US2768508A

US2768508A - Refrigerator condenser

Info

Publication number: US2768508A
Application number: US345569A
Authority: US
Inventors: Robert H Guyton
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-03-30
Filing date: 1953-03-30
Publication date: 1956-10-30
Anticipated expiration: 1973-10-30

Description

Oct. 30, 1956 R. H. GUYTON REFRIGERATOR CONDENSER 4 Sheets-Sheet l Filed March 30, 1953 Oct, 30, 1956 R. H. GuYToN 2,768,508

REFRIGERATOR CONDENSER y Filed March 30V, 1955 4 Sheets-Sheet 2 |l|l|lllllllllllllIIIIIIIIIIIlllllllllllllllllllllllllllllllllll J Il v )j P/If INVENTOR. 'Raaf/vr /f @afro/v Y W] 4a R. H. GUYTON REFRIGERATOR CONDENSER Oct. 3o, 1956 A 4 Sheets-Sheet 3 Filed March 30, 1953 5 JNVENToR. @oaf/er /f 6u rra/v Oct. 30, 1956 R. H. GUYToN 2,768f508 REFRIGERATOR CONDENSER Filed March 30, 1953 4 Sheets-Sheet 4 MQ? I INVENTOR.

055?? H. 60 Y7'0/V BY a @M4/9% iM REFRVIGERATOR CONDENSER Robert H.- Guyton, Lima, Ghio Application Marchl), 195,3, SerialNo. 345,569

- 12 Claims. (Clf.62115) VThisinvention relates to arefrigerator condenser and morevparticularly to a condenser'having a` higher rate of condensation capacity per unitl of surface larea and in whichis incorporated anovel principle of condensing acs tion.

erally in a flat plane. self is insuiicient to eXtricate all` the heat necessary .to

Refrigeratingy condensers as presently constructed for use inthe conventional compressor-condenser-eXpander circuit are usually in the form of a round tube vof suicient cross sectional area to accommodate the volume of gas that has to iiow through it withoutany appreciable pressure drop. The tube is usually provided with a series ofreturn bent portions so that the condenser lies gen- The surface area of the tube itcondense-the gas, and it is the usual customthereflore to provide a plurality of closely spaced fins which serve as secondary cooling surfacesl A condenser of this type ynet .only occupies a relatively large volumeof space but even more serious a problem is the fact that after the condenser has been in luse for a relatively short period n of timethe space between ,the tins becomes clogged with n lint and dustl and the condensing action is seriously impaired. In order to obtain` the necessary cooling with condensers of .this type, it has been found necessary v toprovicie as many as twenty or more ns per each lineal inchof condenser tube.

The natural tendency for such condensers to become clogged is obvious.

Aside from the mechanical design of conventional condensers, there is associated with such condensers another objection, namely, the fact that condensation of the gasev ous refrigerant within the condenser tube occurs through a thermo-Siphon action. A thin layer of gas adjacent the. inside surfaceof-the tube is iirst -cooled and condensedand before further condensation and cooling take place,y this cooled .or condensed layer of .gas must be -V displaced by another layer of gas which moves radially I fromthe central portion of the tube. that thismethod of condensing gaseousrefrigerant into s liquid refrigerant is ineiicient.I In anetiicient condensation action, tiny seedsor droplets of Arefrigerant are formed throughout the condenser, and these .seeds in I have determined turn cause further condensation either by attracting gaseous refrigerant or by absorbingv the heat from the surrounding gas to thereby cool the same.

' Another feature of refrigerating condensers as presently constructed which should be mentioned in connection with the present invention is that such condensers are always designed to producerno appreciable pressure drop across the. condenser. -It has been believed that a drop inpressure across the condenser wouldproduce'a cora respondinglowering Lin the eiiciencyof the condenser. It hasgalso been believed that, if the head pressureon the condensing unit is raised above a predetermined value, ,the -eiciency of l the condensing. u nit ,would likewise, be A decreased..

l It anobjectof this invention to provide acondenser construction which is more efficient thancondensersfof conventional construction described above.

United States Patent@ 2,768,508 lia-treated ,Ostffn 1.956

A further. object: of this inventionresides v infthe .provision of a condenser which isof economical construction and which can be made very lcompact so as .to occupy n a minirntun of space.

A further object of this invention resides in the provision of a condenser which is not susceptible of becoming clogged by dust, lint, and the like.

i. have discovered that the condensing action within a condenser can be materially increased. by constructing the condenser so that ythe passagewayl lfor refrigerant povided bythe condenser is relatively long .and thin.` The Walls of the condenser'are spaced apartfso that the. .jrefrigerant passing therethrough is Ain theform ofv a kvery thin layer, these walls being relatively wide as compared .with thespacing between thewallssothat a maximum amount of cooling surface isprovided yfor the refrigerant ,flowing through theseywalls.

. Furthermore, I have found that the condensing action can be materiallyincreasedby increasing the velocity offlow through the condenser, vand this increase in velocity of ow can be produced by constructingthe condenser so that there ywill be a substantial `drop in .pressure .across the condenser. The condenser is constructed so that this vdrop in pressure will be uniform along the extent ofthe condenser.

In the drawings: Fig. 1 is a perspective .view ofone form of condenser embodying thepresent invention.

Fig. 2. is an enlarged fragmentary view of a portion of the condenser shown in Fig. 1. Y

Fig. 3 is a view similar tolig.' 2 and showing another former" construction of .thecondenser side walls.

Fig. 4 is a fragmentary enlarged sectional View along the'line 4.-4 in Fig. 3.4

Figs. 5 and 6 .are Vviews Isimilar to Fig. 2 and showing y further modications. inthefside wall construction .of

the condenser of this invention.

Figs. 7 and 8 are diagrammatic views illustrating the difference in the condensing action that occurs in a' condenserof conventional construction as compared with a condenserand'blower. embodying another form of the present invention.

Fig. 12 is aperspective view of a condenser and compresser combination illustrated in another form of the present invention.

The condenser illustrated in Figs. l and 2 comprises a spiral 10 formed offlattened tubular shape having an inletA fitting at 12l and an outlet'tting at 14. Intermediate :the ttings the spiral is formed with two at Walls 16 and-18 which (are, joined along their edges as at 20 by seam welding or thelike. `The wall 16 may .be provided with a plurality Yof indentations 22 at spaced kintervals along its width and length which are in contact with-.,thegwall1-18. `'Iheseindentations 22 may be spot welded to the wall 18 if desired, but I have found that with the,` spirally vshapedcondenser. such .as illustrated at .10v spot `welding atl the.` indentations 22 is yunnecessary.

. The curved-contourof the two walls 16 and `-1S ma in n tain *theL indentations ,22pmy contact4k withv AtheA wali .18.

te@ fromheet metal .by

staking two stripe-.terreinen .0 them .tQ..-r. 2t1tsuf illustrated at 16, and seam welding or otherwise welding the plates together at the edges 20. The assembly may then be bent into the form of a spiral and the inlet and outlet fittings 12 and 14 brazed or otherwise secured to the open ends of the spiral.

In order to obtain the maximum benefits from the present invention the condenser should be designed with respect to the system in which it is to operate so that a very high velocity of gaseous ow through the condenser is achieved. The spacing between the

walls

16 and 18 is only slightly larger than the space which will permit capillary action of the liquid to occur. When a condenser of this construction is connected to the usual refrigerat ing circuit, I have found that the condensing action is materially increased per unit of condenser area and furthermore that this results in more efficient operation of the refrigerating system. This may be attributed to several features in the design of my condenser construction.

In the first place, by spacing the

walls

16 and 18 very close together, the refrigerant is caused to flow through the condenser in a very thin layer and is in contact with a maximum area of cooling surface. Thus, the entire layer of gaseous refrigerant owing through the condenser can be cooledsubstantiallyinstantaneously as cornpared with a round tube condenser of conventional construction where the cooling throughout the cross section of the tube necessarily depends upon a thermo-Siphoning action. Furthermore, the spacing of the

walls

16 and 18 creates considerable friction and tends to produce a drop in pressure along the condenser. This drop in pressure increases the velocity of flow through the condenser and at the same time increases the rate of cooling of the hot gaseous refrigerant flowing through the condenser.

Another feature of my design which is believed to be important is the spiral shape of the condenser. This shape prevents the refrigerant from owing in a straight line. The refrigerant continually impinges against the

walls

16 and 18 and small droplets of liquid are caused to form which act as seeds which absorb heat from the surrounding gaseous refrigerant and encourage the further condensation of additional particles of gas into liquid.

Still another feature of the construction shown in Figs. l and 2 which is believed to be important from the standpoint of increasing the eiciency of the condenser resides in the provision of the indentations 22. In the rst place, these indentations form obstructions to the flow of gaseous refrigerant through the condenser and thereby produce a further impingement of the gaseous refrigerant against cooling surfaces. These indentations are also important from another standpoint. Although the

walls

16 and 18 contact one another at the indentations 22, it is impossible from a practical standpoint to prevent gas from entering the minute spaces between

walls

16 and 18 at the indentations 22. The gas which flows into these tiny spaces is immediately condensed and the pressure is locally reduced, thus causing additional gas to ow into these spaces and driving the liquid out into the larger passageways between the

walls

16 and 18. As the liquid is driven out from between the indentations 22 and the wall 18, this liquid absorbs heat from the surrounding gaseous refrigerant and produces additional condensation. With this arrangement the condenser is maintained in a wet condition substantially throughout its length as compared with a conventional condenser which is wet only through the lower portion thereof.

The difference in the condensing action between a condenser of this invention and a condenser of conventional construction is illustrated diagrammatically in Figs. 7 and 8 wherein a conventional condenser in the form of a round tube provided with return bent portions is shown at 24 in Fig. 7 and a condenser constructed in accordance with this invention as shown at 26 in Fig. 8. In the showing of Fig. 7 a compressor is indicated at 28 and the condenser 24 is shown connected to the head of the compressor. Using Freon 12 as refrigerant under one set of normal operating conditions, the pressure in the head of the compressor, which for the purpose of illustration is indicated by a gage 30, might momentarily reach 180 pounds and the pressures at successive points along the condenser as indicated by

gages

32, 34, 36 and 38 will normally be quite uniform, perhaps at 150 pounds gage. Adjacent the inlet end of condenser 24 the refrigerant would be substantially completely gaseous as indicated by the legend and adjacent the outlet end of the condenser the refrigerant would be substantially completely liquid. At a point perhaps one-third the distance from the outlet end of the condenser, at the location of gage 36, the state of the refrigerant changes to predominantly liquid.

With my condenser operating under the same conditions shown in Fig. 7, the pressure at the head compressor 28 might likewise be in the neighborhood of 180 pounds gage as indicated by gage 30; but due to the construction of my condenser, the head pressure on the condenser as indicated at gage 32 would probably be in the neighborhood of 160 pounds gage and the pressure would gradually drop along the compressor so that at gage 34 the pressure would be in the neighborhood of 150 pounds; at

gage

36, 145 pounds; and 140 pounds at the outlet end of the condenser as indicated by gage 3S. The condenser 26 would contain a substantial amount of liquid refrigerant from substantially its inlet 40 throughout the length thereof to the outlet 42. Thus, in operation the head pressure in my condenser is substantially higher than in a conventional condenser, and there is a substantial drop in pressure across my condenser as compared with no appreciable drop in pressure across a conventional condenser.

As an illustration of the results obtainable by this construction, tests have been conducted in comparison with a conventional finned tube condenser. Both condensers were connected with identical A H. P. motor compressor units. At F. room temperature and at 15 F. suction gas temperature using a 9 inch blower fan, the unit using my condenser showed a head pressure of 162 pounds per square inch. Under the same conditions, the unit with a standard finned condenser showed a head pressure of 148 pounds per square inch. However, the wattage of the unit with the spiral condenser was 354 watts while the unit with the standard condenser was 365 watts. The pressure drop through the spiral condenser was 8 pounds per square inch whereas it was negligible in the finned condenser. In this case, the spiral condenser consisted of a three inch wide (two inch effective surface) steel strip approximately ten feet long and wound to a spiral form of about nine inches outside diameter. Thus, the total radiating surface was 5 square feet. The finned condenser was formed of 221/2 feet of 3s inch tubing having six tins and providing a total radiating area of 20 square feet.

To further illustrate the difference in operation of a refrigerating unit employing a condenser constructed in accordance with this invention as compared with a condenser of conventional construction, there is set forth in the table below various operating conditions of two refrigerating units identical in every respect except the condenser. Both units were operated by means of a 1A H. P. motor at 90 F. room temperature with -a 9 inch fan. The condenser of the present invention was identical with the condenser described in the paragraph above having a total radiating surface of 5 square feet and the other condenser was similar to the one described in the paragraph above but having a total radiating surface of 25 square feet.

grag'lesgsos eachfof the operating pressures set forth in the .above tablethereV was `no appreciable pressure drop across the condenser of conventional design. Using the l above-described condenser on a 1/3 H. P. unit, it was `I'rfound that in. a '90 F. room` with a head pressure of l 157; pounds: the pressure at the outlet end of the condenser was about 109 pounds, at 172 pounds head pres- 'fzsure'fthe outlet pressure-was 110 pounds, and at 183 ',cpounds headipressure the pressurey at the outlet end was 115 pounds. Ij have ldetermined that a dropin irpressure `across the condenser of -as Vlittle as 2% of the head pressure produces the desirable operation described Vwherein. `ffI-Iovvever, adrop in pressure of at least of ff-the-head lpressure is' preferred.

`f The above Idata shows that with `my condenser the :"-rhead'fpressure was-'increased While at the same time therefriger'ating system required less wattage and thus 'fvvasfmorezeiiicientV as compared with the conventional -fcondenser. YwWithfa higher head pressure as indicated 1 above, it isobvious that the temperature of the gasentering'thexcondenserY of my construction was higher than `the'temperaturezof the gas entering the condenser of conventional construction. Thus, with my construction there is agreater differential rin temperature between'the refrigerant ,in the condenser near the inlet .end thereof Liandvthe ambient 'temperature within the room where thefunit: is flocated. Condensation is .produced by re- ;nmovingafthe."superheat from the .gaseous refrigerant, @and I'. haveffound .that this superheatcan be removed :'more quicklyrandtmore eciently when `the temperature differential isxgreater. Thus, with a condenserv of my construction condensation of the liquid begins to occur at the inlet endof the condenser and progressively. in- 1' creasesizin the direction .of the outlet end. At the same ftime the pressure in the condenser gradually decreases "lin adirection toward the outlet end.

Ihavelifound by experiment that with a condenser of ii".my-construction I am actually able to obtain "super-'cool-y .fing ofthe. refrigerant in the condenser, that is, by reason G'ofrthe rapid condensation which takes place in a con- .ll densenconstructed. in accordance with .this invention,

the refrigerant can be cooled to below the ambientV temperature of the room; and a re-expansion of the liquid into gaseous refrigerantmay beobtained. Accordingly, the construction shown herein maybe designed to form a 4continuous path, a portion of which serves .as a con- NUdenser and another portion of which serves Yas an evap- .-.orator.

`/-This arrangement is shown in Fig. 9 wherein .the -conduit44, which is fashioned in the manner illustrated in-Figs. land 2, has one portion 46 thereof wound spir- Vally into the shape of a condenser and connected as Yby a--conduit V48 with the high side of a compressor 50.- Anotherportion of conduit 44 is fashioned into an evaporator'52 which is connected as by a conduit 54 with the low side of compressor 50. An intermediate portion 56 serves to connect the condenser portion 46 with the evaporator portion 52 and serves a function similar to the capillary tube used in conventional refrigerating systems. By proportioning the size and length of the several portions of conduit 44, the system may be operated so that the refrigerant is condensed in condenser 46, the pressure of the liquid refrigerant substantially fr reduced inthe-portion -56,f.and causedk to `boil. inthe evaporatorY portionxSZ. ..Withfthis.ar1'ange1nent it will be l:observed/that a single conduitserves as the means for .condensingthe gas. into a liquid, for reducing they pressure thereof, and` for re-expanding the liquid.

,It will be appreciated that the invention here may take y.various forms,.the gist of the invention primarily residing in the closely `spaced walls of thefcondenser which are `preferably fashioned so that throughout the length of the condenser portions the two side walls are in contact Vor Vsubstantially in contact so that condensation is pro- .moted For example, there is shown in Fig. 3 another forrnof. `condensing unit wherein the passageway is lfornred by two

sidewalls

58 and 60 which are seam welded along their edges as at62. Side wall 60zis held in closely spaced relation from side wall `58 by a plu- :rality of indentations .64 which are preferably spot Weld- .ed atthe center Athereof as'indicated aty 66 to the side Wall .53. As an example vof the dimensions of the condensing passageway, a condenser constructed with side walls ten feet long, three inches wide and with a spacing between the sidewalls of approximately 5/32 of an inch "performs very .satisfactorily in a refrigerating unit em- Yploying a 1A.; .H.-P. motor. :ferred-in order to hold the two side walls in a generally The spot welds 66 are prey:spaced .apart relation.

Lln Fig. 4 the-crosssection of the unit' shown in Fig. 3

1 is illustrated. The passageways between indentations 64 rare 'designated 6% .andit will be appreciated that fine .z crevices `are bound to be .present between the indentations yt y 64 ;and=the.adjacent portionvof side wall S3 in which .fgaseous refrigerant will ow.

These crevices indicated VinpanV exaggerated manner at .70, provide a relatively `zlarge coolingV surface for avery `small volume of gas.

' Thus, as soon las. the gaseous refrigerant flows into these small. crevices,"^the .gas will be immediately :condensed :thereby reducing the pressuredn'these crevices and causing additional refrigerant gas to ow therein and drive out the condensed refrigerant. The refrigerant droplets dr1ven from 1the crevices'7t) into the passageway 68 will .'absorbheat from the surrounding gaseous refrigerant and 4 promote further condensation.

1.Alternative'constructions Vfor thecondenser unit are shownfin `Figs. 5 vand 6. ln Fig. 5 side Walls '72 and '74 are welded together along their longitudinal edges at 76, land the side wall 74 is provided with -a series of corrugations27S between which vthe side walls are spot welded "stogether asfati-fid.v VIn the showing in Fig. 6 one side wallSZ is provided with a series of Zig-Zag indentations f-84 which are 'spot welded at successive points indicated at 36 to the other-side wall 88. In each of these constructions small crevices 'are formed in the area surrounding the spot welds which promote the condensing action referred to above with reference `to Figs. 3 and 4. Where the condenserA is `to-be'subjected to forced or induced-air circulation, improved action may be obtained by so forming the spiral as to-shroud themember which induces air circulation. Thus, in Fig. l0 a motors driven screw blade fan 90 is mounted ladjacent the face ofthe spiral yand the outer turns 94 of the spiral are Y displaced laterally of the plane of the inner turns so as jto` shroud the tips of the fan blades and take advantage lof the `air circulation which spills off the ends of the fan tips.

In Fig'. '1l a blower 96' of the Sirocco type is provided with a housing 98 in which a spiral condenser 190 forms a multiple convolution exit path for the output The edges of the spiral condenser are enclosed by -tlat -discsfltlZhaving 1an airintake opening at the axial center thereof to receive the compressor unit 108. The spiral 60, being mounted in a horizontal plane surrounding the compressor unit 108, is in the path of the up-draft induced by the heat of the compressor and also by the heat given olf by the condenser.

Thus, it will be seen that I have provided a condenser construction which possesses distinct advantages over the condenser construction of conventional design. My condenser unit operates more efficiently. It requires less radiating surface as compared with a conventional condenser of the same capacity and occupies a smaller space. Furthermore, the condenser of my construction is designed so that it will not become :clogged by dirt and lint which ow past the spirals or coils of the condenser. No closely spaced radiating tins are required 4to provide the necessary cooling surfaces.

This application is a continuation-in-part of my prior application Serial No. 733,524, filed March l0, 1947, covering Refrigerator Condenser, now abandoned.

I claim:

1. A refrigerating system of the condenser-evaporatorcompressor type characterized in that said condenser comprises a relatively long enclosed passage having an inlet and an outlet, said passage being formed with substantially dat parallel sheet metal walls which are generally spaced apart in close proximity and substantially uniformly throughout the axial extent of said passage a dis tance greater than a distance such as to feed refrigerant by capillary action but being spaced suiciently close together such that the predominantly greater portion of cross section of the refrigerant vapor flowing therebetween is scrubbed by said walls and the friction resulting from said scrubbing action produces decreasing pressure along the condenser so that the drop across the condenser is at least substantially of the head pressure of the refrigerant at the inlet of the condenser at 98 F.

2. The combination set forth in claim 1 wherein the passage formed by said sheet metal walls is arranged as a spiral.

3. The combination set forth in claim l wherein at least one of said sheet metal walls is provided with indentations intermediate the edges of said sheet metal Wall which are in contact with the other sheet metal wall to provide obstructions to the flow of refrigerant through said passage.

4. The combination set forth in claim 3 wherein said indentations are generally in coplanar engagement with said other Wall and provide extremely small crevices therebetween into which gaseous refrigerant is permitted to low, the walls of said crevices being so closely spaced that the gas flowing into said crevices is substantially instantaneously condensed.

5. The combination set forth in claim 4 wherein said side walls are spot welded together at said indentations.

6. The combination set forth in claim 5 wherein the area of said indentations is substantially greater than the area of the spot welds.

7. A refrigerating lsystem of the `condensenevaporatorcompressor type wherein said condenser and said evaporator comprise a relatively long enclosed continuously extending passage having one end communicating with the high side of the compressor and the opposite end communicating with the low side of the compressor, said passage being formed of sheet metal walls and being generally divided into three serially connected portions, the portion of said passage connected with the high side of the compressor forming said condenser, the portion of said passage connected to the low side of the compressor being shaped to provide said evaporator and the intermediate portion of said passage forming a connecting conduit between said condenser and said evaporator, said walls being sufficiently closely spaced throughout their length to produce a pressure drop across the extent of said passage which is substantially equal to the difference in pressures between the high and low sides of said compressor, said intermediate and evaporator portions of themselves serving as a means for reducing the pressure of the refrigerant from the high to the low side of the system and the walls of said portion of said passage forming said condenser being suiciently closely spaced to produce a drop in pressure across the condenser of at least 2% of the head pressure of the refrigerant at the inlet of the condenser at F.

8. The combination set forth in claim 7 wherein at least one side wall of that portion of the passage which forms said condenser is provided with indentations which Contact the other side wall of said passage.

9. The combination set forth in claim 7 wherein at least one side wall of the portions of said passage which forms said condenser and said intermediate connecting portion is provided with indentations which contact the other side wall of said passage.

10. A refrigerating system of the condenser-evaporator-,compressor type characterized in that said condenser comprises a passageway having an inlet and an outlet, the passageway being dened by sheet metal walls which are spaced apart in close proximity throughout a major portion of the axial extent of said passageway a distance greater than such as to feed refrigerant by capillary action but sutciently close together to produce a vigorous scrubbing action of a predominantly greater portion of the gas owing therethrough and produce a substantial pressure drop across the condenser, said walls having a plurality of indentations therein, said walls at said indentations being spaced apart in extremely close proximity such that the gas flowing therebetween from said areas of close proximity is .immediately condensed thereby producing localized low pressure areas at said indentations into which surrounding gas rapidly flows to drive the condensed refrigerant out into the surrounding gas where it re-expands, thus producing further condensation and tending to maintain the walls of said condenser wet throughout the axial extent of said passageway.

11. The combination set forth in claim 10 wherein the portion of said Walls in close proximity and the portion of said walls in extremely close proximity are sufficiently closely spaced to produce a pressure drop across the condenser of substantially at least 5% of the head pressure of the refrigerant at the inlet of the condenser at 90 F.

12. The combination set forth in claim l1 wherein the spacing of the portions of said wall in close proximity is approximately /gg".

References Cited in the file of this patent UNITED STATES PATENTS