Vending Machine External Heat Exchanger

Abstract

A vending machine cooling system incorporating R290 or other flammable refrigerant where there is no risk of the flammable refrigerant leaking inside the vending machine and possibly being ignited, through use of an unjointed dual walled refrigerant transport structure within the evaporator assembly positioned within the interior of the vending machine.

What is claimed is: 
     
         1 . A cooling system for vending machines comprising:
 an outer casing having insulated top, bottom, front, rear and side walls collectively defining an interior vending space containing a plurality of product holding structures;   an evaporator heat exchange system having a first interiorly mounted portion including a dual walled refrigerant transport tube positioned within the interior vending space, and a second exteriorly mounted portion employing single walled tubing operatively connected to the dual walled refrigerant transport tube so that refrigerant is cycled from the second exteriorly mounted portion to and through the dual walled refrigerant transport tube thereby providing a heat exchange mechanism in the vending space.   
     
     
         2 . The cooling system as in  claim 1  wherein the dual walled refrigerant transport tube positioned within the interior vending space is a jointless structure. 
     
     
         3 . The cooling system as in  claim 1  wherein the dual walled refrigerant transport tube comprises a smaller inner tube and a larger diameter outer tube positioned thereover. 
     
     
         4 . The cooling system as in  claim 3  wherein the space between the inner and outer tubes is filled with a heat exchange medium. 
     
     
         5 . The cooling system as in  claim 4  wherein the heat exchange medium comprises ethylene glycol. 
     
     
         6 . The cooling system as in  claim 3  further including sealing fittings between the inner tube and the outer tube located exteriorly of the vending machine outer casing. 
     
     
         7 . The cooling system as in  claim 6  further including a closable opening for inserting said heat exchange medium into the space within the dual walled refrigerant transport tube. 
     
     
         8 . The cooling system as in  claim 3  wherein the inner tube has a volume of about 24 cubic inches and the outer tube has a surface area of about 1900 square inches. 
     
     
         9 . The cooling system as in  claim 2  further including a finned structure positioned to overlie the dual walled refrigerant transport tube. 
     
     
         10 . The cooling system as in  claim 9  wherein the finned structure is comprised of two finned structures each being spaced apart and each being formed from a plurality of segmented portions secured about a coiled section of the dual walled refrigerant transport tube. 
     
     
         11 . The cooling system as in  claim 10  wherein each finned structure includes said plurality of segmented portions comprises a pair of connected portions. 
     
     
         12 . A cooling system for vending machines comprising:
 an outer casing having insulated top, bottom, front, rear and side walls collectively defining an interior vending space containing a plurality of product holding structures;   an evaporator heat exchange system having a first interiorly mounted portion including a pair of opposing first and second segmented housings each comprised of a complementary shaped inner area shaped to receive tubing there within, the opposing first and second segmented housings being structurally interconnected and collectively supporting a dual walled refrigerant transport tube that is arranged to enter and extend through one shaped area in the first opposing segmented housing and to then exit from an opposite side of that first opposing segmented housing and to then curve and enter an inner area of the second of the opposing segmented housing and to then exit an opposite side of that second opposing segmented housing and then to curve back toward the first opposing segmented housing and into an adjacent shaped inner area with that winding of the dual walled refrigerant tube so as to form a continuous coil thereof along the length of the first interiorly mounted portion by passing back and forth between the inner shaped areas within the opposing segmented housings, the opposing segmented housings each having a heat exchange enhancing exterior;   the dual walled refrigerant transport tube having an inlet end and an outlet end each extending beyond the first interiorly mounted portion and through the rear wall, and having fittings terminating the outer tube of the dual walled refrigerant transport tube exteriorly of the rear wall beyond which a single walled refrigerant tube extends;   and a second exteriorly mounted portion including said fittings at the exterior inlet and outlet ends of the dual walled transport tube reforming the dual walled transport tube into said single walled refrigerant tube, a compressor for circulating refrigerant, a condenser coil connected to the single walled refrigerant by which heat is removed from the refrigerant as refrigerant is cycled there through, and an air circulator thereby collectively providing a heat exchange mechanism to cool the vending space.   
     
     
         13 . The cooling system as in  claim 12  wherein the heat exchange enhancing exterior comprises a finned structure. 
     
     
         14 . The cooling system as in  claim 12  wherein the dual walled refrigerant transport tube comprises an inner tube surrounded by a larger tube defining a space there between. 
     
     
         15 . The cooling system as in  claim 12  further including a plurality of pairs of the opposing first and second segmented housings. 
     
     
         16 . The cooling system as in  claim 12  wherein the dual walled refrigerant transport tube comprises an inner tube surrounded by a larger tube defining a space there between, and further including a closeable inlet into said space located exteriorly of the vending machine rear wall. 
     
     
         17 . A cooling system for vending machines comprising:
 an outer casing having insulated top, bottom, front, rear and side walls collectively defining an interior vending space containing a plurality of product holding structures;
 an internal portion comprising an evaporator heat exchanger consisting of first and second blocks each formed from opposing segments, the opposing segments each having an inner portion formed with a plurality of adjacent channels and an exterior portion including fins, the first and second blocks being interconnected and spaced apart, a jointless dual walled refrigerant transport tube arranged to interfit within the plurality of adjacent channels so as to form a continuous coil there within, the dual walled transport tube having an inlet end and an outlet end each extending outwardly beyond an exterior portion of the evaporative heat exchanger and each extending outwardly beyond an exterior portion of the outer casing; 
 an external portion located outside of the vending machine including fittings at exterior ends of the dual walled transport tube reforming the dual walled transport tube into a single walled refrigerant transporting tube, a compressor for circulating refrigerant, a condenser coil connected to the single walled refrigerant transporting tube by which heat is removed from the refrigerant as refrigerant is cycled there through, and an air circulator thereby collectively providing a heat exchange mechanism to remove heat from and thereby cool the interior vending space. 
   
     
     
         18 . The cooling system as in  claim 17  wherein the dual walled transport tube is comprised of a plurality of coils and said opposing segments comprise as plurality of segmented finned portions. 
     
     
         19 . The cooling system as in  claim 17  wherein the opposing segments are molded in place about a plurality of coiled portions of the dual walled transport tube.