Patent Application
20090000320
This invention relates to chilled liquid dispensers of the kind in which a liquid (usually water) is supplied from a bottle to a discharge outlet via a reservoir system in which the liquid is cooled.
In such dispensers the water must remain in the reservoir system for a certain period of time in order to achieve the desired dispensing temperature. After sufficient time has elapsed the water within the reservoir system will eventually reach the target temperature, but the amount of time required depends on a number of factors, including the capacity of the reservoir, the power of the cooling system, and the effectiveness of any heat insulation surrounding the reservoir system.
It is known that maintaining a reserve of ice in a cooling reservoir provides a thermal buffer which can provide additional cooling capacity when a large influx of ambient water occurs due to a significant volume of chilled water being dispensed. Even so, it is difficult to dispense any significant volume of water at near-zero temperatures. If water is drawn from the top of the reservoir the ice-cold water already in the reservoir immediately mixes with ambient water entering the reservoir. On the other hand, if water is drawn from the bottom of the reservoir the minimum dispensing temperature is 4° C. This is because the density of water is highest at this temperature. Since water of the same densities mix together, water below 4° C. will always mix with warmer water of the same density to produce an average temperature of around 4° C.
The present invention seeks to provide a new and inventive form of chilled liquid dispenser which allows greater volumes of liquid to be dispensed at a temperature which is below the temperature at which the liquid is at its maximum density.
The present invention proposes a chilled liquid dispenser having:
Upon entering the inlet chamber the ambient liquid is cooled to a temperature which may be close to its temperature of maximum density. When the chilled water enters the ice chamber it is subjected to further cooling down to its freezing temperature without mixing with ambient liquid, so that significantly higher volumes of ice-cold liquid may thus be dispensed.
The ice generator may include a cooling system which is arranged to cause the liquid to freeze on an internal surface of the reservoir system, and from which frozen liquid is periodically removed. Heating means may be operated periodically to free pieces of frozen liquid. Such an arrangement may produce multiple thin sheet-like pieces of ice, which produce maximum cooling of the liquid.
In a preferred arrangement the inlet chamber communicates with the ice chamber via a bottom chamber which is disposed below the inlet chamber and the ice chamber.
The following description and the accompanying drawings referred to therein are included by way of non-limiting example in order to illustrate how the invention may be put into practice. In the drawings:
The water pathways between the bottle 3 and the four discharge outlets are fully sealed to prevent contact with atmospheric air. On initial use, water flows through the water pathways from the bottle 3 to the four discharge outlets 25, 19, 22 and 15, and air is purged through the discharge outlets so that the water pathways become substantially filled with water. Water displaced from the bottle is replaced by air which enters the bottle through a microfilter 28 and an air passage 29 which leads into the bottle through the feed tube 5.1 separately from the water passage 6. A non-return valve 30 may be included in the air pathway to prevent leakage of water, e.g. due to expansion of air within the bottle.
Water may be transferred from the bottle 3 to the discharge outlets 25, 19, 22 and 15 by gravity. However, by employing a pump-operated pressure-feed system the discharge outlets may be located at a higher level, relative to the feed tube 5.1, than is possible in a gravity feed system. In one form of pressure-feed system an air pump (not shown) may be arranged to supply pressurised air to the bottle 3 via the microfilter 28, non-return valve 30 and air passage 29 to create a pressure head within the bottle. A pressure switch may be provided to sense the pressure in the air pathway, switching off the pump when a suitable operating pressure has been attained and switching the pump on again when the pressure falls. Alternatively, a pressure relief valve venting to atmosphere can be used to limit the air pressure in the system.
In the present water cooler a pressure-feed system is provided by a water pump 40 connected in the transfer passage 6 to pump water through the water pathways from the bottle 3 to the four discharge outlets 25, 19, 22 and 15, thus creating an increased pressure head for dispensing water. The pump 40 is formed in two parts, namely a disposable pumping section 41 and a fixed motor assembly 42. The two parts may be releasably but drivably connected, e.g. by means of a mechanical drive or magnetic coupling.
The reservoir 7 contains two upper chambers, 100 and 101 respectively, which are separated by a vertical baffle 102. Ambient water from transfer passage 6 enters the reservoir through the top of inlet chamber 100, and ice-cold water is removed through outlet passage 14 from the top of the outlet chamber 101, which forms a separate ice chamber. The two chambers 100 and 101 are mutually connected by a common bottom chamber 103 about which the evaporator 13 is disposed. During operation of the refrigeration system, water in the bottom chamber 103 is allowed to freeze adjacent to the evaporator 13, resulting in the formation of a layer of ice on the wall of the bottom chamber. When this occurs the refrigeration system is switched off and an electrical heater 105 is operated to warm the wall of the bottom chamber. This causes sheet-like pieces of ice 106 to separate from the wall of the reservoir so that they become free-floating within the reservoir. Due to their lower density, the pieces of ice rise to the top of the reservoir within the inlet and outlet chambers 100 and 101. Ambient water entering the inlet chamber 100 is cooled by the ice within the chamber 100, resulting in a temperature gradient from ambient at the top down to the densest water at the lowermost part of the bottom chamber 103. When water is drawn off from the outlet chamber 101 the densest water flows through the bottom chamber 103 into the outlet chamber 101, which is filled with ice. In this chamber the coolest water rises to the top whilst slightly warmer water at around 4° C. remains at the bottom chamber due to its higher density. The ice present within the outlet chamber 101 holds the temperature of the water at the top near to freezing, with the result that ice-cold water can be dispensed from the outlet chamber at a temperature of about 0° C. The result is that a significantly higher volume of ice-cold water can be dispensed from the outlet chamber.
Chilled water for dispensing from the discharge outlet 22 is obtained by mixing water from both of the upper chambers 100 and 101 in the passage 21.
The ice generation could be controlled by operating the refrigeration system and the heating element for alternate periods. However, since the ambient temperature may vary, more reliable operation may be achieved by providing sensors within the reservoir. Although temperature sensors may be used it is preferred to provide optical sensors A, B and C which detect the amount of ice present within the reservoir. Sensor A is positioned to detect when the inlet chamber 100 is substantially filled with ice. Sensors B and C are positioned to detect a buildup of ice on the opposite walls of the bottom chamber 103 below the respective inlet and outlet chambers 100 and 101. A light barrier 110 may be mounted in the bottom chamber 103 between the sensors B and C to prevent mutual light interference between the two optical sensors. When either of the sensors B or C detects the presence of ice the refrigeration system is switched off and the heater is turned on. This causes slivers of ice to release from the walls and float to the top of both inlet and outlet chambers. When sensors B and C detect that the ice has gone, after a time delay of around 15 seconds, the heater is switched off and the refrigeration system is switched back on. If the sensor A detects ice for more than a predetermined time the refrigeration system is switched off to stop further ice generation. In general, the inlet chamber will consume more ice than the outlet chamber since more energy is required to cool from ambient to 4° C. than to cool from 4° C. to zero. A pivoted flap 112 is therefore provided to divert pieces of ice freed from the bottom chamber 103 into the inlet chamber 100 when the outlet chamber 101 becomes full. The flap 112 comprises two angularly disposed planar sections 113 and 114, which are pivoted at 115 adjacent to the junction of the two sections. The flap is balanced such that it normally adopts the position shown in solid lines, with the lower section 114 disposed substantially vertically within the bottom chamber and the upper section 113 inclined upwardly within the outlet chamber 101. Ice may pass on both sides of the flap, rotating the flap to the position shown in dashed lines as is enters the outlet chamber. However, when the outlet chamber is full the flap is held in the second position such that the lower section 114 is inclined to divert any further ice into the inlet chamber.
The feed tube 5.1, reservoir 7, the water passages 6 and 14 and the air passage 29 are preferably provided by a replaceable flow assembly 46, shown in more detail in
The feed tube 5.1, which is positioned centrally of the receiver cup 49, contains an axial water passage to receive water from the bottle through the upper end of the feed tube. At the base of the feed tube, the axial passage joins a horizontal passage within the platform 50 leading to the upper end of the impeller assembly 41. A transfer passage leads tangentially from the impeller assembly and travels through the platform to the upper end of the reservoir moulding 55 to conduct water into the reservoir 7. In addition, the transfer passage communicates with ambient water passages leading to the connecting spigots 53 and 54. The platform 50 also contains the necessary passages which connect the reservoir to the chilled water outlet spigot 51 and the ice-cold water outlet spigot 52.
The opposing walls of the bottom part 56 diverge in an upward direction to ensure that ice does not become jammed in the bottom chamber when released from the walls by the heating element 105. The divergent shape also ensures that the bottom part is a close sliding fit within a U-shaped evaporator plate 120 held in the thermal insulation jacket 8 (not shown). The evaporator plate may have double skins which are roll bonded to form an enclosed evaporator passage that cools the evaporator plate. A serpentine evaporator tube could, alternatively, be used. The electrical heating element 105 may be applied to the inner or outer surface of the evaporator plate, with suitable electrical insulation.
Water displaced from the bottle is replaced by atmospheric air which can pass into the bottle through an air pathway which commences at the microfilter 28 within the air inlet housing 76. After passing through the non-return valve, air is conducted through a horizontal air passage in the bottom of the cup 49 to a second axial passage within the feed tube 5.1 to enter the bottle through the upper end of the feed tube 5.1.
The platform 50 may contain an additional drain passage to remove water spillages from the cup 49.
The feed tube, reservoir and associated water passages may be lined with an antimicrobial coating material, as disclosed in GB 2 396 418 B or International Patent Application No. PCT/GB2005/002572 (Ebac Limited).
The ice sensors A, B and C may each comprise a light emitting diode (LED) and a light dependent resistor (LDR) mounted within the insulation jacket 8 on opposite sides of the reservoir 7. The moulding 55 and bottom part 56 are both formed of transparent thermoplastics, so that when ice interrupts the light path through the reservoir the resistance of the LDR changes to signal the presence of ice.
The lid 2 may lift off the housing 1 or it can be hinged to the housing. The flow assembly 48 is inserted through the top of the housing after raising the lid 2. The reservoir 7 drops into the thermal receptacle 8 until the bottom part is snugly received within the evaporator plate 120. The manifold 48 may rest on a suitable support moulding which is fixed within the housing 1 and to which the electric motor assembly 42 of the water pump is permanently fixed. The motor 42 is arranged to rotatably drive the impeller assembly to move water from the bottle 3 into the reservoir 7 and create a sufficient pressure to ensure that water will issue from the discharge outlets 15, 19, 22 and 25 even when the water level within the bottle becomes low.
The water cooler is thus capable of providing the user with a wider choice of dispensing temperatures than is possible with conventional coolers, ranging from hot water for making hot beverages through to ice-cold water.
Although one embodiment of the flow assembly has been described in detail it will be appreciated that various modifications are possible within the scope of the invention. For example, the pump could be omitted in the case of a gravity feed system. The non-return valve in the air inlet to the bottle could take the form of a float valve. It will be appreciated that water could also be supplied from the water transfer passage 6 to a hot tank to be heated and dispensed through a separate discharge outlet above ambient temperature, for use in hot beverages for example. The dispense valves could take the form of pinch valves or poppet valves, either having direct manual activation or operated indirectly by means of electrically-powered actuators.
In a flow assembly such as the one shown in
In a two reservoir system maximum efficiency is achieved by the use of separate cooling systems for the inlet and ice chambers, although in both of the embodiments described herein the use of a single cooling system or separate cooling systems is possible.
It will be appreciated that the features disclosed herein may be present in any feasible combination. Whilst the above description lays emphasis on those areas which, in combination, are believed to be new, protection is claimed for any inventive combination of the features disclosed herein.
* Watertrail is a registered trade mark of Ebac Limited.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0525925.4 | Dec 2005 | GB | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/GB2006/004685 | 12/15/2006 | WO | 00 | 6/18/2008 |
