US2405392A - Refrigerating apparatus - Google Patents

Description

All@ 6, 1946- L.. w ,luTcl-us'oN` 2,405,392I

REFRIGERATING APPARATUS Filed Nov. 8, 1941 2 Sheets-SheffI 1 His Gtovneg.

Aug. 6, 1946. L. w. A'rcHlsoN REFRIGERATING APPARATUS Filed Nov. 8, 1941 2 Sheets-Shea? 2 Fig. i,

Inventor: Leonard Wtchi s on His ttprneg.

Patentec Aug. 6, 1946 UNITED REFRIGERATING APPARATUS uLeonard W. Atchison, Schenectady, N. Y., assignor `to General Electric Company, a corporation of New York A pplieatien November 8. 19 4 1, S erial No- 41;8 3 6l Thisinvention Lrelates te ref i'ieeratiiie apparatus .and :more particularly to reirieerating apparatuefor cooling a plurality of geiles.

,It is an object of mv invention t9 provide improved refrieeratine apparatus adapted to iliaiii-k tain a temperaturedfferential between a plurality of zones.

Further objects and advantages f niv invention will become apparent as the following description proceeds and the features of novelty which characterize yinv invention Will be pointed out .with particularity in the claims annexed to and forming a part of this specification.

Fora better understanding of my invention reference .may be had to the .accompanying drawings 1in which Fis. 1 is ka perspective view ,of a refrigerator cabinet of the d OIllestic type embodying ,the principles of my invention; Fig. 2 is ,an enlarged view illustrating a detail of the refrigerating vapparatus illustrated inFig. 1; vFler. ,3 bis a fragmentary `front elevational view offa vrefrigerator cabinet showing a second embodiment of my invention; Fig. .4 is an exploded and enlarged View of a detail of the arrangement-dis- 4 closed in Fig. 3; and Fie. 5 is a fragmentarviront .elevational view .of a refrigerator cabinet .equipped with a :third embodiment of .mv ,invention-y Referring to the drawings, I have :provided a. `,r efrigerator cabinet. I0 having a vvfreezing chamber .or zone II and a compartment or'aone I 2 maintained at a temperature suitable for the general storage of food, as 4.0 to 5 F. forexam- Vple. In the form of my invention shownin Figs- ,1 to 4 inclusive an ,evaporator is provided for coolingthecompartment I I and a secondarysystemhaving a cooling lportion L4 is provided for Cooling the kcompartment I2. A v heat exchange device ,is provided for transferring heat between the primary and secondary systems. kIn order to maintain ia predetermined differential between .the temperatures of the cooling elements and of the primary and secondary systems, respectively, I have ,arranged a portion of one of the systems to contain a, charge of a Substance `vvhichfis substantially .unvaporizable or inert y,at theteinperaltures involved and refrigerantlintermxed for providing a mixturehaving a different boiling point than that .of the refrigerant alone. A refrigerant and ,aboiling point modifying substance which are miscible or mutually soluble Jis pref- ,erablyemployed s uchas oil and methyl chloride .or l one ,of the refrigerante sold .under the trade name Frech, for example.

The ,embodiment wof my invention illustrated Figs- -1 cand 2 Acomprises -a primary-.secondary system in which the modifying substance is introduced into a portion of the primary system. The arrangement illustrated in Figs. 3 and 4 also employs a primary-secondary system, but in this case the mixture of refrigerant and modifying substance is circulated through the secondary system In Fig. 5 there is illustrated an arrangement in which the principles-of my invention have been applied to a refrigerating `system employing two series-connected evaporators i6 and Il, one of which contains themodifying substance, so that the evaporators run at different temperatures. While YI have shown one evaporator 'within the other, my invention is equally applicable to other arrangements, as for example to evaporators disposed in diiierent compartments wl'iich maybe thermally insulated from each other. My invention is equally applicable to systems employing evapora-tors arranged i-n parallel -relationship.

Describing my invention in greater detail, I have provided a refrigerator cabinet I-D of the domestic type having suitable thermally insulated walls defining fthe compartments or refrigerated zones. Access openings I9 and 2,0 `vto the zones or compartments II and `I2 respectively areprovided, the openings being closed by suitable thermally insulated doors -2Iv and 2 2 respectively.

In the embodiment of my invention illustrated in Figs. 1 and 2 I have provided a lprimary refrigerating system `for main-taining a relatively low Ytemperature in the zone or compartment I-I which -may be below freezing Vfor the storage of frozen foods and the like aswell as for `freezing frozen desserts, ice cubes and the like. The compartment i I is provided with a sheet metal liner 23 of suitable material. The evaporator I3 comprises a plurality of turns of suitable material, such as copper tubing, substantially s iurounding the liner 23 and preferably suitably secured in intimate thermal relation to the outer surface thereof. Any suitable Asystem for circulating refrigerant may be provided but inasmuch as the details of such a system form no part of my present invention, illustration thereof has been omitted 'for purposes of clarity. The refrigerant circulating yand condensing equipment may be conveniently disposed inthe lower portionof -the cabinet I and in order -to provide -accesstoqthe machinery compartment Ihave provided'aipanel ior `closure member 24. The Aprimary system -includes a yliquid jline v25 for conducting .liquid Arefrigerantto allow controlling .device such as float valve 426. for example. the float valve aerviiiein ya Well ,known manner ,to ,supply `yliqliel ,refrigerant to the evaporator I3 through a conduit 21. The last turn of the evaporator I3 is connected to a reservoir or header 28 by means of a conduit 29. A suction line 30 is provided for the Y return of vaporized refrigerant t0 the compressor to Withdraw vaporized refrigerant through the suction line 33. After compression the refrigerant will be liquefied and returned to the'evap-.l

orator I3 through the float valve 26. Any suitablecontrol for the refrigerating apparatus may beprovided. I/ I The secondary system utilized for cooling the compartment I2 comprises a cooling portion I4 preferably ,formed from a suitable conduit such ascopper tubing disposed in a plurality of turns or passes and suitably secured as by soldering to the metal liner defining the compartment or zone I2.` .In 1 I have shown the cooling portion associated With the tWo side, back and bottom .Walls of the compartment but any desired disposition of the cooling portion may be employed. The ends of the conduit are connected to a jacket 3l disposed in intimate thermal relationship with the tank or reservoir 28, the jacket 3l serving as ,a vcondensing portion for the secondary system.

While a jacketM 3l substantially surrounding a header 28 has been illustrated, any suitable heat exchanger may be employed, as a coil of tubing Wound around a cylindrical member, for example. V The secondary system contains a Vaporizable liquid refrigerant and as the temperature Withinthe compartment .I2 increases, the refrigerant is vaporized and Vtherefore rises Vto the upper turns of the cooling portion I4, finally passing to the jacket 3l through the conduit 32.` l

The vaporized refrigerant is condensed in the condensing portion or jacket, 3| andthe liquid lrefrigerant is returned to the cooling portion I4 through the conduit 33.

In order to maintain `a predetermined temperature dilerential between the cooling element I3 and the cooling portion or element I4 of the secondary system with the temperature of elemeint I4 higher than that of element I3, I pro-n vide a substance which will raise the boiling point of the refrigerant in the reservoir 28. The refrigerant and substance or material used are preferably` miscible or mutually soluble, that is, readily soluble in each other in nearly all proportions. 'Ihe substance also should be noncongealable at temperatures normally encountered in the operation of refrigerators andshould not be easily vaporized at the temperatures encountered in the refrigerating cycle. For example, the modifying substance or material may be oil and the refrigerant methyl chloride or a refrigerant known under the name of Freon. The modifying substance need not be a liquid, it

n being sumcent that the substance be suliciently dispersable through the refrigerant to vary the f boiling point thereof to the desired amount. The differential in temperature Will be a function of the proportions of the substance and the refrigerant and also of the temperature Yat which the cold storage compartment is run. Thus, I may utilize an arrangement comprising a plurality of evaporators maintained at a predetermined temperature differential While employing the same refrigerant in each evaporator. The refrigerant vaporized in the primary system Will be drawn off through the suction line 30 While practically all of the substance, such as oil, below the level of .the suction line, will remain in the header 28 inasmuch as it is nonvaporizable or substantially so at the temperatures involved. Since the refrigerant supplied to the evaporator through the float valve 26 is substantially free of the substance, .the temperature of the cold storage evaporator can be held at one temperature and that of thereservoir. or header 28 at a higher tem- L perature and accordingly the condensing effect on the 'vaporized refrigerant in the jacket 3I will be less than if pure refrigerant were contained in the reservoir.

In the embodiment of my invention shown in Figs. 3 and 4, the .differential establishing mixture is employed in the secondary system rather than in the primary system. The cooling portion I4.

of the secondary system communicates with a mixing 'chamber or header 34 and the mixture'of refrigerant and differential providing substance occupies the entire cooling portion, 'a'liquid level beingV established in the header as indicated by the numeral 34a. A condensing portion 35 communicating with the header 34 above the j liquid level therein is secured ingood heat exchange relationship with the primary evaporator I3 as by means of threaded fastening means 42." The condensing portion 35 may take any desiredV form. In the arrangement illustratedV in Fig. 4, the'condensi'ng portion comprises a plurality of substantially U-shaped loops 36, the ends of the loops communicating with the upper portion of 'the header 34. The loops 36 are arranged to engage the liner 23 ofthe evaporator I3 between the turns comprising the evaporator I3. In order to rsecure the condensing portion to the primary evaporator, I'have illustrated a pair ofr metal strips 31 suitably secured to ,thev loops 36' as by soldering or welding. 'The strips are Provided withv tapped 'openings 38 for the reception of suitable screws 42 extending through corresponding openings in the bottom Wall of the lining 23.

The principle of operation is similar to that previously described. Refrigerant will be Vaporized by the absorption of heat from the compartment 'I2 and rise into the condensing portion 35 whereas the unvaporizable substance will rem'ain in the turns of the cooling portion nI4 and in the header 34. The vaporized refrigerant will be condensed by the heat exchange with evaporator I3 and the condensed Vliquid Will return to the header 34 and dissolve in the liquid solution.

In Fig. 5 I have shown a series-connected `system. In the form shown, there is illustrated an inner evaporator II similar in construction to the evaporator I3 shown in Figs. 1 to cl inclusive and an outer evaporator I6 formed from sheet metal and provided with suitably formed laterally extending refrigerant passages I6a communicating at either end thereof with headers 39, the headers being joined by an equalizing connection 40. Substantially pure refrigerant is supplied tothe inner evaporator I'I by the float valve 26. An 'extension of the last turn of the evaporator I'I, indicated by the numeral I8, joinsthe evaporators and serves to inject refrigerant into "the outer evaporator. The boiling point'modifying mixuid refrigerant supplied to evaporator I'I absorbs ized refrigerant is injected into evaporator I6 *through conduit I8 and becomes'mixed with `or dissolved in the mixture in evaporator I6. Vaporizedrefrigerant from the evaporator 16 collects in the headers 39 and is drawn off through the suction line, leaving the nonvaporizable differential producing substance behind. Thus, substantially pure refrigerant is supplied the inner evaporator` l'l so that the inner evaporator is cooled by nearly pure liquid refrigerant.

In order to maintain the freezing compartment ll as cold as possible for any given control setting, and to prevent the temperature of the evaporator ll from exerting an influence on the temperature of the air circulating through the compartment l2 I may close the rear end of the compartment li in any suitable manner, not shown, and provide a suitably hinged door 42' to close the front end thereof.

While I have shown a particular embodiment of my invention I do not desire my invention to be limited to the particular construction shown and described and I intend in the appended claims to cover` all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Refrigerating apparatus comprising means for maintaining a first Zone at a relatively low temperature and means for maintaining a second zone at a higher temperature, both said means being arranged to be connected for operation by the same condensing equipment, each of said means containing vaporizable refrigerant, the one of said means associated with said second zone having a portion thereof containing liquid refrigerant and a material which is substantially unvaporizable at the temperatures involved and miscible with the liquid refrigerant, the mixture having a higher boiling point than that of the refrigerant alone and thereby facilitating the operation of said apparatus to maintain a temperature dierential between said zones, means for conducting substantially pure liquid refrigerant to said portion and means for removing vaporized refrigerant from said portion.

2. Refrigerating apparatus comprising means for maintaining a first Zone at a relatively low temperature and means for maintaining a second zone at a higher temperature, both said means being arranged to be connected for operation by the same condensing equipment, each of said means containing vaporizable refrigerant, the one of said means associ-ated with said second zone having a portion thereof containing liquid refrigerant and a noncongealable material which is substantially unvaporizable at the temperatures involved and miscible with the liquid refrigerant, the mixture having a higher boiling point than that of the refrigerant alone and thereby facilitating the operation of said apparatus to maintain a temperature differential between said zones, means for conducting substantially pure liquid refrigerant to said portion and means for removing vaporized refrigerant from said portion,

3. In refrigerating apparatus comprising means for maintaining a iirst zone at a relatively low temperature and means for maintaining a second zone at a higher temperature, both said means being arranged to be connected for operation by the same condensing equipment, each of said means containing vaporizable refrigerant, the one of said means associated With said second zone yhaving vazportion thereof containing and retain- .ing a material lwhich is :substantially iir'i/vaporir'zable" at the 'temperatures involved and miscible YWit-h the liquid-refrigerant, the mixture having a higherboiling point than that .of thefrefrigerant alone and thereby facilitating `the operation of said apparatus to maintain a temperature differential between said respective zones, means for conducting substantially pure liquid refrigerant to said portion and means for removing vaporized refrigerant from said portion.

4. Refrigerating apparatus comprising a primary and a secondary refrigerating system for cooling a plurality of zones to different temperatures and means providing a heat conducting path for transferring heat between said systems, a vaporizable refrigerant in each of said systems and a substance which is substantially unvaporizable at the temperatures involved and miscible in said refrigerant in said secondary system, the mixture having a higher boiling point than that of the refrigerant alone to facilitate the operation of said secondary system at a higher temperature than that of said primary system, said secondary system being arranged to retain said substance therein.

5. Refrigerating apparatus comprising a cooling element, said element comprising a rst evaporator, a second evaporator within said first evaporator and spaced therefrom, said first evaporator being arranged for operation at a higher temperature than said second evaporator, a vaporizable refrigerant in each of said evaporators, means for circulating refrigerant through said evaporators in series, a substance which is substantially unvaporizable at the temperatures involved in said rst evaporator and which is miscible in said refrigerant for raising the boiling point of the mixture in said first evaporator in order to facilitate the operation of said first evaporator at a higher temperature than that of said second evaporator.

6. A cooling element for use in refrigerators toI provide Zones operating at different temperatures and comprising a first evaporator, a second evaporator within said first evaporator and spaced therefrom, said first evaporator being arranged for operation at a higher temperature than said second evaporator, a vaporizable refrigerant in each of said evaporators, means for circulating refrigerant through said evaporators in series, a substance which is substantially unvaporizable at the temperatures involved ln said first evaporator, said substance being soluble in said refrigerant for raising the boiling point of the solution in said first evaporator in order to facilitate the operation of said first evaporator at a higher temperature than that of said second evaporatorl 7. Refrigerating apparatus comprising a cooling element, said element comprising a pair of evaporators for operation at different temperatures, means for circulating refrigerant through said evaporators in series, and a substance which is substantially unvaporizable at the temperatures involved being disposed in one of the evaporators, said substance being miscible in said refrigerant for raising the boiling point of the solution in said one evaporator in order to facilitate the operation of said one evaporator at a higher temperature than the other evaporator, said one evaporator being arranged to retain said substance therein.

8. Refrigerating apparatus comprising tWo evaporators for operation at different temperatures, a common means for supplying refrigerant :peratures involveddisposed in one of said evaporators, said substance .being miscible in said refrigerant for raising the boiling point of the liquid in said oneevaporator` in order to facilitate the operation of said one evaporator at a higher temperature than the other evaporator, said one evaporator being arranged to retain said suhstance therein.

LEONARD W. ATCHISON.

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