Abstract:
In one aspect the present invention provides a chilled beverage dispense system including a beverage recirculation loop and a glycol recirculation loop, a first chiller to cool the beverage and a second chiller to cool the glycol, a heat exchanger through which the cooled beverage and the cooled glycol are passed to further cool the beverage and a dispense valve located in the beverage recirculation loop downstream of the heat exchanger. The glycol recirculation loop including a bypass valve upstream of the heat exchanger, whereby in a standby, non-dispense mode the glycol bypasses the heat exchanger and when a beverage dispense is required, the glycol is diverted through the heat exchanger.

Description:
The present application is a continuation of application Ser. No. 09/838,925 filed Apr. 20, 2001, now U.S. Pat. No. 6,431,403. 
    
    
     BACKGROUND 
     This invention relates 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. 
     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 utilize 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 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 in one aspect the invention provides a chilled beverage dispense system including a beverage recirculation loop and a glycol recirculation loop, a first chiller to cool the beverage and a second chiller to cool the glycol, a heat exchanger through which the cooled beverage and the cooled glycol are passed to further cool the beverage and a dispense valve located in the beverage recirculation loop downstream of the heat exchanger, the glycol recirculation loop including a bypass valve upstream of the heat exchanger, whereby in a standby, non-dispense mode the glycol bypasses the heat exchanger and when a beverage dispense is required, the glycol is diverted through the heat exchanger. 
     In another aspect the invention provides a method of dispensing a cooled beverage in which the beverage is passed in a recirculation loop through a first chiller to cool it and then through a heat exchanger and then via a dispense head to return to the first chiller, a glycol coolant is passed in a recirculation loop through a second chiller to a bypass valve to avoid passing through the heat exchanger when beverage is not being dispensed and then back to the second chiller, the bypass valve being actuated when a dispense is required whereby the glycol coolant passes through the heat exchanger to further cool the beverage before it is dispensed. 
     It will be appreciated, therefore, that the beverage can be maintained in its first cooled condition, e.g. from 0.5° to 1.5° C., typically 1° C., in the standby mode by means of recirculation through its first chiller but that when dispense is required it is further cooled by heat exchange within the heat exchanger with the colder glycol that is now diverted from its bypass mode to flow through the heat exchanger. The glycol may be maintained at, e.g. from −8.5° to −9.5° C., typically −9° C., to give a second cooling to the beverage which may then be dispensed at e.g. from −4° to −5° C., typically −4.5° C. It will be appreciated that these ranges will vary depending on the beverage to be dispensed. 
     The heat exchanger may be of any convenient plate, tube or other construction. 
     During standby mode, glycol remaining in the heat exchanger will, of course, warm up from its chilled temperature but will be maintained at about the temperature of the recirculating beverage. 
     If the heat exchanger is located close to the dispense valve so that the amount of beverage at any point in time from the heat exchanger to the dispense valve is small relative to the amount to be dispensed, it may be possible to arrange a control system that commences dispense at the same time as operating the bypass valve to divert the glycol through the heat exchanger. However, it is preferred that a control system be used that, on a dispense being actuated, first operates the bypass valve to further cool the beverage and then, after a delay, opens the dispense valve. The delay may be a predetermined time or may be determined by a temperature sensor for the beverage positioned between the heat exchanger and the dispense valve. In this latter embodiment, the dispense valve will only open once the temperature sensor indicates to the control system that the required dispense temperature has been reached. 
     The glycol coolant used may be pure glycol but will usually be a water/glycol mixture, e.g. of proportions from 25:75 to 50:50, depending on the degree of cooling required. 
     In a preferred embodiment a water recirculation loop is included in the system in order to provide a spray of chilled water onto a glass or other receptacle into which the beverage is to be dispensed. The water may conveniently be chilled in the same first chiller used for the beverage recirculation loop. This first chiller may be a single ice bank cooler of conventional design with a portion of the beverage recirculation loop and of the water recirculation loop immersed in water/ice within the cooler. 
     A water dispense valve is provided in the water recirculation loop and controlled quantities of chilled water at from, e.g. 0.5° to 1.5° C., may be sprayed onto the beverage receptacle in response to signals from the beverage dispense control system. The receptacle may be sprayed before, during and/or after beverage is dispensed into it. 
     The 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 heat exchanger is used to provide the extra cooling when required for a dispense. Between dispenses the heat exchanger is bypassed by the recirculating glycol coolant and the system “idles” with the beverage at the temperature achieved by the first chiller. 
     The dispense valve can be permanently chilled in the beverage recirculation loop and so does not harmfully affect dispense temperature after standing unused. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     A better understanding of the structure, function, operation, and advantages of the present invention can be had by reference to the Detailed Description that is set out below and that refers to the following drawing figures, wherein: 
     FIG. 1 is a schematic illustration of a beverage dispense system of the present invention: 
     FIG. 2 is a similar illustration to FIG. 1 of a modified system of the present invention; and 
     FIG. 3 is a diagrammatic representation of possible sequences in time. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 1 a first chiller  10 , which is an ice bank cooler, contains portions of recirculation loops for water and for a beverage. 
     The water flows from a source (not shown), e.g. the mains, via an optional boost pump  11  and a pressure regulator  12  into an outer water loop  13  in chiller  10  which continues into an inner water loop  14 . Loop  14  includes a recirculation pump  15 . Cooled water from inner loop  14  is pumped from chiller  10  around a recirculation loop  16 . A solenoid valve  17 , adjacent a rotatable turntable  18  underneath a beverage dispense head  19 , is connected to loop  16  but is closed in the idle, non-dispense mode. A water line  20  leads from the solenoid valve to a spray head  21  through which cooled water may be sprayed onto a glass  22  underneath the dispense head  19  when solenoid valve  17  is opened. In the idle mode, the water returns to chiller  10  via an optional non-return valve  23  and continues to circulate around its inner loop  14  and its recirculation loop  16 . The water in outer loop  13  in chiller  10  is standing water while valve  17  is closed. When valve  17  is opened to commence spraying of the glass water pressure from its source, boosted if required by pump  11 , introduces fresh water via loop  13  into loops  14  and  16 . 
     An optional bleed line  24  is connected into recirculation loop  16 . 
     Beverage flows from a source (not shown) via metering turbine  24  into an outer beverage loop  25  which passes through chiller  10  and out again where it joins an inner loop  26 . Loop  26  passes through a recirculating pump  27  and then back into the chiller. If desired a flow turbine may be included in this loop  26 , e.g. between pump  27  and the junction of loops  25  and  26 . 
     The cooled beverage leaves chiller  10  in a recirculation loop  28  and passes through a heat exchanger  29 . On leaving heat exchanger  29  where in dispense mode it is further cooled by a glycol line to be described below, the beverage passes through a temperature sensor  30 , e.g. a thermistor housing, and from there through dispense head  19  and via a non-return valve  31  to the chiller  10 . Between non-return valve  31  and chiller  10  the beverage passes through a restrictor tube or compensator valve  33  to control the speed of beverage recirculation to prevent, e.g. decarbonation. The recirculation speed may be kept, for example, to about 1½ liters per minute, which is a typical dispense rate. Restrictor  33  may be dispensed with if the above-mentioned optional flow turbine is used in conjunction with pump  27  to control the flow speed. If the system remains in idle mode without dispense for some time, predetermined, the speed of beverage circulation may be reduced. It may then be speeded up again for dispense and for a period after dispense to maintain the desired temperature. The beverage continues to be recirculated around its loop  28  and inner loop  26  in the idle mode. The beverage in outer loop  25  is standing beverage during the idle mode but when the dispense head  19  is operated to dispense into glass  22 , fresh beverage flows into loops  25  and  26  from the source. 
     A bleed line  32  is connected into recirculation loop  28 . 
     The water and beverage recirculation lines may be contained within a conventional python and may conveniently be contained in a single python for a substantial portion of their lengths. This single python line is indicated generally by arrows AA. 
     The glycol coolant is cooled in chiller  40  and is circulated around a recirculation loop  41  by pump  42 . The glycol flow is indicated by block headed arrows plus line headed arrows. From chiller  40  the glycol travels to bypass valve  43  adjacent heat exchanger  29 . In the idle, nondispense state the glycol bypasses the heat exchanger and returns to chiller  40  for recirculation. The recirculation lines of loop  41  may also be contained within a conventional python, indicated generally by arrows BB. When the bypass valve  43  is opened the glycol flow is diverted through the heat exchanger where it causes further cooling of the beverage passing through in its loop  28 . 
     Glycol chiller  40  has an overflow reservoir  44  whose purpose will be described in more detail below. Reservoir  44  contains a heating element  45  and a thermostat  46 . Glycol from reservoir  44  can be pumped by pump  47  and non-return valve  48  into the heat exchanger  29  from where it leaves in the glycol recirculation loop  41  to return to chiller  40 . 
     One possible routine for operation of the dispense system is now described. 
     In the idle, non-dispense situation the beer and water are recirculating through their recirculation loops at about, say, 1° C. The glycol is recirculating in its loop, missing out the heat exchanger  29 , at about, say, −9° C. 
     A glass  22  is placed on turntable  18  and the control unit (not shown) is pressed to select a ½ pint or 1 pint dispense of the beverage. 
     This actuates the bypass valve  43  which diverts glycol in its recirculation loop to pass through the heat exchanger to further cool the beverage. Solenoid  17  is also actuated and cold water is sprayed via head  21  onto the glass  22 . The turntable  18  motor mechanism (not shown) is also started so that glass  22  rotates on the turntable. 
     Thermistor  30  is sensing the beer temperature as it leaves the heat exchanger  29  and, when it signals that the desired dispense temperature has been reached the dispense valve in dispense head  19  is opened to allow the cooled beverage to be dispensed into the glass. The metering turbine  24  is actuated by the flow of beer in from the source to replace dispensed beer and the water spray and turntable rotation are maintained as dispense continues. 
     If desired, during dispense an ultrasonic shock can be given to the beverage in the glass on the turntable at a predetermined point of the dispense as indicated by the metering of turbine  24 . This can improve the appearance and presentation of the beverage in the glass e.g. by assisting in the generation of a foamed head on the beverage. Means to provide such a shock are not shown here but are known in the art. The water solenoid  17  closes at another predetermined point of the metered dispense. The glycol bypass valve  43  is switched to stop further cooling, again at a predetermined point of the metered dispense, usually towards the end of the metered dispense. As bypass valve  43  is so switched, the glycol pump  47  is actuated to provide a timed flow, e.g. of from 4 to 5 seconds, at about 0.5 liters/minute, of glycol warmed by heater  45  to about, say, 8° C. through the heat exchanger  29 . This is just a sufficient amount of heat glycol to flush colder glycol from the heat exchanger and thereby prevents the risk of beverage freezing in the heat exchanger when the dispense has finished. (It will be appreciated that the bypass arrangement prevents the heat exchanger from getting too cold during periods of no dispense which would also have the risk of beverage freezing.). 
     A second ultrasonic shock may be administered to the beverage in the glass just before or at the end of the dispense to nucleate the beverage for final appearance. 
     When metering turbine  24  indicates that the required amount of beverage has been dispensed, the control system closes the dispense valve at the dispense head. The turntable may be timed to continue to rotate for a preset but adjustable time after dispense is finished. The water solenoid valve  17  can be re-opened after a preset but adjustable time to provide a further spray onto the exterior of the glass for a short time, e.g. 2 or 3 seconds, to clear condensation on the glass as the ice crystal nucleation occurs in the beverage. This water spray and the turntable rotation then conveniently stop to bring the dispense cycle to an end. The system then reverts to its stable, idle mode. 
     When the glycol from reservoir  44  is returned to chiller  40 , this excess volume of glycol in the chiller overflows through overflow pipe  48  into reservoir  44  to maintain the normal level of glycol in the chiller. 
     The above routine is illustrated diagrammatically in FIG.  3 . It will be appreciated that the routine may be varied in a number of respects, particularly in respect of the timings, e.g. of the glass spraying stages, the ultrasonic shocks and the turntable over run at the end of the dispense. 
     In FIG. 2 is shown a modification of the system of FIG.  1 . Like parts have been given the same reference numerals and will not all be described again in detail here. 
     The beverage and water chiller and recirculation loops are the same as in FIG.  1  and the pumping, monitoring and metering means are also the same as are the heat exchanger and dispense head/turntable arrangements. 
     The glycol recirculation loop, chiller and reservoir arrangements are also the same but the heated glycol line from the reservoir to the heat exchanger takes a different route. In the FIG. 2 arrangement, instead of the warmed glycol from reservoir  44  being pumped directly to heat exchanger  29  it is now pumped to the heat exchanger via a glycol line  50  which passes through chiller  10  before reaching the heat exchanger. This is to bring the glycol to the same temperature as the recirculating beverage before it passes into the heat exchanger. As indicated a portion of glycol line  50  may be accommodated in the python AA for the water and beverage recirculation loops. Otherwise, the operation of the glycol line to the thermostat is the same as described above with reference to FIG.  1 . 
     It will be appreciated that many further modifications are possible within the scope of the present invention. For example, chillers  10  and  40  may conveniently be positioned in a single housing. 
     In the unlikely event of the system freezing at some point, this may be detected by an optional turbine, e.g. the optional flow turbine referred to in conjunction with pump  27  above. This turbine by indicating no flow when flow is expected can signal to the control to shut down the system for investigation.