US2994208A - Refrigerating apparatus having frosteliminating means - Google Patents

Description

W. A. HANSON Aug. 1, 1961 REFRIGERATING APPARATUS HAVING FROST-ELIMINATING MEANS Filed Nov. 18, 1958 2 Sheets-Sheet l INVENTOR. 00 7787? @Z/Zznaam MAN/W Aug. 1, 1961 w. HANSON 2,994,208 .REFRIGERATING APPARATUS HAVING FROST-ELIMINATING MEANS Filed Nov. 18, 1958 2 Sheets -Sheec 2 INVENTOR.

warren @Hcznsom BYXPCQ/MMMUWZ/U/J/ United States Patent fiiiee Pam... Affiifi i 2,994,208 REFRIGERATING APPARATUS HAVING FROST- ELIMINATING MEANS Warren A. Hanson, St. Paul, Minn., assignor t Whirlpool (Iorporation, a corporation of Delaware Filed Nov. 18, 1958, Ser. No. 774,686 3 Claims. (Cl. 62186) This invention relates to refrigeration apparatus.

One of the features of this invention is to provide an improved refrigeration apparatus including a refrigerated storage compartment and means for maintaining this compartment in a substantially frost free condition.

Another feature of the invention is to provide an improved refrigeration apparatus including separately refrigerated fast freeze and storage compartments together with improved means for transferring cooling medium between the two compartments.

A further feature of the invention is to provide an improved refrigeration apparatus including means for cooling interior walls thereof and means for substantially preventing frost formation on said walls.

Yet another feature of the invention is to provide an improved refrigeration apparatus including a defrosting system and controls therefor.

Other features and advantages of the invention will be apparent from the following description taken in conjunction with the accompanw'ng drawings, wherein:

FIGURE 1 is a vertical section of a refrigeration apparatus embodying the invention;

FIGURE 2 is a transverse section thereof taken approximately along the line 2--2 of FIGURE 1;

FIGURE 3 is a schematic diagram illustrating the arrangement of the elements of the refrigeration apparatus; and

FIGURE 4 is a fragmentary vertical section of a modified form of apparatus.

Referring now to FIGURES l, 2 and 3 of the drawing, a refrigeration means, illustratively shown as a chesttype freezer generally designated 10, is defined by a bottom wall 11, right side wall 12, left side wall 13, a front wall 14, a rear wall 15, and a closure or lid 16. Each of walls 11-15 and lid 16 is defined by an inner plate 17, an outer plate 18, and an intermediate body 19 of suitable and customary insulating material. Lid 16 is movably secured to rear wall 15 by a suitable hinge means 20 and may be provided with a handle 21 for raising and lowering the lid as desired.

Adjacent right side wall 12 as viewed in FIGURE 1, bottom wall 11 is stepped to define a horizontal wall portion 22 and a vertical wall portion 23. Wall portions 22 and 23 extend between front wall 14 and rear wall 13 to divide the interior of freezer into a large first refrigeration chamber 24 between vertical wall portion 23 and left side wall 13, and a smaller second chamber 25 above horizontal wall portion 22. Wall portions 22 and 23 include outer plates 26 which define, with the outer plates 18, a compartment 2'7 in which a motor driven compressor 28 of usual construction is disposed.

Encircling the inner plates 17 of chambers 24 and 25 on the outer surfaces of said plates 17 is a first cooling evaporator coil 29. A condenser coil 30 is similarly located on the inner surfaces of outer plates 18 of the chambers 24 and 25 to transfer heat from the refrigerant to the exterior. Evaporator coil 29 is against inner plates 17 to provide efiicientheat transfer from chamber 24 through plate 17 which is preferably formed of a heat conducting material such as metal. Thus, proper refrigeration of all items in chamber 24, including items in direct contact with plate 17, may be effected, eliminating the need of space consuming racks, baskets, spacers, and the like. Condenser coil 30 is against outer plate 18 to permit efiicient heat transfer from the condenser outwardly through plate 18 which is preferably formed of a heat conducting material such as metal.

A second evaporator 31 is arranged to extend vertically substantially fully across freezer 10 between chambers 24 and 25. Evaporator 31 defines with inner plate 17 of front wall 14 and rear wall 15 a plurality of small air passages 32 through which air may pass from chamber 24 to chamber 25in heat transfer relationship with evaporator 31.

To provide a positive flow of air through passages 32, a blower 33 is provided. As seen in FIGURE 1, blower 33 is driven by a motor 34 mounted in a downwardly opening well 35 in lid 16. The mid-portion 1.7a of the lid inner plate 17 is recessed upwardly toward the outer plate 18 and a panel 36 is peripherally secured thereto, by suitable means such as screws 37, which also serve to secure a peripheral gasket 38 to the underside of lid 16. A breaker strip 39 is secured to the top of walls 12-15 for cooperation with gasket 38 to seal the lid 16 thereacross when the lid is in the illustrated closed position. A gasket 40 is secured to the top of evaporator 31 to engage the underside of panel 36 when the lid is in the closed position to limit communication between chamber 24 and space 25 to passages 32.

Blower 33 is disposed directly above chamber 25 and panel 36 is provided with an opening 41. for passing air from chamber 215 to the blower. From blower 33, the air is delivered to the space 42 between panel 36 and plate portion 17a above chamber 24. The portion 43 of panel 36 overlying chamber 24 is perforate permitting the air delivered from blower 33 to pass from space 42 into chamber 24.

As will be brought out more fully hereinafter, evaporator 31 which is normally maintained at a temperature lower than that of evaporator 29 is periodically defrosted. The resultant water is collected in a depression 44 provided in horizontal wall portion 22 and passed through wall portion 22 by means of a tube 45 to fall into a pan 46 secured in heat transfer relationship to motorcompressor 28. Thus, the collected water is evaporated by the heat produced by the operation of motor-compressor 28 and discharged to the atmosphere in the form of water vapor in a customary manner.

In use, freezer 10 provides a substantially frost-free refrigeration of items (not shown) within chamber 24. This is effected by passing refrigerant through the first evaporator 29 to lower the temperature in chamber 24 to a first freezing temperature. Refrigerant is also passed through second evaporator 31 to lower the temperature thereof to a second temperature which is below said first temperature. At the same time, blower 33 is operated to draw air from chamber 24, through passages 32 in heat transfer relationship with evaporator 31, through chamber 25, and to deliver the air through space 42 and perforate panel portion 33 back to chamber 24. As the temperature of the evaporator 31 is below that of chamber 24 including the first evaporator 29 and wall surfaces 17, a transmigration of frost from chamber 24 to deposit on evaporator 31 and a continual maintenance of a substantially frost-free condition in chamber 24 is effected. The temperature of the air is lowered to its minimum value in passing evaporator 31 and, thus, chamber 25 comprises the coldest space in freezer 1t), permitting quick-freezing of items therein as desired.

Periodically, evaporator 31 is warmed to melt the frost collected thereon. As it is unnecessary to defrost the main evaporator 29, chamber 24 may be maintained substantially at the desired below freezing temperature at all times. In actual practice it has been found that both evaporators 29 and 31 are maintained well below freezing and that evaporator 31 is at least about 3 to 5 F. cooler than evaporator 29. This is sufficient to bring about the above described frost migration from the walls of chambers 24 and 25 to evaporator 31 as the coldest body in the apparatus.

Referring now to FIGURE 3, power for operating freezer is provided through leads L1 and L2 of a suitable power source (not shown). One side of motorcompressor 28 is connected directly to lead L1 and the other side of the motor-compressor is connected through a lead 47 and thermostat switch contacts 48 to lead L2. Contacts 48 are operated by a usual thermostat bellows 49 controlled by a sensing element or bulb 50 adjacent to a portion of the first evaporator coil 29. When the temperature sensed by element 50 reaches a predetermined high value, switch 48 is automatically closed, thereby operating motor-compressor 28 to circulate refrigerant from the motor-compressor, in series, through an outlet 51, condenser 36, capillary tube 52, first evaporator coil 29, pressure reducing check valve 53, a conduit 54, second evaporator 31, and a return conduit 55 back to motorcompresor 28. The hot refrigerant is cooled in the conventional manner during passage through condenser 38 which dissipates heat therefrom through outer plate 18 of the freezer walls 12-15 as previously described. Passage of the liquid refrigerant through first evaporator coil 29 lowers the temperature of chamber 24 to the desired below freezing temperature. in passing through the pressure reducing check valve 53, the temperature of the refrigerant is further reduced whereby second evaporator 31 is operated at a lower temperature than that of first evaporator coil 29 and chamber 24.

As stated above, blower 33 continuously circulates the air between chamber 24 and chamber 25 in thermal contact with second evaporator 31 to cool the air and thus cool chamber 25 to a relatively extremely low temperature. Thus, chamber 25 is cooled by evaporator 31 and the portion of evaporator 29 in the walls of chamber 25 and also by this air stream.

Motor 34 which drives blower 33 is connected through a lead 56 to a stationary contact 57a of a switch 57 mounted on a top portion of rear wall 15. An actuating plunger 57!; of switch 57 is urged downwardly by the confronting portion of a panel 36 when the lid is in the closed position of FIGURE 2 to urge a movable contact 570 of the switch into engagement with fixed contact 57a. Movable contact 57c is connected to power supply lead L1. When lid 16 is opened, movable contact 570 is moved by a spring 57d associated therewith away from contact 57a to stop operation of blower motor 34. Spring 570? further acts to close contact 57c with a fixed contact 57e. A lamp 59 secured to the underside of panel 43 adjacent rear wall is connected from lead L2 through a lead 64} to fixed contact 57c and, thus, is energized whenever lid 16 is opened.

As indicated above, one side of the blower motor 34 is connected to power supply lead L1 through movable contact 570 and fixed contact 57a of switch 57 whenever the switch is in closed position. The other side of motor 34 is connected through a lead 61 to a fixed contact 62a of a clock operated timer switch 62. A movable contact 62b of the timer switch is connected to lead 47 and is normally closed with contact 62a to complete the circuit from motor 34 through thermostat contact 28 to the other power supply lead L2. This circuit arrangement assures the operation of blower 33 only when second evaporator 31 is being properly cooled by operation of the compressor.

As indicated above, it is desirable at certain intervals to effect a defrosting of second evaporator 31. To effect this, timer switch 62 is provided with a time delay mecha nism 620 connected from lead 47 to power supply lead L1. Thus, clock operated timer mechanism 62 is driven only at such times as operation of the motor-compressor 38 is effected. Timer mechanism 620 operates to move movable contact 62b from engagement with fixed contact 62a and close the movable contact with a fixed contact 62d of timer switch 62. Switch contact 62d is connected through a lead 63 to a solenoid valve 64, the other side of which solenoid valve is connected directly to power lead L1. Valve 64 is arranged to control flow of refrigerant from motor-compressor outlet 51 through a conduit 65 to conduit 54 extending between check valve 53 and second evaporator 31. Thus, whenever timer mechanism 620 closes movable contact 6211 with fixed contact 62d solenoid valve 64 is operated to direct the hot refrigerant from motor-compressor 28, through conduit 65, through conduit 54, through second evaporator 31, and through return conduit 55 to the motor-compressor 28. The high compressor discharge pressure on the back of check valve 53 will cause it to stay closed, thereby closing oif the normal refrigerating circuit of condenser 39, capillary 52 and first evaporator 29. The hot refrigerant defrosts second evaporator 31 as it flows therethrough, the collected water being delivered through tube 45 to pan 46 where it is evaporated and discharged to atmosphere by the heat of motor-compressor 28. As movable contact 62!) is disengaged from fixed contact 62a during this time, blower 33 is not operating and the temperature of chamber 24 is maintained substantially at the desired freezing temperature during the relatively short defrosting cycle. Further, the clock timer 62 can only operate when the motor-compressor 28 is operating, which in turn is controlled by the thermostat 48-59.

FIGURE 4 shows a modified form of blower.

Here a well 135 is provided in the right side wall 112 to dispose blower 133 within space 125. A shroud 166 is secured to the inner plate 117 of right side wall 112 to surround the blower 133 and is provided with an inlet opening 141 through which air from space is drawn into the blower. An outlet opening 167 is provided in a top portion of the shroud adjacent to a complementary opening 168 in the confronting portion of the panel 136. Thus, air passes from blower 133 through shroud opening 167 and panel opening 168 into the space 142 defined by panel 136 and inner plate 117 of lid 116. Blower 133 effects a circulation of 'air similar to the circulation of air efiected by blower 133 of freezer 10, whereby air drawn from chamber 124 to space 125 passes against second evaporator 131.

Having described my invention as related to the embodiments shown in the accompanying drawings, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Refrigeration apparatus, comprising: means defining a first chamber and a second chamber; means defining a passage between said chambers; a first evaporator for cooling the chambers to a first freezing temperature; a second evaporator; surface means extending across said passage and defining a plurality of small air flow passages between said chambers, said surface means being cooled by the second evaporator to a second temperature below said first temperature; means selectively circulating cooling refrigerant through both evaporators, and delivering no refrigerant to said first evaporator while circulating hot refrigerant through said second evaporator to efiect a rapid defrosting of said surface means while said first chamber is maintained at substantially said first freezing temperature; and air moving means for causing air flow in a path from said first chamber, through said passage in heat transfer relationship with said surface means, through said second chamber, and back to said first chamber, and means precluding operation of the air moving means other than when cooling refrigerant is being circulated through said second evaporator.

2. The refrigeration apparatus of claim 1 wherein said References Cited in the file of this patent air moving means is disposed within said second cham- UNITED STATES A T 2,442,978 Jones June 8, 1948 3. The refrigeration apparatus of claim '1 wherein said 5 2 4 7 1 2 Richard N 3 1949 chamber defining means includes a movable closure hav- 2,496,143 B k t Jam 31, 1950 ing means for conducting air from said second chamber 2 770,104 sweynor N 13, 1955 to said first chamber, said air moving means being dis- 2,780,925 McGrew Feb. 12, 1957 posed within said second chamber and delivering air 2,805,555 Schumacher Sept. '10, 1957 therefrom to said air conducting means. 10 2,890,574 Whitesel June 16, 1959

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