Patent Publication Number: US-6701739-B2

Title: Modular refrigeration system for refrigeration appliance

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to refrigeration appliances and more particularly to those having a modular refrigeration system. 
     Conventionally, refrigeration appliances are provided with a refrigeration system to cool the interior thereof One such refrigeration appliance may include, e.g., a vending machine, refrigerator or freezer case, or the like. The refrigeration system typically includes a compressor, evaporator, condenser, and expansion device fluidly connected by a plurality of conduits. The system also includes control electronics for operation of the system. 
     Some refrigeration appliances include a refrigeration system having the components thereof individually mounted within the appliance. In the case of failure of one of the components, the malfunctioning component must be replaced. In order to repair the system, the refrigerant charge in the failed component and the conduits interconnecting the component to the system must be removed. The component is replaced and the system is then recharged with refrigerant. 
     A problem with this type of system is that if the component is replaced on site, the repair could be time consuming and messy, and require a substantial amount of equipment to be brought to the job site to effect the repair. If the entire refrigeration appliance is taken off-site to be repaired, the time necessary to complete the repair and return the appliance may be substantial. The cost of the repair and travel time is also significant. 
     In other types of refrigeration appliances, several of the refrigeration system components may be mounted to a base which is removably mounted in the lower end of the appliance. The base of the refrigeration system may be provided with a condensate pan located beneath the condenser in which condensate produced during operation of the refrigeration system collects. The condensate is then caused to evaporate by directing air over the pan. Additionally, the discharge conduit from the compressor may be located at least partially in the pan to assist with the evaporation process. One particular base plate of the prior art is formed from several layers of material. 
     A problem with this type of refrigeration system is that with the condensate pan being located beneath the condenser, the evaporation of the condensate takes more time as the condenser fan is not directly blowing warm air over the pan. Further, with the base being formed of several layers the assembly time and thus the cost of the system is increased. 
     It is desired to provide a modular refrigeration system which is a removable and replaceable unit providing faster boil off of collected condensate and an improved base plate for the unit. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an integrated, modular refrigeration system having a compressor, evaporator, condenser, expansion device, conduits, and control electronics assembled onto a base which is installed into a refrigeration appliance, such as, e.g., a vending machine. In the event of component failure, the refrigeration system unit may be removed and a new one used to replace the unit. The failed component in the removed system is then later replaced to refurbish the system for use in another refrigeration appliance. The refrigeration system is slid into and out of the appliance as a unit, with the only installation steps including connecting the electrical power and control connections. 
     The present invention includes a one-piece molded base plate to which all of the refrigeration system components are mounted. The base plate includes integrally formed bosses and studs for mounting the compressor to the plate. The compressor includes mounting feet which rest upon the bosses, positioning the compressor above the condensate pan formed beneath the compressor. The mounting feet include apertures through which the mounting studs extend. A push on nut is placed on the stud to secure the compressor to the base plate. The other components may be mounted to the base plate using fasteners such as screws, or the like. 
     The evaporator is mounted to a one-piece evaporator mount secured to the base plate. The evaporator core is attached to the evaporator mount which includes an integral drain where condensate collects and delivers it to a common point such as a drain basin formed in the base plate. The condensate from the evaporator mount collects in the drain basin integrally formed in the base plate and is directed to the drain pan located beneath the compressor by a trough also formed in the base plate. 
     The discharge tube from the compressor is located within the drain pan to assist in the rapid boil off of water collected therein. Air heated by and drawn through the condenser is blown across the surface of the condensate to further assist in evaporation from the drain pan. An integral evaporator fan motor mount is provided in the base plate as well as integral airflow holes through which air enters and exits the chamber defined by an evaporator cover. 
     The evaporator cover encloses the evaporator core. The cover is insulated, being provided with a smooth plastic inner liner in direct contact with the refrigerated air. The liner has large radii so as not to disrupt the flow of air along the inner surface of the cover. A molded foam outer liner having a variable thickness is located over the smooth plastic inner liner. Projections are molded into the base plate which fit into the inner perimeter corners of the interior liner at the open end of the cover to maintain the position of the cover on the base plate. A groove is provided in the outer surfaces of the top and the sides in which a large rubber band is provided. The end of the rubber band is stretched over the cover and is looped around hooks formed in the base plate to retain the position of the evaporator cover. 
     The present invention provides a modular refrigeration system having an evaporator, a condenser, and a compressor fluidly connected by a plurality of conduits. The modular refrigeration system includes a one-piece base plate with the evaporator, condenser, and compressor mounted thereto. A compressor mount is formed in the base plate and includes at least one integrally formed stud extending therefrom. The compressor has at least one mounting flange with an aperture formed therein in which the stud is received. A fastener is affixed to the stud to secure the compressor to the base plate. 
     The present invention also provides a modular refrigeration system having an evaporator, a condenser, and a compressor fluidly connected by a plurality of conduits. The modular refrigeration system includes a one-piece base plate having the evaporator, condenser, and compressor mounted thereto. A drain pan is integrally formed in the base plate located beneath the compressor. A drain basin is integrally formed in the base plate located beneath the evaporator. The basin and the drain pan are fluidly connected such that condensate collects in the drain pan. 
     The present invention further provides a modular refrigeration system having an evaporator, a condenser, and a compressor fluidly connected by a plurality of conduits. The modular refrigeration system includes a one-piece base plate having the evaporator, condenser, and compressor mounted thereto. A drain pan is integrally formed in the base plate located beneath the compressor in which condensate collects. The condenser further includes a fan which directs air over the drain pan to evaporate the condensate. A fan mount is integrally formed in the base plate located beneath the evaporator. At least one airflow passageway is located in the base plate. A cover is mounted to the base plate encasing the evaporator with the fan mount and the airflow passageway being located beneath the cover. 
     The present invention provides a modular refrigeration system having an evaporator, a condenser, and a compressor fluidly connected by a plurality of conduits. The modular refrigeration system includes a one-piece base plate to which the evaporator, condenser, and compressor are mounted. At least one projection is integrally formed with the base plate and engages a cover mounted to the base plate to encase the evaporator. A groove is formed in cover. A hook is located on each of opposite sides of the base plate. An elastic fastener is received in the groove and engages each of the hooks to secure the cover to the base plate. 
     The present invention also provides a method of attaching a cover for an evaporator to a base plate of a modular refrigeration system including engaging the cover with projections extending from the base plate; engaging a first hook formed on a first side of the base plate with an elastic fastener; locating the elastic fastener in a groove formed in the cover; and engaging a second hook formed on a second, opposite side of the base plate with the elastic fastener, whereby the cover is secured to the base plate. 
     One advantage of the present invention is that the modular unit facilitates quick and easy repair of the refrigeration appliances and simplifies assembly of the appliance at the OEM. 
     An additional advantage of the present invention is the integrally formed base plate which is easily constructed and cost effective. 
     A further advantage of the present invention is the method of mounting the evaporator cover to the base plate. The projections in the base plate allow for alignment of the cover over the evaporator with the elastic fastener being quickly and easily removable and replaceable in the case of system refurbishment and repair. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of a refrigeration apparatus having a modular refrigeration system in accordance with the present invention; 
     FIG. 1A is a sectional view of the refrigeration apparatus of FIG. 1 taken along line  1 A— 1 A; 
     FIG. 2 is a perspective view of the modular refrigeration system of the present invention; 
     FIG. 3 is a perspective view of the modular refrigeration system of FIG. 2, with the evaporator cover removed; 
     FIG. 4 is a perspective view of a base plate of the modular refrigeration system of the present invention; 
     FIG. 5 is a top plan view of the base plate of FIG. 4; 
     FIG. 6 is a side elevational view of the base plate of FIG. 4; 
     FIG. 7 is a sectional view of a compressor mounting area in the base plate of FIG. 6 taken along line  7 — 7 ; 
     FIG. 8 is a perspective view of an evaporator mount of the modular refrigeration system of the present invention; 
     FIG. 9 is an end view of the evaporator mount of FIG. 8; 
     FIG. 10 is a side elevational view of the evaporator mount of FIG. 8; 
     FIG. 11 is to view of the evaporator mount of FIG. 8; 
     FIG. 12 is a perspective view of an evaporator cover of the modular refrigeration system of the present invention; 
     FIG. 13 is a bottom plan view of the evaporator cover of FIG. 12; 
     FIG. 14 is a sectional view of the evaporator cover of FIG. 13 taken along line  14 — 14 ; and 
     FIG. 15 is a sectional view of the evaporator cover of FIG. 14 taken along line  15 — 15 . 
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent an embodiment of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 and 1A, refrigeration appliance  20  may be, e.g., a vending machine, refrigerator or freezer case, or the like. Refrigeration appliance  20  is provided with modular refrigeration system  22  which is an integrated, packaged unit mounted in upper compartment  24  of appliance  22 . Upper compartment  24  is defined by cover  25  which has three sides. The top and rear of cover  25  are open so that modular refrigeration system  22  may be slidably installed and removed as necessary. Cover  25  is provided with front vent panel  26  having louvers  28  therein through which air may enter and exit the compartment. Modular refrigeration system  22  is mounted to the upper end of compartment  30  located below compartment  24 . Lower compartment  30  is the cooled or refrigerated portion of appliance  20 . 
     Referring to FIGS. 2 and 3, modular refrigeration system  22  is a unit having base plate  32  onto which condenser assembly  34  including condenser fan  35 , evaporator  36 , compressor  38 , expansion device  39 , fan  40 , and electrical control box  42  are mounted. Cover  44  is secured to base plate  32  to encase evaporator  36  and fan  40 . Conduits  46  fluidly connect the refrigeration system components. With the components interconnected by conduits  46 , system  22  is initially charged with refrigerant prior to being shipped to the OEM which facilitates quick and easy assembly of refrigeration appliance  20 . 
     Refrigeration system  22  may be slidably removed from and replaced in appliance  20  as a unit. For example, in the case of component failure, the failed refrigeration system unit  22  is removed from appliance  20  and a second refrigeration system unit  22  is installed. The installation of a working unit  22  is quick and easy with only an electrical connection to a power source and any control connections needing to be made. The removed unit  22  is refurbished by removing and replacing the failed component off-site. The refurbished system is then recharged with refrigerant and used to replace another unit  22  if necessary. 
     Referring to FIGS. 4,  5 ,  6 , and  7 , refrigeration system  22  includes one piece, integrally formed base plate  32 . Base plate  32  is formed by any suitable method including injection molding, pressure molding, casting, or the like and is constructed from a material such as plastic, reinforced plastic, or lightweight metals such as aluminum. 
     As illustrated in FIGS. 2,  3 ,  4 , and  5 , condenser  34  assembly and electrical control box  42  are mounted to base plate  32 , adjacent compressor  38 , by any suitable type of fasteners  48  such as screws. Fasteners  48  are received in apertures formed mounting feet  50  of condenser assembly  34  and electrical control box  42  and engage apertures  52  formed in plate  32  to secure the components thereto. 
     Base plate  32  is provided with integral compressor mount  54  for mounting compressor  38  thereto. Referring to FIGS. 4,  5 ,  6 , and  7 , compressor mount  54  is formed with four bosses  56  having integral studs  58  extending upwardly therefrom and integrally formed therewith. Bosses  56  are positioned to align with mounting feet  60  (FIG. 2) integrally formed with the compressor housing such that studs  58  are received in apertures located in feet  60 . As shown in FIG. 2, one fastener  62  is secured to the end of each stud  58  to secure compressor  38  into position on base plate  32 . Fasteners  62  may be any suitable type of nut such as, e.g., a pal nut or push nut. 
     Compressor mount  54  is located in condensate drain pan  64  integrally formed in base plate  32  directly beneath compressor  38 . Bosses  56  extend upwardly from lower surface  66  of drain pan  64  a predetermined distance. Mounting feet  60  of compressor  38  engage the upper surface of bosses  56  to locate compressor  38  above the maximum condensate level in drain pan  64 . Condensate drain pan  64  is in fluid communication with drain basin  68  located beneath evaporator  36  by channel or trough  70 . Drain basin  68  and trough  70  are integrally formed in base plate  32 . 
     Referring to FIGS. 3,  8 ,  9 ,  10 , and  11 , evaporator  36  is mounted to base plate  32  via evaporator mount  72 . Evaporator mount  72  is constructed from any suitable material able to support evaporator  36  by a method such as molding or casting, for example. Evaporator mount  72  includes substantially horizontal support platform  74  having substantially vertical legs  76 . Located at the bottom of legs  76  are mounting feet  78  which extend substantially perpendicularly from legs  76 . Mounting feet  78  are received in recesses  80  (FIG. 4) integrally formed in base plate  32  having apertures  82  located therein. Apertures  84  formed in mounting feet  78  align with apertures  82  to receive fasteners  86  (FIG. 3) to secure evaporator mount  72  to base plate  32 . Located about the periphery of support platform  74  is lip  88  which defines drip pan  90  for condensate produced by evaporator  36 . Extending upwardly from support platform  74  near the rear comers thereof are braces  92 . Braces  92  are provided with apertures  94  which align with apertures in evaporator  36 . Fasteners  96  are received by apertures  94  and those in evaporator  36  to secure evaporator  36  to mount  72 . 
     Referring to FIG. 10, drip pan  90  is defined by upper surface  98  of support platform  74  and lip  88 . Integrally formed in support platform  74  is channel  100 . Upper surface  98  of support platform  74  is downwardly inclined toward channel  100  to direct evaporator condensate produced during operation of refrigeration system  22  toward the channel. From channel  100 , the condensate enters funnel shaped drain  102  and travels along passageway  104  to collect in drain basin  68  (FIG.  4 ). 
     As shown in FIGS. 3,  4 , and  5 , fan mount  106  is integrally formed in base plate  32  to mount fan  40  beneath evaporator  36 . Located adjacent fan mount  106  are airflow passageways  108  formed in base plate  32 . Air enters and exits chamber  110  defined by evaporator cover  44  through airflow passageways  108  where it is cooled by evaporator  36 . The cooled air then refrigerates appliance  20 . 
     The airflow path through refrigeration apparatus  20  is illustrated in FIG.  1 A. The temperature of the air within compartment  30  of apparatus  20  increases as heat from the objects being cooled, located in compartment  30 , is transferred to the air. The objects in compartment  30  are thus cooled. The warmed air exits compartment  30  in the direction of arrows  144  through first warm air chamber  152  located in top wall  148  of compartment  30 . The warmed air in chamber  152  passes through airflow passageways  108  formed in base plate  32  to enter chamber  110  defined by evaporator cover  44 . The warmed air flows in the direction of arrows  144  through evaporator  36 . As the warm air flows over coils  142  of evaporator  36 , heat is transferred from the air to the refrigerant through the coils, thus reducing the temperature of the air. The cooled air flows from evaporator  36  in the direction of arrows  156  and by the force of fan  40  through aperture  158  in base  32  over which fan  40  is mounted. The cooled air enters second chamber  154  formed in top wall  148  being separated from warm air chamber  152  by baffle  150 . The cooled air then passes into duct  162  defined by side wall  164  of compartment  30  and louvered wall  166 . The cooled air flows along duct  162 , exiting into the interior of compartment  30  through a plurality of spaced openings  168  formed in louvered wall  166 . 
     Referring to FIGS. 12,  13 ,  14 , and  15 , cover  44  is constructed from a first layer  112  and a second layer  114 . First layer  112  is in direct contact with refrigerated air circulating in chamber  110  defined by cover  44 . Layer  112  is formed from any suitable material including plastic by a method such as injection molding. Inner surface  116  of first layer  112  is smooth to prevent turbulence in the circulating refrigerated air as it comes into contact therewith. Secured to outer surface  118  of first layer  112  is second layer  114 . Second layer  114  is molded from an insulative foam material and may have a variable thickness. In order to fit the entire refrigeration system  22  onto base plate  32 , the thickness of insulating layer  114  can be varied in certain areas. As illustrated in FIGS. 12 and 15, first and second layers  112  and  114  are provided with large radii  120 . Radii  120  direct the airflow in chamber  110  smoothly through evaporator  36 , thus improving the system efficiency. Opening  121  is provided in one side of cover  44  through which conduit  46  and expansion device  39  passes to connect with evaporator  36 . 
     As illustrated in FIGS. 12,  13 , and  15 , cover  44  is provided with mounting means including longitudinal groove  122  formed in the outer surface of insulative layer  114  and projections  124  molded into base plate  32  (FIG.  4 ). Projections  124  engage first layer  112  of cover  44  and are provided for properly locating cover  44  on base plate  32  over evaporator  36  and airflow passageway  108 . Cover  44  is secured against gasket  125  located between base plate  32  and cover  44  by elastic fastener  126  (FIG. 2) received in groove  122 . Elongated elastic fastener  126  may be a rubber band or any other suitable elastic member which retains cover  44  against base plate  32  by means of its self-tensioning, elastic properties. Fastener  126  is secured to hooks  128  integrally formed on respective opposite sides  130  and  132  of base plate  32  (FIGS. 2,  4 , and  5 ). Hooks  128  are located in recesses  131  in sides  130  and  132  so as not to extend past the width of base plate  32 . Groove  122  in ends  134  and  136  of cover  44  align with recesses  131 . Fastener  126  is then looped over respective hooks  128  to secure cover  44  onto base plate  32 . 
     The general operation of refrigeration system  22  includes first supplying power to operate the motor of compressor  38 , condenser fan  35 , and fan  40 . The refrigerant gas in the system enters compressor  38  where it is compressed, pressurizing the gas and thus increasing the temperature. The heated refrigerant gas travels through compressor discharge conduit  138  (FIG. 2) and enters heat exchanger coils  140  of condenser assembly  34  where the gas is condensed to a liquid state. A portion of discharge conduit  138  is located in drain pan  64  where the heat of the refrigerant gas within the conduit assists with the rapid boil off of condensate collected in drain pan  64 . The heat of the gas entering condenser coils  140  is conducted to the ambient air as condenser fan  35  blows air across coils  140 . The heated air then travels over condensate drain pan  64  to further help with the evaporation process of condensate in pan  64 . From the condenser, the liquid refrigerant flows through expansion device  39  which reduces the pressure of the refrigerant as it enters evaporator  36 . The refrigerant is boiling as it flows through heat exchanger coils  142  of evaporator  36  causing it to evaporate. Air is blown across coils  142  by fan  40  and the heat from the air is transferred to coils  142 , thus reducing the temperature of the air as it is forced over evaporator  36 . The cool air then creates the refrigerated environment of appliance  20 . 
     While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.