Patent Abstract:
A merchandiser system includes a case that has a door and a door heater. The system includes a low temperature refrigeration unit sized to fit within a case compartment and to operably couple to the case to maintain food product within a low temperature range. The system also includes a medium temperature refrigeration unit sized to fit within the compartment and operably couple to the case to maintain food product within a medium temperature range. The system includes a controller in communication with the door heater and is programmed to activate the door heater only in response to the low temperature modular refrigeration unit positioned within the compartment. One of the low temperature refrigeration unit and the medium temperature refrigeration unit is removably coupled to the case within the compartment, and is replaceable by the other refrigeration unit to change the temperature range of the product display area.

Full Description:
This application claims priority to U.S. Provisional Application No. 61/711,188, filed Oct. 8, 2012, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     The present invention relates to refrigerated merchandisers, and specifically to dual temperature refrigerated merchandisers that condition low and medium temperature product display areas. 
     Existing refrigerated merchandisers typically include a case that defines one or more display areas accessible by consumers from the front of the case. Some merchandisers include doors that enclose the product display area. The display area is cooled by a refrigeration system that includes an evaporator assembly and a condenser assembly arranged in a circuit, and a fan distributes cooled air toward the product display area. In some merchandisers, the condenser and evaporator assemblies are positioned separate and remote from each other within the refrigerated merchandiser. In some cases, the refrigeration system is modular and can be removed from the merchandiser as a unit. For example, U.S. Pat. No. 7,703,295, assigned to Hussmann Corporation, describes and illustrates a merchandising display cooler that includes an accessible compartment for receiving a removable refrigeration unit, the refrigeration unit including both an evaporator assembly and a condenser assembly. 
     Typically, the product display area of existing merchandisers is maintained within a predetermined temperature range that depends on the type of product to be cooled. For example, a low temperature merchandiser typically maintains the product display area at temperatures less than 32 degrees Fahrenheit, whereas a medium temperature merchandiser typically maintains the product display area at temperatures between 33-41 degrees Fahrenheit. Often, existing merchandisers include either a low temperature refrigeration system or a medium temperature refrigeration system. 
     In some existing low temperature merchandisers, the product display temperature provided by the low temperature refrigeration system is adjusted via electronic control to a temperature that is warmer than the low temperature range for which the refrigeration system is designed. However, product in the product display areas of these merchandisers frequently freezes due to very cold discharge air upon startup of the low temperature refrigeration system. That is, because these low temperature refrigeration systems frequently use a large compressor, which is designed to lower the suction temperature to accommodate the low temperature range, air discharged into the product display area is much colder than desired when trying to use the low temperature system in this manner. 
     While some of these systems incorporate a suction pressure regulating valve in addition to a solenoid valve to avoid frozen product, these systems are typically manually actuated. Also, regardless of how existing systems try to avoid frozen product, use of low temperature refrigeration systems to accommodate a product display temperature associated with a medium temperature merchandiser significantly lowers the efficiency of the merchandiser and necessitates additional components and complex controls. 
     SUMMARY 
     In one construction, the invention provides a refrigerated merchandiser system including a case defining a product display area to support food product. The case has a door adjacent a front of the case and a door heater that is coupled to the door, and the case defines a compartment. The system includes a low temperature modular refrigeration unit sized to fit within the compartment and operably couple to the case to maintain food product within a low temperature range, and a medium temperature modular refrigeration unit sized to fit within the compartment and operably couple to the case to maintain food product within a medium temperature range. The system includes a controller in communication with the door heater, and the controller is programmed to activate the door heater only in response to the low temperature modular refrigeration unit positioned within the compartment. One of the low temperature modular refrigeration unit and the medium temperature modular refrigeration unit is removably coupled to the case within the compartment. The modular refrigeration unit removably coupled to the case is replaceable by the other modular refrigeration unit to change the temperature range of the product display area. 
     In another construction, the invention provides a refrigerated merchandiser system including a case defining a product display area to support food product. The case has a door adjacent a front of the case and a door heater that is coupled to the door, and the case defines a compartment. The system includes a low temperature modular refrigeration unit sized to fit within the compartment and operably couple to the case to maintain food product within a low temperature range, the low temperature modular refrigeration unit including an electronic control. The system includes a medium temperature modular refrigeration unit sized to fit within the compartment and operably couple to the case to maintain food product within a medium temperature range, the medium temperature modular refrigeration unit including an electronic control. The system includes a controller in electrical communication with the electronic control on one of the low temperature modular refrigeration unit and the medium temperature refrigeration unit, and in electrical communication with the door heater. The controller is programmed to activate the door heater only in response to the low temperature modular refrigeration unit positioned. 
     In another construction, the invention provides a method of controlling condensation in a merchandiser having a case defining a product display area includes determining whether the merchandiser is using a low temperature modular refrigeration unit disposed in the merchandiser, and determining whether the merchandiser is using a medium temperature modular refrigeration unit disposed in the merchandiser. The method includes determining whether a product display temperature is above a predetermined threshold in response to determining that the merchandiser is using a low temperature modular refrigeration unit, and activating a door heater to remove condensation from a door on the merchandiser in response to determining that the product display temperature is above the predetermined threshold. The method includes turning off the door heater in response to determining that the product display temperature is below the predetermined threshold. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a refrigerated merchandiser embodying the present invention. 
         FIG. 2  is a cross-section of the refrigerated merchandiser of  FIG. 1 , illustrating a removable modular refrigeration unit disposed in the merchandiser. 
         FIG. 3  is an exploded perspective view of a portion of the refrigerated merchandiser and the modular refrigeration unit of  FIG. 2 . 
         FIG. 4  is a perspective view of the modular refrigeration unit. 
         FIG. 5  is a flow chart of a control process for the refrigerated merchandiser of  FIG. 1 . 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
     DETAILED DESCRIPTION 
       FIGS. 1 and 2  show a refrigerated merchandiser  10  that may be located in a supermarket or a convenience store (not shown) for presenting fresh food, beverages, and other food product to consumers. The refrigerated merchandiser  10  includes a case  12  that has a base  14 , a rear wall  16 , side walls  18 ,  20 , and a canopy  22 . The area partially enclosed by the base  14 , the rear wall  16 , and the canopy  22  defines a product display area  24  for supporting the food product in the case  12 . For example, the food product can be displayed on racks or shelves  26  extending forwardly from the rear wall  16 , and is accessible by consumers through doors  28  adjacent the front of the case  12 . 
     The case  12  can include a frame  30  adjacent a front of the merchandiser  10 .  FIG. 1  shows that the frame  30  includes vertical mullions  32  that define openings  34 , with the doors  28  positioned over the openings  34 . The openings  34  and the doors  28  allow access to food product stored in the product display area  24 . The mullions  32  are spaced horizontally along the case  12  to provide structural support for the case  112 . Each mullion  32  is defined by a structural member that can be formed from a nonmetallic or metallic material. A handle  36  is positioned along an edge of each door  28  to move the door  28  between an open position and a closed position. In the illustrated construction, the refrigerated merchandiser  10  includes three doors  28 . In other constructions, the refrigerated merchandiser  10  may include fewer or more than three doors  28  depending on the size of the case  12   
     Each door includes a door frame  35  and a glass member  37  that is secured to each door  28  by the respective door frame  35  to allow viewing of the food product from outside the case  12 . The glass member  37  can include one or more glass panes that have a low-emissivity coating. Condensation generally forms on a surface of the glass member when the temperature of the surface is lower than a dew point of air that is in contact with the surface. Condensation is a result of a combination of surface temperature and moisture in the surrounding air. Thus, condensation can form on an interior surface of the glass member after the door has been opened due to exposure of the generally cold interior surface to generally warm ambient conditions. Similarly, condensation can form on an exterior surface of the glass member when the temperature of the exterior surface is below the dew point of the ambient air. 
     In the illustrated construction, a door heater  39  in the form of an electrically conductive film or resistive coating is adhered to the interior surface of each glass member  37 . The conductive film is generally transparent to minimize interference with viewing the food product stored in the product display area  24 . In some constructions, the conductive film may be adhered to the exterior surface of the glass member  37 , or alternatively, to the interior surface and the exterior surface. 
     Referring to  FIGS. 1-3 , the base  14  defines refrigeration unit compartments  38  that support refrigeration units  40 . As shown in  FIGS. 1-3 , the compartments  38  are covered by a removable grill  42 , and include front side openings  43  for inserting and removing the refrigeration units  40  relative to the case  12 . The refrigerated merchandiser  10  is equipped with a harness and quick connect features for quickly coupling the refrigeration units  40  electrically to the case  12 . Although two compartments  38  are illustrated, fewer or more than two compartments  38  (and refrigeration units  40 ) can be provided in the merchandiser  10  depending in part on the length of the merchandiser  10  and the amount of cooling needed to condition the product display area  24 . 
     With reference to  FIGS. 3 and 4 , each refrigeration unit  40  defines a modular unit that can be inserted into and removed from one compartment  38 . As illustrated in  FIGS. 2-4 , the refrigeration unit  40  defines a closed refrigerant circuit and includes an evaporator  44 , a compressor  56  (e.g., one compressor or several compressors in an assembly), and a condenser  46 . The refrigeration unit  40  can also include other components. 
     The evaporator  44  (e.g., microchannel or round tube plate-fin) is fluidly coupled with the compressor to deliver evaporated refrigerant from the evaporator to the compressor, and is fluidly coupled with the condenser to receive cooled, condensed refrigerant from the condenser  95 . An expansion valve (not shown) is disposed between the evaporator  44  and the condenser to create a pressure differential and to control the pressure of the refrigerant fluid delivered to the evaporator  44 . As illustrated, the refrigeration unit  40  is positioned in the compartment  38  so that the evaporator  44  is disposed adjacent the rear wall  16 . The evaporator  44  is in communication with an air passageway  70  disposed within the case  12  and in communication with the product display area  24 . As illustrated, fans  54  are coupled to the evaporator to direct an airflow through the evaporator  44  and the air passageway to the product display area  24 . With reference to  FIG. 4 , an evaporator pan  76  is positioned under the evaporator  44  to collect any condensed moisture dripping from the evaporator  44 . 
     The evaporator  44  is mounted to a dividing wall  48 , and the compressor and the condenser  46  are separated from the evaporator  44  by the dividing wall  48 . As illustrated, the compressor  56  and the condenser  46  are mounted on supports  50  that are coupled to the dividing wall  48  and are disposed adjacent and accessible from a front of the case  12  when the refrigeration unit  40  is installed in the merchandiser  10 . Referring to  FIGS. 3 and 4 , support  50  includes forward gripping portions  96  that provide an operator with a convenient gripping surface for moving a refrigerator system  40  into or out of the accessible compartment  38 . 
     As is known in the art, the evaporator  44  receives a saturated refrigerant that has passed through an expansion valve (not shown). The saturated refrigerant is evaporated as it passes through the evaporator  44  as a result of absorbing heat from the airflow passing over the evaporator assembly  44 . The absorption of heat by the refrigerant allows the temperature of the airflow to decrease as it passes over the evaporator assembly  44 . The heated or gaseous refrigerant then exits the evaporator  44  and is pumped back to the compressor  56  for re-processing into the refrigeration unit  40 . The cooled airflow exiting the evaporator assembly  44  via heat exchange with the liquid refrigerant is directed through the remainder of the air passageway and is introduced into the product display area  24  where the airflow will remove heat from and maintain the food product at desired conditions. 
     The refrigerated airflow provided by the evaporator  44  conditions the product display area  24  within a predetermined temperature range based on the type of product supported in the product display area  24 . When the merchandiser  10  is a low temperature merchandiser, a low temperature refrigeration unit  40  is positioned in the compartment  38  to condition the airflow so that the product display area  24  is maintained, for example, at or below 32 degrees Fahrenheit. When the merchandiser  10  is a medium temperature merchandiser, a medium temperature refrigeration unit  40  is positioned in the compartment  38  to condition the airflow so that the product display area  24  is maintained within a temperature range of for example, 33-41 degrees Fahrenheit. 
     The refrigeration units  40  can be either low temperature refrigeration units or medium temperature refrigeration units. Both low and medium temperature refrigeration units include an electronic control  66  (e.g., for controlling the components of the systems  40  based on the desired product display temperature and other factors). The illustrated electronic controls  66  are mounted to the supports  50 , and the electronic controls  66  can be factory preset or adjusted prior to or during installation of the refrigeration unit  40 . 
     The refrigeration units  40  are exchangeable. Thus, a low temperature refrigeration unit  40  is replaceable with a medium temperature refrigeration unit  40 , and vice versa, to selectively alter the temperature range of the product display area  24 . Alternatively, a damaged or older refrigeration unit  40  is replaceable by a new refrigeration unit  40 . 
     In some constructions, the merchandiser  10  can include a partition (not shown) that divides the product display area  24  into a low temperature and medium temperature product display areas  24   a ,  24   b . The partition can be permanent or removable, and defines a vertical wall that extends from the canopy to the base. The partition can be coupled to the case  12  via a quick lock system or another quick attach and release system. Depending on how the partition is installed in the case  12 , one or more of the shelves  26  may be removed prior to insertion of the partition. Depending on the length of the merchandiser  10 , one or more partitions can be provided to define a plurality of product display areas  24 . 
     When a partition is provided in the merchandiser  10 , a low temperature refrigeration unit  40  can be installed into one compartment  38  so that the corresponding product display area  24   a  conditions product within the low temperature range, and so that at least one of the doors  28  corresponds with the low temperature product display area  24   a  and low temperature refrigeration unit  40 . A medium temperature refrigeration unit  40  can be installed into another compartment  38  so that the corresponding product display area  24   b  conditions product within the medium temperature range, and so that at least another of the doors  28  corresponds with the medium temperature product display area  24   b  and medium temperature refrigeration unit  40 . In these constructions, each section of the merchandiser  10  can include at least one independently operable sensor  80  to control the door heaters  39 , as described in detail below, based on the product display temperature (or other factors) and whether the refrigeration unit  40  for that section is a low temperature refrigeration unit  40 . 
       FIG. 1  shows that the merchandiser  10  further includes a control system that has one or more sensors disposed inside the case  12 , and a controller  90  in electrical communication with the merchandiser  10 , the sensors, and the door heaters  39 . As illustrated, the sensors are located adjacent the doors and are in communication with the product display area  24  to detect the product display temperature. In other constructions, the sensors can be located elsewhere in the merchandiser  10  (e.g., located along an interior portion of side walls  18 ,  20 , behind the mullions  32 , etc.), and can sense other characteristics of the case  12  that relate to fogging and condensation of the doors. The sensors are also in electrical communication with the controller  90  to deliver signals indicative of the product display temperature. The illustrated sensors are defined by bi-metal switches wired in series with the door heaters  39  to control the door heaters  39  based on the sensed temperature. The sensors can take any suitable form for detecting the temperature of the product display area  24  or other characteristics of the case  12 , and for controlling the door heaters  39 . 
     The controller  90  is in remote electrical communication with the door heaters to regulate current through the conductive film based on the signals received from the sensors. The current is passed through the conductive film, which heats the glass member to remove condensation. Alternatively the controller  90  can be attached to the merchandiser  10  in any suitable location (e.g., the base  14 , on the case canopy  22 , etc.). 
     Generally, condensation only forms on the doors  28  when the merchandiser  10  is a low temperature merchandiser.  FIG. 5  illustrates an exemplary control process for the merchandiser  10  to determine, among other things, when to apply heat to the doors  28 . At step  100 , the controller determines the status of the merchandiser  10  (e.g., whether the merchandiser  10  is operational, the conditions of the components supported by the merchandiser  10 , etc.). At step  104 , the controller determines whether the merchandiser  10  is being operated as a low temperature merchandiser  10  (i.e. has a low temperature modular refrigeration unit  40  disposed in a compartment  38 ), or a medium temperature merchandiser  10  (i.e. has a medium temperature modular refrigeration unit  40  disposed in a compartment  38 ). For example, the controller  90  can make this determination based on the product display temperature detected by the sensors, based on manual input from an operator, based on communication with the electronic controls  66 , or based on other information indicative of the type of refrigeration unit  40  being used. If the merchandiser  10  has a medium temperature refrigeration unit  40  (i.e., the answer at step  104  is “No”), the door heaters  39  are turned off at step  108 . The process then returns to step  100  and repeats. In some constructions, the control process can include a time delay after step  108  so that the determination at step  104  repeats at predetermined time intervals. In other constructions, the control process only makes the determination at step  104  once each time the merchandiser is varied from an “off” state to an “on” state. 
     If the merchandiser  10  has a low temperature refrigeration unit  40  (i.e., the answer at step  104  is “Yes”), the control process determines whether the product display temperature is above the predetermined temperature threshold at step  112 . If the product display temperature is below this threshold (i.e., the answer at step  104  is “No”), the controller  90  keeps the door heaters  39  in an “off” state (i.e., no current is passed through the conductive film) at step  116 . The control process then returns to step  100  and repeats. 
     If the product display temperature is above the predetermined temperature threshold (i.e., the answer at step  112  is “Yes”), the door heaters  39  are turned on at step  120  to inhibit or remove condensation from the doors  28 . The control process then proceeds to step  124  to determine, at a later time, whether the product display area temperature is at or below the predetermined temperature threshold. If the product display temperature remains above the predetermined temperature threshold (i.e., the answer at step  124  is “No”), the door heaters  39  remain on and the control process returns to step  112 . If the product display temperature is at or below the predetermined temperature threshold (i.e., the answer at step  112  is “Yes”), the door heaters  39  are turned off at step  116 . The control process then returns to step  100  and repeats. 
     The control system regulates the merchandiser  10  so that when the merchandiser  10  is a low temperature merchandiser and the product display temperature rises above a predetermined temperature threshold, the controller  90  activates one or more of the door heaters  39  to warm the corresponding doors  28  to minimize or remove condensation on the doors  28 . The control system also regulates the merchandiser  10  so that when the merchandiser  10  is a medium temperature merchandiser, the door heaters  39  are kept off regardless of the temperature in the product display area  24 . 
     The modular refrigeration units  40  can be removed and installed relative to the case  12  so that the merchandiser  10  can operate as a low temperature merchandiser or a medium temperature merchandiser, or both. As illustrated, the controller  90  controls the door heaters  39  so that the doors  28  are only heated when the refrigeration unit  40  is a low temperature system and the product display area temperature is above the threshold. The sensors  80  keep the door heaters  39  off when the merchandiser  10  is a medium temperature merchandiser to limit the amount of power needed by the merchandiser  10  to operate. In constructions of the merchandiser  10  including a partition installed in the product display area  24 , the sensors  80  can regulate each product display section so that the door heaters  39  are activated only when the section is a low temperature section and the corresponding product display temperature is above the predetermined threshold. 
     A single merchandiser  10  can be modified so that the merchandiser  10  encompasses a low temperature merchandiser, a medium temperature merchandiser, or a low and medium temperature merchandiser depending on desired characteristics for the merchandiser  10 . The product display area or areas within the merchandiser  10  can be can be controlled and adjusted as desired by removing and replacing the low or medium temperature refrigeration units  40  with other low or medium temperature refrigeration units, and by removing or adding partitions within the merchandiser  10 . For example, a low temperature refrigeration unit  40  in the merchandiser  10  can be replaced by removing the grill and the low temperature refrigeration unit  40 , and installing another low temperature refrigeration unit  40  or a medium temperature refrigeration unit  40  in the compartment  38 . Likewise, a medium temperature refrigeration unit  40  can be replaced by a low temperature refrigeration unit  40  or another medium temperature refrigeration unit  40 . 
     Various features and advantages of the invention are set forth in the following claims.

Technology Classification (CPC): 5