US2235125A - Refrigeration means and method - Google Patents

Description

v. V. TORBENSEN REFRIGERATION MEANS AND METHOD March 18, 1941.

Filed April 5, 1939 .dbg

40 oooaooooon e VIIIIIIIIIIIIIIIIIIIIIIIIIII/IIIIIIIIIIIIIIII)III/4 'u' 'I1/11111111111111111111Illll/11111111111111111110 INVENTOR l//GQO M TQCPBE/SE/V SY/Mmm.

ATTORNEYS Patented Mar. 1,8, "1941 l oFFicE l aeraroaaarron MEANsfAND METHOD v1x5 vani-bessen, cleveland, ohio Application April 5, 1939, Serial No. 266,037 i somma (o1. ca -116) I The present invention pertains to linprovej ments in refrigeration means and method. f f An object of the inventionjls to provide an n# proved method of cooling a refrigerator wit out forming ice therein.

A further object is to provide an improved refrigeratlng device having two compartments of different temperature for properly preserving articles of different nature, the nature oi the article placed in one compartment and the temperature of said article partially determining the ilnal temperature in that compartment.-

Another object is to provide a refrigerator of the above character having a compartment L l5 wherein frozen articles may be kept from melting or from'loslng their frozen condition.

other object is to provide a refrigerator wherein de-frosting is minimized, Jwherein condensation is kept low and, proper humidity maintained.

it. further object ls to provide a refrigerator adapted to receive prefrozenice cubes and to preserve them while cooling vthe refrigeration chamber with minimum operation of the re- 25 iria'eratlhg machine.`

`a can further' object is to provides devies of the above character which is simple, lewin cost. and economical in operation.

tion will become evident during the course of the following description in connection with the accompanying drawing, in which-.-

Figure l is a horizontal sectionalview of a refrigerator embodying the invention, the section Figure 5 is a detail side elevation of an. alteri" native form oi evaporator structure: and

Figure 6 is a fragmental view of an alterna-`- tive inlet header structure'. if

- AReferring to the drawing, the numeral III gen- L erally denotes a refrigerator cabinet having an insulated main portion II. cover plate I2 forms the top of thecabinet I0, the plate i2 resting by gravity on a resilient ln @ther advantages and features ofI the inven-V A similarly insulated sulating gasket I3 supported on the upper rim of the main portionv I I, Figures 2 and 3.

A horizontal panel I4 is suspended from the top plate I2 by means "of bolts I5. andfclamps I6,'

spacer members I1 being clamped between panel 5 I4 andthe under surface of the plate I2, as shown in Figure 2. 'I'he panel I4 is of such size as to llt snugly in the inside/poi' the cabinet II), thus forming a partition between an'upper chamber I8 and a lower chamber I9 therein. 10 n Two vertical metalA plates 20 and 2| are se- 1 cured to the bottom of the panel I4 by means of screws 22 passing through the latter and engaging a channel member 23, as shown'in Figure 4. AThe plates 20 and 2| have, respectively counter- .1"

sunk therein, uniplanar evaporator members 24 and 2li, each evaporator member being formed oi. a continuous length of tubing with return bends and parallel straight portions between bends. VThe tubing of members 24 and 25 protrudes be 20 yoncl the surfaces 'of plates 2li and ti, and the latter are drawn toward eachother by screws '26, causing the members it and 25 to be fiat- -tened against each other throughout their enn tire lengths of contact between the plates. This 25 f structure provides Wide firm contact between the evaporator members 'and between theiatter anni the plates iiIlI and 2i, promoting good and uniform heat transfer relations between these parts as hereinafter set forth in the description of the 30j operating characteristics.

The plates tu and ti are provided with a plu.- ralty of laterally extending vertical ilus il, these fins being either cast integrally with plates 20 and 2i or fastened thereto by any suitable 35 means in heat-transfer relation. j

rectangular baffle 2t, open at the bottom, is

secured to the panel it and surrounds the described sub-assembly of evaporator members 2t and 25, plates 20 and 2l, and iins El. Lateral 40 openings 29 Aare provided in the bame 2li to permit air circulation through the interior thereof as hereinafter set forth.

A flat metal pan 30 is secureclon the top of low walls 30a extending upward from the panel 45V Ill.` Uniplanar evaporator members' 3I and 32 of general construction similar to' members 24 and 25, are secured ilat on the`bottom of the pan 30, preferably by soldering or the like to promote good heat conduction. A Vperforated 50 tray 33 for ice cubes fits in the pan 30 and may be removed therefrom through a, door 34 (Figure 3), inthe front ofthe cabinet I0.

Perforations $5 are provided in the pan 30, and Similar pertorations 36 are providedfin the 55 4|, Figures 1 and 3.

-panel I4 immediately above the fins 21 as shown in Figure 4, wherein the sectional plane is`jogged as indicated in Figure 8 in order to show both the perforations 36 and the clamping screws 26 in full section.

The inlet ends 31, 38, 39 and 40, respectively, of evaporator members 24, 25, 3| and 32 are all preferably connected to a common inlet header Similarly, the outlet or suction ends of all the above evaporator members are preferably connected to a common suction header 42.

In Figure 2, the numeral 43 generally denotes a refrigerating machine of any suitable type, herein represented diagrammatically as comprising the usual motor 44, compressor 45, condenser 46, and liquid receiver 41. The receiver 41 is connected via a liquid line 48 and an expansion valve 49 with the inlet header 4|, while a suction line connects the suction header 42 with the compressor 45 in the usual manner. The refrigerating machine may be provided with any suitable type of cycling control means, herein illustrated as a thermostaticswitch 5I havingits feeler bulb 52 clamped to the evaporator member 32 near the outlet end thereof The operation is as follows:

The expansion valve 49 which admits refrigerant to the four evaporator members' 24, 25, 3|, and 32, through the inlet hea-der 4|, is preferably set to maintain a refrigerating temperature at or near the freezing temperature of water. As the refrigerating machine operates, all evaporator units receive liquid refrigerant at the same pressure, evaporate it at the same temperature, and deliver the resultant vapors via the common header 42 and suction line 5U to the compressor 45.

The upper two evaporator .units which obviously function as a single unit and for simplicity may consequently be hereinafter referred to collectively as the upper evaporator, refrigerate the upper chamber I8 together with the pan 3U and tray33. Similarly the lower units 24 and 25, functioning as a single unit which may hereinafter be collectively termed the lower evaporator, refrigerate the plates 20 and 2|, the iins 21 and the compartment I9.

As pointed out above,the refrigerating temperature of the upper and lower evaporators is the same. The upper compartment I 8, however, is comparatively small and low, and the structures therein are so formed and disposed that con-A vective circulation of air is minimized.

Furthermore, the evaporator members 3| and 32 are separated from t-he panel I4 by a substantially dead air space, the perforations 36 being too small to allow any Uappreciable circulation therethrough, and due to the general lackl of circulation noted, but little heat enters the body of the chamber |8. Consequently, as the refrigerating machine operates under control of the switch 5I, the chamber I8 acquires a general temperature differing but little from that of `the upper evaporator itself, this normal general temperature of chamber I8 being substantially at or slightly above the freezing point of Water.

The tray 33 is removed through the door 34, pre-frozen ice cubes 53-that is, cubes from an outside source, whichare a well-'known article of commerce-ate placedtherein, and the tray of cubes is replaced on the pan 30.

As the cubes 53 are already frozen, practically the only refrigeration necessary to preserve them is that required to overcome the heat leakageof the chamber I8, and this, as noted, is very small.

Commercial ice cubes are frequently heavily sub-cooled to avoid meltage in shipment, and when this is the case, the cubes themselves furnish'a certain amount of initial cooling effect below the freezing point which further assists in stabilizing the temperature of the chamber I8. During operation of the refrigerating machine 43, the cubes 53 may receive preservative refrigerating effect by directl conduction from the evaporator units 3| andf32 through the pan 30 ,and the bottom of the tray 33, while between runs of the machine,- :the general low temperature of the chamber' i8 continues the preservative conditions. If at any time the temperature in chamber I8 rises suiciently to permit slight meltage of the cubes, this meltage itself extracts heat from the surrounding media and thereby lassists in maintaining the general preservative temperature near the freezing point of water, as previously set forth.

During such slight meltage, the evolved water drains through, perforations 35 and 36 and drips on the ilns 21 where it assists'humidification in the lower chamber I9 as hereinafter set forth.

Similarly, any condensate or even meltage from possible occasional light frost formation on the evaporator members 3| and 32, also drips through the perforations 36 to the ns 21.

In the lower compartment I9, the openings 29 in the baille 28 permit and assist circulation of ar, the normal paths of circulation being upward outside the baille, inward through the openings 29, and downward` along the fins 21 and plates 20 and 2|.

The refrlgerating temperature in the evaporator members 24 and 25 is the same as that in the upper evaporator, namely, Iat or near 32 F., but due to the large heat absorbing surface provided .by the ns 21 and plates v2|) and 2| in proportion to the inside surface of the lower evaporator members 24 and 25, and also due to the comparatively large amount of material and surface to be cooled in chamber I9 and the free circulation of air therein as noted, the temperature of the heat absorbing surfaces normally is considerably above the freezing point of water.

'The even distribution of heat absorption is promoted by the Wide and intimate contact betweieiiI the evaporator units and the plates v,20 an Consequently the undue formation of frost l With any given cycling operation of the re-n' frigerating machine 43, the normal temperature in the chamber I9 is largely determined by the temperature and heat emitting capacity of the material, such as food, placed therein, and also naturally by the frequency of withdrawals and replacements of materials.

Obviously, the cycling operation of thefrefrigerating machine 43 may be set as desired by means of the switch 5| or its equivalent. It will beseen from the previous description, however, that the temperatur-,es and operating conditions in the main chamber uI9 have negligible eifect on the funbtioning of the upper ice storage chamber i8, wherein the uniform temperature at or near 32 F. is maintained jointly by the upper evaporator and by the stored ice itself.I f

The foregoing description makes clear that the methodand apparatus comprising the invention provide a two-temperature refrigerator operating )from ay common source of refrigeration without. duel controls or like complications, the refriger-l ation being furnished to both evaporators at a single advantageous temperature. 'Ihe economy of power made possibleby the invention is especially large in comparison with the`usual `systems in which the apparatus is required to freeze ice cubes. approximately 32 F., in order toaetually freeze any usable quantity of ice in reasonable time it is necessary to provide an evaporator temperature much lower than132 F. When, as in common small refrigerator practice, the ice freezing function is combined withithe principal function of food preservation, the necessary low evaporator temperature gives rise to well-known difficulties with frosting and necessary defrosting, dehydraf tion of food, and comparatively long operation oi' the refrigerating plant necessary to extract first the sensible heat and then the latent heat of the water being frozen. y

yFurthermore, the necessity of producing the low freezing temperature forces the; refrigerating plant to operate in a range much less economical than that necessary to the preservation-of food products alone, it being also well-known that the` horsepower per ton of refrigerating eil'ect', par-i ticularly in the usual small compression plant;

increases rapidly as y the suction pressure is lowered.

With systems employing dual evaporator tem-ed peratures designed to avoid some of the frosting troubles and dehydration, the apparatus and control become more complicated as previously noted, and the reirigerating plant is still required to provide a comparatively large amount of refrigeration at uneconomically low temperatures in order to produce usable ice.

lin contrastwith the above, in the present in"; vention the refrigeration. to be furnished is limited substantially tothe amount necessary to cool the stored food and tocompensate for heat leakage, and this minimumamount itself is produced in a comparatively high and economical operating temperature range. Harmful frosting and dehydration are eliminated by the means described, and at the same time a zone is provided nected directly to the suction header, is

at the proper temperature `for storing commercially pre-frozen ice cubes which, due to their economical production in large quantities, may normally be purchased at a price ,considerably less than `the cost of producingv them in the usual small Aduel-purpose refrigerator.

In addition tothe above operating advantages,

it will be seen that the invention provides a structure which is simple. cheap: and readily manufactured and assembled. Y

The entire cooling assembly,` being secured only to the top plate I 2, may be bodily lifted therewith from the top of the cabinet I I after loosening the tubing and thermostat connections.

As an alternative constructionof the evaporator units, illustrated in Figure y5, the outlet end 54 of each lower unit 55 instead of being conconnected While the freezing point of water is to the inlet Il ofl the overlying upper unit l. The inlet ll'of lower unit Il is' connected to the inlet header lla, while the outlet 59 of upper unit I1 leads into the suction header 42a. With this' structure. the general operation is the same as previously set-forth, the refrigerant simply,

traversing the corresponding units of the lower and upper evaporators in series instead of `in parallel. e

n desired in connection with the evaporator assembly structure shown in Figures 1 and 3, the inlet header lib may be provided with valves 80 which may be initially adjusted to various settings to balance the distribution of liquid refrigerant to the units of the evaporator.

While the invention has been set forth in preferred form, it is not limited to the exact structures illustrated, as various modifications may be made without departing from the ,scope of the appended claims.

.What is claimed is:

l 1. In a refrigerator, `in combination, a main casing, a horizontal panel in said casing dividing the interior thereof intoan upper and a lower chamber, a horizontal evaporator 4mountedy on said panel and spaced abovethe same in said upper chamber, an ice tray overlyingl said hori- -zontal evaporator in heat exchangel relation therewith, a pair of vertical plates suspended from said panel in said lower chamber, tubular evaporator's countersunk in said plates and having later surfaces protruding `from said plates,

means c amping said plates together whereby said protruding tubing surfaces are pressed together in flattened contact relation, lateral 'heat absorbing fins on said plates, means forming a common liquid inlet to said upper and lower evaporators, and means forming a common vapor outlet from said upper and lower evaporators.

2. In a dual temperature refrigerator, in combination, a main casing. a horizontal panel dividing the interior of said casing into a relatively restrictedupper chamber'and a relativelyv large lower4 chamber, a perforated heat conductingv pan mounted on the upper side of said partition and spaced therefrom, an evaporator secured to l the bottom of said pan in intimate heat exchange relationship therewith, a pair of tubular uniplanar evaporator units disposced vertically in said lower chamber below said panel, heat absorbing means clamping said, tubular units laterally together in flattened contact relationship, l

said clamping means being secured to said panel, a baille secured( to said panel and surrounding said clamping means and lower evapo- -rator units, said bafe being open at the bottom and having lateral openings near the top thereof K whereby circulation of air in said lower chamber may be promoted, means to conduct water from said upper chamber into" said lower'l chamber within said baille, and'means to distribute said water to said circulating air.

3. The invention claimed in claim 2 wherein perforated pan.

5. The combination claimed in claim 2 wherein said refrigerator includes a removable top plate and wherein said panel is secured to said plate, whereby said panel and said parts attached there-` to may be removed as a unit with said plate from the top of said casing.

6. In a device of the character described, in combination, e. pair of parallel tubular uniplanar evaporator units, heat conducting means partially `enveloping,r the tubing of said units and pressing said units laterally together in flattened contact relationship, and lateral ns on said heat conducting means. Y

7. In a device of the character described, in combination, a horizontal panel, a perforated pan secured to said panel in spaced relation above the same, a horizontal. tubular evaporator secured to the bottom of said pan in intimate heattransfer relationship therewith andspaced above said panel, a pair of uniplanar tubular evaporator members disposed vertically below said panel, means forming open iluid communications between said upper evaporator and said lower evaporator members, heat conducting'members partly embracing said tubular evaporator members and pressing the same laterally against each other in attened contact relationship, said heat conducting members being secured to said panel, lateral iins on said heatl conducting members,

said panel having perorations overlying said ns, and a vertical baiiie secured to said panel and surrounding said lower "evaporators, heat conducting members and ns, said bafe having lateral openings near the top thereof.

8. The combination claimed in claim 7 including a perforated ice tray removably disposed in said perforated pan in heat exchange relationship therewith.

9. That method of operating a two-compartment refrigerator which comprises producing refrigeration from a common source in both of said compartments at or about the freezing temperature of water, restricting air circulation in one of said compartments, promoting air circulation in the other of said compartments, storing pre-frozen ice in said first compartment, storing articles to be refrigerated in said second compartment, and delivering moisture of condensation and/or meltage from said first compartment to the circulating air of said second compartment to increase the humidity in said second compartment.

VIGGO V. TORBENSEN.

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