Refrigeration – Using electrical or magnetic effect – Thermoelectric; e.g. – peltier effect
Reexamination Certificate
2000-11-09
2001-12-04
Bennett, Henry (Department: 3744)
Refrigeration
Using electrical or magnetic effect
Thermoelectric; e.g., peltier effect
C062S389000
Reexamination Certificate
active
06324850
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to a beverage dispense system in which a chilled beverage is presented to the consumer. It is particularly applicable to beverages such as beer or lager.
BACKGROUND OF THE INVENTION
Conventional beer/lager cooling systems typically have a bulk beverage supply located at a separate location (called a cellar room) from the bar counter and the beverage is chilled in the cellar by being passed through an ice bank cooler to a temperature just below its ultimate dispense temperature. The chilled beverage is then pumped from the cellar room to the bar within an insulated python.
If one wishes to dispense the beverage at very cold temperatures e.g. below 0° C., such a system has problems. In particular, one has to chill the beverage in the cellar room to an even lower temperature. Whilst one can utilise glycol mixtures in the ice bank cooler instead of water to obtain lower beverage temperatures, the lower the required beverage temperature the greater the risk that it will freeze solid in the cooler or the python during periods when the beverage is not being dispensed. It will then be impossible to operate the dispense system when the next drink is required to be dispensed.
It is therefore an object of the invention to provide a system which is capable of successfully dispensing a chilled beverage from a bulk supply to a temperature close to the freezing point of the beverage.
SUMMARY OF THE INVENTION
Accordingly the present invention provides a chilled beverage dispense system including a beverage recirculation loop and a water recirculation loop, a dispense valve located in the beverage recirculation loop, a first chiller, through which both loops pass, for cooling both the beverage and the water, and a second chiller through which both loops pass, the second chiller comprising a thermo-electric device and being located between the first chiller and the dispense valve whereby the beverage to be dispensed is further cooled in the second chiller and the water removes heat from the second chiller. The thermo-electric device is typically one or more layers of Peltier plate assemblies. As is well known, when connected to a voltage supply, a cold side and a hot side are generated at the assembly.
The first chiller may be a single ice bank cooler of conventional design with a portion of each recirculation loop immersed in water/ice within the cooler. Typically, the system is such that the first chiller cools both the beverage and the water to just above 0° C., say 0.5° C., whilst the second chiller may cool the beverage several degrees cooler (depending upon the freezing temperature of the beverage). With beer/lager, this may be cooler by a further 4° or 5° C., i.e. down to −3.5° C. or −4.5° C.
Water which has passed through the thermo-electric chilling device may also pass through one side of a heat exchanger before returning to the first chiller. The second side of such heat exchanger may carry recirculating beverage which has by-passed the dispense valve and is returning to the first chiller. The cold beverage may, thereby, be warmed from its below zero temperature before re-entering the first chiller. The second chiller is preferably actuated only when dispense from the dispense valve is required e.g. power is supplied to the Peltier (thermo-electric) device upon the pressing of a dispense button. After a predetermined dispense time or predetermined flow of beverage from the dispense valve, the power supply to the device may be cut off. Alternatively, at the end of the dispense cycle the current supplied to the thermo-electric device may be switched off and then reversed for a short time, e.g. a couple of seconds, before being switched off again. This slightly increases the beverage temperature in the device and avoids the risk of beverage freezing in this region. This slightly warmed beverage is not dispensed, since the control system will have closed the dispense valve before the warmed beverage reaches it.
During operation of the thermo-electric device to further chill the beverage before it is dispensed, the water passing through the thermo-electric device is warmed by the Peltier junction effect. As this water passes into the heat exchanger it acts to warm the recirculating beverage on its way back to the first chiller, as indicated above. The heat exchanger may be of the tube-in-tube type with water travelling parallel to the beverage.
In order to ensure that beverage which has been sufficiently chilled is dispensed, the dispense control system may provide for valve actuation (opening) only after the beverage exiting the second chiller has reached a predetermined temperature e.g. −4.5° C. This requires a temperature sensor, which may be located in the beverage recirculation loop between the second chiller and the dispense valve or in the dispense valve housing or even a little downstream of the dispense valve in the beverage recirculation loop. Alternatively, a time delay may be incorporated into the control system so as to open the valve a predetermined time after initiation.
In the event that the temperature of the beverage or water. returning to the first chiller is such that it is starting to freeze, it would then be warmed to the desired temperature in the first cooler. Moreover, as beverage and water continue to be pumped around the recirculation loops and the thermal mass should be sufficient to prevent any permanent freezing of the water or beverage. A water dispense valve may be provided in the water recirculation loop, preferably before the water enters the second chiller. Controlled quantities of chilled water may be dispensed from this valve in response to signals from the dispense control system. Typically such chilled water is projected or sprayed onto a beverage receptacle shortly before the opening of the beverage dispense valve. This enables the receptacle to be cooled by the chilled water ahead of, and possibly during or after, beverage dispense.
As either or both of the beverage and water recirculation loops are depleted by dispense, such loops are topped up by fresh liquid. Typically the incoming connections to the loops are located just ahead of the first chiller. Such incoming liquids may be at ambient temperature or they could be pre-chilled in high temperature environments.
The present invention provides a system in which cooler than usual beverage can be dispensed safely and without risk of freezing. A conventional ice bank cooler can be used for the initial cooling (first chiller) and to maintain the cooled effect between dispenses and the thermo-electric device (second chiller) is used to provide the extra cooling when required for a dispense and may also be used as a temperature control means in the manner indicated above. Between dispenses the second chiller is inactive and the system “idles” at the temperature achieved by the first chiller. The dispense valve is permanently chilled and so does not harmfully affect dispense temperature after standing unused. The system is simple to maintain with a minimum of moving parts and the risk of freezing is substantially eliminated.
REFERENCES:
patent: 2931188 (1960-04-01), Levit
patent: 5279446 (1994-01-01), Cooke et al.
patent: 5287913 (1994-02-01), Dunning et al.
patent: 5535600 (1996-07-01), Mills
patent: 5560211 (1996-10-01), Parker
patent: 6112541 (2000-09-01), Greene
patent: 6250084 (2001-06-01), Sato et al.
Bennett Henry
Hakanson Sten Erik
IMI Cornelius Inc.
Jones Melvin
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