US2483842A

US2483842A - Two-temperature refrigeration system using two refrigerants

Info

Publication number: US2483842A
Application number: US145A
Authority: US
Inventors: Lawrence A Philipp
Original assignee: Nash Kelvinator Corp
Current assignee: American Motors Corp
Priority date: 1948-01-02
Filing date: 1948-01-02
Publication date: 1949-10-04
Anticipated expiration: 1966-10-04

Description

&4835842 L. A-. PHILIPP TWO-TEMPERATURE REFRIGERATION SYSTEM USING TWO REFRIGERANTS Oct. 4, 1949.

Filed Jan. 2, l948 2 Sheets-Sheet l 2 6 7 ZZ n 2 IN V EN TOR. Lflw/EEA/CE fi- PH/L PP BY Oct. 4, %949. PHILIPP & 9

` TWO-TEMPERATURE REFRIGERATION SYSTEM USING TWO REFRIGERANTS Filed Jan. 2, 1948 2 Sheets-Sheet 2 INVENTOR. WEEA/CE H- PH/L/PP 24' I e" !fly/;MI r

Hr TORNE'V Patented Oct. 4, 1949 STTES &483.842

TWO-TEMPERATURE REFRIGERTION SYSTEM USING TW@ REFRIGERANTS Application January 2, 1948, Serial No. 145

Claims. (ci. 62-11@ i This invention relates to refrigerating apparatus and more particularly to such apparatus as is designed to operate at low temperatures.

In storing and preserving confections, such as ice cream, in a rozen condition it has been found that package ice cream including chocolate covered types require a lower temperature than dip ice creams to be maintained in proper frozen condition and accordingly it is both desirable and economical to maintain different temperatures in the refrigerator which stores such confections.

It is an object of the present invention to provide an improved arrangement for maintaining confections in their frozen condition by utilizing a single refrigerant evaporator to refrigerate two compartments and proportion the evaporator so that it has greater refrigerated surface per square inch about the walls of one compartment than the other and to circulate refrigerant through said evaporator by introducing same into said evaporator where it will pass about walls of the compartment which has the greater refrigerated surface about the walls thereof and to utilize as a refrigerant a mixture of refrigerants of difierent boiling points so that the portion of the evaporator which is the first to receive refrigerant will be the colder portion.

Further objects and advantages of the pzsent V invention will be apparent from the following description, reference being had to the accompanying drawings, Wherein a preferred form of i" preserving of confections such as ice creams and other foods to be frozen. The cabinet may comprise a sheet metal casing 22 and a sheet metal liner 24. suitable heat insulation 26 is preferably provided between the casing 22 and the liner to decrease heat leakage into the cabi net. At one end of the cabinet 20, the casing 22 and the liner 24 have their correspondingbottom walls ofiset upwardly providing a machinery compartment 21 within the cabinet outer casing to receive a refrigerant condensing element, designated generally by the numeral 28. Extending upwardly from the cabinet ofiset wall between the ends of the cabinet is a partition 2@ which divides the interier of the cabinet formed by the liner into a relatively large deep storage compartment 38 and a relatively small, shallow storage compartment 32. In the top wall of the cabinet, as at 36, access openings to the

storage compartments

30 and 32 are preferably closed by removable closure members 35. In the present refrigerator the compartments 3@ and 32 are cooled to different temperatures. Compartment 30 may be cooled to a low temperature suitable for preserving foods like ice cream of the dip type whereas compartment 32 may be cooled to a lower temperature for storing chocolate covered ice creams and other package ice creams which require lower temperatures than dip ice cream.

In accordance with my invention I provide a single refrigerant evaporator 40 for the refrigerator and arrange this evaporator to absorb heat from both of the

cabinet compartments

30, 32 in a manner such that the compartments are cooled to different low temperatures. As shown, the evaporator M is preferably in the form of a coil or conduit and is preferably arranged in sinuous form along the side. ends and ofiset wall of the cabinet liner 2 3 to absorb heat from walls of the liner. Preferably, the evaporator coil 40 is attached to the exterior surface of the liner :e out of the way of foods to be stored in the compartments. Any well known suitable cement may be used to secure the evaporator coil ti) to the liner 24 in good heat transfer relationship therewith.

In the machinery compartment 21, the refl-igerant condensing element 28 comprises, in general, a motor-compressor unit 46 and a refrigerant condenser 48. A refrigerant receiver 50 may be provided and also may be located in the machinery compartment 26. Liquid refrigerant is supplied from the condenser 48 to the refrigerant receiver 50, whence the refrigerant is delivered by a capillary or flow controlling tube 52 to the inlet end of theevaporator 40. As is well known, the capillary tube 52 serves to supply proper amounts of the refr'gerant to the evaporator to obtain desired temperatures. From a refrigerant accumulator 54 at the outlet end of the evaporator 40, gaseous refrigerant is returned to the motor-compressor unit 46 through a return conduit 56. A portion of the capillary tube, as at 58, is preferably arranged in good heat absorbing relationship witha portion of the return cor duit 58 so as to cool the refrigerant en route to the evaporator 40 for increased refrigerating emciency. As shown in Fig. 1, the portion of the capillary tube 52 which is in heat transfer relationship with the return conduit 50 preferably extends through or is surrounded by an insulating casing 60. This casing may be made of rubber or of any other suitable heat insulating material. From the insulating caslng 60, the capillary tube 52 and the return line 56 extend through the ofiset, cabinet bottom wall which separates the machinery compartment 26 from the

food storage compartments

30, 32.

In order to maintain different low temperatures in the

compartments

30 and 32 with the single evaporator 40 without use of mechanical or other control devices, I provide a mixture of two miscible refrigerants having different boiling points. While various types of refrigerants may be used to provide this mixture I combine two refrigerants, one of which is dichlorodifluoromethane (CC12F2) commonly called (F-12) and the other is monochlorod'flouromethane (CHClF2) commonly called (F-22). These two refrigerants have different boiling points with (CClzFz) having a lower boiling point than (CHClFz). The proportions of these refrigerants by weight are approximately 40% (CC12F2) to approximateiy 60% of (CI-IClFz). The refrigerant flow through the evaporator 40 is in thedirection of the arrow shown in Figs. 2 and 3. As will be noted in Figs. 2 and 3 the parallel straight runs of the evaporator 40 are closer together about the side walls of the liner portion forming compartment 32 than about the side walls of the liner part which forms the compartment 30. Also the liner part which forms the bottom walls of compartment 32 has a portion of the evaporator 40 attached thereto. Accordingly the walls of compartment 32 have the greater refrigerated surface per square inch of liner surface.

When the refrigerant is introduced into the evaporator 40 the more volatile refrigerant of lower boiling point will evaporate in that portion of the evaporator 40 adjacent the evaporator inlet or in the portion of the evaporator which principally cools the compartment 32 so as to cool this compartment to the desired temperature. The other, or less volatile refrigerant of higher boiling point, will pass along and evaporate principally in that portion of the evaporator 40 which is associated with compartment 30 and thus will cool this compartment to the desired temperature and at a temperature above that of compartment 32. Accordingly, I attach the evaporator coil 40 to the liner 24 so that a desired length of the coil starting with the inlet end thereof is arranged to extend continuously along the bottom and three sides or surface portions of the liner which form th compartment 32. The evaporator coil 40 then extends on the other side of the partition 28 from the compartment 32 and is arranged in heat absorbing relation with the wall portions of the liner forming the relatively higher temperature compartment 30. Thus, it will be seen that the refrigerant of relatively low boiling point will boil out in the anterior portion of the coi140 and the refrigerant of relatively high boiling point will boil out in the posterior portion of the coil 40

cooling compartments

30, 32 to different desired temperatures. In other words the temperature at which vaporization of the refrigerant of low boiling point takes place will be lower p as a result of which heat absorption is greater about the compartment 32.

From the foregoing description it will be noted that I have arranged for the cooling of two refrigerator compartments to different temperatures by a single evaporator using a. mixture of refrigerants of different volatility and boiling points. It will be appreciated that by the use of a mixture of two refrigerants of the proper proportion that two storage compartments may be maintained at different temperatures by a single evaporator without need of pressure differential devices or other control elements. It will also be noted that the liner portion which forms the compartment 32 has a greater refrigerated surface per square inch than the portion which forms the compartment 30. By having a greater refrigerated surface and by evaporating the refrigerant of low boiling point about the liner portion which forms compartment 32 this compartment will be maintained at a lower temperature than compartment 30.

Although only a preferred form of the invention has been illustrated, and that form described in detail, it will be apparent to those skilled in the art that various modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. Refrigerating apparatus comprising a cabinet having a liner, a refrigerating system including a refrigerant evaporator and a refrigerant condensing element operatively connected together, said evaporator having an inlet section in heat exchange relation with a first portion of said liner and another section in heat exchange relation with a second portion of said liner, and a mixture of refrigerants of different boiling points in said system with the refrigerant of low boiling point being proportioned with respect to the evaporator section in heat exchange relation to said first portion of said liner to substantially evaporate in its passage through said inlet section.

2. Refrigerating apparatus comprising a cabinet having a. liner, a refrigerating system including a refrigerant evaporator and a refrigerant condensing element operatively connected together, said evaporator having an inlet section in heat exchange relation with a first portion of said liner and another section in heat exchange relation with a second portion of said liner, the first portion of said liner having a greater refrigerated area per square inch than said second portion, and a mixture of refrigerants of different boiling points in said system with the refrigerant of low boiling point being proportioned with respect to the evaporator section in heat exchange relation to said first portion of said liner .to substantially evaporate in its passage through said inlet section. 4

3. Refrigerating apparatus comprising a cabinet having a liner, a refrigerating system including a refrigerant evaporator and a refrigerant condensing element operatively connected together, said evaporator having an inlet section in heat exchange relation with a first portion of said liner and another section in heat exchange relation with a second portion of said liner, the first portion of said liner having a greater refrigerated area per square inch than said second portion, and a mixture of refrigerants of different boiling points in said system.

4. Refrigerating apparatus comprising a cabinet including sheet metal material forming wails of a relativeiy large and a relatively small compartment, a refrigerating system including a refrigerant evaporator and a refrigerant condensing element operatively connected together, said evaporator having portions in engagement with walls of said sheet metal material about both compartments with a greater effective heat absorbing surface per square inch of material being placed about said relatively small compartment, and a mixture of refrigerants of difierent boiling points in said system.

5. Refrigerating apparatus comprising sheet metal material forming walls of a cooling zone, sheet metal material forming walls of a freezing zone, conduit means arranged for conducting refrigerants about walls of said zones, said means having its inlet end in heat absorbing' relationship with the material forming walls of said freezing zone and having greater heat absorbing area per square inch about said freeing zone than about said cooling zone, a refrigerant condensing element operatively connected with said means and a mixture of refrigerants of difierent boiling I points in said element and said means.

LAWRENCE A. PHILIPP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS