US1909261A - Refrigerator - Google Patents

Description

R. T. FRAZI ER May 16, 1933.

REFRIGERATOR Filed Deg. 19, 1932 Patented May 16, 19 33' UNITED STATES PATENT OFFICE ROBERT T. FRAZIER, OI! CEATTANOOGA, TENNESSEE, .ASSIGNOR TO TENNESSEE FURNITURE CORPORATION, OF- CHATTANOOGA, TENNESSEE, A CORPORATION OF TENNESSEE REFRIGERATOR Application filed December 19, 1932. Serial No. 648,001.

This invention is a novel improvement in refrigerators of the ice box type, and the principal object of the invention is to provide means for maintaining a low temperature evenly distributed throughout the interior of the refrigerator.

Heretofore the great difliculty encountered in domestic refrigeration has been in maintaining a low temperature evenly distributed throughout a refrigerator. This is true even of electric refrigerators, but presents a much more serious problem in refrigerators cooled by ice. In ice refrigerators now in general use it is very diflicult to attain low tempera- 5 tures during warm Weather, and in an ordinary side-icer, when the exterior temperature is 80 F the lowest-interior temperature attained is ab0ut50 F. at the center of the milk compartment, immediately under the ice 0 chamber, and about 60 to 64 F. at the warmest place in the box, i. e., at the top shelf of the provision compartment beside the ice chamber. By building a very heavily constructed and well insulated ice refrigerator,

5 it is possible at such exterior temperature,

during the same weather conditions, to attain a temperature of 42 F.- in the, milk compartment, and 52 F. at thetop shelf in the provision compartment.

A medium type refrigerator, using the cheaper board type insulation, will usually show temperatures of around 4.8? F. in the milk compartment, and 60 F. at the top shelf. Various means, such as special has- 5 v kets for supporting the ice, special fines, and

special ice bottoms have heretofore been developed for attaining lower temperatures,

but such means have not been successful. I

have found that the prime reason for the high 0 temperatures was the sluggish circulation of air within the refrigerator, which condition could not be improved, nor the air circulation stimulatedon a thermo-siphonic basis.

The necessity of maintaining the tempera- 5 ture inside a refrigerator below 50 is generally conceded. This condition is possible in electric refrigerators'by reason of the low temperatures of evaporation of the gas plus the thermostatic control. In ice refrigera- 50 tors however, the temperature varies very widely, first, because of the great differential of from to 12 F. between the temperatures at the bottom of the refrigerator and at its top; and-secondly, because of the variation of temperature due to the decrease in size of the cake of ice as it melts. The rate of exchange of heat from ice to air varies in direct proportionto the surface area of the ice which is exposed to the air. Hence a lb. cake of ice will require as long a time in melting in the open air, or in air of any given velocity, as a 100 lb. cake along side of it under the same conditions. This is due to the fact that as the surface area of the ice is reduced a slower circulation of air in the refrigerator is produced, and moreover the slowly moving air has a higher temperature. Therefore, temperatures of 47 to 54 F. beneath the ice chamber, 'and from 59 to 66 F. on the top shelf, depending upon the amount of ice in the refrigerator at the time,-

are quite usual.

The primary object of my invention is to correct this temperature deficient: in ice rev frigerators, by'providing means or increasing the volume of air flowing over the ice as the surface area of the ice is decreased; also, to reduce the temperature differential between the top and bottom of the refrigerator by providing means for increasin the speed of circulation of the air inside 0% the cabinet. By m invention, a temperature of 40% F. is rea ily produced inside the bottom or milk compartment of the refrigerator, and a temperature as low as 43 F. on

the top shelf, due to the increased speed of a circulation of the air, and increased rate of heat exchange from the ice to the air.

A still further object is to provide an electric fan operated by a thermostat set to close the fan circuit when the temperatureis about 50 F. in the warmest part of the refrigerator, and to open the circuit when about 46 F. is attained, whereby the temperature in the bottom of the refrigerator will remain at about 42 F. substantiallycontinuously.

Y I will explain the invention with reference to the accompanying drawing which illustrates one practical embodiment thereof to enable others to adopt and use the same; and

will summarize in the claims, the novel features of construction, and novel combinations of parts, for which protection is desired.

The drawing is a transverse section through a refrigerator of the side-icer type showing the arrangement of fan and thermostat with respect to the flues of the refrigerator compartments.

The refrigerator may be of any desired "-ype adapted to hold ice, and preferably the easing 1 is heat insulated. In the embodi- 'ment shown in the drawing the interior of the refrigerator contains an ice chamber 2 in one upper corner for receiving the cake of ice 3 in the usual manner, the ice chamber being formed by the usual lining, having a bottom 4a and side wall 46, separating the ice chamber from the main portion of the refrigerator. In the bottom 4a of the lining is a flue 40 leading into the milk compartment 5 disposed immediately below the ice rection of the arrows, and back again to the ice-chamber 2, the forced circulation maintaming the temperatures in the compartments 2, 5 and 6 substantially the same.

The fan 7' is controlled by a thermostat 8' arranged in the electriclead wires 9, which thermostat 8 is preferably adjusted to close the fan circuit when a temperature of F.

is reached in the top of the provision chamber 6, and to open the circuit-at 45 F. The

temperature in a medium insulated ice box was actually lowered to 41% F. in the milk compartment 5, and 45 F. on the-top shelf in compartment 6. 4

The fan 7 will 0 erate about five minutes and remain idle a out twenty-six minutes when the room temperature is constantly at 80 F. Obviously, when the room temperature is lower than this, the off periods will be longer. When the room temperature is higher than 80 the off periods will be slightly shorter. As the ice melts, there is a slight increase in length of the running time during the ton periods which auto- .matically offsets the slower rate of transfer due to the decreased area of the ice. By extending the operation of the fan 7 .for as long a period as 25 minutes, the temperature was reduced to 40 F. in the milk compartment 5, and 43 F. at the top shelf in compartment 6, .temperatures never before attained or maintained in ice refrigerators.

vention, whereas heretofore it had been considered impossible to get it lower than 9 or 10 F. in the most expensively constructed refrigerators.

The electric leads 9 may be ordinary rubber covered extension cords adapted to plug in any electric light socket. The motor being less than a 20th of a horse-power, consumes less current than an ordinary 40 watt light, and develops very little heat in the refrigerator due to the extremely short cycle operation required of it.

Actual tests have shown that with a thermostatically operated fan in the refrigerator the increase in ice consumption in the cheaper board type-insulated ice box of 100 pounds capacity was only 6 pounds per 24 hours and I was able to maintain the temperature between 46 and 50 F. in the warmest part of the refrigerator continuously up tion to those who cannot aiford electric refrigerators as well as to. those who prefer ice refrigerators because of their obvious advantages.

I claim 1. In a refrigerator, having an ice chamber in the upper portion and having a food compartment and having flues connecting the ice chamber and compartment; means for circulating air thrqugh the compartment and icechamber, and means for automatically varying the volume of circulating air in 1nverse proportion to'the surface area of the ice.

2. In a refrigerator as set forth in claim 1, said automatic means comprising a thermostat disposed in the. warmest portion of the food compartment.

3. In a refrigerator, having an ice chamber in the upper portion and having a food compartment below or to one side of the ce chamber and having fiues connecting the ice chamber with the compartment; means adapted to circulate air through the ice chamber and food compartment,,and means for automatically operating the air circulating means within predetermined temperature limits. I I p 4. In a refrigerator as set forth in claim 3, said automatic means comprising a thermostat disposed in the warmest portion of the food compartment.

5. In a refrigerator, having, an ice chamber in the upper portion, and having a milk compartment below the ice chamber, and

having a food compartment beside the ice chamber, and having flues connecting the ice chamber with the milk and food compart ments respectively; anelectric fan in the food compartment flue adapted to circulate air upwardly through the ice chamber and upwardly through the compartments, and

means for automatically opening and closing the fan circuit within predetermined temperature limits.

6. In a refrigerator as set forth in-claim 5, said automatic means comprising a thermostat disposed in the upper portion of the food compartment.

7. In a household refrigerator having an ice chamber and a foodcompartment, and

having fines connecting the ice chamber and the compartment; means for circulating air through the compartment and the ice chambet, and means for automatically varying the volume of circulating air in inverse proportion to the surface area of the ice.

ROBERT T. FRAZIER.

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