US2610476A - Art of congelation and apparatus for use in connection therewith - Google Patents

Description

1 7 NON c. FIELD 2,610,476 ART OF CONGELATION AND APPARATUS FOR USE IN CONNECTION THEREWITH 5 Sheets-Sheet l INVENTOR i; Crosby Fi'eiol BY I fl @1 3 A r ZRNEY Sept. 16, 1952 Filed Aug 15, 1940 A A N:

Sept. 16, 1952 c. FIELD ART OF CONGELATION AND APPARATUS FOR USE IN CONNECTION THEREWITH 5 Sheets-Sheet 2 Filed Aug. 15, 1940 N ww/ m N 8 A l Sept. 16, 1952 c, E D 2,610,476

ART OF CONGELATION AND APPARATUS FOR USE IN CONNECTION THEREWITH 5 Sheeis-Sheet 3 Filed Aug. 15, 1940 -C INVbENTOR 1d 7'08 y Le BY 7 ATTonNe septplfi, 1952 c, FlELD 2,610,476

ART OF CONGELATION AND APPARATUS FOR USE IN CONNECTION THEREWITH Filed Aug. 15, 1940 5 Sheets-Sheet 4 LEI LEE

INVENTOR C'I'osb Field ATTORNEYS Sept. 16, 1952 c. FIELD ART OF CONGELATION AND APPARATUS FOR USE IN CONNECTIFON THEREWITH 5 Sheets-Sheet 5 Filed Aug. 15, 1940 INVZNTOR ATTORNEY Patented Sept. 16, 1952 ART OF CONGELATION' AND'APPAEATUS; FORfUSaE IN CONNEGTION THEREWITH CrosbyFieid, Brooklrn, N. $6., assignor-toFlakicew Corporation, Brooklyn, N. .Y.', a corporation of Delaware Application August 1'5,l9t;-.5erial No. 352,709":

I v This invention relateszto the art .of congealing and apparatus for. use in connection therewith.

. "zsoi i s, (once-106) Oneofthe objectsof'this inventionyis to pro vide an improved methodof obtaining heat-transferring; relationship; between relatively; moving partsr, Another objectnis to provide improved congealing" apparatus which .is practical and: efli-i cientinyoperation. Other objectswillibein'part obvious and-in: part 'pointe dtout: hereinafter.

The invention, accordingly, ccnsistslin the features of; construction, combinations of; e1ements,: arrangements at parts and in. the-several steps andrelationand order of the'same; all aswillbe,

' herein:illustrativelydescribed}: and the scope; of theoapplication of which. willbe. indicated: in the followingjclaims:

Inzthe: accompanying drawings. in whichpisshown an embodiment ofgthis invention,

Figure 1 is a side elevation of an assembled machine, embodying; the; invention showing the side;of=-the-coverremoved;,

I pheric pressure;

surface; and the congealed product; peelsyfrom' the belt ,as thebelt passesover one ofthepulleyss The. heat transferring: relationship between the belt and the evaporator surfaceds improved'by theapplicationpf; a film oi nonecongealing liquid to the underside of the; belt Thisfilm: of liquid: serves alsoto lubricate the."contactibetweenthe beltand the evaporator surface to .minimize slid ing. friction ztherebetween and;serves :further. as.

a meansjor maintaining therbeltandgtheevaporator surface in close contaot-gbymeans of atmos- Referringgnowv to Figuresl, orator; generally; indicated at 10; comprises a series goi:curtVedtubes-lfifl:(Figures 4 and 5) rec-- tangular shapedinnross sectionuliigure 3) which are 'wel-ded: together alongtheir-longitudinal side Figure Z-isa;longitudinal:horizontal staggered sectioirtakenonthe 1ine-2i -2 of Figure 1- which 1ine:2,-.2 hasrabend asindicated EttA'L- I Figure-351s a verticalisection taken entire line.

* 3+3 of Figure 1;:

' iFigureea'isa detaiied'plamview-of the evaporator-.of'Figure 1 having-partsbroken away-to showhow: the various evaporator; sections are.

interconnected; Figure 5." is. a longitudinal vertical section throughza-naevaporator tubeztaken on line 5+5 of Figura V Figu-re-6*=is anenlargeddongitudinal horizontal section taken on the line 3-45 of Figure-1;

Figure 'l is avertical section on an enlarged i ures '1- and :4); and; connect with the'ends of pas- With this constructiom walls: The endsof these "tllbGSflIfiiClOSBdbY end plates; I21: and I22 (FiguresA and'5); 'As bestshownin Figure 4-;the endsofiabuttingside wallscf, the rectangular shaped tubes stop short of and so. are-spaced-irom .end plates 1 I 2 I and I 22. Thus; two; passageways: I24 and; I25- are provided extending across the ends, of the: evaporator.

Inlet E. and exhaust pipes: I 25and I 211' respectively 7 are connected .to, the side of the evaporator (Figsage-ways I 2 and l2 5-.

' a'suitable refrigerant inliquidviormmay be supsoalertaken: on line 'i-l ofil igure 1 showing:

apparatus for applying a liquid filmzto-the under side .of. a travelingflexible belt and: appar'atus for supplying a; liquid to. the-upper sideof the same belt shown iirFigure "7-; and

Figure: 9+is -z a. perspective View onan enlarged scale-ofithetroughaofjthe; apparatus. 2 or supplying: liquimtoi theupper side oi the: belt shown. in

Figure 71' In thei present embodiment; an: endless, thinflexiblemetal belt is. caused to travel overstwo spaced pulleys andto slide. over the convex curved surface of :a stationary evaporator. which cools the belt asst-passes over theevaporator; The .evaporatorz-is refrigerated. by the usual ammonia or other. expansion system. Liquid or. solidiv foodstuffs to =be,.frozen'-are supplied to. the outer-surcface ofthe-bel-t asitpasses over theevaporator plied to the evaporator.through'zpipe- I26. The refrigerant :fioiws across the connected; ends of the. tubesrIrZil-i and up. through" the tubes. The

spent refrigerant in the-form ofv vaporrandany:

unevaporated liquidds. collectedat the upper ends. of theitubes' and returned to the compressing sys-- tem (not shown) through pipe. I'Z-IL' Asshown inFigures At-and 5 ;,this construction provides-an outer convexlyrcnrved, continuous-smooth refrig- Figured-ma diagrammaticshowing of a systemforcirculating the" liquid applied by the apparatu erated surface which is preferably highlypolished orprovided with a platingwhichcgivesit a smooth surface.

The framework supporting this evaporator has fourlegs 35,3 I .32, and-33:..(Figures .1 and 2) which are :braced; in. their=lower:.-portions by pairtof.

transverse bracesBai'and-BB andta pair'of'longir I tudinalhraces, oneaof Which:is;shown.ata36 (Fig? ure 1-) The..LG0l'll'lectl0I1S"btW6en "these braces:

andthelegslmay be madein anysuitablemanner,

such as Icy-welding; The upper; ends of thelegs: arev securedrbyjbolts. to a.:pair of bent-longitudinal.

channel bars, generally.indicatedzat 37! and. 38, at either. side of'the evaporatorjand whiohextend throughout the length offthemachine; The'bent. channel bars may be conveniently constructed"by joiningftwo straight sectionsz39i. and 40, at an angle. by. means of .a. joining, plate :4 I. "Extending transversely. between the channel. bars-:are a pair 4;. and 5; the evapof braces 45 and 46 which are secured to the side walls of the channel bars in any suitable manner, such as by a right-angle flange and bolts shown on the left-hand end brace 45 in Figure 2. The evaporator 'l {l is rigidly secured to and supported by the side channel bars 3'! and 38 by means of uprights 96, 9'5, 98, and 99 (Figure 2) secured to the channel bars and secured at their upper ends to cross bars 94 and 95 extending beneath and welded to the underside of the evaporator tubes [20.

These channel bars carry a pair of cylindrical pulleys, generally indicated at 41 and 48, mounted at opposite ends of the machine and around which the flexible belt is passed. Pulley 48v is mounted on a stationary shaft 49 (Figure 1) and comprises a hub 56 (Figure 6) which is rotatably mounted with respect to shaft 49 in bearings and 52 and held in proper axial position thereon by a pair of collars'5! and 58 which are secured to shaft 49 by set screws 80 and 59. 'Two sets of spokes 53 and 54 radiate outwardly from the hub and are secured to the inside wall of a metal cylinder in any suitable manner, such as by welding. The external surface of this cylinder, which is the running surface of the pulley, is preferably covered witha sheet of rubber 55 which prevents transverse deflection'in the endless flexible belt 56 as it passes over the pulley.

The outer ends of shaft 49 are supported by a carriage, generally indicated at 60, slidably mounted on the horizontal sections 40 of the channel bars. This carriage comprises a transverse bar 6| which has a pair of cylindrical horizontal rods 62 and 63 secured at right angles to its ends. These rods are positioned above channel bars 3'! and 38 respectively and each rod is mounted for longitudinal movement lengthwise of themachine in a pair of journals which are secured to the tops of the channel bars. Thus, rod 62 is slidably mounted in journals 64 and 65 and rod 63 is slidably mounted in journals 66 and 61. The outer ends of rods 62 and 63 carry blocks 68 and 69 which are secured to sliding plates H and which support shaft 49. The carriage, which thus slidably supports pulley 48, is resiliently urged to the right, as shown in Figure 1, by means of a compression spring 18.

Referring to Figures 1 and 6, an angle bar, generally indicated at 13, is secured to the inner ends of sections 40 of channel bars 31 and 38. This angle bar has one side secured to the channel bars and its other side 14 extends upwardly at right angles thereto. The opposed faces of transverse bar 61 and side 14 each have annular rings 16 and l! thereon (Figure 6) which serve to align the ends of spring 73. To draw the carriage back against the compression of spring 18, as when it is desired to place a new belt on the machine,'a rod '19 is provided. This rod extends through the center of spring 18 and has a nut 8| formed on its left-hand end to the left of side 14 (Figure 6). It passes through this side through a hole of slightly greater diameter than the diameter of rod 19 and threads into transverse bar 6| Thus, by turning the rod in one direction by nut 8|, the rod threads a greater distance into transverse bar 6! moving the carriage 66 and pulley 48 to the left, as viewed in Figures 1 and 6.

When the nut is turned in the opposite direction,

the carriage is resiliently urged to the right by spring 78.

Pulley 4! (Figure 1) is of substantially the same construction as pulley 48 and is secured to a shaft 82 which'is parallel to the shaft of pulley 48. The ends of this shaft are journaled in a pair of blocks 83 and 84 (Figure 2) which are rigidly secured to the left-hand ends of channel bars 31 and 38 respectively. A pulley 85 is secured to one end of shaft 82 and this pulley isconnected by a belt 86 to a motor 81. This motor preferably drives belt 86' through a transmission I which permits the rate of drive of the belt to be varied. Thecylinder of pulley 41 is covered with a sheet of rubber which not only prevents transverse deflection of the belt but also insures driving traction between this pulley and the belt.

The endless belt 56 (Figure 1) which rides on pulleys 4! and 48 and travels across the evaporator is preferably made of thin metal, such as described in my Patent No. 2,078,938, and has a pair of V-shaped rubber tracks 88 and 89 (Figures 6 and 7) secured toits edges. These tracks engage V-shaped grooves formed in the peripheries of annular rings secured to the oppositeends of each pulley. For example, pulley 48 has annular rings 90 and 9| secured to its ends and these rings carry V-shaped grooves 92 and 93 respectively. These grooves not onlyprovide the necessary traction to drive the belt through the medium of pulley 41 but also serve to keep the belt in accurate alignment with the evaporator.

This belt 56 (Figure 1) thus passed around the pulleys 4'! and 48 is maintained under tension and against the evaporator I!) by means of the compression spring '18 pushing outwardly on the carriage 63, which influence is imparted to the pulley 48. As above pointed out, the belt is caused to slide along the evaporator and to travel about the pulleys by the friction drive between the belt and the driving pulley 41. The angle with which the belt approaches the leading edge of the evaporator 10 from the top of the roller 48 is maintained equal to the tangent of the curve of the evaporator surface at its leading edge, so that no bending of. the belt takes place along this line and so that the belt starts its contact with the evaporator surface at this line. This is accomplished by making the carriage rods 62 and 63 parallel to said tangent and by making the radius of the pulley 48 equal to the perpendicular distance between the axis of the rods 62 and 63 and the leading edge llll. Thus, as the roller 48 adjusts itself lengthwise of the appara tus, the plane of tangency between the belt and the pulley is maintained coincident with the plane of tangency of said leading edge of the top surface of the evaporator. In this way, the tension on the belt is maintained constantly While the belt at all times is in contact with the leading edge NH.

The non-adjustable pulley 41 is also so positioned with respect to the following edge I00 of the evaporator surface that the plane of tangency between the belt and the pulley 41 is coincident with the plane of tangency of the evaporator surface along the following edge 10 l Thus, in operation, the flexible endless belt is at all times held in contact with the entire refrigerated surface of the evaporator it without permitting any bending of the belt to take place as it approaches the evaporator or as it leaves it.

Liquid, preferably propylene glycol, is supplied to the header Hi2 (Figures 1 and 8) under a substantially constant head by means of a pipe Ill connected with the bottom of a reservoir I09. As the belt moves past the outlets I03 (Figure '7) of the headenthe under surface of the belt is wetted by the propylene glycol, and as the belt continues to move over the evaporator surby a handle use:

aerome face, the propylene" glycol spreads sideways to form a continuous film. This film provides a continuous heat transferring mediumbetween the evaporator and the belt, which medium...h,as:a

' hi'ghcoefficient of heatltransfer as: compared pulleys; 5

The liquidfor'ming the filmis taken from the belt'after it passes from-the evaporator surface and before it reaches the pulley 4-1: hymeans ofa Wiper I05 (Figure 8) extending across the belt. The liquid removed: by the wiper runs down into a trough lflfi 'and is removed-therefrom by means' fa line-I01 connected-with a small pump I08 which discharges 'th rough theline H0 into the reservoir I021. r

As has been pointedxout hereinabove; this'machi-neis suitable for freezing both liquidsand solids; When it is used forfreezinga liquid the apparatusshown in Figures 1, '7, and!) may be usedfof-spreading the liquid on the belt. The apparatus comprisesa trough 1 I I5 (Figure 9) which has grooves l iii-and H1 in. its ends by means of which-it is slidably mounted on a pair of "vertical guide rails P30 and Kit (Figures *1 and. '7) which are secured toevaporator' It in any suitable'manner, such as bysupports I-BZ-and I33. Whenthe-machineis in operation, the trough rests" by gravity on the surface of belt 56 and is free to.- adjust itself to variations in "the belt surface. Liquid is fed totroug-h- I i5 through a supply pipe: I34; and the rate of fi'ow into the trough H5 is governed by a valve-H9 operated Referring te Figure "-1" in which the tea moves to the left; the'r'ight-hand side-'eftrough H5 is lowerthan the left-and thus; the liquid to befrozenoverflows downthis side of the-trough and is spread evenly Sever the side-"of the trough befor'eit reaches the surface of the belt" passing-thereunder. In'ordertosup-'- ply liquidonly to that portion-of the beltwhich passes over the evaporatoiathe ends oftrough i i5 are tapered upwardly tliiigure 7). Th us-,=-by this apparatus; liquid is appliedevenly-and efficiently to thebelt. To exclude moisture from the interior of-the flexible beltand in so far as possible'from' condensing and freezing" on the underside of evaporator IO and from condensing on other cooled parts of the apparatus, the apparatus. is pref"- erably enclosedby a suitablecover H2 provided with "heat insulating qualities, which extends down to a storage bin generally indicatedat 20 l. Furthermore, the apparatus .within. cover H2 is refrigerated by means ofanexpansion coil N3, shown in- Fi'g ures 1 and 2, which coil also tserves m :condense any moisture entering the closure and so-provides-an additional-protection against condensationof moisture'on the interior of the belt.

The apparatus, as shown, is constructed to -provide the freezing surface of the belt 56 i only slightly tipped from the: horizontal.i..This. construction has the advantage of aiding in .the; ap plication of liquid and solid. foodstuffs tothe flexible belt in suchman'ner. that no excess sap. pli'cation. oftthezzmaterial to be. frozen is. necessary. This. is advantageous. particularly when materials such as cream and. eggs .are. frozen, where the. temperatures necessary. for 'congealing must. be. quickly: reachedinprder to avoid 1 de' structive effects.

As has been pointed out hereinabove, the belt rotates in a counter-clockwise direction as viewed in Figure l. Thus, the. articles. or liquid tobe frozenareplaceduponthe belt to the right of the evaporator and the belt is moved at the correct .speed;to..freeze.the article or liquid by the time it leavesthe evaporator; These articles or the liquid areremovedfrom the belt at the lefthanct end'of'the machine by the flexing-of the belt as it passes over pulley 41, and the frozenmaterial' thus-removedpasses down a chute 200 into bin 2.8!. through opening. 202

Thus, it will be seenthatI have provided an efiicient: and-practical. method and apparatus: in which the; several objects. hereinabove mentioned, asrwellas.many-others, are successfully achieved.

As many possible embodiments may be made of the: mechanical features of the above invention and'. as the art. herein described. might: be varied in various parts, all without departing from. the. scope of the. invention, it is to be und'erstood. that. an matter hereinabove set forth, or1shown in the accompanying drawings; is to be interpreted as i'llustratiye and not in a limiting 'senscqr' I claim: a

l. In congeali n-grapparatus of the class described,--in combination, stationary refrigerated memberhaving refrigerated surface having leading and following end portionsand oonvexly curved along its length,- an" endless flexible belt encompassing said refrigerated surface, means for causing said belt to travel abeutsaid refrigerated member and slide alon said refrigerated surface resilient movable means for maintaining 'said belt under tension in contacting-heat trans ferring relationship-withrespect t'o said refrigerated surface, means" for maintaining the -suc cessive portions of the belt" approaching and reaching the leading edge portion ofsaid refrigcrate-d surface in the plane tangent to said edge portion, means for supplying *to said belt material to-be congealedthereon, and means for progressively deflecting saidbelt'as it leaves said refrigeratedsurface to remove therefrom the material congealed thereon.

2. In congealing apparatus of the class-- described-,-in combination, a stationary refrigerated member having; a refrigeratedv surface having leading and followingedge portions and convexly curved along. its. length, a flexible metal belt encompassing said refrigerated surface, means for causing said beltto travel about .saidsurface and .to.. slide therealong in contact therewith,

means for maintaining the successive portions of said belt approaching said leading edge portion in a plan tangent to said edge-1 portion, means forzsupplyingto said belt-- material to be congealed thereon, means :for 'defleotingrsaidbelt as :it: leaves said. refrigeratedsurface to remove therefrom .the material congealed thereon, and resilientmeans for maintaining said-moving belt under tension whei'ebythe desired heat transferring relationship is maintained between said belt 7 and said refrigerated surface as the belt .slides therepast.

3. In congealing apparatus of the class described, a refrigerated member having a con vexly curved refrigerated surface having leading and following edge portions, a flexible belt, means for causing said belt to travel under tension about said refrigerated surface to cause a surface of said belt'to contact and slide along said refrigerated surface as the belt slides thereover contacting surface of said belt in advance of its contacting said refrigerated surface to maintain a liquid film between said contacting surface and refrigerated surface as the belt slides thereon whereby the heat transferring relationship between said belt and refrigerated surface is improved, friction is reduced, and atmospheric pressure may be utilized to aid in maintaining the two in the desired heat transferring relationship.

4. In congealing apparatus of the class described, a refrigerated member having a convexly curved refrigerated surface having leading and following edge portions, a flexible belt, means for causing said belt to travel under tension about said refrigerated surface in sliding contact therewith, means for supplying a liquid to the under surface of said belt to wet the contacting surfaces of said belt and refrigerated surface whereby the heat transferring relationship between said belt and refrigerated surface is improved, friction is reduced, and atmospheric pressure may be utilized to aid in maintaining the two in the desired heat transferring relationship, and means for removing said liquid film from said belt after said belt has passed over said refrigerated member.

5. The method of maintaining the desired heat transferring relationship between a stationary curved refrigerated surface having leading and following edge portions and an endless flexible belt caused to slide over said refrigerated surface which comprises the steps of maintaining said sliding belt under tension against said refrigerated surface, wetting the contacting surfaces of said belt and said refrigerated surface to improve the heat transferring relationship therebetween, and utilizing atmospheric pressure to maintain a close relationship between said surface and said sliding belt.

6. In refrigerating apparatus, in combination, a stationary evaporator having a curved surface, an endless flexible belt contacting said surface, means to move said belt over said surface, and a liquefied film having a freezing point lower than the operating temperature of the evaporator wetting the contacting surfaces of said belt and said evaporator.

7. In refrigerating apparatus, in combination, a stationary evaporator having a curved surface, an endless flexible belt contacting said surface, means for moving said belt over said surface, resilient means to resiliently hold said belt in contact with said evaporator, and a liquid film having characteristics similar to propylene glycol wetting the contacting surfaces of said belt and said evaporator.

8. In refrigerating apparatus, in combination, an evaporator having a refrigerated curved surface, pulley means positioned at opposite ends of said evaporator, an endless belt running on said pulley means and contacting said curved surface, said refrigerated curved surface being positioned above a plane passing through the upper peripheries of said pulley means, resilient means acting through the pulley means at one end of said 8 evaporator to resiliently hold said belt in contact with said evaporator, and a liquid film having a freezing :point lower than the operating temperature of said evaporator wetting the contacting surfaces of said belt and said evaporator.

9. In refrigerating apparatus, in combination, an evaporator having a refrigerated curved surface, pulley means positioned at opposite ends of said evaporatonan endless belt running on said pulley means and contacting said curved surface, said refrigerated curved surface being .positioned above a plane passing through the upper peripheries of said pulley means, resilient means acting through the pulley means at one end of said evaporator to resiliently hold said belt in contact with said evaporator, a liquid film having a freezing point lower than the operating temperature of said evaporator wetting the contacting surfaces of said belt and said evaporator, a moisture-proof housing enclosing said apparatus, and a refrigerated member positioned within said housing to refrigerate and dehumidify the space enclosed thereby.

10. In refrigerating apparatus, in combination, an evaporator having a refrigerated curved surface, a pair of pulleys positioned at the ends of said evaporator, an endless belt mounted on said pulleys, said refrigerated curved surface of said evaporator being positioned above a plane extending between the upper peripheries of said pulleys, and means mounting one of said pulleys for longitudinal movement with respect to said apparatus, the line of said movement being parallel to a plane tangent to the curved surface of said evaporator at the end thereof adjacent said pulley, the uppermost portion of the periphery of said pulley moving in said tangent plane whenever said pulley moves longitudinally with respect to said apparatus.

11. In refrigerating apparatus, in combination, an evaporator having a refrigerated curved surface, a pair of pulleys positioned at the ends of said evaporator, an endless belt mounted on said pulleys, said refrigerated curved surface of said evaporator being positioned above a plane extending between the upper peripheries of said pulleys, means mounting one of said pulleys for longitudinal movement with respect to said apparatus, the line of said movement being parallel to a plane tangent to the curved surface of said evaporator at the end thereof adjacent said pulley, the uppermost portion of the periphery of said pulley moving in said tangent plane whenever said pulley moves longitudinally with respect to said apparatus, and a liquid film wetting the contacting surfaces of said belt and said evaporator, said liquid film having a freezing point lower than the operating temperature of said evaporator.

12. In refrigerating apparatus, in combination, an evaporator having a curved surface, a plurality of pulleys positioned at opposite ends of said evaporator, an endless belt mounted on said pulleys, a carriage mounted on said apparatus for longitudinal movement with respect thereto, said carriage mounting one of said pulleys, and resilient means urging said carriage outwardly from the end of said apparatus, said carriage moving in a plane parallel to a plane tangent to said curved surface at the end thereof adjacent said carriage, said last-mentioned pulley being of the correct radius so that its uppermost periphery moves in said last-mentioned plane.

13. In refrigerating apparatus, in combination, an evaporator having a curved surface, pulley 1 l ating temperature of said refrigerated surface wetting the contacting surfaces of said refrigerating surface and said belt.

22. In refrigerating apparatus, in combination, a refrigerating surface defined by a rigid refrigerating member forming a wall portion of a refrigerating system, an impervious thin sheet-like member, means for moving said sheet-like member into and out of contacting relationship with respect to said refrigerating surface, a heat conducting fluid film between said refrigerating surface and said sheet-like member, said film having a freezing point lower than the operating temperature of said refrigerating surface, said film improving the heat transfer relationship between said members, and means for supplying material to be congealed to said sheet-like member while in contact with said refrigerated surface.

23. In refrigerating apparatus, in combination, a refrigerating surface defined by a refrigerating member forming a wall portion of a refrigerating system, an impervious endless flexible belt, means for moving said belt over said refrigerating surface in heat transferring relationship thereto, a liquid heat conducting film filling any space between said belt and said refrigerating surface, said heat conducting film having a freezing point lower than the operating temperature of said refrigerating surface, said film improving the heat transfer relationship between said members, and means for supplying material to be congealed to said sheet-like member while in contact with said refrigerating surface.

24. In congealing apparatus, in combination, a refrigerating surface defined by a refrigerating member forming a wall portion of a refrigerating system, an impervious thin flexible member having contacting and freezing surfaces, means for causing relative sliding movement between said members, whereby the freezing surface of said flexible member is progressively cooled, a liquid having a freezing point below the operating temperature of said refrigerating member and capable of spreading between said contacting surfaces, means for supplying said liquid to the contacting surfaces to fill any space therebetween to increase the coefficient of heat transfer between said con-' tacting surfaces, and means for supplying to said freezing surface material to be congealed.

25. In congealing apparatus, in combination, a refrigerating surface defined by a refrigerating member forming a wall portion of a refrigerating system, an impervious thin flexible member having a contacting surface and a freezing surface, means for causing relative sliding movement between said members, whereby the freezing surface of said flexible member is successively cooled, a liquid having a freezing point below the operating temperature of said refrigerating member. and capable of spreading between said contacting surfaces, means for supplying said liquid to the contacting surfaces to fill any space therebetween to increase the coefficient of heat transfer between said contacting surfaces, said liquid also having the properties of a lubricant to aid the sliding movement of said flexible member with respect to said refrigerating surface, and means for supplying to said freezing surface material to be congealed.

26'. An ice making apparatus comprising an evaporator forming part of a closed refrigerating system and having a refrigerating surface of constant curvature; an endless flexible belt. of heat conducting material; means maintaining a portion of said belt in close proximity to a major 12 portion of said refrigerating surface and causing said portion of the belt to conform in curvature to said surface, said means including an element spaced from said refrigerating surface and presenting a curved surface in contact with the inner surface of the belt; and means for applying water to be frozen to the exterior of the belt; said belt being movable relative to said surfaces and said apparatus being constructed and arranged to hold a quantity of liquid having a freezing point below the lowest temperature to be reached by the operation of said apparatus and to cause the relative movement of the belt with respect to the refrigerating surf-ace to interpose a portion of said liquid in the form of a film between the latter and the portion of the belt conforming thereto in curvature and to flex the belt across the second mentioned curved surface to break a layer of ice frozen thereto.

27. In refrigerating apparatus, in combination, an evaporator construction including a continuous curved refrigerated surface, an endless flexible belt encompassing said refrigerated surface and contacting a portion thereof, deflector means adapted to flex successive sections of said belt out of contact with said evaporator, and an antifreeze positioned between said belt and said refrigerated surface adapted to engage and spread over the contacting surfaces thereof; said deflector means having belt-supporting surfaces predetermining said endless path in the regions of maximum belt flexure, said belt-supporting surfaces extending across and supporting the marginal edges of the inside of said belt.

28. In refrigerating apparatus, in combination, an evaporator construction including a continuous curved refrigerated surface, an endless flexible belt encompassing said refrigerated surface and contacting a, portion thereof, deflector means adapted to flex successive sections of said belt out of contact with said evaporator, and an anti freeze'positioned between said belt and said refrigerated surface adapted to engage and spread over the contacting surfaces thereof; said deflector means having belt-supporting surfaces predetermining said endless path in the regions of maximum belt flexure, said belt-supporting surfaces extending across and supporting the mar-. ginal edges of the inside of said belt, a pair of endless rubber-like members secured in face-toface contact with the under side of said belt one along each marginal edge thereof, said members being interposed between said belt marginal edges and said deflector means.

CROSBY FIELD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number I Name

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