A DISPLAY APPARATUS

Abstract: The present invention provides a display apparatus comprising a body which defines a cavity for receiving a liquid and means for producing gas bubbles in the liquid wherein a substantially fluid-tight seal is provided between the cavity and an external environment. The present invention also provides a display apparatus wherein the distance between the walls of at least a portion of the cavity is similar to the desired diameter of the bubbles in the cavity. Such display apparatus are useful for simulating a container of bubbling liquid.

Description: A DISPLAY APPARATUS The present invention relates to a display apparatus. In particular, the present invention relates to a display apparatus for simulating a container of bubbling liquid, for example, an effervescent drink. It is known for a display apparatus to comprise a liquid filled chamber and means for passing air bubbles through the liquid in the chamber. There are, however, problems with conventional display apparatus of this type . Firstly, air pumps which are typically used to create the air bubbles are conventionally located outside of the liquid filled chamber and pump air into the chamber via one or more tubes or pipes. Hence, the liquid filled chambers are normally made open to the environment to allow the air bubbles to escape. Over time, this causes large amounts of the liquid to evaporate from the chamber. The apparatus therefore needs to be topped up regularly with more liquid or needs to be provided with a liquid pump for making up evaporation losses. Alternatively, liquid retaining chemicals need to be introduced into the liquid. Secondly, if a pigment or other means is used to colour the liquid, the colouring tends to make the bubbles difficult to see. Thirdly, if the apparatus is relatively large, then the weight of the liquid required to fill the apparatus can cause problems when transporting or installing the apparatus . Further, having air from the external environment continuously pumped through the liquid leaves the liquid susceptible to contamination and to microbial and/or fungal growth. It also makes the liquid more susceptible to freezing. It is an object of the present invention to mitigate the problems associated with the prior art. Accordingly the present invention provides a display apparatus comprising a body which defines a cavity for receiving a liquid; and means for producing a plurality of gas bubbles in the liquid wherein a substantially fluid-tight seal is provided between the cavity and an external environment. Preferably, the bubble producing means is located within the cavity. Alternatively, the bubble producing means is located externally of the cavity and is in substantially fluid- tight communication with the interior of the cavity. Preferably the bubble producing means is an air pump. Preferably, the cavity is arranged to define a receiving portion for the bubble producing means and a liquid display portion, the bubble producing means having an exhaust coupled to one end of the display portion for introducing bubbles into said one end of the display portion whereupon introduction of said bubbles into said one end, the bubbles pass through the display portion and collect in the receiving portion for re-circulation by the bubble producing means. Further preferably, the receiving portion is located, in use, above the display portion so that the bubbles ascend to the receiving portion under the influence of gravity. According to a second aspect of the invention, there is provided a display apparatus having a body which defines a cavity for receiving a liquid; and means for producing gas bubbles having a desired diameter in the liquid wherein the distance between the walls of at least a portion of the cavity is similar to the desired diameter of the bubbles. Preferably, the distance is less than or equal to the desired diameter of the bubbles. Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a perspective view of a first embodiment of a display apparatus according to the invention; Figure 2 is a front perspective view of a second embodiment of a display apparatus according to the invention; Figure 3 is a front perspective view of a backing cover for the apparatus of Figure 2 ; and Figure 4 is a perspective view of the internals of the second embodiment of Figure 2. Referring now to Figure 1 of the drawings, there is shown a display apparatus, generally indicated at 10, according to the invention. The display apparatus 10 has a body 11 comprising a front wall 12 and a rear wall 14 joined together to define a cavity 15 therebetween. The front and rear walls 12, 14 are shaped to define a display chamber 38 as part of the cavity 15. The respective contour of the front and rear walls 12, 14 are substantially similar to one another so that at least the liquid display chamber 38 shares a similar contour. The body 11 is hermetically sealed to isolate the cavity 15 from the external environmen . The distance between the front and rear walls 12, 14, at least in the region of the liquid display chamber 38, is relatively small in comparison with the size of the apparatus 10. For example, for a display apparatus 10 of approximately 0.5 metres in height and width, the distance between the walls 12, 14 is typically between 3 and 25mm and preferably between 5 and 10mm but this will depend on the diameter (size) of bubbles produced as will be described in more detail below. Also, it is preferred that the distance between the walls 12, 14 at least in the region of the liquid display chamber 38, is comparable with the diameter of the bubbles which are to be created in the liquid (as is described in more detail below) . It will be appreciated that the front and rear walls 12, 14 can adopt a variety of shapes to give the body 11 of the display apparatus 10 an overall appearance of, for example, a fizzy drinks bottle, fish tank, or other liquid container comprising a much larger volume of liquid than actually exists between the front and rear walls 12, 14. The apparatus 10 is thus particularly suited for use as an advertising or other display apparatus and may optionally carry a logo or brand name on its outer or inner surface. Referring again to Figure 1, the front and rear walls 12, 14 are shaped to define a pump-receiving chamber 46 and a pipe-receiving channel 50 which encircles the display chamber 38. The pump-receiving chamber 46 is in fluid communication with the rest of the cavity 15 via an aperture 52. A plurality of spaced-apart feed channels 54 are defined between the pipe-receiving channel 50 and the, in use, lower end of the display chamber 38. It will be noted that, in the illustrated embodiment, the display chamber 46 is not sealed from the pipe-receiving channel 50 around its periphery. The display chamber 46 is merely a differently shaped portion of the overall cavity 15. In an alternative embodiment (not shown) , the display chamber 38 may be a generally closed chamber having one or more apertures at its, in use, lower end for receiving gas bubbles and one or more apertures in its, in use, upper end for allowing the bubbles to escape into the remainder of the cavity 15. Means for producing bubbles, in the form of an air pump 16, is located in the pump-receiving chamber 46. A tube or pipe 18 is connected to the outlet or exhaust of the air pump 16 and passes through the aperture 52 into the pipe-receiving channel 50 where it encircles the display chamber 38. The pipe 18 is provided with a plurality of spaced-apart discharge holes 20 which are arranged to correspond with the feed channels 54 adjacent the lower end of the display chamber 38. Clearly, the pipe 18 need not necessarily encircle the display chamber 38 and a single branch pipe (not shown) which terminates at the bottom of the display chamber 38 is equally suitable. In use, the apparatus 10 is assembled with a quantity of liquid (not visible) contained within the cavity 15. Typically the cavity 15 is 75-80% filled with liquid, the remainder being filled with air or other suitable gas. It will be apparent that this ratio is not critical. In the embodiment of Figure 1, the cavity 15 is filled with liquid to approximately the level of the, in use, upper end 56 of the display chamber 38. The apparatus 10 is arranged in use such that the pump chamber 46 is above the discharge apertures 20 and the display chamber 38 is located therebetween. When the air pump 16 is switched on, it sucks air, or other gas, in through its inlet (not shown) and passes it to the pipe 18. The air passes through pipe 18 until it is discharged through the holes 20 in the form of the bubbles 60. The bubbles 60 are directed into the, in use, lower end of the display chamber 38 via the feed channels 54. The bubbles 60 rise, under gravity, through the liquid in the display chamber 38 in a plurality of streams 62 thereby giving the liquid an effervescent or bubbling appearance. When the bubbles reach the periphery of the display chamber 38 they pass through the pipe-receiving channel 50 and the aperture 52 into the pump-receiving chamber 46. Thus the air is returned to the pump chamber 46 for recirculating through the tube 18 by the pump 16. In this way the apparatus 10 operates as a closed system thereby substantially eliminating any evaporation of the liquid from within the cavity 15. It will be appreciated that the air pump 16 may be externally powered by a source of alternating current, or the body 11 may be provided with an internal or external direct current low voltage power supply. The apparatus 10 preferably incorporates a light source (not shown) , such as a conventional fluorescent tube, located behind the rear wall 14. Preferably, a housing (not visible) is mounted on the rear wall 14 to house the light source and, if applicable, the power supply. So that the bubbles 60 may be viewed, at least the display chamber 38 portion of the front wall 12 is formed from a transparent material, preferably plastics. However, to hide the light source components and the power supply, if present, from view the rear wall 14 is optionally formed from an opaque but translucent material, preferably also plastics. It is preferable if the rear wall 14 is also formed from transparent material as this lends brightness and clarity to the liquid and bubbles. When switched on, the light source illuminates the liquid within at least the display chamber 38, and the light passes more easily through the bubbles of air than the liquid, thereby highlighting the effervescent effect. This is particularly the case where dark coloured liquid is used. The larger the bubbles 60, and the less liquid between the bubbles and the front and rear walls 12, 14, the more effectively light passes through the liquid filled display chamber 38. Therefore, the distance between the front and rear walls 12, 14, particularly in the region of the display chamber 38 is preferably made substantially equal to the diameter of the bubbles. More preferably, the distance between the front and rear walls 12, 14 is made smaller than the diameter of the bubbles. In this way, the bubbles are squeezed, for example into an ellipsoid shape, increasing the area through which light can pass. Again, if a dark coloured liquid is used the bubbles appear particularly bright - this is desirable from an advertising point of view. It will be appreciated that the desired effect can still be achieved if the distance between the front and rear walls 12, 14 is greater than the diameter of the bubbles although in this case the extent to which light can pass through the chamber 38 depends on the quantity of liquid between each bubble and the walls 12, 14 and on the darkness of the liquid. In an alternative embodiment (not illustrated) both the front and rear walls 12, 14 are formed from a transparent material so that an object located behind the walls 12, 14 appears to be underwater. The liquid used may be, for example, water based or alcohol based and may optionally contain anti-freeze and/or anti-bacterial and/or anti-fungal additives. It is also optional to use a foam depressor such as, for example, a dilute aqueous solution of isopropanol . Depending on the desired speed of the bubble streams, further agents can be added to the liquid to alter its viscosity to suit the requirements of the application. In general, by controlling the viscosity of the liquid, the surface tension of the liquid, the discharge hole 20 size and the air pressure, the size and speed of the bubbles can be varied. The apparatus 10 can thus be made to resemble an effervescent drink, a fish tank or some other bubbling device. Referring now to Figures 2, 3 and 4, there is shown a second embodiment of the invention generally indicated at 110. Similar numbering to Figure 1 is used for like components on Figures 2, 3 and 4. The body 111 of the apparatus 110 is shaped to resemble a carbonated drinks bottle, the front and rear walls 112, 114 defining a hermetically sealed liquid cavity 115. In this arrangement, the display chamber 138 and the cavity 115 are substantially one and the same. Mounted, in use, on the rear of the apparatus 110 is a backing housing or cover 124 (shown in Figure 3) . Traversing the perimeter of the backing cover 124 is a rubber weather seal 132 which seals the inside of the apparatus 110 from the external environment . Extending down the length of the backing cover 124 is a conventional strip light 122 and the associated working components 126. Due to the shape of the apparatus 110 there is little or no scope for providing a pump-receiving chamber in the cavity 115 above the level of the liquid. The air pump 116 is therefore mounted on the backing cover 124 and, when the apparatus 110 is assembled, is located between the backing cover 124 and the rear wall 114, externally of the cavity 115. The air pump 116 is connected at a lower portion of the backing plate 124, with each free end of an exhaust pipe 118 exiting from the air pump 116 and entering the cavity 115 substantially adjacent the, in use, top of the apparatus 110 via apertures 170, 171 which are sealed around the respective portion of the pipe 118. The pipe 118 then extends along the periphery of the cavity 115 and across the bottom thereof (see cut away portion of Figure 2) . A plurality of discharge holes 120 are provided in the bottom section of the pipe 118 such that upon activation of the air pump 116, bubbles of air exit the discharge holes 120 and ascend through the cavity 115. Due to the positioning of the air pump 116 below the level of the liquid, the air accumulating in the upper portion of the liquid cavity 115 must be re-circulated to the air pump 116. This is achieved by connecting a recycle tube 140 (shown in Figure 4, disconnected from the air pump 116) between the, in use, top of the cavity 115 and the inlet of the air pump 116. Thus, the apparatus 110 is also a closed system although the pump 116 is located externally of the cavity 115. Once the pipe 118 and the recycle tube 140 have been connected and the strip light 122 installed, the backing panel 124 is fitted to the apparatus 110. To do this, a male coupling member 130 provided on the backing plate 124 is inter-engaged with a co-operating female coupling member 128 provided on the rear wall 114. The backing plate 124 is then pressed into engagement with the apparatus 110, the weather seal 132 being seated against the perimeter of the rear wall 114. A screw 136 is then threaded into a hole 134 in the apparatus 110, thereby retaining the two sections of the apparatus in place. An electrical switch (not shown) may be provided on an outer face of the apparatus 110 for activation of the apparatus 110 when fully assembled. As an alternative to using a coloured liquid within the apparatus 10, 110, a transparent solution doped with a fluorescent material, for example, quinine sulphate at a concentration of approximately 100 parts per million may be used. In this case, the strip light 112 is replaced with a black light source to give a fluorescent display due to the ultra-violet nature of the quinine sulphate molecule. It will also be appreciated that any number of differently coloured strip lights 122 may be used in order to achieve a desired effect. The closed system provided by the present invention substantially eliminates the problem of liquid evaporation thereby obviating the need to regularly top up the apparatus 10, 110; provide a liquid pump; or introduce anti-evaporation chemicals such as humectants in the dissolved form of deliquescent salts and glycols. Further, the liquid is more readily protected from contamination or freezing. The arrangement of the front and rear walls 12, 112, 14, 114 in close proximity with one another (i.e. the provision of a relatively thin liquid receiving cavity) reduces the amount of liquid required to fill the apparatus 10, 110 - thereby reducing its weight - while also improving the visibility of the bubbles 60, 160. It will be apparent that this feature is not dependant on the apparatus 10, 110 being a closed system and may therefore also be used in similar display apparatus, or the like, in which the liquid is not isolated from the environment .

Claims: Claims : 1. A display apparatus comprising a body which defines a cavity for receiving a liquid; and means for producing a plurality of gas bubbles in the liquid wherein a substantially fluid-tight seal is provided between the cavity and an external environment. 2. A display apparatus according to Claim 1 wherein the bubble producing means is located within the cavity. 3. A display apparatus according to Claim 1 wherein the bubble producing means is located externally of the cavity and is in substantially fluid- tight communication with the interior of the cavity. 4. A display apparatus according to any preceding claim in which the bubble producing means is an air pump. 5. A display apparatus according to Claim 4 wherein the internal workings and electrics of the air pump are hermetically sealed from the cavity. 6. A display apparatus according to any preceding claim in which the cavity is arranged to define a receiving portion for the bubble producing means and a liquid display portion, the bubble producing means having an exhaust coupled to one end of the display portion for introducing bubbles into said one end of the display portion whereupon introduction of said bubbles into said one end, the bubbles pass through the display portion and collect in the receiving portion for recirculation by the bubble producing means. 7. A display apparatus according to Claim 6 wherein the receiving portion is located, in use, above the display portion so that the bubbles ascend to the receiving portion under the influence of gravity. 8. A display apparatus comprising a body which defines a cavity for receiving a liquid; and means for producing gas bubbles having a desired diameter in the liquid wherein the distance between the walls of at least a portion of the cavity is similar to the desired diameter of the bubbles in the cavity. 9. A display apparatus according to Claim 8 wherein the distance is less than or equal to twice the desired diameter of the bubbles. 10. A display apparatus according to Claims 8 or 9 wherein the distance is less than or equal to the desired diameter of the bubbles. 11. A display apparatus according to any preceding claim, the apparatus incorporating a light source located within the body and adjacent to the cavity, the light source therefore, in use, illuminating the liquid within the cavity. 12. A display apparatus according to Claim 11, the apparatus utilising a black light source in order to give a fluorescent display upon the introduction of a fluorescent material to the liquid. 13. A display apparatus according to any preceding claim in which the body is shaped and dimensioned to house an object adjacent to the cavity.

Inventors: KNIGHT MICHAEL, KNIGHT, MICHAEL
Applicants: KNIGHT MICHAEL, KNIGHT, MICHAEL
Application year: 2000
Main classification: G09F13
IPC codes: G09F13