Patent Publication Number: US-2006010885-A1

Title: Refrigeration unit

Description:
THIS INVENTION relates to refrigeration. It more particularly relates to a method of refrigerating an item, and to a refrigeration unit.  
      The Applicant is of the opinion that the invention will particularly advantageously be applicable to rapid refrigeration of items, and that application will particularly be bome in mind for purposes of this specification. Naturally, however, the invention may be used in other applications.  
      In accordance with one aspect of the invention, there is provided a method of refrigerating an item, which method includes 
          cooling a working fluid to a temperature lower than that of an item to be refrigerated;     dispensing the cooled working fluid onto the item thereby, on account of heat exchange between the working fluid and the item, extracting heat from the item to refrigerate the item; and     collecting the dispensed working fluid for re-use.        

      The working fluid may be cooled to a predetermined temperature and may be continuously dispensed onto the item for a time required to refrigerate the item to a desired temperature.  
      Dispensing of the working fluid onto the item may be by spraying it onto the item.  
      Collection of the dispensed working fluid may be by collecting it under the influence of gravity by means of catchment means.  
      The method may be executed in a substantially enclosed refrigeration zone with walls defining the enclosed zone forming the catchment means.  
      Cooling of the working fluid may be by bringing it into direct contact with an evaporator forming part of a closed-loop refrigeration system.  
      In accordance with another aspect of the invention, there is provided a refrigeration unit which includes 
          a refrigeration zone for receiving an item or items to be refrigerated;     dispensing means oriented relative to the refrigeration zone so as to enable dispensing of a working fluid into the refrigeration zone; and     catchment means arranged relative to the refrigeration zone so as to collect the working fluid after it has been dispensed into the refrigeration zone.        

      The refrigeration unit may include cooling means for cooling the working fluid in use.  
      The refrigeration unit may include a first enclosed compartment, having a sealingly closeable access opening, within which the refrigeration zone is defined, with walls of the compartment forming the catchment means.  
      The dispensing means may include spraying nozzles located within the first compartment. The spraying nozzles may be mounted on or proximate at least some of the walls of the compartment and may be oriented to direct the working fluid away from their associated walls.  
      A floor or bottom wall of the first compartment may be apertured to pass working fluid flowing operatively downwardly under the influence of gravity, thereby to direct collected working fluid in use.  
      The refrigeration unit may include a second enclosed compartment within which the working fluid is received and cooled in use.  
      The second compartment may be in fluid flow communication with the first compartment so as to receive the collected working fluid passing through the aperture or apertures in the bottom wall of the first compartment.  
      The second compartment may be positioned below the first compartment to permit collected working fluid to flow from the first compartment into the second compartment under the influence of gravity.  
      The cooling means may include a primary, closed-loop refrigeration system having an operatively interconnected condenser, expansion means, evaporator, and compressor with associated motor, and having an associated refrigerant, with the evaporator being positioned in the second compartment so as to extract heat from the working fluid in the second compartment in use, thereby to cool the working fluid.  
      The refrigeration unit may include a secondary, closed-loop refrigeration system substantially similar to the primary, closed-loop refrigeration system, with an evaporator of the secondary refrigeration system in heat exchange relationship with the condenser of the primary refrigeration system thereby to extract heat from the condenser and, hence in use, to enable cooling of the primary refrigeration system refrigerant and, accordingly, the working fluid to lower temperatures.  
      The refrigeration unit may include a portable housing which houses the components of the or each refrigeration system and within which the first compartment and the second compartment are defined.  
      The refrigeration unit may include a pump having its inlet in fluid flow communication with the second compartment and its outlet in fluid flow communication with the spraying nozzles. The pump may be activatable so as to pump the working fluid from the second compartment to the spraying nozzles for dispension thereof in use.  
      The refrigeration unit may include circulation means for circulating the working fluid in the second compartment in use.  
      At least the first and the second compartments may be thermally insulated. 
    
    
      The invention is now described, by way of example, with reference to the accompanying diagrammatic drawings.  
      In the drawings:  
       FIG. 1  shows a schematic layout of a refrigeration unit in accordance with the invention;  
       FIG. 2  shows, in part-sectional front view, a refrigeration unit in accordance with the invention; and  
       FIG. 3  shows, in part-sectional top view taken at III-III in  FIG. 2 , the refrigeration unit in accordance with the invention.  
    
    
      With reference to the drawings, a refrigeration unit in accordance with the invention is generally indicated by reference numeral  10 . The device  10  includes a parallelepipedal housing  12  defining a first parallelepipedal compartment  14 , a second parallelepipedal compartment  16  which is slightly smaller than and located operatively below the first compartment  14 , and a third parallelepipedal compartment  18  located operatively alongside the compartments  14 ,  16 .  
      The first compartment  14  defines a refrigeration zone  20  within which an item or items to be refrigerated is/are receivable. The second compartment  16  defines a reservoir within which a working fluid, e.g. ethanol, which is used to refrigerate the item or items, is receivable and coolable to a temperature below that of the item or items to be refrigerated.  
      The unit  10  further includes dispensing means, generally indicated by reference numeral  24 , oriented relative to the refrigeration zone  20  so as to enable dispensing of the working fluid into the refrigeration zone  20 .  
      The first compartment  14  is defined by a top wall  26 , a floor or bottom wall  28  spaced from the top wall  26 , opposing side walls  30 ,  32 , a rear wall  34  and an operatively front wall defined by a door  36 . The door  36  is hingeably connected to the housing  12  (the hinges are not shown) and when in the open position allows access into the refrigeration zone  20 . When in the closed position, the door  36  seals off the compartment  14 . The unit  10  may include a latch mechanism (not shown) for sealingly retaining the door  36  in the closed position.  
      The respective walls defining the first compartment  14 , also define catchment means for catching or collecting dispensed working fluid.  
      The side walls  30 , 32  and the rear wall  34  extend operatively downwardly to define rear and side walls of the second compartment or reservoir  16 . The second compartment is further defined by a front wall (not visible) and a bottom wall or floor  35 . Also, with the exception of the side wall  37 , walls defining the third compartment  18  are mere extensions of the walls defining the first and second compartments  14 ,  16 .  
      The respective walls defining the first and second compartments  14 ,  16  are thermally insulated so as to prevent heat exchange between the interior of the compartments  14 ,  16  and their surroundings.  
      The unit  10  further includes cooling means in the form of a primary, closed-loop refrigeration system generally indicated by reference numeral  38 .  
      The dispensing means  24  is constituted by a first array of spraying nozzles  40  and a second array of spraying nozzles  42 . The first array of spraying nozzles  40  is mounted on a panel  41  which is secured inside the compartment  40  to an inner face  26 . 1  of the top wall  26 . The panel  41  is of a size substantially similar to that of the inner face  26 . 1  of the top wall  26  and, if desired, may be embedded into the top wall  26 . It is to be appreciated, that the nozzles  40 , need not necessarily be mounted on a panel which then, in turn, is mounted to the wall  26  of the compartment  14 , but the nozzles  40 , can instead be mounted on the wall  26 . The second array of spraying nozzles  42  is mounted on an inner face  28 . 1  of the bottom wall  28 .  
      The nozzles  42  can, however, also be mounted on a panel which then, in turn, is mounted to the bottom wall  28 .  
      The bottom wall  28  includes an array of circular apertures  44  spaced inbetween the nozzles  42 . If the nozzles  42  are mounted on a panel, the panel will include circular apertures which are in register with the apertures  44 . These apertures  44  provide fluid flow communication between the first compartment  14  and the second compartment or reservoir  16 . In  FIG. 1  the fluid flow communication provided by the apertures  44  is indicated by a fluid flow communication connection  46 . The purpose of fluid flow communication between the first compartment  14  and the second compartment or reservoir  16  will become more apparent hereinafter.  
      The unit  10  further includes a pump  48  having an inlet thereof in fluid flow communication with the second compartment or reservoir  16 , and an outlet thereof in fluid flow communication with the respective nozzles  40 ,  42 . The pump  48  has an associated motor (not shown) for driving it in use. In the embodiment shown, however, the pump  48  is located within the reservoir  22 . The fluid flow communication between the pump  48  and the respective nozzles  40 ,  42  is provided by a conduit network, generally indicated by reference numeral  50 , and constituted by a conduit  50 . 1  providing fluid flow communication with the nozzles  42  and a conduit  50 . 2  providing fluid flow communication with the nozzles  40 .  
      In a variant embodiment (not shown), instead of having a hingeable door  36  providing access into the first compartment  14 , the top wall  26  of the first compartment  14  may be a sealingly seated, removable lid. In this embodiment, which will typically be used in smaller applications such as portable refrigeration units, the nozzles  40  will typically be mounted on an underface of the lid, or the panel  41  will be an integral part of the lid. Here, the lid will include a fluid flow connector which, upon closure of the lid will be aligned and sealingly engaged with the conduit  50 . 2 .  
      Circulation means in the form of a circulation pump  52  is provided within the reservoir  22 , in use, to circulate the working fluid within the reservoir  22  to get in proper contact with the evaporator  48  cooling the fluid and evenly to spread the temperature in the working fluid. The pump  52  also has an associated motor (not shown) for driving it in use.  
      The primary refrigeration system  38  includes a condenser  54 , an expander or expansion valve  56 , an evaporator  58  and a compressor  60 , which respectively are in fluid flow communication via a conduit network, generally indicated by reference numeral  62 , to form a closed-loop system. The unit  10  includes also a pump (not shown) for driving the compressor in use. The condenser  54 , the expander or expansion valve  56 , and the compressor  60  are all located within the third compartment  18 . The evaporator  58  is located within the second compartment or reservoir  16 . The primary refrigeration system  38  includes also a suitable refrigerant which is circulated within the closed-loop system.  
      In use, the compressor  60  compresses the refrigerant, which at this point is in vapour form, and feeds it via a conduit  62 . 1  to the condenser  54  where it is condensed. From the condenser  54  the refrigerant, which is now in liquid form, flows to the expansion valve  56  via a conduit  62 . 2 . In the expansion valve  56 , the refrigerant is expanded and from there flows to the evaporator  58 , where it is evaporated. On account of the nature of the refrigerant, the evaporation is an endothermic process and heat is thus absorbed from the working fluid within the first compartment or reservoir  16  upon evaporation of the refrigerant. From the evaporator  58  the refrigerant flows, via a conduit  62 . 4 , back to the compressor  60 .  
      In use, the working fluid in the second compartment or reservoir  16  is cooled as hereinbefore described, an item or items to be refrigerated is located within the first compartment  14 , and the cooled working fluid  16  is dispensed, via the nozzles  40 ,  42 , onto the item or items thereby to refrigerate it. Dispensing of the working fluid onto the item or items is effected by actuation of the pump  48 . The device  10  will include also an actuator such as a switch, or the like for actuating operation of the pump  48 . Upon actuation of the pump  48 , it pumps working fluid from the second compartment or reservoir  16  via the conduits  50 . 1 ,  50 . 2  to the respective nozzles  40 ,  42  by means of which it is dispensed, in droplet form, onto the item or items within the first compartment  14 .  
      The working fluid will typically be cooled to a predetermined temperature and will then be continuously dispensed onto an item or items to be refrigerated for a time required to refrigerate the item or items to a desired temperature. Working fluid dispensed into the first compartment  14  is retained within the first compartment by means of its walls  26 ,  28 ,  30 ,  32 ,  34  and its door  36 . After being dispensed, the working fluid flows toward the floor or bottom wall  28  under gravity and passes through the apertures  44  which, in turn, leads into the second compartment or reservoir  16 . The dispensed working fluid is thus collected for re-use.  
      The device  10  shown in  FIG. 1  includes also a secondary closed-loop refrigeration system, shown in dotted, generally indicated by reference numeral  64 . The secondary refrigeration system  64  is substantially similar to the primary refrigeration system  38 . It includes a condenser  66 , an expansion valve  68 , an evaporator  70 , and a compressor  72  with its associated motor, which respectively are in fluid flow communication via a conduit network generally indicated by reference numeral  74 . Respective sections of the network  74  are indicated by reference numerals  74 . 1 ,  74 . 2 ,  74 . 3 ,  74 . 4 .  
      The secondary refrigeration system  64  functions similarly to the primary refrigeration system  38 . Here, however, the evaporator  70  is in heat exchange relationship with the condenser  54  of the primary refrigeration system  38  so as, in use, to extract heat from the condenser  54 . Preferably, the evaporator  70  and the condenser  54  are located within an insulated casing  76 . The primary and the secondary refrigeration systems are thus in combined or cascaded formation. This combined or cascaded refrigeration system enables the primary refrigeration system refrigerant and, hence, the working fluid to be cooled to lower temperatures.  
      It is an advantage of this invention that it provides a refrigeration device which enables rapid refrigeration of an item or items to relatively low temperatures. It is a further advantage that the working fluid used in the device can be collected and re-used.