Equipment for cooling and sterilizing water for dispensing cold drinks

Abstract

The beverage preparation device (1) includes a cryogenic fluid circuit (2) including a fluid inlet (3), an ultraviolet fluid treatment device (4), a chiller (6), and a fluid flow path (7) from the fluid inlet through the ultraviolet fluid treatment device (4) and through the chiller (6). The cryogenic fluid circuit (2) also includes a fluid outlet (9), a fluid return flow path (12) configured to connect the fluid flow path to return chilled fluid to the fluid flow path, and a valve assembly (11) operable in a first state to direct the fluid to the fluid outlet (9) and in a second state to recirculate the fluid through the fluid flow path (7).

Description

[Technical Field]

[0001] The present invention relates to beverage preparation machines, particularly but not exclusively to coffee machines. [Background technology]

[0002] Beverage preparation equipment, particularly those used to prepare cold liquid beverages, faces the challenge of maintaining acceptable standards of hygiene. Fluid flowing through pipe systems can support the growth of undesirable organisms, harmful bacteria, or infectious agents. Furthermore, stationary fluid within such systems can lead to the development of biofilms. Therefore, it is necessary to reduce the levels of undesirable organisms, harmful bacteria, and infectious agents before dispensing fluid that is safe for consumption.

[0003] Existing technologies attempt to achieve this effect through the use of microfilters and frequent flushing of cryogenic fluid systems to the drain. This solution is undesirable for several reasons. For example, microfilters are expensive and clog over time, which negatively impacts system reliability and leads to customer dissatisfaction. Furthermore, microfilters must be replaced periodically, which must be performed by a service engineer. This can become expensive over time and can also have a negative impact on the environment. The need to frequently flush cryogenic fluid systems also wastes fluid that would otherwise be consumed.

[0004] A further problem with such beverage preparation machines is that fluid left standing for a period of time may not be cold enough to satisfy customers. Several techniques are currently used to address this problem, such as flushing warm fluid from the system, but this is a wasteful process that needs to be improved.

[0005] Embodiments of the present invention aim to remedy these drawbacks and provide an improved, hygienic cold fluid supply for beverage preparation machines. Summary of the Invention [Problem to be solved by the invention]

[0006] According to a first aspect of the present invention, there is provided a beverage preparation machine comprising a cryogenic fluid circuit, the cryogenic fluid circuit comprising: a) a fluid inlet; b) a UV fluid treatment device; c) a chiller; d) a fluid flow path from the fluid inlet through the ultraviolet fluid treatment device and through the cooler; e) a fluid outlet; f) a fluid return flow path configured to connect to the cooler and return cooling fluid from the cooler to the fluid flow path; g) A beverage preparation device is provided comprising a valve assembly operable in a first state to direct fluid to a fluid outlet and in a second state to recirculate fluid through the fluid flow path via a fluid return flow path.

[0007] The beverage preparation apparatus thus provides a means for reducing the microbial load in the cold fluid and preventing biofilm buildup, while maintaining the chilled fluid temperature to ensure the outlet fluid is at a consistently chilled temperature. The beverage preparation apparatus does not require a breaker tank for storing fluid, and therefore the beverage preparation apparatus can be significantly more compact than other inventions disclosed in the prior art. This is beneficial for use, for example, but not limited to, incorporation into hot and / or chilled coffee machines.

[0008] As used herein, "ultraviolet fluid treatment device" is intended to refer to a fluid treatment device that treats fluids with ultraviolet (UV) radiation in the 100-400 nm wavelength range, which can be divided into three bands: UVA (315-400 nm), UVB (280-315 nm), and UVC (100-280 nm). In one preferred form, UVC light is used.

[0009] The valve assembly may include one or more valves. When two or more fluid outlets are provided, there may be at least one valve associated with each fluid outlet for selectively controlling fluid flow through each fluid outlet.

[0010] The cold fluid circuit may be provided in a beverage preparation device that also includes a hot or heated fluid circuit.

[0011] Both the cold fluid circuit and the hot or heated fluid circuit may be connected to the same fluid outlet.

[0012] The cryogenic fluid circuit and the hot or heated fluid circuit may be connected to separate fluid outlets. The hot or heated fluid circuit may be connected to the cryogenic fluid circuit. This allows the hot or heated fluid to be used to flush the cryogenic fluid circuit.

[0013] In one form, the beverage preparation device may be operable in a chilled fluid dispensing mode, in which the valve assembly is in a first state and chilled fluid may be discharged from the beverage preparation device through the fluid outlet. This fluid has already passed through the ultraviolet fluid treatment device and the chiller. Fresh fluid may enter the fluid flow path of the cryogenic fluid circuit through the fluid inlet, pass through the ultraviolet fluid treatment device, the chiller, and then to the valve assembly, and because the valve assembly is in the first state, chilled fluid may be discharged through the fluid outlet.

[0014] In one form, the beverage preparation device may be operable in a chilled fluid recirculation mode. When the beverage preparation device operates in the chilled fluid recirculation mode (as opposed to the chilled fluid dispense mode or the flush mode), the valve assembly operates in a second state. Instead of the chilled fluid being discharged through the fluid outlet, the chilled fluid is recirculated through the fluid return path.

[0015] The fluid return flow path is preferably connected to the fluid flow path. The fluid return flow path is preferably connected to the fluid flow path at any position. Preferably, the return flow path is connected to the fluid flow path between the fluid inlet and the ultraviolet fluid treatment device, before the chiller, but can also be connected after the ultraviolet fluid treatment device and before the chiller.

[0016] The fluid return flow path may pass through the chiller before being connected to the fluid flow path. Thus, the fluid return flow path may pass through the chiller towards the valve assembly for distribution or recirculation, or may pass through the chiller after the valve assembly before connection of the fluid return flow path to the fluid flow path.

[0017] The fluid return flow path is preferably connected to the fluid flow path after the fluid inlet and before any process equipment on the fluid flow path, thereby allowing recirculation through all of the process equipment on the fluid flow path.

[0018] The fluid return flow path may be provided with a check valve. A check valve may be provided on the fluid flow path after the inlet, preferably before any process equipment and before the fluid return flow path connection.

[0019] In one form, the beverage preparation machine may be operable in a flush mode, which may utilize hot or heated fluid from the hot fluid circuit or fluid circuit, and the chiller is preferably turned off when in the flush mode so as not to chill the hot or heated fluid being used to flush the cold fluid circuit.

[0020] The controller may be configured to actuate the valve assembly between a first state and a second state to recirculate fluid through the fluid flow path via the fluid return path at selected intervals.

[0021] The controller may be configured to operate the second valve assembly to direct hot or heated fluid from the hot fluid circuit into and / or through the cold fluid circuit when in the flush mode. The chiller may be shut off during the flush mode. A single controller may be configured to control the valve assembly and the second valve assembly.

[0022] The fluid may be recirculated through the fluid flow path via a fluid return path at regular intervals, maintaining a chilled temperature, reducing microbial load, and preventing the buildup of biofilm in the fluid within the fluid flow path. Therefore, the amount of fluid wasted is reduced because frequent flushing to remove hot water from the fluid flow path is eliminated. Furthermore, customers experience greater satisfaction when their beverages are at or near the desired temperature. Furthermore, because the chilled fluid within the cryogenic fluid circuit is cooled each time it is recirculated, maintaining the chilled fluid within the cryogenic fluid circuit ready to be dispensed, the temperature of the chilled fluid released from the fluid outlet upon demand is more likely to be at or near the desired temperature.

[0023] The time interval can be any length, for example, the time interval can be about 120 minutes, more preferably about 60 minutes.

[0024] The controller may shorten or lengthen the time interval based on use of the beverage preparation machine. For example, if the cold fluid is being dispensed frequently, the controller may increase the length of the time interval for recirculation because the cold fluid is unlikely to remain in the cold fluid circuit for any reasonable length of time.

[0025] The controller may automatically switch to the chilled fluid recirculation mode when the beverage preparation machine is in the chilled fluid dispensing mode but has been idle for a period of time. The controller may utilize a timer that is initialized after a certain amount of fluid has been dispensed. The timer may be reinitialized after each dispense of fluid, such that recirculation begins only after a preferred period of time has elapsed and the beverage preparation machine has not operated in the dispensing mode for that preferred period of time.

[0026] In one embodiment, the controller may operate the beverage preparation machine in chilled fluid recirculation mode for a period of time before switching to chilled fluid dispensing mode. This may be done, particularly if a period of time has elapsed between the last recirculation and any request to dispense fluid. This may aid in dispensing chilled fluid at or near the desired temperature.

[0027] The fluid may be a liquid, which may be water or another liquid such as, but not limited to, milk and / or coffee and / or tea and / or chocolate.

[0028] The fluid flow paths may be arranged and configured to direct fluid through the cryogenic fluid circuit or to allow fluid to be flowed through the fluid flow paths. Fluid may be flowed through the fluid flow paths via mechanical or electrical means. Fluid may be flowed via a pump.

[0029] Fluid may be flowed through the return fluid flow path when the valve assembly is in the second state.

[0030] Any pump or similar device is preferably located in the fluid flow path between the fluid inlet and the ultraviolet fluid treatment device. Any pump or similar device is preferably located in the fluid flow path after the connection of the return fluid flow path.

[0031] The fluid flow path may be defined to include one or more fluid flow conduits, such as, but not limited to, pipes, channels, or tubes.

[0032] One or more portions of the fluid flow path may be insulated. One or more portions of the return fluid flow path may be insulated. The insulation may preferably serve to isolate the cooling fluid from any heat sources, including any heat from the heating fluid circuit, thereby improving the overall efficiency of the device.

[0033] The fluid inlet may be configured to receive a fluid flow from a fluid source, which may be a fluid dispenser valve, which may be, for example, a tap.

[0034] The ultraviolet fluid treatment device is positioned to emit ultraviolet light to treat the fluid. The ultraviolet treatment device may be located within the cooler. The ultraviolet treatment device may be located along the fluid flow path at a position before the valve assembly. Thus, any microbial load in the cooling fluid is significantly reduced. The installation of the ultraviolet fluid treatment device eliminates the need for expensive and environmentally unfriendly microfilters, improving device reliability. This is advantageous because microfilters can clog, which can lead to reduced flow rates and customer dissatisfaction. Furthermore, filters often require a service engineer to install a replacement, which is costly.

[0035] Any suitable ultraviolet fluid treatment device may be used in the present invention. Preferably, the ultraviolet treatment device is a flow-through device in which the fluid to be treated flows through a housing having one or more ultraviolet lamps or light sources disposed therein. The ultraviolet fluid treatment device may preferably be disposed in-line with a portion of the fluid flow path.

[0036] The chiller can reduce the temperature of the fluid in the cryogenic fluid circuit. The chiller may be a heat exchanger or other cooling means. Providing such a temperature reduction ensures that the fluid is maintained at a constant temperature, ensuring a consistent fluid temperature at the outlet, thus improving customer satisfaction.

[0037] The valve assembly may be operable in at least two, and possibly multiple, states. The valve assembly may preferably be operable in at least two states. In a first state, the valve assembly is configured to direct the fluid to the fluid outlet. In a second state, the valve is configured to recirculate the fluid through the return fluid flow path and through the fluid flow path. Thus, two separate circuits are not required, one for recirculating the cooling fluid and one for distributing the cooling fluid through the fluid outlet. Thus, the device is less complex and more compact.

[0038] The fluid outlet is configured to direct the fluid from the fluid flow path and out of the beverage preparation machine. The fluid outlet may be configured to dispense the fluid into a container. The container may be a container configured to hold a fluid, such as, but not limited to, a mug, a glass, or a cup. The fluid outlet may direct the fluid towards further process equipment and therefore may not be an exit from the beverage preparation machine. One or more fluid outlets may be provided. Any one or more of the plurality of fluid outlets may be connected to the fluid flow path.

[0039] The fluid outlet may be configured to be incorporated into a larger beverage preparation machine, which may for example be a coffee machine.

[0040] The operation of the beverage preparation unit may be such that the valve assembly operates to maintain a quantity of fluid in the fluid return flow path when the valve assembly switches from the first state to the second state. This avoids the need for a breaker tank or other storage vessel. Instead, it is preferred that a quantity of fluid is retained in the fluid return flow path when the valve assembly switches from the first state to the second state.

[0041] When in dispensing mode, the fluid simply flows through the fluid flow path where it is treated with ultraviolet light, cooled, and dispensed. Once dispensing is complete, the valve assembly preferably switches to a cooled fluid recirculation mode, allowing the fluid to be recirculated through the fluid return and fluid flow paths as needed without being dispensed. This reduces the microbial load in the cold fluid and prevents biofilm buildup while still allowing the fluid to be maintained at a lower temperature than the temperature at which it is prepared to be dispensed on demand, if needed. The fluid is preferably recirculated through an ultraviolet fluid treatment device that treats the fluid as it passes through, and the recirculated fluid is preferably recirculated through a chiller to maintain the reduced temperature.

[0042] According to a second aspect of the present invention, there is provided a cryogenic fluid circuit unit for retrofitting an existing beverage preparation machine, comprising: a fluid flow path, the fluid flow path comprising: a fluid inlet; an ultraviolet fluid treatment device located in the fluid flow path; a fluid outlet connection configured to connect to a chiller unit; A cryogenic fluid circuit unit is provided that includes a fluid return flow path connection configured to connect to the fluid flow path for returning fluid.

[0043] The unit may be provided in a housing, which may be configured to house the components in a secure or convenient manner for retrofitting.

[0044] The fluid outlet connection may be configured to connect to a chiller unit, which preferably allows fluid entering the cryogenic fluid circuit unit to flow through the cryogenic fluid circuit unit, in particular through ultraviolet fluid treatment devices located on the fluid flow path, and then enter the chiller to be cooled.

[0045] The fluid return connection may allow connection of the fluid return flow path to a cryogenic fluid circuit unit, which in turn may allow recirculation of fluid through the cryogenic fluid circuit.

[0046] The cryogenic fluid circuit unit may be retrofitted to the cryogenic fluid circuit with appropriate valve assemblies installed or utilized to allow the cooling fluid to be distributed or recirculated around the recirculation loop when not distributed.

[0047] In one embodiment, an optional additional high temperature circuit may be provided, which may include a fluid inlet, at least one heater, and a high temperature fluid flow path.

[0048] The hot or heated fluid circuit may be configured to direct a hot or heated fluid to the hot fluid outlet. The fluid may be a liquid. In a preferred embodiment, the liquid may be water. The fluid may be heated to its boiling point. Thus, the fluid exiting the heater may be heat-treated above a certain temperature to inhibit the growth of undesirable organisms, harmful germs, or infectious agents and / or to kill undesirable organisms, harmful germs, or infectious agents.

[0049] The hot fluid circuit may be arranged or configured to connect with the cold fluid circuit. The hot fluid circuit may be configured with a fluid outlet or arrangement suitable for flushing through the cold fluid circuit. The hot fluid may be heat treated to avoid introducing and / or be used to kill undesirable organisms, harmful bacteria, or infectious agents, including, but not limited to, bacteria, viruses, and pathogens. This can be advantageously used to flush or purge any microbial load within the cold fluid circuit when necessary or desired. [Detailed Description of the Invention] In order that the invention may be more clearly understood, one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0050] [Figure 1] FIG. 1 is a fluid flow diagram illustrating the beverage preparation device in fluid recirculation mode. [Figure 2] FIG. 2 is a fluid flow diagram illustrating the beverage preparation device in a fluid dispensing mode. [Figure 3] FIG. 1 is a fluid flow diagram illustrating the beverage preparation device in a flushing mode. [Figure 4] FIG. 10 is a fluid flow diagram illustrating an alternative embodiment of a beverage preparation device. DETAILED DESCRIPTION OF THE INVENTION

[0051] Referring initially to Figures 1, 2 and 3, a beverage preparation machine 1 according to a first embodiment of the present invention comprises a cold fluid circuit 2 (indicated by a block arrow in Figure 2) having means for cooling fluid passing therethrough. The cold fluid circuit 2 has a fluid inlet 3 for receiving a fluid flow from a fluid source (not shown) and a UV fluid treatment device 4. The UV fluid treatment device 4 is arranged as a flow-through device such that fluid enters the cold fluid circuit 2 through the fluid inlet 3 and flows through the UV fluid treatment device 4. The UV fluid treatment device 4 is arranged within a housing 5. The housing 5 contains one or more UV light sources (not shown) that irradiate the fluid passing through the UV fluid treatment device 4 with UV light to treat it.

[0052] The cryogenic fluid circuit 2 also includes a chiller 6 that reduces the temperature of the fluid passing through the cryogenic fluid circuit 2. In this embodiment, the chiller 6 is located after the ultraviolet fluid treatment device 4, although in other embodiments the chiller 6 may be located within the same housing 5 as the ultraviolet fluid treatment device 4.

[0053] The cryogenic fluid circuit 2 also has a fluid flow path 7 arranged to originate at the fluid inlet 3 and pass through the ultraviolet fluid treatment device 4 and the chiller 6. The fluid flow path 7 is defined by a plurality of fluid flow conduits (not shown). In these embodiments, the plurality of fluid flow conduits are a plurality of insulated tubes 8 that maintain the chilled temperature of the fluid in the cryogenic fluid circuit 2 exiting the chiller 6. The plurality of insulated tubes 8 isolate the chilled fluid from any heat sources, thereby improving the overall efficiency of the beverage preparation device 1.

[0054] The cryogenic fluid circuit 2 further comprises a fluid outlet 9. The fluid outlet 9 is arranged to distribute the cooled fluid exiting the cryogenic fluid circuit 2.

[0055] The cryogenic fluid circuit 2 in these embodiments has means for directing fluid through the cryogenic fluid circuit 2 in the form of a pump 10. The pump 10 is located after the fluid inlet 3 but before any process equipment. In these embodiments, the pump 10 is also located in the fluid flow path 7 after the connection of the return fluid flow path 12.

[0056] The cryogenic fluid circuit 2 also includes a valve assembly 11 operable in at least two states to meet different operational requirements. In the illustrated embodiment, the valve assembly 11 includes a plurality of flow control valves 20, 21, and 22. Each of the flow control valves 20, 21, and 22 is respectively installed at one of a plurality of outlets 9 from the device, thereby enabling the device to output a variety of different beverages from the same fluid.

[0057] In the illustrated embodiment, a second valve assembly 19 is provided to allow hot water from the heater 15 to be utilized as part of an optional high temperature flush circuit 27. The high temperature flush circuit also includes a flush valve 23 which, when opened, allows flush fluid to be removed from the system via a flush outlet 28.

[0058] A controller (not shown) is used to operate the necessary valves 20, 21, 22 of the valve assembly 11 between a first state and a second state. In the first state, one open valve in the valve assembly 11 directs fluid to a respective fluid outlet 9. In the illustrated embodiment, the valve assembly 11 consists of three valves 20, 21, 22. Each valve is operable in a first state and a second state. Each valve 20, 21, 22 controls fluid flow to a respective fluid outlet 9.

[0059] Referring to FIG. 1 , beverage preparation machine 1 is operable in a chilled fluid recirculation mode. Beverage preparation machine 1 has a fluid return flow path 12. When multiple valves in valve assembly 11 are in a second state, fluid is recirculated and directed through fluid flow path 7 and through fluid return flow path 12. Fluid return flow path 12 is connected to fluid flow path 7 to allow fluid not dispensed through fluid outlet 9 to be recirculated, treated by ultraviolet fluid treatment device 4, and have its temperature reduced by chiller 6. This ensures that no fluid is wasted and that the temperature of all fluid passing through fluid outlet 9 is cool enough for customer use. In the illustrated embodiment, fluid return flow path 12 connects to fluid flow path 7 after fluid inlet 3 and check valve 13, but before other process equipment, including ultraviolet fluid treatment device 4 and chiller 6.

[0060] In the cooling fluid recirculation mode, the fluid is recirculated without distribution through the fluid return flow path 12 and fluid flow path 7 as needed, while maintaining the fluid at a lower temperature ready to be distributed if required, while reducing the microbial load in the cold fluid and preventing biofilm buildup.

[0061] Valve assembly 11 operates to maintain a volume of fluid trapped within fluid return flow path 12 as multiple valves within valve assembly 11 switch between a first state and a second state. This trapped fluid has already been treated by ultraviolet fluid treatment device 4.

[0062] A flow meter 30 is also provided to ensure a steady dosage of fluid through the system.

[0063] The fluid return flow path 12 is defined by a plurality of fluid flow conduits connecting the process equipment. The plurality of fluid flow conduits in this embodiment are a plurality of insulated tubes 8 that maintain the chilled temperature of the fluid in the fluid return flow path 12 that has already passed through the fluid flow path 7, so that the fluid may be at a reduced temperature. The plurality of insulated tubes 8 isolate the chilled fluid from any heat sources within the beverage preparation apparatus, such as the heater 15, thereby improving the overall efficiency of the beverage preparation apparatus 1.

[0064] The beverage preparation machine 1 of the preferred embodiment has a controller (not shown) for activating a chilled fluid recirculation mode when the beverage preparation machine 1 has been idle for a period of time. Fluid is periodically flowed through the fluid return flow path 12 to maintain a reduced temperature of the fluid, a reduced microbial load of the fluid, and prevent the buildup of biofilm in the system.

[0065] The first check valve 13 is installed in the fluid flow path after the fluid inlet 3 and before the connection of the fluid return flow path 12 to the fluid flow path 7, and before the ultraviolet fluid treatment device 4 and chiller 6 on the fluid flow path 7. The first check valve 13 prevents backflow of fluid from the fluid inlet 3.

[0066] 2, the beverage preparation device 1 is shown in a fluid dispensing mode in which one of the valves 20, 21, 22 of the valve assembly 11 is in a first state, directing chilled fluid to a corresponding fluid outlet 9. A single fluid outlet 9 typically dispenses fluid into a single container.

[0067] In this embodiment, there are multiple fluid outlets 9. The valve assembly 11 includes multiple valves 20, 21, 22 operable in at least a first state and a second state. When any one of the multiple valves 20, 21, 22 is actuated in the first state, it directs fluid flow to the corresponding outlet 9. When all of the valves 20, 21, 22 are actuated in the second state, it directs fluid to the fluid return flow path 12.

[0068] Referring to Figure 3, beverage preparation machine 1 is shown in hot fluid flushing mode. Beverage preparation machine 1 has a hot fluid circuit 14 (from boiler 15 to one of multiple outlets 9 as shown in Figure 3). Hot fluid circuit 14 utilizes heated fluid from heater 15 via a fluid inlet located at heater 15. Heater 15 heats the fluid to a boiling point above a temperature that inhibits the growth of or kills undesirable organisms, harmful bacteria, or infectious agents.

[0069] The beverage preparation device 1 has a hot fluid flow path 16 arranged to pass through the heater 15. The hot fluid circuit 14 has a flush outlet 28 arranged to allow removal of flush fluid exiting the hot fluid circuit 14 when the flush valve 23 is open.

[0070] The hot fluid flow path 16 is defined by a plurality of fluid flow conduits, which in this embodiment are a plurality of insulated tubes 8 that help maintain the heating temperature of the fluid in the hot fluid circuit 14 exiting the heater 15.

[0071] The hot fluid circuit 14 includes a second valve assembly 19. The second valve assembly is operable in a first mode of operation and a second mode of operation. In the first mode of operation, the valve assembly 19 is in a closed configuration and prevents hot fluid from the hot fluid circuit 14 from entering the cold fluid circuit 2. In the second mode of operation, the valve assembly 19 is in an open configuration and, when valve 23 is also open, directs hot fluid into and / or through the cold fluid circuit 2 in a flush mode.

[0072] As shown in FIG. 3 (independent of the hot fluid flush mode), the hot fluid can be distributed through any one of multiple fluid outlets 9 by opening the respective flow control valves 24, 25, 26 associated with the heater 15.

[0073] The hot fluid circuit 14 connects with the cold fluid circuit 2 at a point after the fluid flow path 7 but before the valve assembly 11. When one of the valves 20, 21, 22 of the valve assembly 11 is in a first state, hot fluid from the hot fluid circuit 14 is directed out the corresponding fluid outlet 9 and distributed into the vessel. When the second valve assembly 19 is in a second state, the hot fluid is recirculated along the fluid return flow path 12. The hot fluid passes through the ultraviolet fluid treatment device 4 and the chiller 6 (which is inactive in the hot fluid flush mode), passes through multiple fluid flow conduits to flush the insulated tubes 8, and is removed through the flush outlet 28 by opening the flush valve 23.

[0074] As shown, a second check valve 18 is installed in the fluid return flow path 12. The second check valve 18 is installed before the connection point between the fluid flow path 7 and the fluid return flow path 12 to prevent backflow of fluid through the fluid return flow path 12.

[0075] An alternative configuration of beverage preparation machine 1 is shown in Figure 4. The major components of this embodiment are depicted in Figures 1-3. This configuration also allows fluid to flow from inlet 3 through check valve 13, flow meter 30, pump 10, UV fluid treatment device 4, and chiller 6 in fluid flow path 7. Valves V12, V22, and V32 are operable to allow cooled, UV-treated fluid to travel to a mixer associated with the coffee outlet, a mixer associated with the milk outlet, or a cold outlet as shown, as desired. These valves can also be operated to recirculate cooled fluid to fluid flow path 7 via return fluid flow path 12.

[0076] Valves V11, V21 and V31 are connected to boiler 15 and can be operated to allow heated fluid to flow to the mixer associated with the coffee outlet, the mixer associated with the milk outlet or to the hot outlet as shown (which may also be the cold outlet), as desired.

[0077] One difference from the embodiment shown in FIG. 4 is that the return fluid flow path 12 is provided with a two-way valve 41 rather than the check valve depicted in FIGS.

[0078] One or more embodiments have been described above by way of example only, and many variations are possible without departing from the scope of protection granted by the appended claims.

Claims

1. 1. A beverage preparation machine comprising a cryogenic fluid circuit, the cryogenic fluid circuit comprising: a. a fluid inlet; b. an ultraviolet fluid treatment device; c. a chiller; d. a fluid flow path from the fluid inlet through the ultraviolet fluid treatment device and through the chiller; e. a fluid outlet; f. a fluid return channel configured to connect the fluid flow channel to return cooling fluid to the fluid flow channel; g. A beverage preparation device comprising a valve assembly operable in a first state to direct said fluid to said fluid outlet and in a second state to recirculate said fluid through said fluid flow path.

2. The beverage preparation device of claim 1 , wherein the fluid return flow path is connected to the fluid flow path.

3. 3. The beverage preparation machine of claim 2, wherein the fluid return flow path is connected to the fluid flow path before the chiller and between the fluid inlet and the ultraviolet fluid treatment device.

4. 4. A beverage preparation machine according to any one of claims 1 to 3, wherein the fluid return flow path passes through the chiller before being connected to the fluid flow path.

5. 3. The beverage preparation device of claim 2, wherein the fluid flow path passes through the chiller toward the valve assembly for distribution or recirculation, and the fluid return flow path passes through the chiller after the valve assembly before connection of the fluid return flow path to the fluid flow path.

6. 6. A beverage preparation machine according to any one of the preceding claims, wherein a controller is arranged to recirculate the fluid through the fluid flow path via the fluid return path at regular time intervals.

7. 8. A beverage preparation machine according to claim 7, wherein the time interval is about 120 minutes, more preferably about 60 minutes.

8. 8. A beverage preparation apparatus as claimed in claim 6 or 7, wherein the controller adjusts the time interval based on usage of the beverage preparation machine.

9. 9. A beverage preparation machine according to any one of claims 1 to 8, wherein the ultraviolet fluid treatment device is positioned along the fluid flow path before the valve assembly.

10. 10. The beverage preparation machine of claim 1, wherein the ultraviolet fluid treatment device is a flow-through device in which the fluid to be treated flows through a housing having one or more ultraviolet lamps or light sources disposed therein.

11. 11. The beverage preparation machine of any one of claims 1 to 10, wherein the beverage preparation machine is operable in a chilled fluid dispensing mode in which the valve assembly is in the first state.

12. 12. The beverage preparation apparatus of claim 11, wherein fresh fluid enters the fluid flow path of the cryogenic fluid circuit through the fluid inlet, flows through the ultraviolet fluid treatment device, the chiller, and to the valve assembly, with the valve assembly in the first state allowing cooled fluid to be released through the fluid outlet.

13. 13. The beverage preparation machine of any one of claims 1 to 12, wherein the beverage preparation machine is operable in a chilled fluid recirculation mode in which the valve assembly operates in the second state.

14. 15. The beverage preparation device of claim 14, wherein fresh fluid enters the fluid flow path of the cold fluid circuit through the fluid inlet, flows through the ultraviolet fluid treatment device, the chiller, and to the valve assembly, and because the valve assembly is in the second state, cooled fluid is recirculated through the fluid return flow path.

15. 15. The beverage preparation machine of claim 13 or 14, wherein the controller automatically switches to the chilled fluid recirculation mode if the beverage preparation machine is in the chilled fluid dispensing mode but has been idle for a period of time.

16. 16. The beverage preparation device of claim 15, dependent on any one of claims 11 or 12, wherein the controller utilizes a timer that is initialized after a certain amount of fluid has been dispensed, such that the recirculation begins only after a certain period of time has elapsed and the beverage preparation machine has not operated in the dispensing mode for that certain period of time.

17. 17. The beverage preparation machine of claim 16, wherein the controller operates the beverage preparation machine in the chilled fluid recirculation mode for a period of time before switching to the chilled fluid dispensing mode.

18. 18. A beverage preparation machine according to any preceding claim, wherein the cold fluid circuit is provided in a beverage preparation machine which also includes a hot or heated fluid circuit.

19. 19. The beverage preparation device according to claim 18, wherein the hot fluid circuit or the heated fluid circuit is connected to the cold fluid circuit.

20. 20. The beverage preparation device of claim 19, wherein the beverage preparation device is operable in a flush mode utilizing hot or heated fluid from the hot or heated fluid circuit to flush the cold fluid circuit.

21. 21. The beverage preparation machine of claim 20, wherein a flush mode controller is provided for operating the second valve assembly to direct the hot or heated fluid from the hot fluid circuit into and / or through the cold fluid circuit when in the flush mode.

22. 22. The beverage preparation machine of claim 21, wherein a single controller is provided to control the valve assembly and the second valve assembly.

23. 1. A cryogenic fluid circuit unit for retrofitting an existing beverage preparation machine, comprising: a. a fluid flow path, the fluid flow path comprising: b. a fluid inlet; c. an ultraviolet fluid treatment device located in the fluid flow path; d. a fluid outlet connection configured to connect to a chiller unit; e. a cryogenic fluid circuit unit comprising a fluid return flow path connection configured to connect to said fluid flow path for returning fluid.

24. 24. The cryogenic fluid circuit unit of claim 23, wherein the fluid outlet connection is configured to connect to a chiller unit.

25. 25. A cryogenic fluid circuit unit according to claim 23 or 24, wherein the fluid return connection is configured to connect to a fluid return flow path to the cryogenic fluid circuit unit, which in turn allows recirculation of fluid through the cryogenic fluid circuit.

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