US2133956A

US2133956A - Refrigerating apparatus

Info

Publication number: US2133956A
Application number: US103507A
Authority: US
Inventors: Leslie B M Buchanan
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1936-10-01
Filing date: 1936-10-01
Publication date: 1938-10-25
Anticipated expiration: 1955-10-25

Description

06L .1 L. B. M. suHANAfi 2,133,956

REFRIG ERATING APPARATUS I Filed Oct. 1, 1936 INVENTO R' LESLIE-7B. M. BUCHHNHN.

ATTOR I 30 ature refrigerator substantially ineffective for mechanism I1.

5 lowing description and claims, taken in connecceives energizing current from line'conductors 35 40 in accordance with my invention. 1 accordance-with the evaporator temperature. A 40 55 finned as shown, andfunctions to cool the air in of the fluid in the bulband bellows. The con- 55 gear oeezs, 1938 I 2,133,956

UNITED STATES PATENT ori ice REFBIGERATING APPARATUS Leslie 1:. M. Buchanan, Springfield, Mass asignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a col- 7 poration of Pennsylvania Application October 1,' 1936, Serial No. 103,507

. 8 Claims; (01. 52-4) My invention relates to refrigeration appathe compartment l2 which defines a-storage space ratus, more particularly apparatus for maintainfor perishables, such as, articles of food.

ing first and second zones of a refrigerator at Included among the elements of the condensdifferent temperatures, and it has for an object ing unit l5 are compressor mechanismJl, driven 5 to provide improved apparatus of this kind. by a motor 20, and a refrigerant condenser I8 "5 It has been suggested, heretofore, to provide a that is preferably cooled by. a fan I9. The latter common refrigerant condensing unit for circulatfan is driven by a motor 2| having a winding 22. ing refrigerant through the evaporatorelements The winding of the motor 20 that actuates the of relatively high and low temperature chambers compressor mechanism ,l-I isshown diagrammati- 10 of a two-temperature refrigerator and to increase cally at 23 and may be connected in parallel with 10 and decrease the cooling effect of one of .the the fan motor winding 22 so that both the mechevaporators as the heat load impressed thereon anism I! and the fan l9 are operated together. increases and decreases. If the heat load on one The refrigerating system operates on the well or both evaporators increases beyond a predeterknown compressor condenser expander cycle mined value, difficulty is experienced'in' depresswherein vaporou's refrigerant is withdrawn from 15 ing the temperature of the evaporator elements the evaporator elements l3 and f4, through a when a condensing unit having suificient capacity conduit 24, by the compressor mechanism ll'.

to refrigerate the elements normally, but insuffl-. The refrigerant gas is compressed to a relatively cient to depress their temperature when the heat; high temperature by the compressor l1 and is load increases beyond said predetermined or abdelivered to the condenser l8 wherein it is cooled 20 normal value, isemployed. and condensed. The condensed refrigerant flows In accordance with my invention, the load imto a suitable expansion device 25, shown by way pressed on the condensing unit by one of the of example, as a high side float valve. The presevaporators is substantially reduced or termisure of the refrigerant is reduced by the float nated until the temperature of the evaporators is valve 25 and is conveyed to the evaporator por- 25 reduced to a value at whichnormal control may tions l3 and I wherein it is vaporized for abbe restored. stracting. heat from the evaporator portions l3 Accordingly, it is an object of my invention to and ll. This cycle of operation continues rerender one of the evaporators of a two-temperpeatedly during operation of the compressor cooling when the heat load on the refrigerating During periods when the higher temperature mechanism is abnormally high. U chamber l2 requires cooling, forced circulation The foregoing and other objects are efiected of the air therein is effected by a fan 21 prefby my invention as willbe apparent from-the folerably driven by amotor 28. The'motor 28 retion with theaccompanying drawing, forming a L1, La which also provides the source of power part of this application, in which: for the

motors

20 and 2|. The single figure of the drawing shows dia- In accordance with my invention, operation of grammatically, refrigerating apparatus arranged the compressor mechanism I1 is controlled in Referring now to the drawing, I have shown thermostat 3|, preferably f t as type. conmy improved apparatus including a cabinet trols energization of the motor windings 22 and .having relatively low and high temperature 23 and includes an 'expansible bellows 32 conchambers II and i2, respectively. An evaporator nected by tube 33 to bulb The lat'tet is structure including first and second elements, l3 pr'iembly secured to the evaporator element 45 and M, respectively, receives condensed 'refrigerfiggfi g g g g ag ggg g ggp if g gsggfi 7 ant from a suitable condensing unit shown at l5. m ent will be rle-rred to hereinafter.

The evaporator elements I3 and I are disposed As h 1 ation of thermostat is for cooling media in the low and higher te'n'ipert e ope! gas type s we 1 known in the art, no detailed description of their 50, 94mm chambers and respectively- T operation is deemed necessary. Briefly stated, may be arranged the however, the bellows expands and contracts as Chamber H and for the freezing of fluids 6011- the pressure therein increases and decreases, tained in receptacles IS. The element 14 may be which pressure is a function of the temperature sponse to a predetermined high temperature of the evaporator structure and is disengaged from the contact 38 in response to a predetermined low temperature of' the evaporator structure. One terminal of the compressor motor winding 23 is connected directly to line conductor L1 and the other terminal is connected to contact 38 by a conductor 39. The movable contact 35 is conmovable contact 35 continuously during the normal operation described heretofore and is disengaged therefrom during abnormal periods or periods when the temperature of the evaporators is above a predetermined value, higher than the value at which the contacts 35'and 38 first engage. The contact 4| is connected by a conductor 42 to one terminakoa trlgfan motor 28, so that, the energizing circui or the fan motor 28 is conditioned to operate the fan motor during normal operating periods or the periods when the contacts 4| and 35 are engaged. The other terminal of the fan motor 28 is connected to the line conductor L1 by a conductor 43 controlled by a thermostat 44. Y I

The thermostat 44 operates in response to the temperature of the air in the chamber |2 in such manner that it energizes and deenergizes the fan motor 28 when the temperature of the air attains predetermined high and low ,values. Forced circulation of air in the compartment I2 is, therefore, effected in the chamber l2 duringperiods when it is calling for cooling and, during periods when it is satisfied, forced circulation ceases.

The position of the apparatus as shown in the drawingindicates that cooling is not required by either chamber II or I2. Both thermostats 3|- and 44 are in their open positions and neither air nor refrigerant is circulated. Some limited circulation of air in chamber I2 may be induced thermally but it is ineffective to reduce the temperature of the body of air in the chamber l2, as the transfer of heat between the air and the evaporator I4 is at a relatively low rate.

The temperature of the evaporators l3 and I4 is maintained between predetermined temperatures such as, for example, 5 to 15 F., by the thermostat 3|, and the thermostat 44 may be adjusted to maintain the air in thevchamber l2 between 40 and 45 F. The evaporator I4 is so proportioned that with a temperature differential of between 25 to 40 F. prevailing between the evaporator l4 and the air, cooling of the body of air in the chamber I2 is not eifecte'd except during periods of forced circulation when the rate of heat transfer is high.

Operation Assume that the thermostat 44 is satisfied and the circuit of the fan 28 is open. Assume further that the temperature of the evaporators 3 and I4 rises to 15 in the example previously cited, the thermostat 3| effects engagement of contacts 35 tact 35 engages a stationary contact 38 in re-,

and 38 for initiating operation of the condensing unit l5. Refrigerant is vaporized in both evaporators, but mainly in the evaporator l3 due to the low rate of heat transfer between the air l2 and evaporator l4.- Heat is abstracted from the evaporator l3 and media cooled thereby until the temperature of the evaporators has been depressed to 5 F., at which temperature the thermostat 3| becomes satisfied and opens

contacts

35 and 38. Circulation of refrigerant by the condensing unit I5 is, therefore, terminated.

Closure of the contacts of the thermostat 4'4,

due to a rise in temperature of the air in the chamber l2, effects energization of the motor 28 and circulation of air by the fan 21. Accordingly,

the transfer of heat from the air to the evaporator colder compartment II, at which location temperature variations .in either portion 3 or M are quickly reflected. At this location the bulb 34 is contacted by the circulated air and its temperature is therefore affected by the relatively warm air circulated by the fan, as well as by the temperature of the evaporators. With this arrangement, the thermostat 3| may operate in an anticipating manner to start the condensing unit l5 when the relatively warm air is circulated in contact with its bulb 34.

The foregoing described operation of my improved apparatus'may be termed normal operation during which the media in chambers II and 2' are maintained at temperatures within prescribed limits. There may be periods when it is difiicult to quickly effect cooling' of the evaporators I3 and 4, such as during an initial startwhen ,bothchambers and I2 are warm, or when an exceptionally high. heat load prevails in the compartments H and I2. This condition may prevail unlessa condensing unit having a capacity greatly'in excess of the capacity necessary for normal operation is employed. During these periods, itis understood that the fan 21 is operating. evaporators l3 and I 4 may be depressed in a relatively short space of time, I provide means including the contacts 35 and 4| for. rendering the In order that the temperatures of the fan 21 inactive when the temperature of the evaporators is above a predetermined value of say 30 F. This may be termed an abnormally high temperature.

The bellows 32 of the thermostat 3| is expanded sufficiently to disengage contacts 35 and 4| when the temperature of .the evaporators l3'and 4 is above 30 F., and therefore, the fan motor 28 is rendered incapable of operation regardless of the position of the thermostat 44. In this position,

the contact 35 remains in engagement with con-' tacts 38 so that the .condensing unit l5 operates to circulate refrigerant.

The evaporators l3 and 4 are readily cooled due to the heat loadon evaporator |.4 being reduced. As the temperature of the evaporators l3 and I4 is depressed to 30 F., the contacts 35 and engage for restoring normal control.

From the foregoing, it will be apparent that I have provided improved two-temperature.refrigrefrigerated at different temperatures,,an' evaperating apparatus wherein refrigeration of both zones may be eifected selectively, with preference being 'given normally to one zone and, in'the event of an abnormal operating condition, preference is transferred to the other zone.

The form of refrigerant condensing unit employed in the disclosure is shown by way of ex- I ample and it will be understood that other types of condensing units may be employed in accordance with my invention. The thermostats disclosed are shown in their simplest form for the sake 'of clearness and it will be understood that certain refinements have been omitted, particularly, quick acting switch mechanisms.

While I have shown my invention in but one form, it will be obvioustd those skilled in the are that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon asare imposed by the prior art or. as are specifically set forth in the appended claims.

What I claim is:

1. In refrigerating apparatus, the combination of means defining first and second zones to be refrigerated, an evaporator structure disposed for cooling media in both'zones, means for circulating refrigerant through the'evaporator structure, means for effecting forced circulation of the air in one zone in heat transfer relation with the evaporator for cooling the air, and means responsive to a predetermined abnormally high temperature of the evaporator structure for rendering the air circulating means incapable of operation. w v

2. In refrigerating apparatus, the combination of a cabinet structure having relatively high and low temperature zones formed therein, an evaporator structure having portions disposed within bothof saidzones, means for circulating refrigerant through said evaporator for effecting cooling of the media in the zones, means responsive to the temperature of said evaporator for controlling the circulating means, a device for effecting forced circulation of the medium to be cooled in heat transfer relation 7 with the evaporator portion in one of the zones, means responsive to\ a predetermined temperature of the medium in said one zone for controlling the operation of the device, and means for rendering said device ineffective when the temperature of the evap-v orator in'creasesto' a predetermined value.

'3. In refrigerating apparatus, the combination of means defining first and second zones to be orator structure having first and second portions disposed for cooling the air in the zones, respectively means for circulating refrigerant through the evaporator, a fan for translating the air in one of thezones in heat transfer relation with the evaporator portion therein, means responsive to the temperature of the air in said one zone for controlling the operation of the fan, means responsive to the temperatureof an intermediate portion of the evaporator for controlling the operation of said refrigerant circulating means, and means for terminating. operation of said fan in response to an abnormally high temperature of the evaporator.

4. In refrigerating apparatus, the combination ,of means defining first and second compartments to be refrigerated, an evaporator structure-hav-' ing first and second portions thereof disposed for cooling the air inthe first and second compartments, respectively, .means for circulating re-' frigerant through the evaporator structure, said second evaporator portion being so proportioned that limited cooling of the air in the second compartment is effected by thermally induced air currents, means for translating air within the second compartment in heat transfer relation with the second evaporator portion whereby effective cooling of the air is obtained, means responsive to the temperature of the air in the second compartment for controlling the operation of the air 1 translating means, and means responsive to the temperature of the evaporator for controlling the operation of the refrigerant circulating means,

said last-mentioned [temperature responsivemeans being so disposed that it is affected by the 7 air circulated by the air translating means.

5. In a refrigerating system, the combination of a cabinet having first and second chambers therein, first and second evaporator elements disposed in heat transfer relation withthe air within said chambers, respectively, means for supplying condensed refrigerant to the evaporator elements for vaporization therein at substantially equal pressures, means for controlling said refrigerant supply means in accordance with the temperature of the evaporator elements, a fan for translating air in said second chamber in heat transfer relation with the evaporator element therein, a thermostat actuated by the temperature of the air in the second chamber for controlling the operation of the fan, and means responsive to an abnormally high temperature of the evaporator elemeans for rendering the fan inactive .in re-. dependently of the thermostat.

6. In a refrigerating system, the combination 7 of a, cabinet having first and second chambers therein, first and second evaporator elements disposed in heat transfer relation with the air within said chambers, respectively, means for supplying condensed refrigerant ,to the evaporator elements for vaporization therein at substantially equal pressures, means for controlling said refrigerant supply means in accordance with the tempera tures of the evaporator elements, a fan for translating air in said second chamber in heat transfer relation with the evaporator elements therein, and means responsive to the temperature of the air in said second chamber for controlling the operation of the fan; said first-mentioned temperature responsive means being so; disposed that it is affected by the temperature of the air translated by the fan.

with the evaporator therein, means responsive to the temperature of the air in the high temperature chamber for controlling said fan, and

means for rendering the fan inactive in response to a predetermined abnormally high temperature of the conduit.

' 8. In refrigerating'apparatus, the combination of a structure defining relatively high audio wt? perature chamber in heat exchanging relation temperature zones to be refrigerated, first and second evaporator elements for abstracting heat from said zones, respectively, first means for effecting refrigeration by the first element in response to a predetermined temperature within the high temperature zone, second means for effecting refrigeration by said second element in response to a predetermined temperature thereof,

said first-temperature responsive means being effective to control refrigeration by said first evaporator element during normal operation of the apparatus, and means for rendering said first temperature responsive means ineffective in response to an abnormally high temperature of the evaporator elements.

LESLIE B. M. BUCHANAN.

- CERTIFICATE OF'CORRECTION. w Patent No. 2,155,956 Y v h October 25, 1958'.

-- LESLIE B. M. BUCHANAN It is hereby; cerc-tji'iedv that errer appear's intheprinted specification of theabove nunbered patent requiriiig eorrectiqn as follows Page j second coltmn,-, line 5b,, claim 5 strike out the words and syllable means for rendering the fan inactive in re-" and insert ir stead'tlpe syllable, wordsland syllable ments fer terminating operatien bfthe fan 1n-- and that the Said Letters Patent shouldbe read with this correctibnthez ein that the same may conform to the record of the case in-the Patent; Office.

Signed and aealed thisv 6th day of 'Decembe i', A. D. l958'.

Henry Van Arsdale (Seal) Acting lcozmnisslener of Patents.