This invention relates to containers, and in particular, but without limitation, to containers suitable for use as beer kegs.
Kegs are ubiquitous in the brewing industry and are used to transport quantities of beer from the brewery to retail establishments, such as pubs, bars and restaurants. The beer is stored in the keg under pressure, and so the keg needs to be able to withstand the internal hydrostatic pressure, as well as being sufficiently strong and durable to withstand the rough handling that occurs in the brewery (where kegs are rolled, dropped and bumped around as they move along a filling line, for example) and during transport (where kegs are often dropped off the back of delivery lorries and/or into basements from street level, for example). It is therefore imperative that a beer keg is able to safely contain its pressurised gas and/or liquid contents, even when subjected to repeated impacts, vibration and shaking.
A further requirement of beer kegs is their ability to be re-used. In order to meet this objective, they must be sufficiently robust and durable to withstand repeated filling, transportation, storage and emptying cycles. Beer kegs, due to the nature of their contents (normally beer), need to be sterili sable (usually by using pressurised steam injected into the interior of the keg on the filling line). A thither requirement of a beer keg is its resistance to absorbing, or adsorbing on its interior surfaces, contaminants that may taint or spoil the contents.
Traditionally, therefore, beer kegs comprise a stainless steel pressure vessel with an inlet/outlet aperture through which it can be filled, cleaned and emptied. The inlet/outlet aperture generally comprises an internal screw thread for screw-threading receiving a corresponding external screw thread of a “spear”, which spear is generally brewery-specific (i.e. each brewery uses its own type of spear to prevent their kegs from being used by other breweries, or vice-versa). The spear comprises a screw threaded boss that engages with the inlet/outlet aperture of the keg, and which comprises a tube that extends into the interior of the keg's pressure vessel. The function and construction of keg spears is largely outside the scope of this disclosure, other than to note that it sealingly engages with the keg via a screw-threaded connection.
The vast majority of beer kegs also comprise circumferential ribs extending around the main body of the pressure vessel, which facilitate rolling the keg over a floor or ground surface. A base ring is also usually provided, which is typically welded to the base of the pressure vessel, to stabilise it when the keg is stood upright. An upper ring is also usually provided, surrounding the inlet/outlet aperture of the keg, to facilitate manual handling (i.e. comprising handle portions) and to protect the inlet/outlet aperture and the external part of the spear.
A stainless steel keg will also usually comprise a pressure-relief safety valve. This is usually formed as a line of weakness on the base of the pressure vessel so that in the event of an internal over-pressure, the line of weakness breaks preferentially, thereby discharging the keg's contents out through the base (i.e. away from bystanders) in a relatively controlled manner.
Metal, and in particular, stainless steel kegs suffer from a number of well-known drawbacks, including: the considerable weight of metal kegs can be problematic from both a manual handling, and a cost-of-transportation, perspective; and the high cost of metal kegs and their high “scrap metal” value, which makes them very susceptible to theft.
In an attempt to address one or more of the above problems, it has been proposed to manufacture beer kegs out of high-impact polymers, typically polyethylene and polypropylene, which are thermoplastic materials that can be readily injection- or blow-moulded.
Examples of known containers are described in U.S. Pat. No. 4,589,536A [BORN, 20 May 1986]; and in EP0934815A2 [JMK NT INC, 11 Aug. 1999].
However, when manufacturing the pressure vessel of a plastic beer keg from thermoplastic materials, it is not possible to form the internal screw threading of the inlet/outlet aperture to a sufficiently high tolerance to reliably accept a spear. On solution is to blow-mould the pressure vessel with a “blank” inlet/outlet aperture, which can be tapped subsequently to produce the requisite internal thread, but due to the nature of the polymer from which the pressure vessel is manufactured, the threads tend to break when the vessel is pressurised, potentially leading to catastrophic failure. Put simply, plastic kegs manufactured to mimic metal kegs, have been found to be unsuitable in actual use.
In order to overcome the de threading problem outlined above, it has also been proposed to provide re-manufactured kegs, which comprise a plastics outer shell that is adapted to receive a disposable plastic film liner to which a screw threaded inlet/outlet aperture is bonded. In these types of plastic keg, the outer shell provides the requisite durability and impact resistance, and effectively contains the liner, which expands upon filling to bear against the inner walls of the outer casing. After each use, the keg is stripped down by removing the liner, and a replacement liner is fitted prior to re-filling. However, these known kegs produce waste (i.e. the discarded liners) during each fill cycle, and it is also necessary to recover and re-fit the spears during each fill cycle, which tends to be a labour-intensive procedure.
A need therefore exists for a solution to one or more of the above problems and/or an alternative to kegs that are currently available.
Various aspects of the invention are set forth in the appended independent claims. Optional or preferred features of the invention are set forth in the appended defendant claims.
By providing an insert manufactured from a different material to that of the pressure vessel, it is possible to manufacture the pressure vessel from a relatively inexpensive, high-impact polymer, such as polyethylene or polypropylene (thus meeting the mechanical requirements of the pressure vessel) whilst at the same time being able to manufacture the insert from a different material (such as ABS) that is more suited to forming a thread for screw threading receiving, in use, a connector, such as a spear.
In other words, the invention provides somewhat of a hybrid container falling somewhere between a completely moulded plastics container (which is unsuitable for subsequent attachment of a spear) and a (high cost) metal keg with its precision neck. By making the container from several components, which are sealingly united, or fused, together during the manufacturing process, the invention suitably provides the best of both worlds, that is to say: a low cost container and a precision neck to which a spear can be affixed.
A thither possible advantage of the invention is one of rationalisation, by which a manufacturer could have one tool for making the pressure vessel, and a stock of different inserts that can be fitted to the containers to suit different customer's needs. This advantageously obviates the need for a separate tool for the pressure vessels for each customer.
Suitably, the pressure vessel is manufactured via a blow-moulding process, which process is particularly suited to the manufacture or relatively large, hollow plastics components. Suitably, the pressure vessel is manufactured from polypropylene, nylon or other recyclable or reprocessable polymer material which meet one or more of the aforementioned requirements of the pressure vessel, which in particular include some degree of shock and shatter resistance.
The insert is manufactured from a plastics material, being most preferably of much higher density (and thus structural strength and rigidity) than the material from which the pressure vessel is manufactured, and in which a screw thread can be formed, either as part of the moulding process or thereafter by tapping or other screw thread formation process. Suitably, the insert is manufactured from a plastics material that is compatible with the plastics of the pressure vessel so that the two can be sealingly united.
Suitably, the insert is manufactured from a material such as high density polyethylene (HDPE), an acetal-based polymer with glass bead or glass fibre reinforcement, or a high strength glass-filled nylon material, such meeting one or more of the above requirements, in particular by being structurally much stronger and more rigid (still elastic but much less so) than the material of which the pressure vessel is constituted. Alternatively, an example is the HDPE known as “Hostalen® ACP 6541A UV” available from LyondellBasell® Industries NV.
Suitably, the insert is generally tubular and may comprise a flange portion. The flange portion, where provided, suitably provides a region of increased surface area for sealingly uniting the insert to the pressure vessel. In preferred embodiments of the invention, the flange is receivable in a corresponding annular recess surrounding the periphery of the pressure vessel's inlet/outlet aperture. Such a configuration suitably aligns and/or temporarily retains and/or forms a mechanical connection (e.g. an interference fit) between the insert and the pressure vessel. In certain embodiments, particularly when the pressure is blow-moulded in-situ around the insert, said interference fit will arise naturally as a result of the contraction of the polymer of the pressure vessel as it cools after the blow-moulding process.
The flange, where provided, is suitably located at least partially within the hollow interior of the pressure vessel to resist outward movement or subsequent removal of the insert.
The pressure vessel is sealingly united with the insert, and this can be accomplished in a number of ways. For example, where the insert and pressure vessel are manufactured from similar and/or compatible materials, they may weld or fuse together during the manufacturing process to form the requisite seal. In certain embodiments (e.g. when the pressure vessel is being blow-moulded around the insert) the polymer material of the pressure vessel is plastically deformed while at elevated temperature. As the plastic comes into contact with the relevant surface of the insert, it can cause the material of the insert to soften to some degree, and thus the materials of the respective components may meld together in the region of their interface. Such a physical (or indeed possibly chemical, should the interaction between the materials in the region of their interface be chemical in nature) bond between the respective components would significantly reduce the likelihood that the insert might detach itself from the pressure vessel and start to rotatingly slip relative to the pressure vessel when an operative attempts to screw a spear into the threaded aperture of the insert, particularly as the spear is tightened therein.
Additionally or alternatively, the insert may be forcibly welded to the pressure vessel, for example, using ultrasonic welding. Additionally or alternatively, a bead or film of solvent and/or adhesive may be applied to the insert and/or the periphery of the inlet/outlet aperture during the manufacturing process such that the two become sealingly bonded together.
The insert comprises a neck around the exterior surface of which, said neck exterior surface being that surface with which a periphery of the inlet/outlet aperture of the pressure vessel is sealingly united, are provided one or more rotationally (and optionally circumferentially or radially) asymmetric formations which mechanically interact with the aperture periphery of the pressure vessel to prevent the insert from disengaging with, and rotating relative to the pressure vessel aperture in which it is disposed. Various different formations are possible, but one particularly useful formation is a continuous bead in which a plurality of recessed flats are machined, formed or otherwise provided. An alternative (and equivalent) formation would be a discontinuous bead. Regardless of the particular shape of the formation(s), their purpose is the same—to completely prevent (except in the event of catastrophic failure) the insert from rotationally slipping within and relative to the pressure vessel aperture in which it is seated.
For instance, In the case where the pressure vessel is blow-moulded such that the polymer thereof is plastically deformed onto, around, and within said formation(s), and then sets in place, the insert is completely secured within the pressure vessel aperture, both axially (by the radial flanges provided above and below the neck of the insert and between which a corresponding neck of the pressure vessel is formed and thus disposed), and also rotationally (by virtue of the said formation(s) being essentially embedded within said neck of the pressure vessel). For the avoidance of doubt, it should be mentioned that the asymmetry of the formations should be such that there is at least some difference in shape, depth, or width of the formation provided at one circumferential position around the neck as compared to the formation provided at one, or any other circumferential position.
Suitably, the container comprises an outer casing. The outer casing, where provided, may serve, in use, to protect the pressure vessel. The outer casing may comprise circumferential ribs extending around it to facilitate, in use, rolling the container over a floor or ground surface. The outer casing may further comprise a base portion adapted, in use, to stabilise the container when it is stood upright. The outer casing may further comprise upper portion adapted, in use, to facilitate manual handling of the container, and/or to protect the inlet/outlet aperture and the external part of an attached spear. The upper portion may additionally comprise handle portions.
Suitably, the outer casing, where provided, comprises three parts, namely a base portion, a waistband portion and an upper portion. The aforementioned three casing portions are suitably united by clip fittings and/or by ultrasonic welding and/or by an adhesive. By making the outer casing in three parts, a further possible advantage of rationalisation may flow from the invention, by which a manufacturer could use the same base and/or upper portions on every container, but vary the waistband portion to suit different customer's needs, for example, by providing customer-specific colours, branding, embossing, debossing etc.
The container of the invention may also comprise a pressure-relief safety valve.
Suitably, the thermoforming process comprises a blow moulding process. The method may thither comprise the step of forming an internal screw thread on an interior surface of the tubular insert. The method may thither comprise the step of applying a bead or film of solvent or adhesive to the insert and/or to the periphery of the pressure vessel's inlet/outlet aperture. The method may thither comprise the step of welding, for example ultrasonically welding, the insert to the periphery of the pressure vessel's inlet/outlet aperture.
The method may thither comprise the step of forming, and affixing, an outer casing around, the pressure vessel. Suitably, the outer casing is formed in two or more parts that can be placed around the pressure vessel and joined or united subsequently, for example, by clip-fitting together and/or using an adhesive and/or using ultrasonic welding.
Preferred embodiments of the invention shall now be described, by way of example only, with reference to the accompanying drawings in which:
In
The upper casing portion 18 comprises a pair of diametrically opposed cut-outs forming handles 26 into which have been inserted clip-fitting, slidably receivable grip portions 28. The waistband portion 16 of the outer casing 12 also comprises a display portion 30 onto which indicia (such as advertising or branding) can be printed, embossed or debossed, as required.
It will be noted from
The central waistband portion 16 of the outer casing 12 comprises a pair of circumferential ridges 36 which facilitate rolling the container 10 when it is laid on its side.
The pressure vessel 20 and the outer casing, handles 28 and the insert 24 are all manufactured from plastics materials, which makes the container 10 considerably lighter than a stainless steel equivalent.
Turning now to
It will be seen from
The insert 24 is formed as a generally tubular plastics component, which comprises an internal thread 40 around its upper periphery, which is designed to engage with a complementary external screw thread of a dispensing spear (not shown). The lower end of the insert 24 terminates in an outwardly radially projecting flange 42, which seats in a correspondingly shaped recess 44 surrounding the periphery of the inlet/outlet aperture 22 of the pressure vessel 20.
The inlet/outlet aperture's periphery and the flange portion 44 of the insert 24 are fused together during the manufacturing process of the pressure vessel 20. Specifically, the pressure vessel 20 is blow moulded from a tube of softened plastics material (the blank), which is lowered into a mould. A first crimping device (not shown) clamps around the outside of the softened blank to pinch the bottom part 46 of the pressure vessel 22 together during the moulding process. The insert 24 is pre-located inside the mould and a second crimping device (not shown) draws the upper parts 48 of the softened blank together around the outside of the insert 24 during the moulding process. Then, pressurised air or gas is blown into the interior volume 38 formed by the softened blank to form the shape of the pressure vessel 20 by outward expansion onto the interior form of the mould. Because the blank for the pressure vessel 20 is in a softened state during this procedure, it is able to form an intimate joint with the outside surface and/or flange 42 of the insert 24. Furthermore, because the blank is in a semi-solid-state during the moulding process, it is able to fuse and sealingly bond to the flange portion 42 of the insert 24 during the moulding process.
It will be appreciated this manufacturing technique forms a unitary structure comprising the shaped pressure vessel 20 and the now integrally formed insert 24.
The pressure vessel 20 is typically manufactured from a thermoplastic material such as polyethylene or polypropylene, whereas the insert 24 is typically manufactured from a harder, machinable material, such as ABS. Therefore, the pressure vessel provides a tough, durable and waterproof enclosure for the contents of the container 10 in use, whereas the insert 24 provides a much harder component, which can be accurately machined, moulded or threaded to receive a dispensing spear (not shown), in use.
It can be seen from
Suitably, the upper, lower and waistband portions comprise a radially outwardly disposed lip portion, which overlaps the join line between the lower portion and the waistband portions; and the upper portion and the waistband portion.
Conveniently also, the overlapping portions 56 form the radially outwardly projecting ribs 36 previously mentioned, to facilitate rolling the container 10 across a floor or ground surface.
Turning back to
Turning now to
It can also be seen in
It can also be seen from
Referring briefly to
It is to be specifically noted also from
It will be appreciated that the pressure vessel 20 will require a pressure relief valve to safeguard against a risk of explosion, and a pressure relief valve suitable for use in conjunction with a container according to this invention is shown in
Referring first of all to
An O-ring seal 112 is located on top of the barb portion 108 such that once the main body portion 102 has been inserted through the hole 110, it can be raised such that the O-ring seal 112 seats correctly, and is trapped between the upper part of the barb portion 108 and the underside 114 of the sidewall of the pressure vessel 20.
A screw threaded locking ring 116 is then screwed onto the outside of the main body portion 102 to clamp the periphery of the hole 110 in the pressure vessel 120 between the barb portion 108 and the locking ring 116.
The locking ring 116 comprises a stepped upper portion 118, which comprises two axially spaced apart edges 120, 122 that are adapted to engage an internal bath ring 124 of a push-on cover 126 of the valve 100.
The push-on cover 126 is manufactured from a single piece of injection moulded plastics material, such as polyethylene, and has a lower skirt portion 128 that covers the locking ring portion 116 thereby preventing tampering with the locking ring 116 after installation.
The cover portion 126 also comprises a number of vent apertures 130 which, when the cover portion 126 is pushed onto the locking ring, as shown in
Referring to
In certain embodiments of the invention, the locking ring 116 is manufactured from an anodised metal ring, for example being coloured red, such that once the cover portion 126 has popped-up during a pressure relief event, it will become apparent to an observer that something is amiss because the red locking ring 116 will be visible from outside the valve 100. It will also be noted from
Embodiments of the pressure relief valve are shown in
It can also be seen in
The invention is not restricted to the details of the foregoing embodiments, which are merely exemplary of the invention. For example, and shapes, materials or dimensions, whether explicit or implied, are illustrative of the invention, except where they are mentioned in the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
1521509.8 | Dec 2015 | GB | national |
This application is a U.S. National Phase application of International Application PCT/GB2016/05381 filed Dec. 5, 2016, which claims priority to GB Application 1521509.8 filed Dec. 7, 2015, the entire disclosures of which are hereby incorporated by reference herein in their entireties.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/GB2016/053818 | 12/5/2016 | WO | 00 |