted to open when the external pressure is higher than the pressure in space 24 by a given value. The same rule can be applied to the control valve 115 in case the closing means 4 are pierced open.

Claims (18)

1. A bag-in-container (2) comprising an inner layer (21) forming a bag filled with a fluid (10), said bag being separable from an outer layer (22) forming said bag-in-container , and also includes a mouth (5) that fluidly connects the volume bounded by the bag to the atmosphere and is separated from the atmosphere by a sealing means (1), the bag-in-container also includes at least one space vent (3), the vent (3) fluidly connects the space (24) between the inner layer (21) and the outer layer (22) to the atmosphere, characterized in that the vent includes a (24) closure means for gas flow between the atmosphere and when the bag is full, the contained fluid is not being dispensed and no external pressure source is coupled to the inner bag-in container, the space (24) is in the amount of gas contained at a pressure (P _i ) above atmospheric pressure is insufficient to compress the bag to expel more than 80% of the fluid contained in the bag, wherein the space (24) is at a pressure above atmospheric The quantity of said gas contained at said pressure (P _i ) of pressure is the initial volume (V _s,i ) of said space ( 24 ). 2. A bag-in-container according to claim 1, wherein said closing means are opened when the pressure in said space (24) drops below a given value. 3. The bag-in-container according to claim 1, wherein said closing means are opened when the external pressure is higher than the pressure in said space (24) by a given value. 4. A bag-in-container according to claim 1 or 2 or 3, wherein the closure means is pierceable. 5. Bag-in-container according to claim 1 or 2 or 3, wherein said pressure (P _i ) of the gas confined in said space (24) is comprised at high Between 0.1 bar and 6 bar of the atmosphere. 6. The bag-in-container according to claim 1 or 2 or 3, wherein said starting volume (V _s,i ) of said space (24) is less than 10% of the total container volume (V _c ). 7. The bag-in-container according to claim 1 or 2 or 3, wherein said initial volume (V _s,i ) of said space (24) is less than 5% of the total container volume (V _c ). 8. The bag-in-container according to claim 1 or 2 or 3, wherein said starting volume (V _s,i ) of said space (24) is less than 1% of the total container volume (V _c ). 9. The bag-in-container according to claim 1 or 2 or 3, obtainable by integrally blow molding two polymeric preforms together. 10. A bag-in-container according to claim 1, 2 or 3, wherein the fluid contained in the bag is a beverage. 11. A bag-in-container according to claim 1 or 2 or 3, wherein the fluid contained in the bag is a carbonated or fermented beverage. 12. Kit of parts comprising a bag-in-container (2) according to any one of the preceding claims and means for cooperating with said bag-in-container and comprising a dispensing conduit and an external source (103) of pressurized gas, the Said dispensing conduit has connection means for connecting said dispensing conduit to said mouth (5) of said inner bagged container (2), said external source of pressurized gas (103) has connection and fitting means (101 ), when additional pressure is required to expel the fluid out of the bag, the connecting and mating means (101) connects the external source of pressurized gas (103) to the vent (3) and with the Cooperate with the closing tool (4) described above. 13. The kit of parts according to claim 12, wherein said connecting and mating means ( 101) comprising a piercing tool for creating a fluid connection through said vent (3) between said external source of pressurized gas and said space (24), and further comprising A valve for controlling the flow of gas into said space (24). 14. A kit according to claim 12 or 13, wherein the external source of pressurized gas is a cartridge of pressurized or liquefied gas. 15. A kit according to claim 12 or 13, wherein the external source of pressurized gas is a cartridge of pressurized or liquefied _CO2 or _N2 . 16. The kit of parts according to claim 12 or 13, wherein the dispensing conduit (105) comprises a valve for controlling the flow of fluid out of the bag. 17. A kit according to claim 12 or 13, for the dispensing of beverages. 18. A kit according to claim 12 or 13, for the dispensing of soft drinks or beer.