Patent Publication Number: US-10306906-B2

Title: Chilled food product dispenser and method with adaptive control of refrigeration system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Patent Application No. PCT/US2014/014557, filed Feb. 4, 2014 which claims the benefit of provisional U.S. Patent Application No. 61/761,616, filed on Feb. 6, 2013 which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     There are many different types of preparation or dispensing devices for chilled, viscous edible foods such as soft ice cream commonly known as “soft serve”, custard, gelatin and the like. These systems commonly operate as a stand alone unit that can be moved about on casters. They may contain a refrigeration unit, a reservoir or hopper that can be used as a storage vessel for unfrozen food, and a barrel or vessel where the food is frozen. The barrel may contain an agitator to move the food about in the barrel or vessel. 
     For quality control purposes and food safety concerns these preparation or dispensing devices often contain one or more temperature sensors that are used to sense the temperature of the product or the temperature of the refrigeration unit. The temperature sensors are often used to control the temperature of the refrigeration unit, particularly by setting a high temperature where the refrigeration unit compressor will cut-in or turn on and a low temperature where the compressor will cut-out or turn off. 
     There remains a need in this area for improved chilled food preparation or dispensing apparatuses. 
     SUMMARY 
     A compressor actuator controls the compressor of a refrigeration unit in response to the rate of change of temperature measured per unit time. This rate of change is then compared to a calculated or set value to determine whether the compressor should be actuated from an ON state or an OFF state. The rate of change may be measured by a variety of mathematical methods. These mathematical methods may include a calculation of change in temperature divided by change in time, numeric linear regression analysis, numeric derivative methods, or any other suitable method. The compressor actuator may include a microcontroller, microprocessor, or other digital or analog circuitry. The present invention may be implemented in an apparatus with one, two, or more freezing barrels. 
     Still further objectives, features, and advantages of the present invention will be more readily understood upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the schematic of one embodiment of a chilled food processing apparatus of the present invention. 
         FIG. 2  shows a flow diagram of a first portion of a compressor actuator program suitable for use with the apparatus of  FIG. 1 . 
         FIGS. 3A and 3B  together show a flow diagram of a second portion of a compressor actuator program suitable for use with the apparatus of  FIG. 1 . 
         FIG. 4  shows a flow diagram of a third portion of a compressor actuator program suitable for use with the apparatus of  FIG. 1 . 
         FIG. 5  shows a flow diagram of a fourth portion of a compressor actuator program suitable for use with the apparatus of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to certain embodiments and possible variations thereof and specific language will be used to describe the same. It should nevertheless be understood that no limitation of the scope of this disclosure and the claims is thereby intended, and that such alterations, further modifications and further applications of the principles described herein are contemplated as would normally occur to one skilled in the art to which the disclosure relates. In several figures, where there are the same or similar elements, those elements are designated with the same or similar reference numerals, for example, in  FIG. 1  where elements are labeled with a number in the 100&#39;s and a similar element exists elsewhere the similar element is labeled in the 200&#39;s. 
       FIG. 1  shows a preferred embodiment of a chilled food product dispensing apparatus  100 . Apparatus  100  contains a compressor  101  having a compressor input  102  and a compressor output  103 . The apparatus also contains a condenser  104  with a condenser input  105  and a condenser output  106 . The condenser input  105  couples to compressor output  103  through connection  107 . 
     This preferred embodiment contains chilled food product containers  108  and  208 , each with a dispensing member  109  and  209  connected to it, respectively. These chilled food product containers are conventionally cylindrical, and thus are referred to as barrels, as shorthand. Evaporator units  148  and  248  are associated with the chilled food product container  108  or  208 , respectively. Each of the evaporator units  148  or  248  has an input  110  and  210 , and an output  111  and  211 , respectively. Evaporator units  110  and  210  are coupled to the condenser output  106  by connections  112  and  212 , respectively. The output of the evaporator units  110  and  210  are connected to compressor input  102  through connections  113  and  213 , respectively. The apparatus also contain temperature sensors  114  and  214 , preferably located near or at the evaporator unit  148  and  248 , respectively. In one embodiment of the present invention, temperature sensor  114  and  214  are thermistors. While thermistors are preferred, alternative temperature sensors can be used, such as thermocouples, bimetal-strip based sensors, or other temperature-sensitive devices. 
     Compressor  101  is controller by compressor actuator  115 . Compressor actuator  115  preferably includes a microcontroller, but could as well be microprocessor, other digital devices, or even an analog circuit. The compressor actuator is ideally built into an original preparation or dispensing apparatus, but it could alternatively be retrofitted into an existing preparation or dispensing apparatus. The compressor actuator  115  is electronically coupled through connection pairs  116  and  117 , and  216  and  217  to the temperature sensors  114  and  214 , respectively. 
     Apparatus  100  includes hoppers  120  and  220 , each serving as a liquid food reservoir with outputs  121  and  221 , respectively. The outputs  121  and  221  of hoppers  120  and  220  each fluidly couple to the inputs  122  and  222  of the food product containers  108  and  208  through connections  123  and  223 . A relay  125  is preferably used for direct control of compressor motor  149  that powers compressor  101 . The relays shown ( 125 ,  155 , and  255 ) are electro-mechanical but could equally well be solid-state alternatives. Relay  125  may be connected to compressor actuator  115  by electrical connections  158  and  159 . Power to the apparatus is provided connecting to a power supply at  156  by way of connections  162 ,  163  and  164  (ground). Power connects preferably through a transformer  157  and electrical connections  165  and  166  to supply power to the compressor actuator  115  and through relay  125  to the compressor motor  149 . 
     In the preferred dual dispensing form of apparatus  100 , there are control valves  150  and  250  to separately control refrigeration of the two portions. Control valves  150  and  250  connect to compressor actuator  115  by electrical connection pairs  152  and  153 , and  252  and  253 . Thermal expansion valves  151  and  251  provide restricted flow between the condenser portion and evaporator portions of the single stage vapor compression refrigeration system. Chilled food product containers  108  and  208  each preferably have an agitator (hidden from view) to automatically agitate chilled food product within it. These agitators are rotated by motors  154  and  254 , when their corresponding control relays  155  and  255  are closed, allowing power to flow from power supply  156  to the corresponding motors. Relays  155  and  255  are controlled from compressor actuator  115  through electrical connection pairs  160  and  161 , and  260  and  261 , respectively. 
     In one embodiment, sensors  130  and  230  sense the operation of dispensing member  109  or  209 . The output of sensors  130  and  230  are electrically connected via connections  132   a ,  132   b  and  232   a  and  232   b  to the compressor actuator  115 . The hoppers  120  and  220  may optionally contain a further cooling source or refrigeration unit not shown. 
     Compressor actuator  115  is preferably a microcontroller programmed to actuate compressor  101 . Alternatively, compressor actuator  115  could be a microprocessor, other digital or even purely analog circuitry. Referring now to  FIG. 2  which shows one embodiment of a program that may be programmed into a microcontroller acting as a compressor actuator  115  ( 300 ). A run may be commenced ( 301 ) and an index may be set to an initial value, for example 0 ( 302 ). This index may be compared to a calculated or constant value, for example, 1 ( 303 ). A function may be called that senses or compares the state of the secondary cooling system for the reservoir or hopper  120  and  220  ( 304 ). A run may be terminated or finished ( 305 ). Alternatively, the demand on the apparatus may be sensed from a sensor  130  or  230  on the dispensing member  109  or  209  of the apparatus or by other appropriate sensor ( 306 ). In one embodiment of the invention the compressor actuator may check to see if barrel  108  or  208  needs cooling ( 307 ). The compressor actuator may check or update the status of control valves  150  and  250  ( 308 ). The compressor actuator  115  may actuate the compressor  101  ( 309 ). The compressor actuator may actuate the beater motor  154  or  254  ( 310 ). The apparatus of the current invention may also check the status of a secondary cooling system for reservoir or hopper  120  and  220 , and update a status variable in response to that check ( 311 ) and may optionally update or control the secondary cooling system ( 312 ). The apparatus may also check the fluid level in reservoir  120  and  220  by any appropriate means including, but not limited to conductivity, and optionally update a status variable depending on the status of the fluid level ( 313 ). An index variable may be updated ( 314 ) and the loop of the compressor actuator program may then be repeated by returning to step  303 . 
     The compressor actuator  115  may optionally contain a sub-routine ( 400 ) to determine if the barrel  108  or  208  needs cooling. When such a sub-routine begins ( 401 ), a status variable may be set or checked to determine if the machine is, for example but not limited to, in a day mode or a night mode ( 402 ). Depending on such a status, a variable may be checked or set ( 404 ) and a cut-in or cut-out temperature for the compressor  101  that is used to cool the barrel  108  and  208  may be checked or set ( 405 ). A status variable then may be set or checked to determine if cooling of barrel  108  and  208  is necessary ( 406 ). A temperature may be read from temperature sensor  114  or  214  and this temperature may then be compared to a set or calculated cut-out temperature for the compressor  101  ( 407 ). 
     A status variable may be set or checked to determine if the apparatus needs cooling at the current state ( 408 ). A status variable may be set or checked to determine what temperature comparison algorithm may be used to control the compressor  101  of the chilled food product apparatus ( 409 ). The sub-routine may compare the temperature sensed at temperature sensor  114  or  214  to a variable that may be set or calculated to determine a cut-in temperature at which the compressor is actuated to the on state, this comparison may also include adjusting the temperature sensed at temperature sensor  114  or  214  by a value that is set or calculated ( 411 ). A variable used to indicate whether the apparatus or whether the compressor needs cooling at this state may then be set or updated ( 414 ). The comparison of  411  may set or check a variable on the status, for example, day or night status of the apparatus ( 412 ). The system may set cut-in or cut-out temperatures, depending on the status, for example, day or night, of the apparatus and further, this cut-in or cut-out temperature may be modified by a value that is set or calculated by the compressor actuator  115  ( 413 ). 
     The steps from  FIG. 3A  then continue to  FIG. 3B  and begin at “A” ( 415 ). Compressor actuator  115  may check or set the state in response to user demand from sensor  130  or  230  ( 416 ). A variable may be set or checked in response to whether the apparatus still needs cooling ( 417 ). A comparison may be performed which checks or sets the status of the compressor  101  or compares a calculated slope to a set or calculated rate of the rate of change of the temperature over a unit time, or compares the temperature sensed from temperature sensor  114  or  214  to a set or calculated temperature ( 418 ). 
     Other numerical methods used to calculate the rate of change in temperature per unit time may include, but is not limited to, performing a linear regression according to the formulas: 
     
       
         
           
             
               
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     S x , S y , and S xy  are defined as above where x i  is a measured value in the x dimension, and  x  is a point on a best-fit line in the x dimension, and y i  is a measured value in the y dimension and  y  is a point on a best-fit line in the y dimension and b is the calculated rate or slope of the best-fit line. 
     Or, calculating the rate of temperature change according to the formula:
 
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where m is the calculated rate or slope and y2 and y1 are points in the y dimension, for example temperature dimension, and x 2  and x 1  are points in the x dimension, for example time.
 
     A variable which indicates that a minimum temperature has been reached may then be set or checked ( 419  and  420 ). A comparison may be performed which checks the status of the compressor  101  in an on or off state or compares the calculated rate of change of temperature over a unit time to a set or calculated value, or compares the temperature sensed from temperature sensor  114  or  214  to a temperature that is set or calculated ( 421 ). The temperature sensed from temperature sensor  114  or  214  may then be adjusted by a value that is set or calculated. A step may be performed that sets or checks other system variables, for example, that a minimum temperature has been reached or a status variable that the system no longer needs cooling ( 422 ). Additional steps may be performed to set or check other variable ( 423 ,  424 ) before the sub-routine  400  is completed ( 425 ). 
     The compressor controller  115  may further contain other sub-routines used to check or set system statuses or affect system events. For example, sub-routine  500  may be used to set or check the status of control valve  150  or  250 . The sub-routine begins at step  501 . A status variable may be set or checked to determine whether the system needs cooling ( 502 ). A variable may be set or checked to determine whether the control valve  150  or  250  needs to be actuated ( 503 ). The sub-routine of  500  may contain a call to a function to set or reset a timer that may be used in the sub-routine of  500  or another sub-routine ( 504 ). A comparison may be performed to determine whether the valve of  150  or  250  is in an open or closed state and further, the comparison may evaluate the timer of step  504  ( 505 ). The sub-routine may also contain a step to set or check the control valve  150  or  250  ( 506 ) before the sub-routine ends ( 507 ). 
     The compressor actuator  115  may also contain additional sub-routines, for example, to check or determine whether a barrel  108  or  208  needs cooling, and to actuate the compressor  101 , accordingly ( 600 ). Such a sub-routine may begin ( 601 ) and in a multi-barrel apparatus such as the one shown in  FIG. 1 , the sub-routine may determine which barrel needs cooling, for example, barrel  108  or barrel  208  ( 602 ), and may set or check a status variable in response to which side needs cooling ( 603 ). A comparison may be performed to determine if cooling is needed for a barrel, for example,  108  or  208  ( 604 ) and if cooling is needed, a status variable may then be set or checked in response to this comparison ( 605 ), and control valves may be actuated ( 605 ). The status of the control valves may be set or checked ( 606 ), a timer may be set or re-set ( 607 ), and a system variable may be compared to a timer ( 608 ). Other system variables may be checked or set ( 609 ), or a timer may be set or re-set or a variable may be compared to a timer ( 610 ). Compressor  101  may be actuated from an OFF state or an ON state and a timer may be set or re-set ( 611 ). Such a subroutine as in  600  may be called repeatedly in a loop, or may be called discretely. 
     Although preferred embodiments and the best mode of the invention have been described in the foregoing description, it will be understood that the invention is not limited to the specific embodiments disclosed herein but is capable of numerous modifications by one having ordinary skill in the art. It will be understood that the materials used and details may be slightly different or modified from the description herein without departing from the methods and compositions disclosed and taught by the present invention. 
     This disclosure serves to illustrate and describe the claimed invention to aid in the interpretation of the claims. However, this disclosure is not restrictive in character because not every embodiment covered by the claims is necessarily illustrated and described. All changes and modifications that come within the scope of the claims are desired to be protected, not just those embodiments explicitly described.