WO2021156352A1

WO2021156352A1 - Accessories for drinking vessels

Info

Publication number: WO2021156352A1
Application number: PCT/EP2021/052638
Authority: WO
Inventors: Declan FEARON; Marek REBOW; Richard Woods
Original assignee: Freezadome Limited
Priority date: 2020-02-08
Filing date: 2021-02-04
Publication date: 2021-08-12

Abstract

An accessory for a drinking vessel, comprises an insert body member (54) adapted for insertion into a drinking vessel interior, the insert body member (54) providing a heat sink effect to stabilise the temperature of a liquid when immersed therein, and means for securing said insert body (54) to the interior of a drinking vessel. The securing means is preferably in the form of a pair of magnetically attractive members, the first of which is located on the insert body member (54) and the second of which is positioned in use on the exterior of a wall of the drinking vessel against whose interior the first member is located. A preferred embodiment is in the form of an elastomeric dome (56) with a flat base (58), filled with a thermal energy absorbing material (62) such as a mixture of water and an alcohol.

Description

Accessories for drinking vessels

Field of the Invention

The present invention relates accessories for drinking vessels to lower the temperature of the contents of the vessel or stabilise the temperature of the vessel contents against warming due to ambient conditions for a period of time.

Background of the Invention

Normally it is desirable when consuming beverages to maintain the beverage at a suitable temperature (a serving temperature), which may be above or below ambient temperature.

Conventional rates of consumption of beverages such as beer are usually at a relatively slow rate such that the beverages remain exposed to normal ambient temperatures for sustained periods of time. Consequently, the temperature of the beverage steadily rises towards ambient temperature as it is being consumed with a corresponding loss of desirability for the beverage. For example, all beers should be served between 3.5 and 13°C, but lagers may be served colder than ales, and certain ales may be served colder than stouts. Beers served at near-frozen temperatures retain more CO2 gas (resulting in a more filling experience for the consumer). Carbonated cider can be served from anywhere between 4°C and 6°C. However, it is difficult to provide a way of ensuring the optimum serving temperature for a range of different beers from a bar, let alone to give the consumer any choice in the serving temperature.

The optimum serving temperature for enjoyment of full-bodied white wines and fruity reds involves refrigerating or chilling the wine bottle to say 10 -15°C, while light and dry white, dessert and anything sparkling are at their best from 4°C to 10°C. Red wines are normally served and enjoyed at close to normal room temperature at say 12-18 °C . This is problematic on an airplane, where due to space limitations for refrigeration and storage in business and first class sections, white wines are often served too warm and red wines too cold.

Coca-Cola advises that the "perfect" temperature to serve its drink is from 1°C to 3.3°C (34 to 38 degrees Fahrenheit) so ice is recommended to lower their temperatures. But usually, cold beverages should be served at 8-10°C. l Several prior art devices are available which attempt to remedy the aforementioned problems. Early attempts to provide a constant chilled beverage temperature included the use of a double walled drinking vessel with a sealed chamber containing a refrigerant, such as water or a gel, e.g. as described in U.S. Patent Nos. 3,680,330 and 2013/0233866 A.

This is normally made of plastic and has to be stored in a refrigerator or freezer for an hour or so before use. The refrigerant is intended to maintain the beverage at a suitable temperature, but of course once the refrigerant turns back from a frozen state to an unfrozen state, the cooling effect is quickly lost. It is also unpleasant to drink wine or beer from a plastic drinking vessel, and condensation on the outer surface is a problem. A foam-moulded outer layer has been used to insulate the drinking vessel. However, using an outer insulation layer to keep a liquid cooler for a longer period of time, in conjunction with the use of a refrigerant results in a very bulky and more expensive drinking vessel.

Similarly, prior art devices exist as inserts for cooling the liquid contents of a bottle which are dipped into the bottle through the open neck, containing a refrigerant, such as water or a gel, e.g. as described in n U.S. Patent Application No. 2006/191238 A1. A disadvantage here is that the cooling device, which has a spindle shape to fit through the neck of the bottle, displaces a certain amount of liquid when dipped into the bottle, so that this amount of liquid has first to be poured out of the bottle, if it is full. A freezable insert for fitting into a stem drinking glass is described in U.S. Patent Application No. 2009/0056368 A1.

Rather than employing a liquid refrigerant, phase change materials (PCMs) can be incorporated into a drinking vessel in order to cool, or warm, the contents of the vessel, by removing or releasing or heat. US Patent Application No. 2013/0221013 A1 describes double-walled drinking vessels, cup holders, jugs and baby’s bottle warmers with a sealed interstitial chamber containing a PCM.

DE102013 114 507 B3 describes a double walled drinking vessel or cup with a sealed compartment containing an organic PCM such as stearic acid mixed with graphite powder in a paste form, for keeping coffee warm. The outer layer of the cup may be an insulating layer with low heat conductivity and the inner layer, or insert, may be of metal or have higher heat conductivity. The cup may be made using a porcelain shell whose hollow interior is filled with a honeycomb structure made of highly conductive material, such as aluminium. This honeycomb structure is then filled with PCM. When the cup is filled with a hot liquid, such as coffee, heat from the coffee is directed straight into the solid phase PCM. This heat, in term, melts the PCM and turns it into its liquid phase. The PCM then retains thermal energy, but without absorbing any more heat, and slowly releases the stored or latent heat back into the coffee. The PCM can be designed to melt at say at 58°C and maintain this temperature, thereby keeping the coffee at that optimum enjoyment temperature for a longer period, following activation of the phase change. However, this is still quite a bulky and expensive drinking vessel to manufacture.

Phase change materials (PCMs) are substances which allow for the storage of heat energy as latent heat and sensible heat. For example, as the substance changes phase from solid to liquid (melts) it is capable of absorbing a large amount of latent heat around its melting point temperature. Conversely, as the substance changes from liquid to solid (solidifies, crystallizes or freezes) it is capable of releasing a large amount of latent around its solidification temperature. A drinking vessel incorporating a PCM, may be regarded as latent heat storage unit. Similarly, a pad containing an inorganic PCM, such as sodium acetate, which becomes warm when it crystallises, may be used as a hand warming pad. Organic PCMs include paraffin waxes, fatty acids, palm oils, esters, glycerine, phenols, etc. which have advantages of being non-toxic, and may be formulated to have melting points within a useful range of from -20°C to +60°C. They may have a bulk structure or may be macro or micro -encapsulated. However, most PCMs suffer from being unsuitable in terms of their thermal properties, i.e. being unable to maintain a drink at a suitable serving temperature, or because they are not food-grade which can cause some health & safety issues when a vessel is broken.

PCMs are sometimes mixed with graphite in powder form, or combined with a graphite foam, for example as described in US Patent No.6, 037, 032, in order to increase the effective thermal conductivity through the volume of the PCM, and so increase the rate in which latent heat is absorbed or released, as compared to bulk PCMs.

While the discussion above focusses on modifications to the drinking vessel itself, it is also known to provide accessories that cool the beverage in the vessel or stabilise a cooled beverage against warming for a period of time. Such accessories, which may be known as “whiskey stones” are chilled in advance of use, and can then be dropped into a drinking vessel to provide an effective substitute for ice cubes, in particular without diluting the drink as they absorb heat from the beverage.

A drawback with such whiskey stones is that they can be relatively heavy and pose a risk of damaging the glass or of injuring the user (e.g. if the drink is tipped back and the stones fall onto the mouth, teeth or lips of the user).

Summary of the Invention

The invention provides an accessory for a drinking vessel, comprising: an insert body member adapted for insertion into a drinking vessel interior, the insert body member providing a heat sink effect to control the temperature of a liquid in which the insert body member is immersed; and means for securing said insert body to the interior of a drinking vessel.

The accessory can be retrofitted to conventional drinking vessels, whether of glass, plastic or any other material. It can be affixed permanently within the vessel or it can be removably secured.

In contrast to whiskey stones and similar ice cube replacements, the accessory includes securing means which hold it in place within the vessel interior. As such, the user is assured that the accessory will not fall out or slide onto the user’s mouth or teeth when the vessel is tipped back as the beverage is consumed.

In comparison with other solutions for controlling the temperature of a beverage, such as modified drinking vessels (as also described herein), the accessory has the advantage of being inexpensive, easily mass-produced, and capable of being fitted into many existing designs of drinking vessel. Furthermore, unlike modified glasses which can take up significant freezer or refrigerator space when being chilled or frozen before use, the accessory occupies much less space (typically a fraction of the interior volume of the beverage container.

The accessory is particularly advantageous for environments where space is at a premium (such as on aircraft or onboard boats, ships or trains), in environments where storage and refrigeration facilities may be ad hoc or temporary (e.g. festivals, concerts, parties and catering events in a location not having extensive bar or kitchen facilities), and in environments where there is a disincentive to hand users a relatively expensive vessel or a glass vessel (such as concerts and sports events and such like). It provides a premium solution to the problem of controlling the temperature of a beverage after serving even in a disposable plastic “glass”.

Furthermore, because the accessory can be added to some drinking vessels and not to others, it may be preferred as providing an additional sales channel to increase per- customer profit.

Preferably, said securing means comprises a pair of magnetically attracted members, a first one of which is provided on or in the insert body and a second one of which is adapted to be disposed, in use, against an external wall surface of the drinking vessel and thereby secure the insert body against a corresponding internal wall surface.

A magnetic securing solution is particularly attractive because it allows the accessory to be secured in place even after the beverage has been poured and the accessory added to the glass as the securing means can be engaged without having to manipulate the accessory in the liquid.

Preferably, said insert body member has a top side and a bottom side, wherein said bottom side is configured to rest stably on a flat interior base surface of a drinking vessel, wherein said first magnetically attracted member is located at said bottom side, and wherein said second magnetically attracted member is shaped to sit below and against the exterior of the base surface of the drinking vessel or within a recess provided below the exterior of the base surface.

In preferred embodiments, said top side is generally dome shaped.

Preferably, said first and second magnetically attractive members each present a generally flat surface such that in use, the respective flat surfaces may be positioned against opposed sides of a drinking vessel base and secured in place by mutual magnetic attraction, thereby securing the insert body member within the vessel.

The first magnetically attractive member may be formed integrally with the insert body member. Alternatively, it may be secured to an external surface of the insert body member. As a further alternative, it may be secured to an internal surface of the insert body member, e.g. where the insert body member defines an internal void. In another alternative, the first magnetically attractive member may be secured within the thickness of a wall of the insert body member (e.g. being embedded or moulded therein, or inserted into a pocket or cavity in the wall).

Preferably, said insert body including said first magnetically attractive member has a negative buoyancy in water, and the buoyancy thereof is unequal across its volume such that the insert body tends to sink in water with said first magnetically attractive member at the underside of the insert body.

This provides a significant advantage in that the insert body member with first magnetically attractive member can be dropped into a vessel containing liquid of density similar to water, and it will sink to the bottom, reaching the bottom of the vessel with the first magnetically attractive member downmost and resting on or very close to the base of the vessel. The second member may then be secured in place by positioning it on the exterior of the base where it will be directly opposed to the first member.

Preferably, said insert body comprises a sealed elastomeric membrane defining an internal void, the membrane being shaped to have a rounded upper wall and a flat base wall, and said first magnetically attractive member is a flat member attached to or embedded in the flat base wall.

As an alternative to a magnetic securing means, securing means may be a food grade or food-safe adhesive with neutral taste properties, allowing the accessory to be permanently affixed within the base of the vessel.

In other embodiments, the securing means comprises a resilient member disposed on a perimeter of the insert body, such that when inserted into a drinking vessel the resilient member is adapted to frictionally engage with an internal sidewall of the drinking vessel and thereby secure the insert body within the vessel.

Preferably, in this case, said insert body member has a top side and a bottom side, the bottom side being generally flat and having said resilient member is projecting outwardly from the periphery thereof.

Further, preferably, said resilient member is an outwardly projecting skirt formed of a resilient material.

One example of this is a frictional securing mechanism, such as a resilient skirt, for example made of silicone, which fits snugly within the walls when the accessory is pushed down into the vessel’s interior and resists being dislodged by gravity. It may be designed for semi permanent or permanent insertion, or it may be configured to permit easy removal, such as by pushing down on one side to break a seal, or it may have a tab allowing it to be pulled free with a positive force while nevertheless being resistant to removal by gravity.

As a further alternative, said securing means comprises a formation provided on the insert body member that is adapted to mechanically engage with a corresponding formation provided on the interior of a drinking vessel.

Such a formation is preferably selected from a snap fit formation, a cam lock element and a twist lock element. Preferably, said insert body member comprises a sealed internal void, and wherein said accessory further comprises a thermal energy absorbing material contained in said sealed internal void.

However, other body member types are envisaged including solid bodies having a sufficient heat capacity to act as a heat sink.

In the case where the insert body member comprises a sealed internal void containing thermal energy absorbing material, preferably at least a portion of the insert body member defining the internal void comprises a wall section formed of a flexible membrane which permits the volume of the internal void to expand and contract with changes in temperature.

The provision of a flexible membrane allows for the void to be filled completely (or substantially completely) while permitting expansion of the PCM when it is frozen prior to use. This gives a significant advantage in maximising the thermal transfer between the PCM and the liquid in the vessel, by minimising air bubbles that would insulate the PCM from the liquid in the vessel. By saying that the PCM “substantially fills” the internal void, is meant that the structure either fills the void, or the amount of empty space occupied by air is insufficient to cover more than 15%, and preferably more than 5%, of the internal surface of the upper wall in a normal orientation. In this way, the adverse performance of air bubbles, which may insulate the upper wall from the temperature control structure, is minimised. In general, the design and manufacturing process should be optimised to eliminate air bubbles which could travel to the interface with the upper base wall. It is envisaged that in some cases, there may be additional structural elements within the void, such as an open cell foam within which the thermal energy absorbing material is distributed, or a compressible member as discussed further below.

Preferably, said insert body member is formed predominantly of an elastomeric membrane filled with said thermal energy absorbing material.

Preferably, said thermal energy absorbing material comprises water and one or more of a freezing point depressant and a thickening agent.

Preferably, said thermal energy absorbing material comprises water, an alcohol and a thickening agent.

Preferably, said thickening agent is selected from carboxymethyl cellulose, sodium polyacrylate, food-grade hydrogels, food-grade cellulose ethers, food-grade polymeric foams, agar, carrageenans, natural gums, graphite powder, copper powder and aluminium powder

The thickening agent is strongly preferred to be food safe,. This ensures that in the event of breakage, cracking, bursting or leakage, there is no hazard to health and therefore no concern about the use of this invention.

Food safe materials are those that have been specified by a public health body as conforming to the standards set for materials coming into contact with food. For example, the European Food Safety Authority maintains a list of food contact materials (FCMs). Similarly the U.S. Food and Drug Administration regulates a list of approved Food Contact Substances (FCSs). See for example https://www.fsai.ie/publications foodcontactmaterial/ and https://ec.europa.eu/food/sites/food/files/safety/docs/cs fern plastic- guidance 201110 en.pdf for source lists of food safe materials.

The accessary may optionally include an open-cell foam located in the internal void, wherein said thermal energy absorbing material is distributed within and through the cells of the open-cell foam.

A temperature control structure provided in an internal void of the insert body can further comprise an open-cell foam located in the internal void, the thermal energy absorbing material being distributed within and through the cells of the open-cell foam.

In this way the open cell foam can assist in efficient heat transfer through the bulk of the thermal energy absorbing material, providing a more efficient heat sink. An open cell foam is particularly good for this, having a very high surface area of contact between the foam material and the thermal energy absorbing material in the foam’s cells.

Preferably, said foam is formed of a material having a thermal conductivity of at least 10 Wnr¹K ¹.

The minimum thermal conductivity level of 10 Wnr¹K ¹ for the open cell foam material refers to the bulk material value. This conductivity helps ensure good thermal distribution and rapid conductivity through the volume of the thermal energy absorbing material. Preferred open cell foams will have thermal conductivity values of in excess of 50 Wnr¹K ¹ and preferably several hundred Wnr¹K ¹

Preferably, the foam is formed of a metal or of graphite. Preferably the metal is selected from copper, copper alloys, aluminium, aluminium alloys, or steel.

Most preferably, the foam is a copper foam.

Preferably, said compressible member is disposed between said open-cell foam and a lower wall of said internal void.

In cases where the foam substantially fills the upper part of the void, the compressible member may be sandwiched between the foam and a lower wall of the void.

In preferred embodiments, the thermal energy absorbing material further comprises a freezing point depressant.

A freezing point depressant enables the freezing point of the PCM to be tailored to specific applications. The freezing point will typically be set to several degrees Celsius below the intended serving temperature, with the optimum temperature offset being determined by the volume of the PCM, the composition of the open cell foam, the wall thickness between the void and the interior volume of the vessel, and so on. However, using typical values and materials, it has been found that a target freezing point of between 5°C and 15°C below the desired serving temperature is advantageous, and particularly between 7°C and 12°C degrees below desired serving temperature, even more preferably by 8°C to 10°C.

Preferably, the freezing point depressant is ethyl alcohol.

Alternatively, a salt may be used to depress the freezing point. The thickening agent may have both thickening and freezing point depressive properties, in which case the amount of freezing point depressant (if required) can be adjusted accordingly, e.g. freezing points of 5% and 10% by weight of sodium chloride brine are -3°C and -6.5°C, respectively.

Other food grade fluids, which mix well in water solutions, lower a freezing point and reduce super-cooling of water, are natural ester oils containing poly-unsaturated fatty acids (PUFA) extracted from soya bean or corn. By adding of these commonly called ‘vegetable oils’ by 5% to 10% in a water solution could decrease the freezing temperature from 0°C down to - 3.5°C to -6.5°C, respectively.

Preferably, the freezing point depressant is added in an amount effective to depress the freezing point of said thermal energy absorbing material to between -1 5°C and -10°C. Preferably, the thickening agent is provided in a volume of between 1% and 20% of the volume of said thermal energy absorbing material.

In certain preferred embodiments, the thickening agent comprises sodium polyacrylate (or polyacrylic acid sodium salt) and is provided in a volume of between 2% and 8% of the volume of said thermal energy absorbing material.

In other preferred embodiments, the thickening agent comprises a natural gum and is provided in a volume of between 4% and 15% of the volume of said thermal energy absorbing material.

Preferably, the upper wall which separates the internal void from the interior volume of the vessel is configured to project into the vessel interior above its base.

Further, preferably, the upper wall is defined by a protrusion into the interior volume of the vessel, said protrusion being an introverted bulbous protrusion, a hollow finger shaped protrusion, a bell-shaped protrusion or a domed protrusion.

Preferably, the base further comprises a lower wall which together with the upper wall seals the internal void.

Preferably, in such embodiments, the compressible member is sandwiched between said open-cell foam and said lower wall.

Brief Description of the Drawings

The invention will now be further illustrated by the following description of embodiments thereof, given by way of example only with reference to the accompanying drawings, in which:

Fig.1 is an elevational cross section of a drinking glass in accordance with a first embodiment not currently claimed;

Fig. 2 is a sectional elevation of a drinking glass in accordance with a second embodiment not currently claimed;

Fig. 3 is a sectional elevation of a drinking glass in accordance with a third embodiment not currently claimed;

Fig. 4 is a sectional elevation of a temperature control structure for use in a drinking vessel;

Fig. 5 is a sectional elevation of an accessory for a drinking vessel in accordance with of the invention, referred to herein as the fourth embodiment; Fig. 6 is a sectional elevation of the accessory of Fig. 5 in place in a drinking vessel;

Fig. 7 is a sectional elevation of an accessory for a drinking vessel in accordance with the invention (fifth embodiment);

Fig. 8 is a sectional elevation of the accessory of Fig. 7 in place in a drinking vessel;

Fig. 9 is an exploded view of an accessory for a drinking vessel in accordance with the invention (sixth embodiment);

Fig. 10 is an exploded view of an accessory for a drinking vessel in accordance the invention (seventh embodiment);

Fig. 11 is a perspective view of the accessory of Fig. 9 or Fig. 10 and a drinking vessel when the accessory is being inserted into a drinking vessel;

Fig. 12 is a perspective view of the accessory and drinking vessel of Fig. 11 when the accessory is inserted and secured;

Fig. 13 is a sectional elevation of the accessory and drinking vessel of Fig. 11 at an intermediate stage during insertion of the accessory;

Fig. 14 is a sectional elevation of the accessory and drinking vessel of Fig. 11 when the accessory is inserted and secured;

Fig. 15 is a comparative plot showing the effect on beverage temperature versus time of a drinking vessel as described herein as compared with a conventional drinking vessel under different experimental conditions;

Fig. 16 is a comparative plot showing the effect on beverage temperature versus time of a drinking vessel as described herein as compared with a conventional drinking vessel under different experimental conditions;

Fig. 17 is a comparative plot showing the effect on beverage temperature versus time of a conventional plastic drinking vessel fitted with an accessory according to the invention as compared with a conventional plastic drinking vessel without the accessory

Fig. 18 is a sectional elevation of a drinking glass in accordance with a fourth embodiment not currently claimed;

Figs. 19 and 20 are enlarged views of the base of a drinking glass in accordance with a fifth embodiment not currently claimed; and

Figs. 21 and 22 are sectional elevations of a drinking glass in accordance with a sixth embodiment not currently claimed. Fig. 23 and 24 are sectional elevations of accessories for a drinking vessel in accordance with the invention, referred to herein as the fourth embodiment.

Detailed Description of Preferred Embodiments

In Fig. 1 there is indicated, generally at 10, a drinking vessel of a tulip shape typically used for serving beer or cider (though of course it is by no means limited to such applications).

The vessel is made of glass, the glass shape having a generally cylindrical sidewall with a tulip profile, and a concave (when viewed from below) domed upper base wall 14, which together define a vessel interior 16, shown here filled with liquid.

Below the upper base wall 14 and sealing the base of the vessel 10 is a disk 18 which may be of a flexible or compliant sealing material such as a setting or curable resin. The disk may also be of glass, plastic, or any other suitable material which bonds to the main glass body. The disk 18 provides a seal and a flat base for the glass to rest upon. Within the base, between the disk 18 and the upper base wall 14 is a sealed internal void 20 having a volume of about 30 ml, filled with a temperature control structure 22 which will be described in detail below. At a minimum the temperature control structure has a thermal energy absorbing material (or PCM) comprising water, and a compressible member, the temperature control structure filling or substantially filling the internal void.

The temperature control structure is designed to absorb heat efficiently from the liquid in the interior volume of the glass, with this effect being increased by the domed shape which increases the surface area of liquid in contact with the upper base wall’s top surface.

Prior to pouring beer, the glass is kept in a freezer or refrigerator to allow a thermal energy absorbing material in the temperature control structure to change its phase from liquid to solid (freeze or solidify). When beer is poured into the glass, the dome is completely covered. The cooling effectiveness of the temperature control structure will depend on the temperature of the beer, the temperature of the ambient environment, the initial glass temperature and the volume of liquid in the glass, as well as the manner in which it is held.

However, using the compositions and structures disclosed herein, with internal void volumes of about 30 ml in a pint glass, under normal conditions (i.e. commercial bar freezers, beer served at 3.5°C, ambient temperatures of 20°C), it was found that the glass of Fig. 1 was effective to maintain the beer temperature below 4°C even after 30 minutes, whereas a conventional glass taken from the same freezer exhibited a rise in temperature to about 12°C over the same period. These experimental results are discussed further below. The thickness of the upper base wall between the beverage and the internal void should be as thin as possible within the constraints of manufacturing processes and the strength of glass to avoid its brakeage in normal use. However a wall thickness of 2-3mm is achievable and provides the results discussed above.

While the glass of Fig. 1 may be conventional glass used in beverage applications, one can employ glasses having a higher thermal conductivity than a typical glass to reduce thermal resistance between beverage and the temperature control structure and thereby increase heat transfer rates.

In Fig. 2, indicated generally at 24, is a second embodiment of drinking vessel, in which like parts are designated with like reference numerals as in Fig. 1. However, in place of the domed upper base wall 14 of Fig. 1 , the vessel 24 has a bell-shaped upper base wall 26 forming a more pronounced protrusion into the interior volume 16. The bell-shaped protrusion is suited to providing more intimate indirect contact between the material inside the internal void and the liquid contents of the glass. Preferably, the dome of the Fig. 2 embodiment extends about one third the overall height of the glass, but it may be configured as a finger extending to about three-quarters the height of the glass. This design prevents complete mixing of a fluid in the lower and upper part of the glass resulting in a cooler fluid at the end of drinking than in the glass in Fig. 1. The same design principle is presented for the accessory in the example 3.

In Fig. 3 there is indicated generally at 28 a third embodiment, constructed entirely of glass, having a tapered straight sidewall 30, a flat upper base wall 32, and a flat glass lower base wall 34 sealing a frusto-conical internal void 36 within the base 38 of the glass.

While the walls are all shown as having equal thickness, in practice the sidewalls of the main liquid-containing volume may be thinner than the walls of the base. For example, one possible design (whether of the glass of Fig. 1 , 2 or 3) has main sidewalls of 1 mm to 3.5 mm thickness, an upper base wall of 2 mm to 3.5 mm thickness, and sidewalls around the base of 4 mm to 7 mm thickness. The thickness of the lower base wall or of the disk sealing the base can be from 1 mm to 8 mm depending on the material used (as this may be glass or some other sealing material).

The temperature control structure filling the internal void 36 of Fig. 3 can be seen to have an upper component 44 and a lower component 46 which will now be described in further detail.

Fig. 4 shows the temperature control structure used in Fig. 3, which may be adapted with suitable changes in shape for use also in the vessels of Figs. 1 and 2. The upper component 44 is an open cell copper foam member 48 shaped to occupy most or all of the upper portion of the internal void and fit within whatever shape is chosen for the upper base wall’s lower surface. Thus, while a flat top is specified in Fig. 4, this would be a domed shape for Fig. 1 and a bell shape for Fig. 2.

It is not necessary that the copper foam member be in close contact with the upper base wall, though it is preferred; the main function of the copper foam is to assist in heat transfer through the volume of liquid with which it is saturated. Indeed, it is not essential that the foam be used at all, though it does provide optimum heat transfer efficiency.

The open cell foam is saturated with a thermal energy absorbing material 50 that is distributed within and through the cells of the open-cell foam. The material 50 comprises water and a thickening agent so as to provide a viscous liquid, or a gelatinous or semi-solid material that can be absorbed by the open cell foam.

The lower member 46 of the temperature control structure is a compressible member 52 that ensures that the internal void is completely filled and nevertheless permits thermal expansion of the material 50, particularly when the material 50 is cooled down to and below its freezing point. The skilled person will be aware that water expands by approximately 9% as it changes its phase to ice below 0°C. The material 50 may have a different freezing point due to the presence of the thickening agent and optionally a freezing point depressant, but it will nevertheless exhibit similar amounts of expansion due to the water content.

The open cell foam used in the specific example shown here is copper with a 95% porosity and 10 pores per inch. Thus, if the volume of the copper foam body is 20 ml (a typical value for use in the base of a drinking glass), this will contain 1 ml of copper, the remaining volume being the voids.

The thermal energy absorbing material 50 is with a food-grade hydrogel solution consisting of (in one embodiment used in experimental results discussed below): 21.5 ml water, 5.5 ml alcohol solution (40% ethyl alcohol, 60% water), 1 ml sodium polyacrylate (polyacrylic acid sodium salt crosslinked, FCM substance No. 1015, CAS No. 0009003-04-7), 1 ml graphite powder.

The compressible member 52 is a disk of polyurethane 1.5 mm thick, 50 mm in diameter (therefore with a volume of just under 3 ml). Other compressible members may be used provided that they provide sufficient compressibility (e.g. 9% or more) and that, for applications where the vessel is to be used for beverages, they are food-grade or food safe materials.

The optional addition of graphite powder assists in thermal conductivity through the material. Some other compositions for the thermal energy absorbing material are shown in Table 1 below, with the just-described material identified as composition #1. Values in Table 1 are expressed as volumes of additive per 1 ml of water/alcohol. The proportion of alcohol in the water can be varied in order to adjust the intended freezing point. Thus, in the material described above, there is 21.5 ml water plus 5.5 ml of 40% alcohol solution giving 27 ml water/alcohol in the composition. This 27 ml is composed of 0.4 * 5.5 = 2.2 ml alcohol, and 21.5 + (0.6 * 5.5) = 24.8 ml water. The sodium polyacrylate (polyacrylic acid sodium salt) is added in an amount of 1 ml per 27 ml water/alcohol, or 0.037 ml per 1 ml water/alcohol, which is the value in Table 1. The same composition, with a different alcohol concentration, could be employed to achieve a different freezing point.

Table 1

The inventors have found that excellent cooling results are found when the thermal energy absorbing material or PCM is adjusted to have a freezing point about 8.5°C below the desired serving temperature of the beverage.

Table 2 below shows, for different PCM volumes (25, 30, 35, 40, 45 and 50 ml), the required volume of 40% ethyl alcohol solution that is required to achieve a particular PCM freezing point, and the corresponding optimum serving temperature associated with such a PCM. Thus, for a 25 ml PCM volume, with a desired serving temperature of 2°C, the target PCM freezing point of -6.5°C is achieved with 6.5 ml alcohol solution in the 25 ml PCM volume. Similarly, for a 40 ml PCM volume and desired serving temperature of 5°C, the target PCM freezing point of -3.5°C is achieved with 5.6 ml 40% alcohol solution in the 40 ml PCM volume. The skilled person will be able to adjust the values accordingly for other PCM volumes and alcohol solution concentrations to achieve the same differential of 8.5°C, or indeed adapt this to achieve an alternative differential between serving temperature and PCM freezing point.

Table 2

Fig. 5 shows, generally at 54, an accessory for use with a drinking vessel. The accessory 54 takes the form of an insert body member having a domed top surface 56 and a flat underside 58, which together define a sealed internal void 60. The domed top surface may be made of food-grade plastic, of aluminium or of glass, and the flat underside may be made of food- grade plastic, of glass, or sealed with aluminium foil.

The void 60 has a thermal energy absorbing material or PCM 62 within it, which comprises water. In its simplest form, the entire volume of the internal void is taken up by water.

The PCM may also include a thickening agent such as natural gum, carboxymethyl cellulose or sodium polyacrylate. The compositions given in Table 1 and 2 may all be used as the thermal energy absorbing material.

Optionally, the void may include an open cell foam structure within and through which the thermal energy absorbing material is distributed. It may also include thermally conductive particles such as graphite, copper or aluminium.

It may include a freezing agent depressant, such as alcohol, salt or natural ester oils extracted from soya bean or corn as previously described. In particular, the temperature control structure of Fig. 4 may be incorporated into the internal void of the Fig. 5 device.

Fig. 6 shows the accessory of Fig. 5 in place in the bottom of a drinking vessel 64, with the flat underside secured to the base 66 of the vessel by a food-safe adhesive 68. It can be inserted and adhered immediately before use (in which case the accessory alone only needs to be frozen) or prior to use including when the vessel is being manufactured or as a separate fitting or retrofitting operation. When it is secured in advance, then in preparation for use the vessel with the accessory in situ is frozen before the beverage is poured.

Fig. 7 shows a further accessory, indicated generally at 72, in perspective view from below. The accessory is generally similar in shape to that of Fig. 5 in that it has a domed upper surface 56 and a flat underside 58 defining an internal void (not shown in Fig. 7). However, it differs in the addition of a food-grade silicone skirt 69 which has an annular shape with an internal diameter less than that of the base 58 and an external diameter greater than that of the base, so that it extends beyond the periphery 70 of the insert body member.

In use, as shown in Fig. 8, the accessory 72 is inserted into a glass with an internal diameter which is greater than that of the insert body but less than the external annular diameter of the silicone skirt 69. This has the effect of displacing the skirt upwardly as the accessory is slid downwardly towards the base 66 of the glass 64. The skirt therefore conforms to the internal sidewall 74 of the glass and resists being displaced, securing the accessory 72 in place at the bottom of the glass.

The insertion can be permanent, or it can be removable. The accessory can be removed using a purpose designed pincer or suction cup. Alternatively, a pull tab can be provided on the top surface or on the skirt to assist in manual removal. Further alternatively, the skirt can be made long enough to allow a user to grasp and displace it from engagement with the glass.

In Fig. 9 an exploded view of an accessory 75 is seen, showing a plastic dome 76, a plastic base 78 which seals to the dome, and a volume of thermal energy absorbing material 80 which is contained within the assembled dome. As previously described, the thermal energy absorbing material may (but need not) be supplemented with an open cell foam, with a freezing point depressant, with graphite powder and so on.

Fig. 10 shows a similar exploded view of an alternative internal construction for accessory 75. The embodiment of Fig. 10 differs from that of Fig. 9 in the inclusion, below the thermal energy absorbing material, of a compressible member 82. While a compressible member is advantageous, it may not always be necessary, particularly when the dome 76 and base 78 are made of materials with sufficient flexibility to absorb thermal expansions and compressions of the thermal energy absorbing material.

A preferred embodiment takes the form generally shown in Fig. 9, with the dome 76 and the base 78 both made of silicone 1 mm thick. The thermal energy absorbing material is a 5% aqueous solution of sodium chloride, and there is no copper foam or thickening agent. The base is sealed to the dome with a neodymium magnet embedded within the base as will be discussed further below.

The thermal energy absorbing material may be of alternative composition, such as a mixture of water and a thickening agent such as carboxymethyl cellulose. A preferred ratio CMCihhO is in the range from 3:97 to 15:85, more preferably 5:95 to 10:90, with a particularly preferred range of 6:94 to 8:92. To this, salt or alcohol may optionally be added as a freezing point depressant.

In the accessories of Figs. 9 and 10, the base 78 is provided with magnetic properties. For example, a magnet may be secured to the top or bottom surface of the base member or the base member may itself be magnetic. Alternatively, the base member may be made of, or may be provided with, a material that it attracted to a magnet.

As seen in Fig. 11, the accessory 75 may be inserted, similarly to Figs. 6 and 8, into the interior of a drinking vessel 84, flat side 78 downwards. A disk 86 is provided externally off the drinking vessel and is adapted to fit into a recess 88 on the underside of the drinking vessel 84, as best seen in Fig. 12. The disk is magnetically attracted to the base 78. Thus, the disk may be a magnet, or may have a magnet provided on it, or it may be made of, or may be provided with, a material that it attracted to a magnet in the base 78.

A preferred construction incorporates a small, strong, neodymium magnet in the base 78, and has a disk made of steel, nickel, or other ferromagnetic material.

It has been found that with the construction shown, having an elastomeric body construction defining the internal void, and a metallic or other magnetically attractive member on the base, the accessory has a differential buoyancy whereby it tends to orient itself with the base downwards when immersed in a fluid. The materials are chosen to ensure an overall negative buoyancy in water or liquids of similar density, so that it can be dropped into a liquid and it will sink down in the correct orientation to land on the base with the disk against the base. The buoyancy characteristics are preferably chosen so that any additional positive buoyancy arising from bubbles adhering to the accessory (such as when it is dropped in beer, cider, sparkling wine, or any other carbonated or effervescent liquid) is overcome and the net buoyancy is negative. In Fig. 12, the accessory (not shown) is in place at the bottom of the vessel 84 and the disk 86 is in place in the recess 88. Due to the magnetic attraction between two magnetically attracted members, one in or on the disk and the other in or on the base member 78, the accessory is held in place.

Figs. 13 and 14 show the insertion of the accessory 75 and the final configuration, respectively, in cross section. Obviously, the magnetic attraction must be sufficiently strong through the base of the vessel as to hold the accessory in place during normal serving and drinking of a beverage. Preferably it is of a strength that also permits the disk to be detached from its magnetic engagement relatively easily when it is desired to remove the accessory for cleaning or for reuse.

Furthermore, there is a combination of two above inventions: a fluid containment vessel having an internal void which projects into the vessel interior containing a fluid (see Fig 1 or Fig 2) and the insert body member (see Fig 5) adapted for insertion into the drinking vessel internal void. The insert body member, in this combination, is placed in the silicone skirt (see Fig 8) and provides a seal at a flat base for the vessel to rest upon. The internal annular diameter of the silicone skirt (Fig 8) is slightly less than the external diameter of a base of the glass. The skirt therefore conforms to the external sidewall of the glass (Fig 1) and resists being displaced, securing the insert body member in place at the internal void of the glass.

It will be appreciated that the embodiments of Figs. 9-14 are particularly advantageous in permitting the rapid and easy insertion and removal of the accessory, as well as being commercially attractive in providing an external surface 90 of the disk that is very well suited to branding and advertisement purposes.

Example 1

The tulip glass of Fig. 1 was constructed with a temperature control structure as in Fig. 4 in the internal void in the base. The glass was a pint glass (568 ml internal volume). The thickness of the upper base wall was 3 mm.

The dome was filled (from its underside, with the glass inverted) with 29 ml of thermal energy absorbing material, made up of 21.5 ml water, 5.5 ml 40% alcohol solution, 1 ml polyacrylic acid sodium salt, and 1 ml graphite powder. This material had a freezing point of - 5°C.

A 20 ml block of copper open cell foam was also inserted into the dome (porosity 95%, 10 pores per inch, copper volume 1 ml) such that the foam was saturated with and fully immersed in the thermal energy absorbing material, and bringing the overall volume to 30 ml. It will be noted that the volume of the open cell foam (20ml) was less than the volume of thermal energy absorbing material and so there was excess fluid within the dome with the foam being completely immersed.

Then, while the glass was still inverted, a 3 ml polymeric foam disk (ca. 1.5 mm thick, 50 mm diameter) was placed and then the base was sealed to compress the disk and seal the internal void. At this point the internal void, which was constructed with a volume of 33 ml, was completely filled with no air bubbles.

The following external conditions were established: room temperature, 21 °C; initial temperature of the empty beer glass when taken from a freezer, -15°C; initial temperature of control beer glass not taken from a freezer, 21 °C; serving temperature of beer, 3.5°C.

A typical drinking habit was imitated in such a way that after every 1 minute a 20 ml volume of beer was removed from a glass, and the remaining beer was mixed every 5 minutes. This was repeated for 20 minutes, after which time no further beer was removed, but the remaining 100 ml allowed to stand until 30 minutes.

Fig. 15 shows four temperature curves of beer recorded using this protocol for the glass of Fig. 1 as has just been described and also for a conventional tulip pint glass (i.e. without any temperature control structure).

The line 121 in Fig. 15 shows the results for glass of Fig. 1, which was taken from the freezer before being filled with beer. It will be seen that the beer temperature was kept remarkably stable and remained in the range 2.8°C - 3.6°C throughout the 30 minutes.

Line 122 shows a comparative result for the conventional tulip pint glass under the same conditions. It can be seen that while there is a temporary cooling effect due to the chilled glass absorbing heat from the beer for the first five minutes, the effect is then lost and the beer heats up linearly from 3.4°C at 5 minutes to 11.8°C at 30 minutes.

Comparing further to line 123, this shows the temperature curve for the conventional pint glass without it having been placed in the freezer beforehand. The beer heats up throughout the process, having initially risen to 6.3°C at 5 minutes, and then continuing to rise up to 14.5°C at 30 minutes.

Notably, the slopes of lines 122 and 123 are almost identical after the initial chilling/warming over the first five minutes due to the starting temperature of the conventional glass. In other words, both lines show an almost identical linear increase in temperature from 5 to 30 minutes (+8.4°C for the frozen glass, +8.2°C for the room temperature glass).

Finally, to demonstrate the effect of body temperature on the warming, line 124 shows the temperature curve for the same conditions as line 123, but with the glass held in hand throughout. The temperature rises linearly over 30 minutes from 5.7°C at 5 minutes to 19.0°C at 30 minutes. From a comparison with line 123, it can be seen that the slope of the line increases, so that the body temperature seems to add about 0.75°C per five minutes. It can be seen that the ambient temperature causes an 11°C rise over the 30-minute period while the body temperature adds a further 5.5°C.

The experimental results presented in Fig. 15 prove that the invented glass with its temperature control structure is far superior to a standard glass in ensuring that beers can be consumed at their optimum serving temperatures. The effect of chilling a conventional glass is minimal in comparison.

Example 2

A tulip pint glass was again made as in example 1 and as shown in Fig. 1, but with a different temperature control structure in the internal void. The dome was filled with 30 ml of a thermal energy absorbing material comprising 22.5 ml water, 5.5 ml 40% alcohol and 2 ml thickening agent (gum tragacanth). This material, which had a freezing point of -4.5°C, was then covered with 3 ml polymeric foam (c.a. 1.5 mm thick, 50 mm diameter) and sealed as before

The following external conditions were established: room temperature, 20°C; initial temperature of the empty beer glass from the freezer, -15°C; initial temperature of the empty beer glass not taken from a freezer, 21 °C; serving temperature of beer, 4°C.

Fig. 16 shows three comparative temperature plots over time, along with a fourth line representing the percentage improvement achieved by the invention. The same protocol was used in these measurements as in example 1 to imitate a typical drinking habit both for the glass with temperature control structure and for the reference tulip pint glass. For each of the three experimental measurement curves plotted in Fig. 16, the glass was not held in the hand, i.e. it was left on the bench throughout.

Line 221 is the plot of the glass having the gum tragacanth temperature control structure just described, when taken from the freezer. It can be seen that this glass causes the temperature to first drop to 3.2°C at five minutes and then very slowly rise to 5.1°C at 30minutes. Thus the beer remained within 1.1 °C of the serving temperature throughout. The slight difference with respect to the performance of example 1 may be due to the different thickening agent, or the absence of the copper foam, but the performance is nevertheless excellent in maintaining the beer at the desired temperature range for an extended period. Line 222 shows the performance of the conventional glass taken from the freezer, and this is almost identical (as would be expected) to the results from experiment 1, giving an initial cooling effect which had disappeared by 5 minutes, and then a steady linear rise to 11°C.

Line 223 shows the performance of the conventional glass, when not chilled beforehand in a freezer. The performance is again almost identical to that of the equivalent experiment in Example 1, although the final temperature is slightly lower (12.5°C versus 14.5°C). The difference can be accounted for by the slight difference in ambient room temperature.

Line 224 shows a measure of the improvement achieved by the invention versus the conventional glass taken from the freezer, expressed as a percentage. The calculation of the percentage value is made by comparing the temperature values (degrees above 0°C being the base point) and determining at each measurement time how much lower the value on line 221 for the glass with temperature control structure was when compared with the corresponding value for the conventional glass on line 222. So for instance at 5 minutes, the value on line 221 (3.2) was 20% lower than that on line 222 (4.0). At 15 minutes, the value on line 221 (3.7) was 43% lower than the value on line 222 (6.5). At 30 minutes, the value on line 221 (5.1) was 54% lower than the value on line 222 (11.0).

Example 3

In this example, an accessory was made according to Fig. 9. A plastic dome with a plastic base, providing a sealed internal void volume of 33 ml, was filled with a temperature control structure having three components. First, a 20 ml volume of copper open cell foam (porosity 95%, 10 pores per inch, copper volume 1 ml) was added. Then a thermal energy absorbing material comprising 30 ml water and 2 ml polyacrylic acid sodium salt was added and this was absorbed into the pores of the copper foam, with the copper foam being fully immersed in the solution before the dome was sealed with the base. The accessory was then placed in a freezer.

The following external conditions were established: room temperature, 21 °C; initial temperature of accessory on being taken from freezer, -15°C initial temperature of an empty plastic cup, 21 °C; serving temperature of beverage 9°C. A typical drinking habit was again imitated using the same protocol as in Examples 1 and 2.

Fig. 17 shows comparative temperature curves for the same plastic cup, with and without the accessory having been placed in the base before pouring the beverage. In neither case was the cup held in the hand. Line 321 shows the temperature curve when the accessory is in the plastic cup. The beverage remains at a temperature between 8.7°C and 9.7°C over the full 30-minute period. Line 322 shows the temperature curve for the same cup and beverage without the accessory, and it can be seen that there is a linear temperature rise from 9°C to 14°C over the 30-minute period.

Fig. 18 shows a further embodiment, similar to Fig. 1 , in which corresponding elements have the same reference numerals but incremented by 400 (thus drinking vessel 10 becomes drinking vessel 410, etc.).

The embodiment of Fig. 18 differs from that of Fig. 1 in that a different temperature control structure 422 is employed. The sealed internal void 420 is completely filled with a gel 422 having dispersed throughout numerous miniature gas bubbles. The gel is sufficiently viscous and stable during freeze/thaw cycles to retain the bubbles in position within the volume of the gel.

The aggregate volume of gas provided by the bubbles is sufficient to accommodate the expansion and contraction of the gel during freezing and thawing in use. In this way, a separate compressible member can be dispensed with, and the compressibility (or expansibility) of the gas acts to absorb volumetric changes in the gel.

In one embodiment, the gel may be made by dissolving sodium polyacrylate in of deionised water to form a viscous, semi-solid gel. During dissolution of the polyacrylate, gas bubbles are introduced, or a foaming agent is added to create a foam with entrained gas bubbles, and the bubbles are entrapped as the gel solidifies.

Fig. 19 shows a detail of a further embodiment, the view being an enlarged view of the base of a glass 500.

In the embodiment of Fig. 19, the temperature control structure 502 comprises a 5% sodium chloride solution in water providing the freezing point depression of -3°C, with no thickening agent and no compressible member. Instead of a compressible member to absorb freezing- induced expansion, the bottom of the internal void 504 is sealed with a flexible membrane 506 of silicone which is bonded to the glass within a recess 508 in the base.

The flexible membrane 506 can flex upwards or downwards to accommodate volumetric changes in the temperature control structure 502. In this way the temperature control structure need not include a compressible member (although such a member could equally be included in this embodiment if desired to take up some of the expansion or contraction, with the membrane’s movement providing a contribution also). The embodiment of Fig. 19 can therefore have a temperature control structure in the form of a thermal energy absorbing material (like water with or without a thickening agent, and with or without a freezing point depressant), and can be implemented with or without a metal foam structure.

It can be seen that the perimeter 510 of the glass at the base extends below the membrane when the membrane is in its neutral or relaxed, flat, configuration as shown in Fig. 19.

Referring to Fig. 20, when the membrane is displaced downwards due to freezing of the aqueous saline solution 502, the extended perimeter 510 provides a space within which the movement of the membrane 506 is accommodated without risk of the glass upsetting or becoming unstable.

Figs. 21 and 22 shows a further embodiment of glass vessel according to the invention. In Fig. 21 , the main glass body 600 is shown. It is generally similar to the glass body of Fig. 1 , and has a vessel interior 602 defined within a generally cylindrical, tapering sidewall 604 and a domed base wall 606. The thickness of the base wall 606 at dimension A is 5.2 mm in this embodiment.

Below the base wall a domed space 608 is defined for an internal void to contain a temperature control structure (not shown in Fig. 21). The lower surface of the base wall 606 is 27.5 mm (dimension B) above the perimeter 612 of the base where it contacts the surface on which the glass rests. It can be seen that the domed underside of the base wall 606 terminates above a recess 612 which is adapted to receive a sealing disk (not shown) of glass and thereby seal the generally hemispherical internal void.

Fig. 22 shows the finished glass 600 after the internal void has been sealed by a glass disk 614 of thickness 3 mm and diameter 62 mm, which is bonded using a UV-curable adhesive into the recess 612 (Fig. 21).

A disk 616 of expanded polyethylene foam (diameter 55mm, thickness 5mm - not shown to scale) is positioned immediately adjacent glass disk 614 within the internal void. This disk 616 acts as a compressible member as previously discussed herein. It can be seen that, due to the decreasing width of the internal void in the upward direction defined by the dome shaped underside of the base wall 606, the disk 616 is held in position and is not free to move within the internal void.

Above the foam disk 616 is a volume of thermal energy absorbing material, which in this case is a 5% aqueous solution of sodium chloride. In this embodiment, there is no thickening agent or copper foam, but the thermal characteristics of the glass are nevertheless excellent due to the heat sink effect provided when the thermal energy absorbing material is frozen before use. It should also be noted that the thicker base wall in this embodiment (preferably of between 4 and 7 mm thickness, more preferably 4.5 to 6.5 mm, most preferably 5 to 6 mm) contributes to the heat-absorbing qualities of the glass, the thermal energy absorbing material keeping the base wall cold as it absorbs heat from a beverage in the vessel interior.

An alternative composition for the thermal energy absorbing material is a solution of carboxymethyl cellulose in water. A preferred ratio CMCihhO is in the range from 3:97 to 15:85, more preferably 5:95 to 10:90, with a particularly preferred range of 6:94 to 8:92. To this, salt or alcohol may optionally be added as a freezing point depressant.

The glass of Fig. 22 is manufactured by creating the main glass body shown in Fig. 21 using conventional glass manufacturing techniques. This body is then inverted and the thermal energy absorbing material 618 is filled with a precise volume into the void 618. The filling volume is chosen so that when the foam disk 616 is added, it is flush with the perimeter of the domed sidewall where it meets the recess 612, i.e. the internal void is exactly filled with negligible amounts of air remaining.

Then a UV curable adhesive is applied to the recess, the glass disk 64 is positioned in the recess, and the adhesive is cured to bond the disk to the main glass body and seal the internal void.

Figs 23 and 24, and Figs. 25 and 26 respectively show two accessories with a special design to prevent complete mixing of a fluid in the lower and upper parts of a drinking vessel resulting in a much colder fluid at the end of drinking.

In Figs. 23 and 24 the accessory takes the form of an insert body member 700 having an external cylindrical surface, an internal truncated circular conical surface, flat top and base, which together defined a sealed internal void. Fig. 23 shows a cross-section in the horizontal plane, and Fig. 24 a cross-section in the vertical plane.

The internal 705 and external 710 surfaces may be made of food-grade plastic, of aluminium or of glass, and the flat top 715 and underside 720 may be made of food-grade plastic, of glass, or sealed with aluminium foil. The void 725 has a thermal energy absorbing material or PCM within it, which comprises water. When the accessory is placed in a drinking vessel filled with a beverage (not shown) the internal truncated circular conical volume 730 is filled with the beverage fluid. The height H of the accessory can be adjusted to increase a volume of beverage fluid which is trapped in the internal truncated circular cone 730. The conical shape inhibits mixing of a fluid in the lower and upper part of a drinking vessel and at the same lowering its temperature below a serving one.

Figs. 25 and 26 show a similar accessory 750 in the same horizontal and vertical cross sections respectively. Like numerals denote like parts as in Figs. 23 and 24. This accessory 750 has multiple internal truncated circular conical volumes 730 which due to their smaller volumes further reduce a temperature of fluid at the end of drinking.

Example 4

In this example, an accessory was made according to Figs. 23 and 24. A plastic cylinder with the internal empty volume of a circular truncated cone and a plastic top and base, providing a sealed void volume of 30 ml, was filled with a temperature control material having three components: 22.5 ml water, 5.5 ml 40% alcohol and 2 ml thickening agent (polyacrylic acid sodium salt). This material, which had a freezing point of -4.5°C, was then covered with 1.5 mm thick polymeric foam and sealed as before. The accessory was then placed in a freezer.

The following external conditions were established: room temperature, 21 °C; initial temperature of accessory on being taken from freezer, -15°C initial temperature of an empty plastic cup, 21 °C; serving temperature of beverage 4°C. A typical drinking habit was imitated in such a way that after every 2.5 minute a 50 ml volume of beer was poured from a glass. This was repeated for 25 minutes, after which time no further beer was removed, but the remaining 50 ml allowed to stand until 30 minutes. The total volume of beer in the plastic cup was 500 ml.

Temperature measurements were taken to establish the temperatures of beverage inside and outside the circular truncated cone, respectively when the accessory was in a plastic cup. The temperature of beverage remained below serving temperature 4°C over the full 30- minute period with the temperature of beverage inside the circular truncated cone below 3.2° reaching the lowest point of 1.6°C at the end. After 20 min beverage filled only the circular truncated cone. Corresponding measurements of the temperature for the same cup and beverage without the accessory exhibited a linear temperature rise from 4°C to 10.9°C, over the 30-minute period. The temperature difference of the last 50 ml of beverage in the cup with and without the accessory is more than 9°C. This special design of the accessory with the internal truncated circular conical volume prevents complete mixing of a fluid in the lower and upper part of the cup resulting in a much cooler fluid at the end of drinking.

This demonstrates the effectiveness of the accessory in allowing the beverage to remain at its serving temperature throughout the 30-minute experimental period.

While the above examples and embodiments focus on beer glasses it will be appreciated that the invention is in no way limited to this specific application. Wine glasses, other beverage glasses and cups may all incorporate the temperature control structures disclosed herein in their bases, or may receive the accessories disclosed herein. While intended primarily for drinking vessels such as glasses and cups, the invention may also be applied to other fluid containment vessels such as jugs and bottles.

Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations may be substituted for the specific embodiment shown and described without departing from the scope of the present invention. Those with skill in the art will readily appreciate that the present invention may be implemented in a very wide variety of embodiments. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.

The words comprises/comprising when used in this specification are to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Claims

1. An accessory for a drinking vessel, comprising: an insert body member adapted for insertion into a drinking vessel interior, the insert body member providing a heat sink effect to control the temperature of a liquid in which the insert body member is immersed ; and means for securing said insert body to the interior of a drinking vessel.

2. An accessory according to claim 1 , wherein said securing means comprises a pair of magnetically attracted members, a first one of which is provided on or in the insert body and a second one of which is adapted to be disposed, in use, against an external wall surface of the drinking vessel and thereby secure the insert body against a corresponding internal wall surface.

3. An accessory according to claim 2, wherein said insert body member has a top side and a bottom side, wherein said bottom side is configured to rest stably on a flat interior base surface of a drinking vessel, wherein said first magnetically attracted member is located at said bottom side, and wherein said second magnetically attracted member is shaped to sit below and against the exterior of the base surface of the drinking vessel or within a recess provided below the exterior of the base surface.

4. An accessory according to claim 3, wherein said top side is generally dome shaped.

5. An accessory according to any of claims 2-4, wherein said first and second magnetically attractive members each present a generally flat surface such that in use, the respective flat surfaces may be positioned against opposed sides of a drinking vessel base and secured in place by mutual magnetic attraction.

6. An accessory according to any of claims 2-5, wherein said first magnetically attractive member is formed integrally with the insert body member.

7. An accessory according to any of claims 2-5, wherein said first magnetically attractive member is secured to an external surface of the insert body member.

8. An accessory according to any of claims 2-5, wherein said first magnetically attractive member is secured to an internal surface of the insert body member.

9. An accessory according to any of claims 2-5, wherein said first magnetically attractive member is secured within the thickness of a wall of the insert body member.

10. An accessory according to any of claims 2-9, wherein said insert body including said first magnetically attractive member has a negative buoyancy in water, and wherein the buoyancy thereof is unequal across its volume such that the insert body tends to sink in water with said first magnetically attractive member at the underside of the insert body.

11. An accessory according to claim 10, wherein said insert body comprises a sealed elastomeric membrane defining an internal void, the membrane being shaped to have a rounded upper wall and a flat base wall, and said first magnetically attractive member is a flat member attached to or embedded in the flat base wall.

12. An accessory according to claim 1 , wherein said securing means comprises a resilient member disposed on a perimeter of the insert body, such that when inserted into a drinking vessel the resilient member is adapted to frictionally engage with an internal sidewall of the drinking vessel and thereby secure the insert body within the vessel.

13. An accessory according to claim 12, wherein said insert body member has a top side and a bottom side, the bottom side being generally flat and having said resilient member is projecting outwardly from the periphery thereof.

14. An accessory according to claim 12 or 13, wherein said resilient member is an outwardly projecting skirt formed of a resilient material.

15. An accessory according to claim 1, wherein said securing means comprises a formation provided on the insert body member that is adapted to mechanically engage with a corresponding formation provided on the interior of a drinking vessel.

16. An accessory according to claim 15, wherein said formation is selected from a snap fit formation, a cam lock element and a twist lock element.

17. An accessory according to any preceding claim, wherein said insert body member comprises a sealed internal void, and wherein said accessory further comprises a thermal energy absorbing material contained in said sealed internal void.

18. An accessory according to claim 17, wherein at least a portion of the insert body member defining the internal void comprises a wall section formed of a flexible membrane which permits the volume of the internal void to expand and contract with changes in temperature.

19. An accessory according to claim 18, wherein said insert body member is formed predominantly of an elastomeric membrane filled with said thermal energy absorbing material.

20. An accessory according to any of claims 17-19, wherein said thermal energy absorbing material comprises water and one or more of a freezing point depressant and a thickening agent.

21. An accessory according to claim 20, wherein said thermal energy absorbing material comprises water, an alcohol and a thickening agent.

22. An accessory according to claim 21 , wherein said thickening agent is selected from carboxymethyl cellulose, sodium polyacrylate, food-grade hydrogels, food-grade cellulose ethers, food-grade polymeric foams, agar, carrageenans, natural gums, graphite powder, copper powder and aluminium powder.

23. An accessory according to any preceding claim, further comprising an open-cell foam located in the internal void, and wherein said thermal energy absorbing material is distributed within and through the cells of the open-cell foam.