LIQUID STORAGE

Abstract: Apparatus for storing water, especially purified water, for use in a beverage dispenser is provided with a microbiological agent to kill or deter microbiological growth and maintain the quality of the water. The agent is provided in a physical form to promote with the water and may be renewable to maintain effectiveness of the agent over a period of time. In one arrangement, the agent is contained in a cartridge (92) arranged in a re-circulation loop (89) through which the water in a reservoir (80) is passed and returned to the reservoir (80). The cartridge (92) and/or a carrier for the agent within the cartridge (92) may be replaceable to renew the agent. The agent may also be provided within the reservoir (80) and various arrangements for this are also disclosed.

Description: LIQUID STORAGE This invention relates to the storage of liquids, particularly but not exclusively water. For convenience it will be described below with specific reference to water. There have been numerous proposals for the treatment of water to purify it and many of these proposals have been devised bearing in mind that water quality and purity vary considerably from location to location and that a relatively simple treatment means is required that can be used in a wide variety of situations and that is, preferably, renewable. Many of the known treatments involve filtration and heat stages and are successful to greater and lesser degrees in providing a convenient, economical means of providing water of acceptable purity in respect not only of content of chlorine, heavy metals, organics, carbonates and the like but also in respect of microbiological quality. Regardless of the actual treatment method used, many treatment processes are devised to provide a reservoir of treated water which can be drawn off for use as and when required, i.e. the treated water is not used immediately but must be stored for varying periods of time. One specific example is in the treatment of water for post-mix beverage dispensers in which a beverage is mixed from a concentrate and a diluent, usually water, at the point of sale. The water to be used may have been subjected to a purification treatment and it may then be stored in a suitable reservoir before being drawn off in a required amount for each beverage dispense. Although such stored water may be of high purity and of high microbiological quality on entering the reservoir or other storage system, neither it nor the reservoir will normally be sterile. There is, therefore, always a risk that the microbiological state of the stored water will deteriorate with time. Simple addition of microbiocidal material to the reservoir has not proved to be a satisfactory solution as adequate contact is difficult to achieve. It is, therefore, an object of the present invention to provide a liquid storage apparatus in which this problem may be ameliorated or eliminated. Accordingly the invention provides a liquid storage apparatus, the apparatus comprising a reservoir for the liquid, the reservoir containing a microbiological agent to kill or deter microbiological growth, the microbiological agent being in a physical form to present a sufficient contact area with the liquid to provide the required effect. In a first general embodiment the wall of the reservoir may be formed of material, usually plastics material, in which the microbiological agent is present or onto which it is coated. Thus the agent may conveniently have been compounded into the composition used to form the walls of the reservoir. The "walls" may, of course, include the floor and roof and the agent may similarly be incorporated in conduits and fittings of the reservoir. However, we have found that such an arrangement does not by itself provide the desired degree of contact time and area to effectively treat all the water or other liquid that may be contained in the reservoir. Thus in this embodiment of the invention, we have found that it is preferable to provide agitation means within the reservoir to promote increased water/wall contact or recirculation means to pass the water out of and back into the reservoir. Both means may be used in combination. Where the water is recirculated, it may also be passed through, e.g. a cartridge, containing further microbiological agent, to further improve the treatment and contact time. The further microbiological agent may be in any convenient form, e.g. granular or in a reticulated foam. A labyrinth may be provided in the cartridge in the recirculation line to further improve flow path contact time with the agent. Ln a second general embodiment, the microbiological agent is present in the tank in an open cell, e.g. reticulated, foam, in fibre, or in granular form to provide the required surface area to allow adequate contact. It may be coated onto the foam, fibres or granules but it may be found more convenient for it to be compounded into the compositions from which these bodies are formed. The microbiological agent may be any suitable biocide or biostatic agent and examples include triclosan, zinc pyrithione, silver compounds and KDF. The latter is a metallic combination of copper and zinc, which is available in a variety of forms including granules, wool and reticulated foam. The agent may be incorporated in a variety of readily available plastics materials which can be processed by conventional means including injection moulding, blow moulding, rotational moulding and extrusion for use in the first embodiment of the invention. Alternatively it may be incorporated in plastics compositions which are processed to a carrier form, e.g. reticulated foam, granule or fibrous form for insertion into the reservoir in the second embodiment. In the second embodiment of the invention, the carrier form of the agent may be of volume to completely fill the reservoir, in which case a vent will be needed to allow filling of and drawing from the reservoir. For example, the reservoir may be completely filled with reticulated foam containing the agent and the water enters to fill the voids in the foam and thereby ensures a good and sufficient contact area for the agent to work. An air filter may be fitted into the vent. Alternatively the reservoir may be a sealed tank, i.e. unvented, with sufficient headspace left during use to allow filling and emptying to take place or it may contain a collapsible membrane as a barrier to atmosphere. Alternatively the carrier may form a layer in the reservoir through which the water must pass on its travel from the reservoir inlet to the outlet. The layer may be attached to the reservoir walls or take the form of a floating layer of, e.g., foam or granules. Again the reservoir may be vented, with a filter, if desired. In another arrangement the carrier may form a layer on the floor of the reservoir or be in a "sump" in the base of the reservoir. Where a foam is used as the carrier for the agent, it may be used in compressed or uncompressed state whereby the volume to surface area ratio may be enhanced by changing the cell size. It will be appreciated that the carrier, e.g. the foam, can present an extremely large surface area to contact the water. Reticulated foam, for example, can absorb almost up to its own volume of liquid thereby ensuing maximum effective use of the microbiological agent. Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a diagrammatic representation of a reservoir tank according to the invention; Figure 1 A is an enlarged view of an alternative form of a portion of the apparatus of Figure 1; Figure 2 is a similar view to Figure 1 of a second reservoir tank of the invention; Figure 3 is a similar view of a third reservoir tank of the invention; Figure 4 is a similar view of a fourth reservoir tank of the invention; Figure 5 is a similar view of a fifth reservoir tank of the invention; Figure 6 is a similar view of a sixth reservoir tank of the invention; and Figure 7 is a similar view of a seventh reservoir tank of the invention. In Figure 1 a reservoir for water is a tank 10 having an inlet 11 in its roof 12 and an outlet 13 in its floor 14. The tank is filled with reticulated foam 15 which has been impregnated with a biocide and/or a biostatic agent. A vent 16 in roof 12 of the tank allows water to be filled into and drawn out of the tank. The reticulated foam, which may be polyurethane foam, may be replaced by granules which have been poured in to fill the tank. As shown in Figure 1A, vent 16 may contain an air filter 17 of, for example, 0.2 micron pore size. In Figure 2 a tank 20 has an upper housing 28 which leads into a smaller "sump" housing 29 extending below the floor 24 of housing 28. As above, the tank has an inlet 21 in its roof 22 and in this instance has an outlet 23 from the base of sump 29. The sump 29 is filled with reticulated foam or granules containing the microbiological agent. A vent 26 is provided in roof 22. This may again contain a filter, if desired. In Figure 3 a tank 30 has an inlet 31 in its roof 32 and an outlet 33 in its floor 34. A vent 36, with or without a filter, is again provided in roof 32. A blanket 35 of foam, fibre or granules impregnated with the desired microbiological agent floats on the surface of water 37 in the tank. In Figure 4 a tank 40 again has an inlet 41 in its roof 42 and an outlet 43 in its floor 44. A vent 46 with a filter 47 is also provided in roof 42. In this embodiment a non-floating layer 45 of foam, granules or fibre, suitably impregnated with the desired agent lies on the floor 44 of the tank. It will be appreciated that the embodiment of Figures 1 to 4 are all variants of the second general embodiment of the invention and that in each instance, the water, or other liquid, must pass through the microbiological agent carrying layer on its journey from the inlet to the outlet. Good contact is, therefore, ensured for all the water before it is drawn off for use. Figures 5, 6 and 7 represent embodiments within the first general embodiment of the invention. In Figure 5 a tank 50 is made of a material containing a microbiological agent or has a coating of such an agent applied to its internal surfaces. Water can enter through inlet 51 in roof 52 and leave through outlet 53 in floor 54. The roof contains a vent 56 with an optional air filter 57. Inside the tank a paddle 58 attached to an arm 58A is rotatable by external motor 59. Thus when the paddle 58 is submerged in water in the tank, it can be rotated to agitate the water and to cause improved contact between the water and the treated tank surfaces. In Figure 6 a tank 60 is made of similar material to that of tank 50. It has an inlet 61 in its roof 62 and an outlet 63 in its floor 64. It also has a vent 66 with a filter 67 in its roof 62. Outlet 63 leads via a non-return valve 68 to the desired end use, e.g. a dispense nozzle, not shown, for the water. A recirculation loop 69 runs from between outlet 63 and non-return valve 68 to a further inlet 70 in roof 62 of the tank. A pump 71 in the recirculation loop enables water in tank 60 to be pumped either continuously or intermittently from the tank around loop 69 and back to the tank, thereby improving contact time with the internal surfaces of the tank for all the water. In Figure 7 a tank 80 is made of similar material to that of tanks 50 and 60. It has an inlet 81 in its roof 82 and an outlet 83 in its floor 84. It also has a vent 86 with a filter 87 in its roof 82. As in Figure 6, outlet 83 leads via a non-return valve 88 to the desired end use for the water. A recirculation loop 89 leads back into the tank via inlet 90 in the tank roof. Again loop 89 runs from between outlet 83 and nonreturn valve 88. A pump 91 enables water to be recirculated from the tank and around the loop. In this embodiment the recirculation loop also contains a chamber or cartridge 92 filled with a microbiological agent, e.g. in foam or granule carrier form 93. Thus the recirculation not only improves contact with the tank walls but provides a further microbiological contact zone in the cartridge 92. The cartridge 92 and/or an insert carrying the microbiological agent within the cartridge 92 may be replaceable after a period of use. In this way, the microbiological agent may be renewed to maintain the effectiveness of the agent to kill or deter microbiological growth in the water. In a variation of the Figure 7 arrangement, the microbiological agent may be present in the re-circulation loop only, e.g. in cartridge 92. The cartridge 92 and/or insert may be replaced at regular intervals of time. Alternatively, the cartridge 92 and/or insert may be replaced after a pre-determined volume of water has been drawn off. In this way, variations in use of the apparatus are taken into account before replacing the cartridge 92 and/or insert. Means may be provided to give a visual and/or audible warning locally or at a remote location when the cartridge 92 and/or insert needs to be replaced. For example a light or buzzer may be activated on the apparatus or a signal may be transmitted to a remote location when the cartridge 92 and/or insert needs to be replaced. It will be understood the invention is not limited to the embodiments above-described. For example, features in any of the embodiments may be employed separately or in combination with features from any of the other embodiments to provide apparatus with a microbiological agent to kill or deter microbiological growth. Thus, the re-circulation arrangements shown in Figures 6 and 7 may equally be used in conjunction with any of the tank arrangements of the other Figures. Where the microbiological agent is provided by a carrier or other, support medium arranged internally or externally of the tank, it is preferably renewable to maintain the effectiveness of the agent. In other words, the carrier or support medium is replaceable. The apparatus may include means to monitor the quality of the water in the reservoir and/or re-circulation loop where provided. The monitoring means may provide a warning of microbiological growth outside acceptable limits. The monitoring means may provide a warning locally or generate a signal for transmission to a remote location. The monitoring means may activate a shut-off valve to prevent dispense of water if the detected quality is outside acceptable limits. The invented apparatus may be used to provide a source of water in a beverage dispenser for hot and/or cold drinks. The water may be mixed with other components e.g. flavouring agents, colouring agents, sweeteners etc, to produce different beverages for user selection. The dispenser may include a carbonator for dispense of still or carbonated water with or without additional components added. Other modifications and improvements will be apparent to those skilled in the art and are deemed within the scope of the invention.

Claims: CLAIMS 1. A liquid storage apparatus, the apparatus comprising a reservoir for the liquid, the reservoir containing a microbiological agent to kill or deter microbiological growth, the microbiological agent being in a physical form to present a sufficient contact area with the liquid to provide the required effect. 2. An apparatus according to Claim 1, in which the walls of the reservoir are formed of material in which the microbiological agent is present or onto which it is coated and an agitator is provided in the reservoir to promote increased contact between the walls and the liquid. 3. An apparatus according to Claim 1, in which the walls of the reservoir are formed of material in which the microbiological agent is present or onto which it is coated and the apparatus includes a recirculation loop to pass the liquid out of and back into the reservoir. 4. An apparatus according to Claim 3, in which the recirculation loop includes a treatment station containing further microbiological agent. 5. An apparatus according to Claim 4, in which the station includes a labyrinth to further improve contact time with the agent. 6. An apparatus according to Claim 1, in which the microbiological agent is present in the reservoir in or on a carrier, which carrier is in open-cell foam, fibre or granular form to provide a surface area for contact with the liquid. 7. An apparatus according to Claim 6, in which the microbiological agent is incorporated in a plastics composition which has been processed to the carrier form. 8. An apparatus according to Claim 6 or 7, in which the carrier is of volume to completely fill the reservoir and the reservoir is vented. 9. An apparatus according to Claim 6 or 7, in which the reservoir is unvented and contains a collapsible membrane as a barrier to atmosphere. 10. An apparatus according to Claim 6 or 7, in which the carrier forms a layer through which the liquid must pass on its travel from the inlet to the outlet of the reservoir. 11. An apparatus according to Claim 10, in which the layer is attached to the walls of the reservoir. 12. An apparatus according to Claim 10, in which the layer floats on the liquid that has passed through it. 13. An apparatus according to Claim 6 or 7, in which the reservoir has a sump in its floor and the carrier is in the sump. 14. An apparatus according to any one of Claims 6 to 13, in which the carrier is a foam material used in a compressed state. 15. An apparatus according to any one of Claims 6 to 14, which includes a recirculation loop to pass the liquid out of and back into the reservoir. 16. An apparatus according to Claim 15, in which the recirculation loop includes a treatment station containing further microbiological agent. 17. A liquid storage apparatus, the apparatus comprising a reservoir for the liquid and a recirculation loop to pass the liquid out of and back into the reservoir, the recirculation loop including a treatment station containing a microbiological agent to kill or deter microbiological growth. 18. An apparatus according to any one of the preceding claims, in which the microbiological agent is renewable. 19. An apparatus according to claim 18, in which the microbiological agent is provided by a replaceable support medium. 20. An apparatus according to claim 18 or claiml9, in which means is provided for indicating when the microbiological agent needs to be renewed. 21. An apparatus according to any one of the preceding claims, in which means is provided for monitoring water quality and providing a warning if the water quality is outside acceptable limits . 22. A method of killing or deterring microbiological growth in a liquid contained in a reservoir by providing a microbiological agent in a physical form for contact with the liquid and promoting contact between the liquid and the agent. 23. A beverage dispenser including liquid storage apparatus according to any one of the preceding claims.

Inventors: WILLIAMS GRAHAM, WILLIAMS, GRAHAM
Applicants: IMIS CORNELIUS UK LTD, WILLIAMS GRAHAM, IMIS CORNELIUS (UK) LIMITED, WILLIAMS, GRAHAM
Application year: 2001
Main classification: C02F1
IPC codes: C02F1