LIQUID CONTAINER

Abstract: A liquid container which comprises a rigid or semi-rigid housing (3), a charging and discharging opening defined by a mouth (3a) of the housing for permitting the passage of liquid content into or out of the container, a flexible and open-ended bag (2) suspended from the housing opening, and valve means (4, 5, 5a, 6) for controlling the charging and discharging of the liquid content of the bag (2) via the opening. The bag (2) is made of an elastomeric material and is of sufficient wall strength to expand without rupture within the confines of the housing (3) from a relaxed contracted state (2a) upon charging of the bag with liquid, and is returnable to its contracted state by its own inherent resilience in order to discharge its liquid content. To facilitate the expansion and contraction of the flexible bag (2), a pressure control valve (8) communicates with the internal space (3b) defined between the exterior of the bag (2) and the internal wall of the housing (3), the control valve (8) being operable manually or automatically to allow venting of the internal space (3b) during expansion of the bag (2) as it is charged with liquid, and also functions normally as a one-way valve which allows ingress of ambient air to the internal space (3b) as the bag (2) contracts during liquid discharge.

Description: LIQUID CONTAINER The present invention relates to liquid containers, and in particular to liquid containers which will hereinafter be referred to as "bag in a tube" containers. As used herein, the term "bag in a tube" container refers to a container in the form of a flexible inner bag located within a more rigid vessel, such as a tubular vessel. Although reference is made herein to a bag in a tube container, it should be appreciated that the outer vessel can be of any suitable shape, including tubular. Typically, such a container is used for holding liquids, especially beverages, and has a tap associated with the flexible inner bag so that the liquid may be dispensed. This type of container may be used for holding both non-pressurised and pressurised liquids, but in the latter case there is a requirement that no space should be left above the partially dispensed liquid into which the gas (normally carbon dioxide ) contained in the liquid can escape. Unless this can be achieved, the liquid in the container will go flat. Currently known containers of this type have a flexible inner bag for holding a pressurised liquid, the bag being contained within a cylindrical outer casing through which a tap associated with the bag projects near the base of the casing, and include means for reducing the volume of the bag as the liquid contained therein is dispensed. For instance, the casing may include upper and lower end caps, the container including a mechanism by which the upper end cap can be moved downwards within the casing to reduce the volume of the bag, this mechanism being lockable against the inner walls of the casing to prevent subsequent increase in the volume of the bag due to the pressure exerted by the liquid. One of the problems with this type of container is that some pressurised beverages exert very high pressures on the container, and the pressures at which the container can operate successfully are determined primarily by the resistance to increase in volume offered by the locking means provided to prevent such increase. It is therefore the purpose of the present invention to provide a container which overcomes the above-mentioned limitation. According to the invention there is provided a liquid container which comprises a rigid or semi-rigid housing, a charging and discharging opening provided on the housing for the liquid content of the container, a flexible and open-ended bag arranged in the housing to communicate with the housing opening, and valve means for controlling the charging and discharging of the liquid content of the bag via said opening, in which: the bag is made of an elastomeric material and is of sufficient wall strength to expand without rupture within the confines of the housing from a relaxed contracted state upon charging of the bag with liquid, and is returnable to its contracted state by its own inherent resilience in order to discharge its liquid content; and a pressure control valve communicates with the internal space defined between the exterior of the bag and the internal wall of the housing, said control valve being operable to allow venting of said internal space during expansion of the bag as it is charged with liquid, and said valve also being arranged to allow ingress of ambient air to the internal space as the bag contracts during liquid discharge. Thus, in order to charge the container with liquid it is necessary to operate said valve means in a charging mode so that liquid, usually under pressure, can fill the bag via said housing opening, and the valve means is then operated in a closing mode so that the liquid is retained in the bag. During filling of the bag, it expands from its relaxed state and progressively diminishes the volume of the internal space defined between the bag and the inner wall of the housing, and this expansion is readily permitted in that the pressure control valve is operated so that this space can be vented. However, in order to discharge all or part of the liquid content of the bag the valve means is operated in a discharging mode, and the bag automatically discharges its liquid content through the housing opening as it contracts with its own pre-stored elasticity. In a preferred arrangement, the valve means is provided on a tap-like fitting which is mounted on or in the housing opening, and this fitting is provided with an '• intake port to which a liquid dispenser can be coupled, the port having a respective valve element which is normally maintained closed but which is automatically opened upon coupling of the dispenser with the intake port to allow the bag to be charged with liquid, but which then re-closes and remains this way for the life of the container or until re¬ charging takes place. The fitting also has an outlet port or tap, having a one-way valve element which is operable when liquid discharge is required, but which prevents air from entering the container. A particularly preferred use of a container according to the invention is for containing beverages, in which case the bag will be made of an elastomeric material which is of food grade and suitable for use with beverages. Further, when the container is intended for use with a carbonated beverage the bag will be made of an elastomer which has a very high gaseous carbon dioxide retention property. Alternatively, and preferably in addition, the elastomer will have the property of having a very low permeability to gaseous oxygen. When beer is stored, it is most important that contact between the beer and gaseous oxygen should be avoided during storage prior to initial opening, and thereafter should be kept to an absolute minimum, since beer quickly deteriorates upon contact with oxygen. The elastomer from which the flexible bag is made is preferably one which permits the bag to be expanded from its relaxed contracted state, to between 200 and 1,200 per cent of its contracted state. • In this preferred range, it is particularly suitable for the bag to be capable of being expanded to at least 500 per cent of its contracted state. One example of a suitable elastomer from which the bag can be made is a suitably treated polyurethane material. Preferable the flexible bag is suspended from the housing opening, the bag having a lip which is -trapped between the mouth of the housing opening and an engaging portion of the fitting, thereby to form a seal for the flexible bag in the housing. The housing which is rigid or semi-rigid, may be made of any suitable material or composite, and may be made of metal, glass, paper, or plastics. An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section of a container in accordance with the present invention; Figure 2 is an end view of a similar container to that shown in Figure 1, but fitted with a combined carrying handle and "anti-roll bar"; and Figure 3 is a detailed view of a tap-like fitting for mounting in a housing opening of the container shown in Figure 1. Referring to Figure 1 of the accompanying drawings, a container 1 in accordance with the present invention comprises a flexible and open-ended inner bag 2 located within an outer housing 3. The housing 3 is formed with a mouth 3a which defines a charging and a discharging opening via which the liquid content of the container can pass during charging and discharging o the container. As will be described in more detail below, the bag 2 is suspended within the housing 3 via its open end and on the mouth 3a. The bag 2 is made from an elastomeric material of food grade, suitable for use with beverages, and capable of being expanded between 200 per cent and 1,200 per cent of its original contracted (relaxed) dimensions, as shown in full lines in Figure 1. An example of such a material is suitably treated polyurethane. * The bag 2 has a closed lower end, -and is of tubular form prior to filling with liquid. The upper end of the bag 2 has a lip 4a which is trapped between the annular end surface of the mouth 3a and a cap 4. The outer housing 3 and the cap 4 are both screw threaded so that the cap 4 can be screwed onto the housing 3, trapping the bag 2 between the cap 4 and the housing 3. The cap 4 includes an outlet tap 6 through which liquid may be dispensed. The cap 4 also includes a liquid inlet 5 through which the bag 2 may be filled with liquid. When the cap 4 is screwed onto the housing 3, a seal is formed between the cap 4 and the outer housing 3. Thus, the cap 4 forms a tap-like fitting which can be mounted on or in the opening in the housing 3. The outer housing 3, which is rigid or semi-rigid, may be made of metal, glass, paper, plastics, or any other suitable material or composite. The tap 6 may be moulded from plastics material with a metal or plastics cap. In use, the container is filled via the liquid inlet 5 which forms an intake port to which a liquid dispenser can be coupled, the port having a respective valve element 5a (see Figure 3) which is normally maintained closed but which is automatically opened upon coupling of the dispenser (not shown) with the intake port to allow the bag 2 to be charged with liquid. However, the valve element 5a automatically re-closes and remains this way for the life of the container after charging or until re-charging. As an alternative to charging via the liquid inlet 5, the container may also be filled with liquid through the tap 6. Prior to filling of the container with liquid the bag 2 is contracted and takes a relaxed tubular state, as shown by reference 2a in full lines in Figure 1. As the bag 2 becomes filled with liquid to more than its minimum contracted volume, it expands so that when the container is approximately half full, the bag assumes the position indicated by dashed lines 2b. When the container is completely full of liquid, the bag takes up the position indicated by 2c, in which it fills all-of the space available within the outer housing 3 and presses intimately against its wall. Then, as the liquid is dispensed through the tap 6, the bag 2 contracts by an amount approximately equivalent to the volume of liquid dispensed, thus ensuring that no air space is left above the liquid remaining in the bag 2. Accordingly, the valve element 5a, and the tap 6 jointly constitute a "valve means" for controlling the charging and discharging of the liquid content of the bag 2 via the opening defined by the mouth 3a of the housing 3. Furthermore, the bag 2 is made of an elastomeric material and is made so as to have sufficient wall strength to expand without rupture within the confines of the housing 3 from a relaxed contracted state upon charging of the bag with liquid, and is returnable to its contracted state by its own inherent resilience (pre-stored elasticity) in order to discharge its liquid content. However, to facilitate the expansion of the bag 2 during liquid charging, and its contraction during liquid discharge, a pressure control valve (which is described in more detail below) communicates with the internal space 3b which is defined between the exterior of the bag 2 and the internal wall of the housing 3. The pressure control valve will be located at any convenient position in the wall of the housing 3, and is shown by way of example only, schematically as pressure control valve 8 which. is mounted in the base 9 of the housing 3. The pressure control valve 8 is arranged to be capable of operation, manually or automatically as desired, to allow venting of the internal space.3b during expansion of the bag 2 as it is charged with liquid. This therefore allows the bag to expand without significant pressure resistance during liquid filling. The pressure control valve 8 is mounted in the base 9 and may be arranged to be triggered automatically to an open position upon ' lacement of the base 9 on a suitable support during liquid filling of the container in a factory. However, upon removal of the housing 3 from this special support, the valve 8 returns to its normal position, in which it can function as a one-way valve which only permits throttled ingress of extern ambient air to the internal space 3b when there is a pressure differential in this direction ie when sub- atmospheric pressure is generated in the internal space 3b during contraction of the bag 2. The valve 8 is a throttle valve which slowly allows the internal space 3b to be charged with air as th bag 2 contracts thereby preventing excessive liquid discharge from the bag 2 upon opening of the tap 6. As indicated above, the flexible bag 2 is made of an elastomeric material of food grade, and capable of expanding by up to 1,200 per cent of its relaxed state. For beverage use, the elastomeric material will be a specially treated material which has special properties in relation to its operation when exposed to gaseous oxygen and gaseous carbon dioxide. Thus, when beer is stored within the bag 2, it is important to prevent access of gaseous oxygen to the beer, during storage prior to initial use, and to minimise any contact with oxygen after first use. It is well known that gaseous oxygen contact with beer rapidly results in deterioration of the beer. Therefore, the elastomer should have the property of having very low permeability to gaseous oxygen. Evidently, when the container is fully charged with beer, the bag 2 will be expanded so that it totally and intimately contacts the housing 3 throughout* its internal wall surface, so that there is no cha'nce of gaseous oxygen coming into contact with the beer. However, during progressive contraction of the bag 2, there will be ingress of ambient air into the internal space 3b, and it is therefore important to minimise the extent of any gaseous migration through the wall of the bag 2 and into contact with the beer. Clearly, the greater the extent of minimising gaseous oxygen migration, the greater will be the acceptible storage life of a beer container following initial opening. A typical wall thickness of the bag 2 may be about 2 mm when beer is stored in the bag, and about 3 mm for a carbonated beverage. In addition to the property of low gaseous oxygen permeability, when a carbonated beverage is stored within the bag 2, it is important to minimise loss of gaseous carbon dioxide. Therefore, desirably the elastomer should have the property of a very high gaseous carbon dioxide retention. The bag 2 may be provided with longitudinally extending ribs extending outwardly from the outer surface of the bag. These ribs are provided in order to ensure that air passageways, between adjacent ribs, allow air to flow from around the bottom of the bag towards the neck region of the bag. The bag typically will expand outwardly from the top towards the bottom, the top of the bag engaging the wall of the casing before the bottom of the bag has fully expanded. Without the provision of these ribs there is a danger that air may be trapped between the bottom of the bag and the housing 3. At its neck region, the bag is provided with an annular groove which is in communication with the passageways formed between the ribs and this annular groove in turn communicates with a valve (not shown, but corresponding in function to valve 8) which may be actuated to allow escape of air from between the bag and the casing to the exterior of the device. The arrangement may be such that the valve may be manually or automatically actuated. Automatic actuation would take place when a filling head is connected to the device and allows evacuation of air while the bag is being filled. The valve is such that, as liquid is emptied from the device, the drop in pressure between the bag and the casing will cause the valve to open and allow air to be sucked into the space between the bag and the casing. Referring to Figure 2 of the accompanying drawings, a container 21 is essentially similar to the container of Figure 1 but is fitted with a removable carrying handle 23. Handle 23 includes a collar 25 extending around the neck of the container, arms 27 made of relatively thin, flexible plastics material, and grip portion 29 formed of larger section material. In its "rest" position, handle 23 extends laterally from the container neck and when the container is on its side for dispensing purposes, the handle acts as an "anti-roll" bar, as illustrated in Figure 2. However, because of the flexibility of arms 27, the handle will "bend" so that grip portion lies above the valve when the container is being carried in a vertical orientation by means of the handle. In an alternative embodiment, the handle may be formed integrally with the container. It should be appreciated that a container in accordance with the present invention may be used equally successfully with pressurised or non-pressurised liquids.

Claims: CLAIMS 1. A liquid container which comprises a rigid or semi-rigid housing, a charging and a discharging opening provided on the housing for the liquid content of the container, a flexible and open-ended bag arranged in the housing to communicate with said housing opening, and valve means for controlling the charging and discharging of the liquid content of the bag via said opening, in which: the bag is made of an elastomeric material and is of sufficient wall strength to expand without rupture within the confines of the housing from a relaxed contracted state upon charging of the bag with liquid, and is returnable to its contracted state by its own inherent resilience in order to discharge its liquid content; and a pressure control valve communicates with the internal space defined between the exterior of the bag and the internal wall of the housing, said control valve being operable to allow venting of said internal space during expansion of the bag as it is charged with liquid, and said valve also being arranged to allow ingress of ambient air to the internal space as the bag contracts during liquid discharge. 2. A liquid container according to claim 1, in which the bag is made of an elastomeric material which is expandable to at least 200 per cent of its relaxed state. 3. A liquid container according to claim 1 or 2, in which the elastomeric material is made of a food grade suitable for use with beverages, and has very low permeability to gaseous oxygen. 4. A liquid container according to any of claims 1 to 3, in which the elastomeric material is made of a food grade suitable for use with beverages, and has the property of very high retention of gaseous carbon dioxide. 5. A liquid container according to any one of the preceding claims, in which the valve means is provided on a tap-like fitting which is mounted on or in the housing opening, said fitting being provided with an intake port to which a liquid dispenser can be coupled, said port having a respective valve element which is normally maintained closed but which is automatically opened upon coupling of the dispenser with the intake port to allow the bag to be charged with liquid. 6. A liquid container according to claim 5, in which the fitting has an outlet port or tap, having a one-way valve element which is operable when liquid discharge is required, but which prevents air from entering the container. 7. A liquid container according to any one of the preceding claims', in which the pressure control valve is mounted in the base of the housing and normally functions as a one-way valve permitting air flow only from externally of the container to the internal space defined between the bag and the internal wall of the housing, said valve being • operable manually or automatically in order to over-ride its operation so that the internal space between the bag and the housing can be vented to atmosphere during expansion of the flexible bag when the latter is being filled with liquid. 8. A liquid container according to any one of the preceding claims, in which the housing is made of metal, glass, paper, plastics or other suitable material or composite. 9. A liquid container according to any one of the preceding claims, in which the bag has external ribs which define communicating passages within the housing when the bag is expanded into contact with the inner wall of the housing. 10. A liquid container according to any one of the preceding claims, in which the open end of the bag is suspended from a mouth of the housing which defines said housing opening.

Inventors: SHARPLES LEONARD, SHARPLES, LEONARD
Applicants: SPLICERITE LTD, SPLICERITE LIMITED
Application year: 1986
Main classification: B65D83
IPC codes: B65D47, B65D83, B67D1