Patent Publication Number: US-6662592-B2

Title: Ice cream machine including a secondary cooling loop

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATIONS 
     The present application is related to U.S. patent application Ser. No. 09/639,062 filed Aug. 15, 2000 entitled, “Batch Process and Apparatus Optimized to Efficiently and Evenly Freeze Ice Cream”, which is a continuation-in-part of U.S. patent application Ser. No. 09/234,970, filed by Ross on Jan. 21, 1999, now U.S. Pat. No. 6,119,472, which is a continuation-in-part of U.S. patent application Ser. No. 09/083,340, filed by Ross on May 22, 1998, now U.S. Pat. No. 6,101,834, which is a continuation-in-part of U.S. patent application Ser. No. 08/869,040, filed Jun. 4, 1997, now U.S. Pat. No. 5,755,106, which was a continuation of U.S. patent application Ser. No. 08/602,302, filed Feb. 16, 1996, abandoned. The above-referenced U.S. patent application Ser. No. 09/639,062, U.S. Pat. No. 6,101,834, U.S. Pat. No. 6,119,472, and U.S. Pat. No. 5,755,106 are incorporated herein by reference. 
     The present application is also related to U.S. application Ser. No. 10/1075,089, entitled “Ice Cream Machine Including a Controlled Input to the Freezing Chamber” filed on an even date herewith and assigned to the assignee of the present application. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to refrigeration or cooling systems. More particularly, the present invention relates to an evaporator design for refrigeration or cooling systems or to control of the entry of ice cream mix into a freezing chamber. 
     BACKGROUND OF THE INVENTION 
     Ice cream or frozen custard machines, as well as other systems for cooling or freezing food stuffs, condiments, or other materials, typically include an evaporator situated proximate the material being chilled. For example, in ice cream machines and soft serve machines, liquid ice cream (e.g., the mix) is typically inserted in a freezing chamber or barrel associated with the evaporator and is removed from the barrel as solid or semi-solid ice cream. The evaporator removes heat from the freezing chamber as a liquid refrigerant, such as, FREON®, ammonia, R-404a, HP62, or other liquid having a low boiling point, changes to vapor in response to the heat from the liquid ice cream. Typically, the evaporator is partially filled with vapor as the liquid refrigerant boils (e.g., becomes vapor) in the evaporator. 
     Quick freezing of liquid ice cream and high capacity are desirous features of ice cream makers. In addition, custard or ice cream quality and efficient manufacture of such custard or ice cream are dependent upon maintaining a constant evaporator temperature (e.g., constant barrel temperature). The barrel temperature must be kept in a proper range for making ice cream. If the custard or ice cream is allowed to become too cold, the mix or liquid ice cream in the evaporator becomes highly viscous and can block the travel of the ice cream through the barrel. Blockage of the barrel in the freezing process is commonly known as “freeze up”. If the ice cream or custard is allowed to become warm, its texture is adversely affected. 
     Maintaining the temperature of the barrel at a constant level is particularly difficult as ice cream flow rates through the machine vary and change the cooling load on the evaporator. For example, more heat dissipation is required as more ice cream is produced (i.e., the flow rate is increased). Additionally, if the barrel temperature is too low, refrigerant flood-back problems can adversely affect the operation of the compressor. For example, if the refrigerant is not fully evaporated as it reaches the compressor, the liquid refrigerant can damage the compressor. 
     Problems associated with temperature consistency are exacerbated during periods of non-production (e.g., an idle mode, a period of slow sales, a hold mode, etc.). Generally, ice cream machines, particularly soft serve machines, can experience non-production modes, periods of little or low production operation or a “hold” mode. During this mode, liquid ice cream and frozen ice cream product remain in the barrel (the cooling chamber) awaiting to be processed. However, due to the low demand for ice cream, ice cream is not removed from the barrel. The ice cream in the barrel can be subjected to temperature fluctuations during these periods of non-production due to heat infiltration. 
     Heretofore, ice cream machines have required that the refrigeration system (the compressor) be cycled on and off to maintain the ice cream in the barrel at the appropriate temperature. Such conventional systems have been unable to accurately maintain the barrel temperature at a proper and consistent temperature. For example, the fairly large compressors associated with the ice cream machine cool (e.g., overcool) the barrel down and then allow it to warm back up before the compressor is engaged to cool the barrel. The temperature within the barrel fluctuates according to a sawtooth wave. The gradual freezing and thawing causes the product to break down such that texture of the product becomes more grainy and less desirable to the taste. 
     Further, conventional systems have allowed the liquid ice cream mix to have constant access to the barrel. Generally, conventional systems have included a liquid ice cream reservoir connected to the evaporator via an aperture. The allowance of liquid ice cream to enter the barrel during non-production times contributes to the warming of the ice cream in the barrel, thereby affecting the quality of the ice cream within the barrel when liquid ice cream is allowed to fill the barrel, the liquid ice cream can become frozen against the barrel, thereby reducing the freezing efficiency of the barrel. 
     Further, conventional systems have allowed the ice cream product to be periodically and automatically mixed (i.e., beaten) in the evaporator during non-production modes or slow sales periods. Overbeating of the ice cream product results in poor ice cream texture and less desirable taste. 
     Thus, there is a need for an ice cream machine which can operate in a hold mode and not allow the barrel temperature to fluctuate drastically. Further still, there is a need for a process and a machine which can more efficiently and more evenly cool ice cream. Even further still, there is a need for a frozen machine which utilizes a barrel and maintains the ice cream product at a consistent temperature. 
     Yet even further still, there is a need for a process or method which does not allow liquid ice cream to affect the temperature in the barrel while in a hold or non-production mode. Yet even further, there is a need for an ice cream machine which does not allow the chamber wall to become coated with ice cream. Further still, there is a need for an evaporator and a control system for an ice cream machine which prevents breakdown of the ice cream product during slow sales periods. Further, there is a need for a hold mode for an ice cream machine which requires little or no beating of the ice cream product. 
     SUMMARY OF THE INVENTION 
     The present invention relates generally to an ice cream making system. The ice cream making system includes an evaporator and a compressor system. The evaporator includes a first refrigerant input, a second refrigerant input, a first refrigerant output, and a second refrigerant output. The evaporator further includes an exterior surface and an interior surface. The interior surface defines an interior cooling chamber. The interior cooling chamber having an ice cream input and an ice cream output. The compressor system including a compressor input assembly and a compressor output assembly. The compressor input assembly being coupled to the first refrigerant output and the second refrigerant output. The compressor output assembly being coupled to the first refrigerant input and the second refrigerant input. 
     Another exemplary embodiment of the present invention relates to an evaporator for an ice cream making machine. The evaporator includes an interior surface for defining a cooling chamber for chilling a product, an evaporator chamber, and a second evaporator. The evaporator chamber surrounds the cooling chamber. The secondary evaporator surrounds the evaporator chamber. 
     Another exemplary embodiment of the present invention relates to a method of manufacturing ice cream. The method utilizes an ice cream machine having a cooling chamber, an evaporator chamber, and a secondary chamber. The method includes providing liquid ice cream contents into the cooling chamber, cooling the liquid ice cream contents via the evaporator chamber, removing frozen ice cream from the cooling chamber and entering a non-production mode. The ice cream is not removed from the cooling chamber in the non-production mode. The secondary evaporator maintains a temperature within the cooling chamber in the non-production mode. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and: 
     FIG. 1 is a schematic diagram illustrating an advantageous ice cream making system according to an exemplary embodiment; 
     FIG. 2 is a schematic diagram illustrating another advantageous ice cream making system according to another exemplary embodiment; 
     FIG. 3 is a state diagram showing the operation of the systems illustrated in FIGS. 1 and 2; 
     FIG. 4 is a more detailed side cross-sectional view of an evaporator for use in the systems illustrated in FIGS. 1 and 2; 
     FIG. 5 is a more detailed side planar view of an alternative evaporator for use in the systems illustrated in FIGS. 1 and 2; 
     FIG. 6 is a more detailed side planar view of an alternative evaporator for use in the systems illustrated in FIGS. 1 and 2; 
     FIG. 7 is more detailed side planar view of an alternative evaporator for use in the systems illustrated in FIGS. 1 and 2; 
     FIG. 8 is a general block diagram of a gate, valve and auger control system for the ice cream machine systems illustrated in FIGS. 1 and 2; and 
     FIG. 9 is a flow diagram showing exemplary operation of the systems illustrated in FIGS. 1 and 2. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENT OF THE PRESENT INVENTION 
     A soft serve, frozen custard, or ice cream machine or making system  10  is diagrammatically shown in FIG.  1 . Ice cream machine  10  includes a cooling or refrigeration system  12  and an evaporator  20 . Refrigeration system  12  can include any number of components for providing and processing liquid refrigerant to and receiving and processing a vapor refrigerant from evaporator  20 . For example only, system  12  can include an expansion device, such as, a valve, a shut-off device, such as, a solenoid valve, a sight glass, a filter, a condenser, a compressor, an accumulator, and a valve. Although not limited to such systems, system  12  can utilize any of the components or systems described in U.S. Pat. Nos. 6,119,472, 6,101,834, 5,755,106, and application Ser. No. 09/639,062. 
     Evaporator  20  can be a system including a number of components on a single integral unit. For example only, evaporator  20  can include a cylindrical cooling tank, a secondary evaporator, and an auxiliary tank. Evaporator  20  can have a design similar to any of the evaporators discussed in U.S. Pat. Nos. 6,119,472, 6,101,834, 5,755,106, and application Ser. No. 09/639,062. Evaporator  20  is modified to include a secondary evaporation or another jacket for maintaining the temperature within evaporator  20  during non-production modes. 
     Evaporator  20  includes a first refrigerant input  40 , a first refrigerant output  42 , a liquid ice cream input  44 , and an ice cream output  46 . Evaporator  20  further includes a second refrigerant input  41  and a second refrigerant output  43 . Refrigeration system  12  utilizes refrigerant input  40  and refrigerant output  42  to provide primary cooling for ice cream making system  10 . Refrigerant input  40  and output  42  are in fluid communication with an evaporator chamber which surrounds a cooling chamber between ice cream input  44  and ice cream output  46 . Output  42  can also be coupled to an auxiliary evaporator tank as described below with reference to FIG.  4 . 
     With reference to FIG. 3, system  10  can manufacture ice cream or other frozen or semi-frozen food stuff in an operational mode  61 . Ice cream can be manufactured utilizing a quick draw gate which creates ice cream whenever gate  52  is opened. During the manufacture of ice cream in mode  61 , system  10  uses the primary cooling loop associated with input  40  and output  42 . Alternatively, both the primary evaporator chamber and the secondary evaporator chamber (the secondary loop associated with input  41  and output  43 ) can be utilized. 
     When demand ceases, system  10  operates in a non-production mode  62 . When demand returns, such as, when gate  52  is opened, system  10  returns to mode  61 . Various sub-states or intervening states may occur between modes  61  and  62 . For example, system  10  maynot reach a non-production mode until the temperature within evaporator  20  reaches a particular level. Further, system  10  may be maintained in mode  61  until ice cream is not demanded for a period of time or until the temperature within evaporator  20  falls below a predetermined level after gate  52  is closed. 
     Advantageously, when system  10  operates in a non-production mode  62 , it maintains the contents within evaporator  20  at a consistent temperature. Non-production mode  62 , such as, an idle mode, or hold mode, refers to any period of time at which system  10  is not allowing ice cream to exit outputs  46  and yet ice cream product, whether or not completed or partially completed, remains in the freezing chamber of evaporator  20 . The non-production mode can be utilized during periods of slow sales, when system  10  is idling between business hours (system  10  is idle for the night), etc. 
     In mode  62 , refrigeration system  12  (FIG.  1 ), second refrigerant input  41  and second refrigerant output  43  maintain the interior cooling chamber of evaporator  20  at a consistent temperature. A secondary evaporator chamber is in fluid communication with input  41  and output  43 . The secondary evaporator can encompass the primary evaporator chamber associated with input  40  and output  42 . 
     The secondary evaporator preferably cools refrigerant trapped within the primary evaporator chamber, thereby acting as a second loop for cooling the primary refrigeration loop (the primary evaporator chamber). The trapped refrigerant within the primary evaporator surrounding the interior freezing chamber provides a stabilizing effect to hold and transfer temperature into the ice cream product held within the interior cooling chamber. 
     The refrigeration system  12  can utilize a primary compressor system and/or a secondary compressor system to provide refrigerant to the secondary evaporator. The secondary evaporator can be any or any combination of wrapped tubing, refrigeration jackets, and/or chambers. By maintaining the temperature at a more consistent temperature via refrigerant input  41  and refrigerant output  43 , fluctuations in product temperature that can break down the ice cream and cause poor tasting ice cream are reduced. Further, product which has been left in the interior chamber for prolonged period of time is not wasted. 
     In one embodiment in which system  10  is configured as a soft serve ice cream machine, ice cream can be stored in the interior chamber within the barrel to keep it at the appropriate temperature between draws (e.g., servings). This advantageously allows ice cream to be served directly from evaporator  20  and eliminates the need for a dipping cabinet or other refrigeration unit for storing post manufactured ice cream. In this way, ice cream directly from the machine can be immediately served. 
     Applicant has found that by using a secondary cooling loop (e.g., secondary evaporator between input  41  and output  43 ), a consistent temperature can be provided in the interior chamber for long periods of time, such as, 60 hours. Accordingly, over long periods of time in non-production mode  62 , the contents of the interior chamber do not need to be emptied and discarded due to on/off cycling. Rather, the contents can remain in evaporator  20  and be served accordingly. Further, since ice cream is not discarded, the interior chamber does not need to be cleaned after each entry into non-production mode  62 . 
     According to one embodiment, at least one non-positive shutting control valve can be provided at input  40  to the primary evaporator. Liquid refrigerant is allowed to enter through the control valve to evaporator  20  (to the first cooling loop of evaporator  20 ). Allowing liquid refrigerant through input  40  in a metered but continuous fashion allows the liquid in the first stage loop to become saturated and subcooled. The liquid refrigerant completely fills the first stage loop and its presence acts as a stabilizing effect on temperature swings by means of thermal mass and thermal transfer. 
     According to another preferred embodiment, machine  10  can control auger  56  at different speeds during different periods of production. During production of ice cream (mode  61 ), machine  10  allows auger  56  to spin at a first speed (slow rpm) for production. When gate  52  is open, auger  56  spins at a second speed (a faster rpm) for discharging product through output  46 . Various speeds can be chosen in accordance with design criteria to achieve highest production and optimal discharge rates. 
     System  10  further includes an advantageous ice cream transport control system. Ice cream is provided at ice cream output when a gate  52  is opened. Gate  52  is preferably linked to a valve  54  at ice cream input  44 . Accordingly, when gate  52  is opened and closed, valve  54  is also open and closed. A delay for opening and closing valve  54  after gate  52  is opened can also be implemented by a control mechanism. In one embodiment, once opened, valve  54  can remain open until a particular capacity is reached in the cooling chamber. 
     Valve  54  can be controlled by mechanical linkage coupled to gate  52 . Alternatively, an electronic control system can be utilized to control the opening of valve  54  with respect to gate  52 . 
     Liquid ice cream is not allowed to enter the interior chamber and warm the contents of interior chamber when gate  52  is closed and system  10  is in a hold or non-production mode  62  (FIG.  3 ). In this way, valve  54  only allows an appropriate amount of mix to be in the interior chamber according to dry barrel technology. Further still, applicants have found that by limiting the quantity of material within the interior chamber, system  10  operating as a direct draw machine produces higher quality fresh ice cream having a superior taste. Product is produced with low overrun, thereby operating with results similar to a standard machine. 
     In another preferred embodiment, machine  10  utilizes valve  54  to meter and limit the amount of product stored in evaporator  20 . By eliminating the amount of products stored in evaporator  20 , the surface area available for production of product is increased, thereby increasing the speed at which ice cream is frozen. Faster freezing generally results in a better ice cream product texture. 
     As discussed above, since the amount of custard stored in the barrel of evaporator  20  is minimized (the heat exchange area is maximized), a more effective surface area for production is achieved. This is a significant advantage over conventional soft serve ice cream machines in which liquid ice cream product fills evaporator  20  (e.g., the freezing chamber is flooded). With such conventional systems, the inner wall of the chamber is coated with frozen product and becomes less effective for freezing the remaining product in the chamber. 
     According to another embodiment, the dry barrel technology discussed above can be implemented via valve  54 . Valve  54  can be a metering valve controlled by an actuator. An electric control circuit coupled to a sensor can ensure that actuator restricts the chamber to be less than half-filled during non-production modes. Preferably, the freezing chamber in evaporator  20  is 25% to 50% filled with pre-made product. A conventional machine typically allows of the chamber to be 75 to 100% filled with pre-made product. The metering valve is controlled to be positively shut when gate  52  is shut and ice cream is not drawn from evaporator  20 . This allows the barrel to store pre-made product but only have 25-50% of the barrel full of pre-made product, thereby resulting in faster freezing of new product. 
     In addition, a control circuit or system is preferably provided which prevents an auger  56  within the interior chamber from overbeating the contents of interior chamber when gate  52  is closed. Embodiments of control systems mechanisms and schemes for system  10  are described with reference to FIG.  8 . The control schemes monitor the operation of auger  56  and valve  54 . 
     With reference to FIG. 2, an ice cream making system  100  is substantially similar to ice cream making system  10 . However, refrigeration system  12  of FIG. 1 includes a primary refrigeration system  112  and a secondary refrigeration  114 . Systems  112  and  114  can share components. Preferably, systems  112  and  114  have separate compressors. Alternatively, system  100  can include three or more refrigeration systems if three or more evaporator chambers or coils are utilized by evaporator  20 . 
     Although evaporator  20  is shown as having four separate interfaces (inputs  40  and  41  and outputs  42  and  43 ) in FIGS. 1 and 2, the interfaces can be integrated together and/or separately divided within evaporator  20 . For example, a gate or valve can be used to divert refrigerant from a single supply line to input  40  and input  41  located within evaporator  20 . Similar systems can be designed for outputs  42  and  43 . 
     Primary refrigeration system  112  preferably includes a relatively large compressor for use in making ice cream during normal operating temperatures. A smaller compressor can be utilized in secondary refrigeration system  114 . The smaller compressor can more efficiently provide limited amounts of refrigerant to evaporator  20 . Preferably, the secondary compressor is rated between ¼ and ¾ horsepower, depending on design. In a preferred embodiment, a ⅓ horsepower rating is utilized. The primary refrigeration system  112  can utilize a compressor with a 1 ½ to 3 horsepower or more rating. In a preferred embodiment, a compressor rated at a ½ horsepower rating is utilized. The use of the smaller compressor during mode  62  (FIG. 3) reduces energy consumption. Limiters may be used to make the capacity of a 1 ½ to 3 HP compressor act like smaller unit. 
     In an alternative embodiment, a separate condensing unit can also be provided for the secondary evaporation chamber and the hopper. 
     With reference to FIGS. 4-7, more detailed drawings of alternative embodiments of evaporator  20  (FIGS. 1 and 2) are shown. Each of the embodiments provides for an evaporator with a primary evaporator chamber and a secondary evaporator chamber. The secondary evaporator chamber is used to advantageously maintain the interior chamber at an appropriate cooling temperature. In FIGS. 4-7, reference numerals having the same last two digits are substantially similar unless otherwise noted. 
     With reference to FIG. 4, an evaporator  124  includes an auxiliary evaporator tank  126 , a primary evaporator chamber  128 , and a secondary evaporator  130 . Primary evaporator chamber  128  is provided about an interior cooling chamber  134  which can include an auger such as auger  56  (FIG.  1 ). Chamber  134  can be defined by a 0.125 inch thick stainless steel tube  135  having exemplary dimensions of a 4 inch outer diameter. Chamber  128  can be defined by a stainless steel tube  129  having exemplary dimensions of an inner diameter of 4.5 inches and a length of 18 inches-20.5 long. 
     Chamber  134  includes a liquid ice cream input  142  which can be controlled by a valve and an ice cream output  144  which can be controlled by a gate. Preferably, chamber  134  has a volume of approximately 226 cubic inches. 
     Evaporator chamber  128  includes a refrigerant input  152  corresponding to refrigerant input  40  and a refrigerant output  154  corresponding to refrigerant output  42  (FIGS.  1  and  2 ). Preferably, evaporator chamber  128  has a volume of approximately 60 cubic inches (e.g., length of 18 inches and a jacket width of 0.25 inches). 
     Auxiliary tank  126  includes a refrigerant output  156  which can be coupled to refrigeration system  12 . Tank  126  operates as an accumulator similar to the accumulator described in U.S. Pat. Nos. 6,119,472 and 5,755,106. Tank  126  should not be confused with secondary evaporator  130  which operates in parallel with evaporator chamber  128 , rather than in series with chamber  128  as tank  126  operates. Secondary evaporator  130  includes a refrigerant input  158  corresponding to refrigerant input  41  (FIGS. 1 and 2) and a refrigerant output  160  corresponding to refrigerant output  43 . Preferably, secondary evaporator  130  is comprised of copper tubing wrapped completely around the barrel associated with evaporator chamber  128 . 
     The tubing associated with secondary evaporator  130  can be ⅜ copper tubing. The tubing is closely wrapped in a single layer from end-to-end of evaporator chamber  128 . Alternatively, other wrapping configurations and tubing materials and sizes can be utilized. Evaporator can include two or more layers of tubing. 
     With reference to FIG. 5, an evaporator  224  is substantially similar to evaporator  124  including a refrigerant input  252  and a refrigerant output  254 . Output  254  can be coupled to system  12  (FIG. 1) or system  112  (FIG.  2 ). Evaporator  224  does not include an auxiliary evaporator tank such as evaporator tank  126  in FIG.  4 . 
     With reference to FIG. 6, evaporator  324  includes a secondary evaporator  350 . Secondary evaporator  350  is defined by an outer barrel  355 , and an inner barrel  360 . A primary evaporator chamber  328  is defined by an intermediate barrel  360  and an inner barrel  365 . Secondary evaporator  350  includes a refrigerant input  370  and a refrigerant output  380 . Evaporator  324  can also include an auxiliary evaporator tank such as tank  126  (FIG.  4 ). Inner barrel  365  defines interior cooling chamber  334 . In a preferred embodiment, inner barrel  365  has an outer diameter of 4 inches and a length of 18 inches. Barrel  360  has an outer diameter of 4.76 inches and a length of 18 inches, and barrel  355  has an outer diameter of 5.25 inches and a length of 18 inches. Barrels  355 ,  360 , and  365  can be 0.125 inches thick and manufactured from stainless steel. 
     With reference to FIG. 7, evaporator  424  includes secondary evaporator  452  including a double wrap of copper tubes. A first wrap  480  is provided about a second wrap  482 . Second wrap  482  is provided about evaporator chamber  450 . Chamber  450  includes a refrigerant input and a refrigerant to output similar to refrigerant input  352  and  354  (FIG.  6 ). Wraps  480  and  482  are provided from end-to-end of chamber  450 . 
     Second wrap  482  includes a refrigerant input  490  and a refrigerant output  492 . First wrap  480  includes a refrigerant input  494  and a refrigerant output  496 . Refrigerant input  490  and refrigerant output  492  can be coupled to a separate refrigeration system than that used for wrap  480  and chamber  450 . Similarly, refrigerant input  494  and output  496  can be utilized with a different compressor or refrigeration system than that used for wrap  482  and chamber  450 . Preferably, wraps  480  and  482  are provided on top of each other. 
     With reference to FIG. 8, a control system  500  is provided to more accurately control the temperature and consistency of product within interior chamber  134  during non-production mode  62 . For example, control system  500  can include electronics or mechanical devices to ensure that valve  54  is open and closed simultaneously with gate  52 . Alternatively, a delay can be utilized between opening and closing gate  52  with respect to valve  54 . 
     Auger  56  is controlled by control system  500  to ensure auger  56  stops when the interior cooling chamber within evaporator  20  reaches an appropriate temperature. By sensing the amperage being provided through the motor associated with auger  56 , the consistency of the contents within interior chamber  134  can be determined. The consistency can represent the appropriate temperature associated with the contents in evaporator  20 . When the amperage is at the appropriate level, control system  500  can turn off the motor which drives auger  56 , thereby preventing overbeating of the contents in evaporator  20 . 
     Once gate  52  is opened, the motor can be reset and allowed to run until gate  52  is closed. After gate  52  is closed, the motor will continue to run until current sensed through the motor indicates that the appropriate temperature in interior chamber  134  is reached. Alternatively, control schemes can be utilized to stop auger  56  appropriately. For example, system  500  can utilize a temperature sensor situated in chamber  502  or chamber  134 . Preferably, control system  500  includes a micro switch or other device for sensing when gate  46  is opened to re-engage the motor which drives auger  56 . 
     With reference to FIG. 9, the various modes associated with systems  10  and  100  described with references to FIGS. 1 and 2 are discussed. In a first mode, or production mode  602 , manufacture of an ice cream product can begin. Generally, the production mode operates auger  56  and uses a primary evaporator associated with refrigeration input  40  and refrigeration output  42 . An operator can open gate  46  and remove ice cream from evaporator  20  in an operational mode  604 . When gate  52  is open, valve  54  is open, thereby allowing liquid ice cream into evaporator  20 . After gate  46  is closed and valve  44  is closed, system  10  can enter a non-production mode  606 . 
     Non-production mode  606  can occur once the temperature within evaporator  20  reaches a particular temperature. In mode  606 , the primary evaporator and auger are utilized. Similarly, as ice cream is removed, the auger and primary evaporator are utilized. In mode  606 , the secondary evaporator is utilized and the auger is stopped to prevent overbearing of the ice cream. 
     The term “coupled”, as used in the present application, does not necessarily mean directly attached or connected. Rather, the term “coupled” in the present application means in fluid or electrical communication there with. Two components may be coupled together through intermediate devices. For example, the evaporator input is coupled to the condenser or compressor output even though the expansion valve, accumulator/heat exchanger, and sight glass are situated between the evaporator input and the condenser or compressor output. through intermediate devices. For example, the evaporator input is coupled to the condenser output even though the expansion valve, accumulator/heat exchanger, and sight glass are situated between the evaporator input and the condenser output. 
     It is understood that, while the detailed drawings and specific examples given to describe the preferred exemplary embodiment of the present invention, they are for the purpose of illustration only. The apparatus of the invention is not limited to the precise details and conditions disclosed. For example, although food stuffs and ice cream are mentioned, the invention may be utilized in a variety of refrigeration or cooling systems. Further, single lines for carrying liquid refrigerant can represent multiple tubes. Additionally, although a particular valve, accumulator, compressor, condenser, and filter configuration is shown, the advantageous machine can be arranged in other configurations. Further still, the evaporator barrel and freezer can have any number of shapes, volumes, or sizes. Various changes can be made to the details disclosed without departing from the spirit of the invention, which is defined by the following claims.