US2045048A - Refrigerating apparatus - Google Patents

Description

June 23, 1936. E. B. NEWILL REFRIGERATING APPARATUS 2 Sheets-Sheet 2 Filed July 31, 1934 r vu xp/ /d /u /d\ a PatentedqJ une 2 3,; 1936 PATENT OFFICE asramm'rma mmrus Edward B. Newlll. Dayton, Ohio, auignor to Gena J oral Motors Corporation, Dayton, Ohio, a cornotation of Delaware Application July 31, 1934, No. 787,787

8 Claims.

This invention relates to refrigerating apparatus and particularly to evaporators or cooling elements thereof.

Refrigerating apparatuses or systems of the 6 present-day type usually have two major features embodied therein. The first of these features is the provision of an evaporator am. a refrigerant flow circuit therethrough which will produce rapid freezing of substances placed in trays or receptacles and positioned on or in an evaporator while at'the same time coolingthe air within a refrigerator cabinet to the proper temperature for food preservation. The second of these major features is the provision of some sort of means for causing semi-automatic or antomatic defrosting of the evaporator or in other words to cause a temporary higher temperature of the air cooling walls of the evaporator for melting frost orice accumulated thereon therein extensive development of evaporators of special or unique design for refrigerating systems and the invention herein disclosed is an improvement in the art of evaporator design constructed especially to carry out the desirable features of a refrigerating system without loss of efliciency.

An object of the invention is to provide an evaporator or cooling element having an arrangement of passages therein which will permit effective circulation of refrigerant in the evaporator so as to'. cool certain surfaces thereof as desired and to provide an evaporator which can be readily fabricated from sheet metal shells or plates.

Another object of the invention is to provide an-improved evaporator of the type having a pluralityof walls forming an air cooling portion for the evaporator and a chamber therebetween adapted to receive receptacles containing substances tobe congealed or. frozen, within the chamber and to construct and arrange the shelves in such mannerthat a difference in the temperature of the air cooling portion or walls of the 4 evaporator relative to the temperature of the shelves will not materially affect the normal low temperature of the shelves.

In carrying out the foregoing object it is still a further object to'provide temperature 'hold-over means in thermal contact with a refrigerated shelf within a freezing chamber or compartment defined by walls of an evaporator for maintaining the temperature of the shelf substantially constant during a temporary increase in the tem- 55 perature of the evaporator walls.

from. These two desirable features have resulted with a refrigerated sharp freezing shelf or shelves,

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the. present invention is clearly shown.

, In the drawirigsz- Fig, 1 discloses a refrigerator cabinet ofthe household type having an evaporator constructed according to 'the present invention installed. therein;

Fig. 2 Ban enlarged side ,eiev'ational view of my-improved evaporator;

Fig. 3 is an enlarged vertical sectional view of my improved evaporator taken on the line 3--3 of Fig.2 and showingthe chamber formed by the evaporator walls as being divided into a plurality of compartments by refrigerated shelves; and- Fig. 4 is a sectional view taken on the line 44 of Fig. 3 showing the bottom of one of the refrlgerated shelves. I

Referring to the drawings, for the purpose of illustrating the present invention, I have shown in Fig. 1 thereof an evaporator constructed according to my invention mounted in the refrigerator cabinet 2 i of any suitable construction or design. Preferably the cabinet 2| comprises an insulated food storage compartment 22 having a door 23'providing access thereto and a machine compartment (not shown) disposed below the food compartment. The refrigerant liquefying and circulating unit or machine of the re-.

' frigerating system, connected with the evaporator 20, may be of any suitable type. and is adapted to be mounted in the machine compartment. Mechanical refrigerant liquefying and circulating 35 units or machines of type mentioned are well known to those familiar with the art and need no detailed description.

The evaporator 20 is produced by uniting in any suitable manner superimposed sheet metal plates or telescoped sheet metal shells 25 and -26 (see Fig. 3) to provide a double walled structure having passages formed between the plates or shelves. The united plates or shells 25 and 26 are arranged to form a top wall 21, a bottom wall 28 and side walls 29 and 30 of an elongated horizontally extending freezing chamber or compartment. A liquid refrigerant inlet connection 32 and a gaseous refrigerant outlet connection 33 are connected with the evaporator 20. The refrigerant connection 32 may be-connected with a refrigerant control device (not shown) of any well known type for governing or controlling the flow of liquid refrigerant to the evaporator. The refrigerant flow control device may be in the I by these walls by members 51.

form of a restriction expansion or float valve. The refrigerant connection 33 leads from the evaporator 20 to the crankcase or suction side ofa compressor, ordinarily included as an element of the refrigerant liquefying and circulating unit, for withdrawing gaseous refrigerant from the evaporator, In order to provide the evaporator with a fast freezing portion and a relatively warmer portion for cooling air the refrigerant connection 32 leads to a serpentine refrigerant conduit 35 formed in the shelf 33. A

pipe 31 conducts refrigerant from the conduit 35, in shelf 36, to a conduit 33 formed in a shelf 33. The shelves 36 and 39 provide the evaporator with fast freezing supports adapted to receive receptacles 40 containing a substance to be congealed'or frozen. The shelves 36 and 39 divide the chamber or compartment, formed by the walls 21, 26, 29 and 30 of the evaporator, into a plurality of superimposed compartments. Shelves 55 and 39 each include superimposed sheet metal portions or members 4| and if: (see Fig. 3) secured together in any suitable manner. The refrigerant conduits 35 and 38 provided in shelves t6 and 39 extend horizontally through the chamber or compartment formed by walls of the evaporator and are formed by depressions provided in the lower sheet metal portion 42 of the shelves. A pipe 43 conducts refrigerant from the conduit 38, in shelf 39, to a header or distributing manifold 65 formed by and located between the sheet metal plates or shells 25 and 23 in the bottom wall, 28 of the evaporator. A plurality of refrigerant passages 46 formed by and located between the sheet metal plates or shells 2!: and 26 extend outwardly from each side of' the manifold 45 and upwardly along the walls 28 and 33 and along the top wall 21 and communicate with a gaseous refrigerant outlet header or chamber 41 to which the gaseous refrigerant return pipe 33 is connected.

It will thus be seen that I have provided a refrigerant flow circuit through the sheet metal evaporator 20, between the refrigerant inlet and outlet connections thereof, which includes an extended portion comprising the shelves 33 and 33 connected in series with the inlet connection 32 and which portion is capable of producing very low temperatures and another portion connected in parallel circuit relation with the outlet connection 33 to provide refrigerated wall portions which are maintained at a higher temperature than the shelves for cooling and causing circulation of air within the food storage compartment 22 of cabinet 2|.

The refrigerated shelves 33 and 33 have the major portion thereof spaced from the side walls 29 and 30 of the evaporator and are supported The members 3| may be of any suitable material, preferably of a material of low heat conductivity and being separate from and independent of the material of the-evaporator walls and of the shelves 33 and 33. Members 5| are secured to the shelves 33 and 33 and to the side walls 29 and 33 in any suitable manner. The feature of supporting the shelves 36 and 39 as disclosed will become'apparent from the folllowing description of the present invention. Each refrigerated shelf includes a sheet metal portion 52 having the portion thereof adJacent its edges secured in any suitable manner to the lower sheet metal portion 42 of the shelves. The portions of the sheet metal member 52 intermediate its secu'redportions is bulged outwardly so as to be spaced from the frigerator cabinet.

metal shelf portion 42 to provide a sealed chamber 53 along the bottom of the shelves. A nonfreezing solution such as brine or the like is adapted to be placed in and sealed within the chamber 53.

The refrigerant flowcircuit through the evaporator as hereinbefore described provides a portion adjacent the refrigerant inlet which is main-' tained at a very low temperature to produce fast freezing and a portion adjacent the outlet pipe 33 of the evaporator which produces a temperature sufficient to cool and cause circulation of air in the food storage compartment of the re- It is well known to those skilled in the art that the temperature of the air cooling walls of the evaporator is sufficiently low to cause moisture within the air in the food compartment, upon being chilled or cooled by flowing over the evaporator, to condense on the air cooling walls thereof. This moisture soon- I mulates on the evaporator walls in the form of a layer of frost or ice. If this layer of frost or ice is permitted to build up or accumulate beyond a certain thickness it will render the refrigerant liquefying and circulating unit of the refrigerating system inefficient because each operating period thereof will be extended over a longer period of time than normal to cause the evaporator to produce the proper low temperature in the food compartment. This results in excessive wear on the operating parts of the unit and increases the cost of operating the refrigersting apparatus. It is to be understood that this fact has been generally recognized by those skilled in the art and by their provision of automaticaliy or semi-automatically operated devices in conjunction with a refrigerating system to cause periodic intervals of non-operation of the refrigerant liquefying and circulating unit to permit the temperature of the evaporator to increase above the freezing point of water so that the frost or ice accumulated on walls of the evaporator will be melted or so that the air cooling walls will be defrosted.

According to my invention the brine solution 7 contained in chamber 53 below each of the refrigerated shelves 36 and 33 serves as a temperature hold-over and prevents softening or melting of frozen substances contained in the trays or receptacles 43 supported on the shelves during a defrosting period of the air cooling walls of the evaporator. The refrigerated shelves 33 and 33 and the hold-over chambers 53 are substantially isolated or protected from the environment temperature surrounding the evaporator by the evaporator walls 21, 23, 23 and 30 and, if desired, by a rear and front cover plate or door (npt shown) provided on the evaporator. Therefore the temperature of the air within the foods compartment does not materially affect the temperature of the shelves. The brine hold-over solution/in chambers 53, after having been reduced to the proper low temperature, serves to main-- by absorbing heat therefrom and thereby de-' creases, the maximum load on the refrigerating machine. 7 i v From the foregoing it will become apparent that I have provided an improved evaporator for refrigerating systems having all the desired characteristics of present-day refrigeration requirements. My improved evaporator providesfor fast form, it is to be understood that other forms might be adopted, all coming within the scopeof the claims which follow.

What is claimed is as follows:

1. An evaporator for refrigerating systems comprising in combination, refrigerant conveying. means arranged to define a plurality of walls of a sharp freezing compartment, a refrigerated shelf disposed horizontally within said freezing compartment for supporting a receptacle adapted to contain a substance to be congealed or frozen, a closed chamber containing a temperature holdover substance adjacent to and in intimate thermal contact with said shelf, and means for supporting said refrigerated'shelf and said chamber in spaced relation to the walls of said freezing compartment. 2. An evaporator for refrigerating systems comprising in combination, refrigerant conveying means arranged to define a plurality of walls of a sharp freezing compartment, a refrigerated shelf disposed horizontally within said freezing compartment for supporting a receptacle adapted to contain a substance to be congealed or frozen, a closed chamber containing a temperature holdover substanceadjacent to and in intimate ther-' mal contact with said shelf, and means for sunporting said refrigerated shelf and said chamber in spaced relation to the walls of said freezing compartment, said last named means being of a material separate from and independent of'the walls of said compartment and of the hold-over chamber and shelf.

3. An evaporator for refrigerating systems com-- prising in combination, sheet metal portions having certain parts thereof secured together and certain other parts thereof spaced apart to provide refrigerant passages therebetween, said sheet metal portions being arranged to provide a plurality of walls of a freezing compartment, sheet metal portions having certain parts thereof secured together and certain other parts thereof spaced apart to provide a refrigerant passage therebetween and arranged horizontally within said freezing compartment to provide a shelf for supporting a receptacle adapted to contain a substance to be congealed or frozen, a sheet metal member secured to said shelf and forming a closed chamber containing a temperature hold-over substance in intimate thermal contact with said shelf.)

and means for supporting said shelf and said chamber from the walls of said freezing compartment, said supporting means comprising a plurality of members of low heat conductivity and formed of material separate from and independent of the material of said shelf and -said evaporator walls.

' l 4. Anevaporator for refrigerating systems comprising in combination, sheet metal portions hav vide refrigerant passages, therebetween,

v ment.

therebetween andjarranged horizontally within said freezing compartment to provide a shelf for supporting a receptacle adapted to contain a substance to be congealed or frozen, 9. sheet metal member secured to the underside of said shelf spaced apart to provide arefrigerant passage and forming a closed chamber containing a tem:-

perature holdover substance in intimate thermal contact with said shelf, and means for sup- V porting said shelf and said chamber in spaced relation to the walls of said freezing compart- 5. An evaporator for refrigerating systems comprising in combination, refrigerant conveying means arranged to define a plurality of walls of a sharp freezing compartment, means forming a .combined receptacle receiving shelf and closed container, said combined shelf and container being disposed horizontally within said freezing compartment and said'container having a temperature holdover substance therein, and means for supporting said combined shelf and container in spaced relation to the walls of said freezing compartment. v i

6. An evaporator for refrigerating systems comprising in combination, refrigerant conveying means, arranged to define a plurality of walls of a sharp freezing compartment, means forming a combined receptacle receiving refrigerated shelf and temperature holdover element, said combined shelf and element being disposed horizontally within said freezing compartment, and means for supporting said combined shelf and eleprisingin combination, refrigerant conveying means arranged to define a plurality of walls of a sharp freezing compartment, means forming a temperature holdover element, said element being disposed horizontally within said freezing compartment and providing a shelf for the reception of a receptacle adapted to contain a substance to be congealed or frozen, and means for supporting said element in spaced relation to the walls of said freezing compartment.

8. An evaporator for refrigerating systems comprising in combination, refrigerant convey-" EDWARD B. NEWILL-

Images