US2667762A - Condenser for refrigerating systems - Google Patents

Description

Feb. 2, 1954 J. R. HORNADAY 2,667,762

CONDENSER FOR REFRIGERATING SYSTEMS Filed April 26, 1951 2 Sheets-Sheet l 7 &

JUL,

(00/ 14/! Currenfs Feb. 2, 1954 J HQRNADAY 2,667,762

CONDENSER FOR REFRIGERATING sYsFEMs,

Filed April 26, 1951 2 Sheets-Sheet 2 James ffi fiorrcczd'gy AWMMZ Patented Feb. 2, 1954 [TED rs TATETS T OFiFiil GE signor .'to Borg-Warner vCorporation, Chicago, IIll.,la corporation of Illinois Application April 26,

2 Claims. .-1

This invention :relateswin general to :refrigermuting apparatus "and has .xparti'cular "reference to an improved form :zof :condenser menstruation which, for example, is advantageously :adaptable tfor .employment in srefrigerating asystems' of the type wherein :a :refrigeratingmediumzis circulated through :a sclosedisystem and is'tsuocessively com :pressed in a gaseous :state, condensed ,into .v'amlidui'dtandtthen expanded by evaporation Joy ;a relatively=lhigh pressure. The :condenser :of :theipres- :ent invention, :in addition to its :inh-erent .im- :-proved heat transfer characteristics, is :par'ticula'rly characterized bythe provision of ran aeiiectire and :improved irefrigerant cooling arrange- :ment :directl-y rand ioperatively associated with the :condenser proper.

iotherwisesstat'ed,ithe invention :is :embodied in a rcondenser particularly arranged tot-provide :for the? minimizing :of thettransferenceof heat from the imotor to the :compressor and i.to the 1 sealing sand/or .lubricating rliquicl and 111 rconnection therewith I .to produce and:maintain, :to as ;perfect a degree as possible, adiab'atic compression.

More: specifically stated, it is. aniobjectrand accom'plishm'ent: of ithei inventionzto aprovi'dean improve'd condenser, said acondenser embodying structure whereinthe 'm'otor of the compressor? is cooled by contact with gaseous irefrig'erant 56118- 1 charged iefrom ith'e Icompressor iand iit-l'iereby the filow df theirefrigerant isvrcontrolledvand directed in i'proximityito :the zmotor 60f the :oompressor iin a 'suffici'entuvolumeito;.provideiadequateccooling :of ithetmotor Zby lithe ;gaseous i'refrigerant as will me "manifest :by 'i'the 'adetailed :description :iollowing hereinafter.

:Another:importantzobizect andiaccomplishment aof'zthe inventionzisitomrovidetan:improvedacondenseriifors-ai refrigeratingzsystem :ioy aeliminating -zsexp'ensive :i-finned :prior art 160116811881 construc- "tions i 'an'd employing iaiplurality ;of :relativeiy rinexpensive srods:disposediinathermal:contact with im t-refrigerantitubes :of the ccondensen'thismonvi s'truction affordingiaisubstantial-:rednction: imt-he costliofz' manufactnrmandgyetitpitoviding m'oreaefficientidissipation'iof heat byeconvection.

nnotherzobjectaandtaccomplishment;of UhiSz-illven'tion .is to :provide .-a refrigerating @system in whichathe superheat l is ;-removed from it'he-tcompressed gas before being discharged intottheilu- #bricantwseparatingtchamber. V

1 A :furthen object and -accomplishment ,of the ..-inventionh.is to provide ans improved refrigeration system; having incorporated Itherein protision lifor motor .:and compressor l "coolingand, in ,aiddition vthereto, an "improved condenser, .lsaid fim'proved elements "cooperatin "andbe'irig 'efiective'to 'pro- 1951, Serial -No. k2223084 2 =duce;efiicientoil separation so that oil islcept out not the low side of :the system and the emciency of the system is not-reduced by circulating Jaljge amounts of oil through the evaporator.

anancillary object and 'accomplishmentzoi the invention is itoprovide amore efiicientrefriger- ,atin system having incorporated therein a new and improved condenser which is adapted .to be economically manufactured and whicn iszso designed as to permit the imanuiactnre and assembly {thereof in accordance with present -;day lalfge scale mass production ,manufacturing (methods of ;construction and assembly.

The invention seeks, as a final ;.object-,and= accomplishment, to provide-a refrigerating system which includes an improved condenser particularly characterized by ;a design arrangement to more a eously nd sat sfact rily p r o m the functions required of litand adapted to provide a compact unit which :will successfully; com- ;bine the factors of structural simplicity and durability and ,yet be: economical to manufacture. Additional objects, ,features and advantages of the invention disclosed herein -.willibe apparentjzo :persons skilled in ,the art after the; construction and operation are understood from the -;within description.

,It;.is preferred to 5accomplish the rvarious objects of-this invention and to practice the same substantially, as, hereinafter; more flullydeseribed,

" :and as-more, particularly pointed tout inthe apgpended claims.

Embodiments of the invention ;are illustrated in "the accompanying drawings :for-ming a apart .hereof and wherein:

,Fig. =11is a side-elevational viewofa partflof :a -.refrigeration system and disclosing :the 10. denser embodying the features of the presentiin- :vention; I

Fig. 2 .is a .front elevational vview of the .-,cons-densendepicted in i 1;

.Fig. 3': is ayfragmentary perspective view of the condenser d picted in-Fie. .11 and; illu tratin 3 5. :sp'e'cificz associationzof theparts of the condenser -Fi'g.=-"4 diagrammatically:illustratesxa refrigeration system m -which the condensed-contemplated by this invention may advantageously loe employed; v

Figfi5 is -a fragmentary sectional view -of the condenser tubing and rod arrangement-depicted in FigJ-B;

' Fig-'6 isa fragmentarysectional-view-of a modified form of condenser tubing and *rod --arrange- -'-ment and Fig. -'7"-is -a 'fragmentary v-ievwof -a conventional 3 prior art finned condenser illustrating the path of air flow therethrough by convection.

The drawings are to be understood to be more or less of a schematic character for the purpose of illustrating and disclosing typical or preferred forms of the improvements contemplated herein and in the drawings like reference characters identify the same parts in the several views.

Referring to the drawings, particularly Figs. 1 and 4, there is illustrated a sealed motor cornpressor unit designated in its entirety by the letter A and including a motor housing indicated at 29 and a compressor housing indicated at 21.

The sealed motor compressor unit A may comrise a part of a refrigerating system of the compressor-condenser-expander type, such as' diagrammatically illustrated in Fig. 4, and wherein the refrigerant is circulated by means of the compressor disposed in the housing 2 I, through a condenser indicated in its entirety by the numeral 30 and with which the present invention is particularly concerned, for extracting or dissipating heat by convection from the refrigerant medium and thence to a freezer or evaporator B in which the refrigerant medium is expanded or vaporized for absorbing heat and the refrigerant medium is thereafter returned to the compressor from whence the cycle is repeated.

Suffice it to say, since the invention is not particularly concerned with the precise construction of the complete refrigerating system and/or its associated parts, they will not be further described in detail, and it is deemed sufiicient for all intentions and purposes herein contained to show only portions thereof adjacent to and cooperating with the condenser 38 with which the invention is particularly concerned. It is to be understood that details of construction of such refrigerating systems and/or their associated parts may be modified to suit particular conditions or to satisfy the engineering genius of various competitive manufacturers, and I do not wish to be limited to the construction of these elements as set forth except where such construction particularly concerns the invention contemplated herein.

Having thus described, by way of example, a possible adaptation of the condenser 35 and having described the general environment surrounding the adaptation, the specific construction and function of the parts of said condenser when disposed in the refrigerating system hereinbefore described, will now be described in detail.

In general, it may be stated, that an ancillary function of the improved condenser construction contemplated by this invention is to act as a cooling device for the motor of the motor compressor unit.

This is advantageously accomplished by the provision of the cooling coil 3 I, portions of which are directly associated with the condenser as and interconnected with the compressor and which are so arranged to receive the refrigerant directly from the compressor in a first phase of operation wherein there are employed principles of operation whereby the superheat of the refrigerant gas is unloaded by convection in the ambient outside the compressor proper by means of the cooling coil 3 l, the unloading of the superheat of the refrigerant to the air in this manner offering the advantages of not adding unnecessary heat to the motor disposed within the motor housing of the motor compressor A, thereby permitting the motor to run cooler. The cooling coil 3! is designed to provide the advantage in that a small portion of the refrigerant contained therein may be changed to condensate and the heat absorbed by the refrigerant from the motor and required to reheat this liquid upon its reentry into the com pressor dome as illustrated in Fig. 4 and which will be more fully described hereinafter, will fur-- ther reduce the operating temperature of the motor compressor unit, thereby to provide reduction in head pressure, improved torque feed performance of the motor and improved operating efiiciency of the motor.

Attention is directed to Fig. 1 wherein the condenser 30 with which the present invention is particularly concerned is illustrated in its operative position in conjunction with a compressor A and secured to the back wall M of a refrigerator and arranged at a slight angle as shown, the importance of which will be hereinafter described in detail, said back wall of the refrigerator being disposed in spaced relationship to a wall 4| of a house or the like to provide therebetween an air tunnel 42 through which air currents may pass for contact with portions of the condenser by convection.

In the exemplary embodiment of the invention depicted in Figs. 1, 2 and. 3, the condenser 35 with which the present invention is particularly concerned comprises, in general, a first serpentine shaped coil 3! herein before described as being a part of a cooling device for themotor-compressor unit, and a series of serpentine shaped coils generally indicated at 35 adapted to receive the refrigerant from the head of the motor housing 20 in order to cool the same and dissipate the heat before the refrigerant is directed to the evaporator, said coils 3| and 45 having welded thereto in staggered relationship as shown a plurality of rods generally indicated at 41, said rods being I disposed in thermal contact with the coils 3| and 45 in order to provide additional surface area for contact with the air currents flowing therethrough thereby to provide a more effective heat transfer by convection.

Brackets 5|, 52, 53 and 54 are suitably secure to the rods as shown and these brackets are provided with means for securement thereof to brackets 55 and 56 carried by the rear wall 40 of the refrigerator.

Particular attention is directed to Figs. 3 and 5 which show the general relationship of the coils 3| and 45 with respect to the rods 41. These rods are disposed in staggered relationship so that the air currents flowing therethrough will define a foil section air flow (Fig. 5) to more effectively wipe the surfaces of the coils 3| and 45 and the rods 41 because the air currents may pass through these elements without unusual restriction and absorb heat therefrom more effectively because all of the surfaces ofthese elements are clearly exposed to the naturally flowair currents and after the air currents have wiped the surfaces of one element they pass off and away from any of the other elements without coming in contact therewith, this action will prohibit any heat taken off one element from being deposited on an adjacent element. Moreover, the air currents will be cooler in that the flow through the elements is natural and unrestricted.

Heretofore, condensers were constructed with finned elements having a substantial area because it was thought that the more area provided for contact with the air currents the more effective would be the transfer of heat from'the elements to the air flowing therethrough. These assumes piioraitfl' n'n' eueaziseas'ers were effective seizin a air was rereeuf-tnrtugh the eoiraenser byzmetms fans or the like which would asse-re pro-per wiping 0': all the-surfaces of the fins.

-It has been found desirable refrigeration c'o'nstruc'uen of recent msnuracture to eliminate forced air systems and he like anil' to rearrange Becaus'eofthe inherent oharacteristics of construction of the finned condenser in providing isolated channels (Fig. 7-) through which the air currents must flow, it was found that the heat'wasnot dissipated f rom the condenser and that the'finned elements provided certain chambers which locked or directed the flow of air in a streamline path as shown-in-Fig. 7 which remsulted in directing the air away from much -of the exposed areas of the fins to cause overheating of the condenserandasubstantial reduction in the 'liat transfer from the condenser to the air warrants.

In the present invention the deficiencies found in the prior art finned constructions have been overcome in that the natural air currents define a foil section about the rods 41 and are free to fiow through the condenser and to wipe thoroughly all of the surfaces exposed which tend toward a more efficient dissipation of heat from the condenser to the air currents.

In reviewing Fig. 1 it can be seen that the air currents enter from the bottom of the refrigerator for passage upwardly through the tunnel 42 into contact with the condenser by convection which is a disturbance of the atmospheric equilibrium by ascensional and expanding heated air, thus causing a wind system by the underflow of cooler air. Since heated air by its nature will flow upwardly the air currents drawn through the tunnel 42 will flow upwardly drawing fresh air from underneath the refrigerator in the direction indicated by the arrows. Particular attention is directed to the angular disposition of the condenser 30 with respect to the rear wall of the refrigerator. This angular disposition permits more effective wiping of the coils 3| and 45 and the rods 41 by the air currents flowing through the tunnel 42. Moreover, after the air currents have contacted the condenser elements to define a foil section air flow, it flows outwardly therefrom (Fig. 5) and is free to continue its flow upwardly in the tunnel 42 without recontacting any of the elements of the condenser. This is important in that once heat has been dissipated from the condenser elements to the air currents it is never redeposited on any of the condenser elements. Furthermore, this action results in a rapid dissipation of the heat from the condenser elements to the air currents. Another important advantage is that the dissipation of heat from the condenser elements to the air currents is more uniform over the entire area of the condenser in that fresh air currents contact all of the surfaces uniformly and, aftersuch contact, leave the ecndenserfiarea formassage ubwsrdlyitmnugh and out of' the tunnel 1'2.

' Thus it ean be se'e'n that substantial exposed "areas "of the pr.ior art innned -type constructions the entire' a'rea 'thus' -exposed thoroughly wiped bylthe :aircurrents -(l ig. 6*) "which results a rapid*dissipation 'of ith'e hat drom the condnse'r to the air currents byi'convection.

[n' som'e 'applications it-zm'a'y'ibe to advantage :to

employ J'a condenser tubing Zo'f -irregular 'sha pe as iilustrateii :in Fig. 6. condenser rods el,

cfr-igerant vapor.

"which may be *of substantially similar construction to that *discl'osed with respect :tothe mods 4*? of the -c'o'ndenseribonstruction depicted :inEig. l3, may be suitably welded it-"o the tubing in'dshe undulations defined by theiirregula'r shapeofithe tubing 'The'impor'tanceof tlie irregnlar shape in the condenser tubing is obviousthat turbulenc'e in the gas-flow will b'e caused to result in a better K factor for superheated and 'saturatedtre- It has been found that when the fiow 'of the refrigerant vapor through the tub- :ing is disturbed better wiping contact i'a'ction "with the surfaces of the tube is established and thereforea more eiiicient'fiheat transfer:from"theh'ei rigerant to the tubing is accomplished.

The instant condenser construction being formed of relatively simplefparts 'facilitating 'ea-se assembly and maintenanceilentisiitselfito ma-s8 productionmanufacturing principles, thustifiording a substantial saving in the manufacturing cost and a substantial saving in repair and maintenance.

From the foregoing disclosure, it may be observed that I have provided an improved condenser construction which may be employed to advantage, for example, to a refrigerating system and which efficiently fulfills the objects thereof as hereinbefore set forth and which provides numerous advantages which may be summarized as follows:

1. structurally simple, efiicient and durable;

2. Economical to manufacture and readily adaptable to mass production manufacturing principles; and

3. The provision of an improved condenser construction by eliminating expensive finned prior art condenser arrangements and employing a plurality of relatively inexpensive rods disposed in thermal contact with the tubes of the condenser, this construction affording a substantial reduction in the cost of manufacture and yet providing more efiicient dissipation of heat by convection.

While I have illustrated preferred embodiments of my invention, many modifications may be made without departing from the spirit of my invention, and I do not wish to be limited to the precise details of construction set forth but wish to avail myself of all changes within the scope of the appended claims.

I claim:

1. In a refrigerating system, having an evaporator and casing means forming a chamber within which a compressor is disposed, a refrigerant superheat removing coil, an outlet from said coil discharging the partially cooled refrigerant into the chamber, a condenser, an outlet from the chamber through which the compressed refrigerant is discharged into said condenser, fluid flow connections between said condenser, evaporator, and compressor, said condenser comprising a ser-. pentine coil adapted to contain refrigerant, means mounting th loops of said serpentine, coil and superheat removing coil in substantially a single plane disposed at a small acute angle to the vertical, and the means providing additional surface area for contact with air currents comprising a plurality of straight rod-like elements, means mounting some of said elements in contact with first surfaces of said serpentine and superheat coils each of which first surfaces face in the same direction, and means mounting the remainder of said elements in contact with surfaces of said coils opposite to said first surfaces andin staggered relationship to said elements in contact with said first surfaces of said coils whereby air currents passing upwardly and through said condenser by convection define a foil section to wipe the surfaces of said coils and said rod-like elements.

2. Refrigerating apparatus comprising a motor compressor unit for increasing the pressure of refrigerant fluid exhausted from a refrigerant evaporating unit and a housing enclosing said motor compressor unit provided with a chamber, a first condenser for receiving the fluid discharged from the high side of the compressor and having communication with the chamber for delivering liquid refrigerant and gas thereto for absorbing heat generated by the motor compressor unit, and a second condenser connected to the chamber for receiving the refrigerant therefrom and converting it into liquid refrigerant, said second condenser forming a part of said first condenser,

, 8 means mounting said first and second condensers in substantially a single plane disposed at a small acute angle to the vertical, and means providing additional surface area for contact with air currents comprising a plurality of straight rod-like elements, means mounting someof said elements in contact with first surfaces of said condensers each of which first surfaces face in the same direction, and means mounting the remainder of said elements in contact with surfaces of said condensers opposite to said first surfaces and in staggered relationship to said elements in contact with said first surfaces of said coils whereby air currents passing upwardly and through said condensers by convection definea foil section to wipe the surfaces of said rod-like elements. I

JAMES R. HORNADAY,

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,160,018 Higham May 30, 1939 2,280,554 Steenstrup Apr. 21, 1942 2,420,442 Rataiczak May 13, 1947 2,445,988 Ayers July 27, 1948 2,462,511 Kramer Feb. 22, 1949 2,469,635 Dalin et a] May 10, 1949 2,620,170 Brickman Dec. 2,- 1952 FOREIGN PATENTS Number Country Date 452,231 Great Britain Aug. 19, 1936

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