US3491543A - Moving band icemaker with lubricant purification - Google Patents

Description

Jan. 27, 1970 c. FIELD 3,

MOVING BAND ICEMAKER WITH LUBRICANT PURIFICATION Filed Dec. 15. 1967 4-Sheecs-Sheet 1 INVENTQR. CROSBY FIELD ATTORNEYS Jan. 27, 1970 I c. FIELD 3,491,543

MOVI NG BAND ICEMAKER WITH LUBRICANT PURIFICATION q Filed D80. 15, 1967 4 Sheets-Sheet 2 c R015 g YE EE L D m.& BY M, m r

ATTORNEYS c. FIELD Jan. 27, 1970 MOVING BAND IGEMAKER WITH LUBRICANT PURIFICATION 4 Sheets-Sheet 3 Filed Dec. 15, 1967 FIGJO FIG.

INVENTOR. CROSBY FIELD ATTORNEYS Jan. 27, 1970 c. FIELD 3,491,543

MOVING BAND ICEMAKER WITH LUBRICANT PURIFICATION Filed Dec. 15, 1967 4 Sheets-Sheet 4 INVENTOR. CROSBY FIELD 4/ ATTORNEYS United States Patent 3,491,543 MOVING BAND ICEMAKER WITH LUBRICANT PURIFICATION Crosby Field, 8029 Harbor View Terrace, Brooklyn, N.Y. 11209 Filed Dec. 15, 1967, Ser. No. 691,055 Int. Cl. F25c /06, 7/12 US. C]. 62-72 8 Claims ABSTRACT OF THE DISCLOSURE Congealing apparatus is disclosed which is particularly suited for freezing ice and congealing liquid products. There are two refrigerated plates over which a steel belt passes in two runs at an angle to the horizontal. A heat conducting lubricant is supplied beneath the belt as it starts along each run. A special arrangement is provided for removing the lubricant at the bottom of the path of the belt and special means is provided to evaporate water from the lubricant.

This invention relates to the art of congealing, and to apparatus for use in connection therewith. Thus, for example, the invention may be used for making ice or in general for congealing material to convert it from a liquid state into a solid state. The present invention is related to those disclosed in my United States Letters Patents Nos. 2,610,479, 2,610,476 issued Sept. 16, 1952, 2,990,199 issued June 27, 1961, and 3,037,366 issued June 5, 1962.

An object of this invention is to provide improved freezing apparatus. Another object is to provide evaporators having a high rate of heat transfer and also with a surface hardened against erosion and protected against corrosion. Another object is to provide very sensitive method of maintaining close and uniform contact between a stationary evaporator and a freezing belt travelling over it. Another object is to provide a method of tracking such belts. Still another object is to double the output of such a freezing belt by having it pass over the surface of an additional evaporator on the return from the idler pulley to the drive pulley, after passing over the surface of the evaporator betweenthe drive pulley and the idler pulley, as disclosed in my previously cited patents. Another object of the invention is to provide a separator, such as an air dam, between the unfrozen liquid and the ice so as to produce dr and subcooled ice on the belt. These and other objects will be in part obvious and in part ointed out below.

In the drawings which show one embodiment of the invention:

FIGURE 1 is a right hand side view, with the side of the cabinet removed;

FIGURE 2 is a diagrammatic view of the refrigeration system; I

FIGURE 3 is a rear view of the rear side of the cabinet removed; I

FIGURE 4 is a diagrammatic view of the system for tracking the belts; j

FIGURE 5 is a diagrammatic view of the belt lubricating system;

FIGURE 6 is a representation of the groove pattern Patented Jan. 27, 1970 FIGURE 11 is a transverse sectional 'view of the belt; FIGURES 12 and 13 are fragmentary side views of the portions of one evaporator;

. FIGURE 14 is a somewhat diagrammatic view showmg the manner in which the lubricant is collected; and,

FIGURES 15 to 18 are enlarged sectional views, respectively on lines 1 515 and 1616 of FIGURE 12, 1717 on FIGURE 14, and 1818 on FIGURE 17.

Referring particularly to FIGURES 1 and 3 of the drawings, the ice maker has four evaporators 1 assembled with evaporator frames 3 in the manner more fully described hereinafter. The four sub-assemblies of evaporators 1 and evaporator frames 3 are supported by a base frame 5 bolted to it means of brackets 7. Wooden skids 13 form an insulating foundation for the metal base frame 5. This frame has two central support members 6 and 8 which carry two centrally supported tubular arms 10 which, in turn, support slant portions of the frame 5 cantilevered on both sides. These two identical slant portions carry ice making sub-assemblies which are also identical except that they are left-hand and righthand respectively. The following description of the righthand subassembly (near side in FIGURE 1) applies equally to the one on the left. The evaporator sub-assemblies are mounted in upper and lower slant positions as shown. Pads of rubber 9 provide cushioned mountings on the brackets 7 that permit final adjustment of the alignment of the evaporators 1 by means of bolts 11, which by means of their nut 12 control the compression of the pads 9.

As best shown in FIGURE 1, a weldment 21 is bolted to the upper end of frame 5 and supports four parallel guide rods 23, two on each side. The guide structure is completed by end plates 25 secured to the ends of guide rods 23 by screws 27. Bearing block 31 is bored to slide on guide rods 23, thus permitting the hearings to move longitudinally of the slant frame. Each of the pair of bearing blocks 31 has a bearing 33 for an idler shaft 35. Mounted upon a free turning shaft is an idler pulley 37. A drive pulley 19 is keyed to a shaft 17, which is rotatably mounted in the pair of bearings 15 secured to the lower ends of the slant members of frame 5. Freezing belt 39 is supported by pulleys 19 and 37 and is tensioned between them as will be described more fully hereinafter. Movement of belt 39 is imparted to it by drive pulley 19. Pulleys 19 and 37 are of rigid metal and have their cylindrical faces covered by a layer 41 of an elastomer, such as rubber (see FIGURE 14). Pulley 19 is driven as described hereinafter in connection with FIGURE 7. The frame 5 is built so that the line between the centers of the shafts of the pulleys 19 and 37 may make with any horizontal line any angle between 45 above to 45 below horizontal. As pulley 19 turns, it drives the belt 39 so that it is drawn along the curved top surface of the upper evaporator and along the curved bottom surface of the lower evaporator. The portions of the belt in contact with the evaporators are maintained at a low temperature. As shown in FIGURE 4, the belt is held under tension by rods which bear upward against bearing blocks 31. The force on the inner rod 43 is produced by a coaxial spring 45 which is screw adjusted for changing the pressure. The force on the outer rod 43 is produced by a coaxial spring 45 which is screw adjusted for changing the pressure. The force on the outer rod 43 is produced by a coaxial hydraulic cylinder 47 which is automaticaly controlled as described hereinafter. The belt is driven by pulley 19 in a clockwise direction in FIGURE 1; that is, with the upper run moving to the right.

As shown in FIGURE 3 and FIGURE 11, each edge of belt 39 has bonded to it a continuous molded darn structure 49 of an elastomer, e.g. rubber. As shown in the cross vsectional view .of FIGURE. 11, this dam structure has portions on both sides of the belt; the one portion to retain the liquid or fluid 40 (product) being congealed upon the congealing surface and the other portion to retain theliquid heat transfer lubricant 42 which acts both as a lubricant and as a heat transfer agent between the metal of the belt and the evaporators. By maintaining a thin film of heat transfer lubricant on the undersurface of the 'belt, any irregularities in the surface in normal contact are compensated for.

The dams 49 are formed with a thinner section on the product side than on the lubricant side. This prevents the edges where the dams 49 meet the metal belt 39 at points 44 from getting cold enough for the product 40 to freeze along its edges.

From drive pulley 19, shaft 17 is extended inwardly beyond bearing 15 (see FIGURES 1 and 7) where sprocket 51 is keyed to it. Sprocket 51 is driven from upper jack-shaft 53 by chain 55 and sprocket 56 which is keyed to jack-shaft 53. Jack-shaft 53 is turned by sprocket 57, driven by chain 63 from motor 291, gearmotor sprocket 59 and gear-motor shaft 61. Jack-shaft 53 turns'in two bearings 65, bolted one on either side to the center post of frame 5. A lower jack-shaft 67 turns in two bearings 69 which are similarly bolted to the center post of frame 5. J ack-shaft 67 is turned by sprocket 71 from chain 63. A hydraulic pump sprocket 73 is driven from this jack-shaft by a chain 79 and a sprocket 75, and 73 and chain 79. The sprocket 81 of the lubricant pump is also driven by chain 63. Vertical adjustment of sprocket 81 produces the proper tension in the chain 63. Proper tension in chain 55 is maintained by vertical adjustment of bracket 87 which supports an idler sprocket 83 and its pivot 85.

The evaporator (see FIGURE 8) in contact with the freezing belt is a plate 95 of a high heat conducting material, i.e., aluminum, to one side of which has been attached, by brazing or welding, parallel refrigerant tubes 97. The other side of the plate 95 is coated with a hard erosion resistant yet high heat transfer material, i.e., molybdenum, into the pores of which has been inserted a corrosion resistant coat, i.e., a polyvinylchloride, rendered high heat conducting by the inclusion therein of graphite. At the respective ends, tubes 97 are welded into headers 99 and 99a (see also FIGURE 1), the flanges 101 (FIGURE 8) of which are connected to the refrigerant piping described hereinbelow. In this embodiment, there are ten refrigerant tubes 97, and the tubes are slightly flattened to increase the contact with the plate, thus increasing the heat transfer rate between the plate 95 and the refrigerant in the tubes. Additional heat transfer is provided by enclosing the tubes in a layer of heat conducting cement 103 'which is also in contact with the plate 95.

As shown in FIGURE 6, lubricant groovesv are pro.- vided on the other side of the plate 95. Evaporator plate 95 is supported (FIGURE 8) by three radius guide plates 105, of an insulating material, which in turn are supported on their lower edges by the three transverse angles 107 which, together with two longitudinal angles 109 form the evaporator frame 3. Radius guide plates 105 are maintained in the correct transverse positions by rods 111 and spacer nuts 113 which also secure the outer guide plates to the longitudinal angles 109 of the frame. The sub-assembly includes two insulating strips 115 which. extend along the curved sides of the respective outer radius guide plates 105 and up alongside the edge of the evaporator plate. Near the lower edge of strip 115 an insulated heater wire 117 is secured. It is covered by a metal foil strip 119 and then by a plastic insulating strip121. The heat produced by the electric current in Wire 117 is thus conducted by the foil 119 up to the edge of the evaporator isolated by insulators on both sides.

The. heat along this .lineprevents frost accumulation under the edge of the metal freezing belt 39.

The upper and lower evaporator assemblies are identical except only in the handling of the heat transfer lubricant. FIGURE 12 illustrates the lubricant feed end of the upper evaporator and FIGURE 13 illustrates the other end, and FIGURE 6 shows the top of the evaporator. The direction of belt travel is indicated by arrows 123. Referring to FIGURE 12, casting 125 and insulating block 127 provide end support for plate allowing clearance for header 99 and (see also FIGURE 6) lubricant feed block 129, being firmly bolted to the frame at transverse angle 107. The method of securing plates 95 to end castings 125 is shown in FIGURE 15 which is a cross section near the end of the evaporator. Screws 120 in countersunk holes in insulating block 127 secure the evaporator to end casting 125, screws 122 in countersunk holes in plate 95 secure it to block 127. Thus there is no metallic contact for heat conductivity between plate 95 and end casting 125. Insulating block 127 prevents frosting on casting by conductivity from plate 95.

As shown in FIGURE 16, lubricant is fed into feed block 129 by a nipple 131 and thence by means of holes 124 in screws 126 through the plate 95 to the belt as more fully described hereinbelow. Any excess lubricant not carried up by the belt is collected in drain groove 133 (FIGURE 12). Referring to FIGURE 13, casting 125a and insulating block 127a provide support for the other end of plate 95. A transverse windshield wiper 135 wipes the bottom surface of the belt as it moves away from the evaporator surface, and removes the film of lubricant and it collects in drain 137. Referring to FIG- URE 8, a metal sleeve 139, larger in diameter than header 99 covers this header concentrically between the adjacent radius guide plate 105 and the flange 101. Heater wire 117 makes approximately three turns around sleeve 139. Heat conducting cement is used to increase the effectiveness of wire 117 in heating sleeve 139.

After all these evaporator parts have been assembled, the space below the plate 95 and tubes 97 is filled with a chemically expanded insulation (such as a polyurethane foam) flush with the bottom of radius guide plates 105. This insulation also fills the space between headers 99, 99a and sleeves 139 after insulating between the headers the lower evaporator assembly is the same as that of the upper evaporator assembly, except that end has a lubricant feed block 129 and connection nipple 131. There are no lubricant drain connections in casting 125b or isulating block 127b and no wiper 135, since the lubricant drains into the inside of the lower part of the and the end castings 125 and 125a. The construction of belt. Its return to the system will be described hereinbelow in connection with FIGURE 5. Both upper and lower evaporator plates 95 have lubricant grooves 141 as shown in FIGURE 6.

REFRIGERATION OF EVAPORATOR FIGURE 2 is a diagrammatic representation of the refrigeration system for the evaporators 1 which omits accessories such as controls, oil separator and others Well known in the art. On the'low pressure side two levels of operation are used since the evaporators are operated flooded. The upper evaporator 1a operates in parallel off surge drum 145a and the lower evaporators 1b operate in parallel off surge drum 145b. Liquid refrigerant from condenser 147 is fed through conduit 149 into the surge drums through their respective valves 151a and 151b which are controlled by level responsive elements 153a and 153b so that the levels in the surge drums are maintained at their respective levels 155a and 155b which are the respective optimum operating levels. The refrigerant liquid flows by gravity from the surge drums into the evaporators. The surge drums are constructed as dis closed in my Patent No. 3,037,366. The refrigerant vapor formed in the upper evaporator flows through conduits 157a into surge drum 145a, displaced by liquid refrigerant under the static head at level 155a. The liquid refrigerant flows through an orifice in a nozzle into each of the evaporator tubes 97 to provide proper distribution of refrigerant between the tubes and increase velocity and turbulence therein resulting in a higher rate of heat transfer as disclosed in my Patent No. 3,037,366. The refrigerant vapor reurns to the compressor 171 via he surge drum 145a where any liquid carried with it is separated out before it enters suction line 163. Oil return is obtained by bleed-off tubes 165a and 167a from the lower evaporator headers through the oil stills 169a and 16911 and back into the suction line 163 to compressor 171. Oil still 169a is heated by a small amount of discharge gas from compressor discharge line 173 through tubes 175 and 177a to the top of surge drum 145a. The lower evaporators 1b and surge drum 1451; operate together, in the same way as the upper evaporator 1a and surge drum 145a, but the operation is based on the lower liquid level 155b.

LUBRICANT SYSTEM FIGURE 5 is a diagrammatic representation of the system which maintains a thin film of heat transfer lubricant between the evaporators and the belts. This lubricant may be an antifreeze compound such as an aqueous solution of propylene glycol. The two evaporators and their respective associated elements on the right hand side of this embodiment have been omitted for clarity. A supply of lubricant is maintained in reservoir 179. When the belts are driven, pump 181 supplies lubricant to the leading ends of evaporators, through filter 182, 1a and 1b via capillaries 183 and 1831b and feed blocks 120 (see also FIGURE 12). Each of the capillaries 183 may be of a different length to ensure equal and proper distribution of lubricant between the four evaporators. Pump 181 is driven by sprocket 81 as previously described With reference to FIGURE 7. Used lubricant from wiper 135 (FIGURE 13) and drain 137 returns to reservoir 179 via drain line 185. Drain line 187 returns the lubricant from drain groove 133 (FIGURE 12) to reservoir 179. Referring to FIGURE 5, the lubricant used by the lower evaporator 1b collects on the inside of the belt 39 at its low point where drive pulley 19 is located.

The molded dam structure 49 at each edge of the belt retains this lubricant (see FIGURES 17 and 18) so that it flows in along the edges of the inside of the pulley. Each of these edges has a large number ofequally spaced grooves 188 which lead to four aligned arcuate grooves 189 adjacent the web 190 of the pulley (see FIGURE 14). Grooves 188 are spiral so that the rotation of the pulley causes them to direct the lubricant from the extreme edge of the pulley into grooves 189. Positioned at the trailing end of each groove 189 is a cup 191 which is open on their leading sides to its groove. Hence, as the pulley moves clockwise from the bottom position in FIGURE 14, the lubricant flows from the groove 189 into its cup. The cup is otherwise closed except for a discharge tube 192 which at this time extends upwardly, but which has its discharge end extending out beyond the edge of the belt toward a stationary drain tray 193. Upon continued movement of the pulley the cup is tipped toward its upright position and the lubricant starts to discharge through tube 192 into the drain tray which is positioned at the side of the pulley adjacent the pulley shaft. Hence, as each cup moves past the lowest point in its travel, it scoops up a quantity of lubricant and then deposits it into tray 193 from which it returns through a tube 195 to reservoir 179. The arrangement is such that the lubricant is completely discharged from each cup before its tube moves over the pulley shaft and no lubricant is deposited on the shaft. When the ice maker is stopped a timer keeps the belts39 running for a preset period with the refrigeration off. During this period solenoid valve 197 opens diverting all lubricant from the discharge of pump 181 to reservoir 179 while the above described lubricant system returns the lubricant in use to reservoir 179 also to prevent loss of lubricant by overflow on shutdown.

Since the lubricant used is water soluble, it may be gradually diluted by moisture condensed from the air as the ice maker operates. Further, since the freezing point is raised by dilution, this accumulation of water must be constantly removed to avoid possible freeze-up. Since the boiling point of the lubricant and water mixture is a function of its water content a rectifier 199 is used, maintained at a practically constant temperature by means of an electric immersion heater and thermal switch. The temperature of the rectifier is set to correspond to th boiling point of the desired concentration of lubricant solution. A small convection flow in tubes 201 maintains the solution concentration in reservoir 179 substantially the same as that in rectifier 199 without heating the solution in the reservoir. Thus when the solution is diluted in the reservoir 179, it is also diluted in rectifier 199 depressing its boiling point below the rectifier temperature. The boiling in the reservoir drives water out of the solution, thus concentrating it until its boiling point reaches the predetermined rectifier temperature, a which time the boiling stops. AA reflux condenser 203 having glass ball packing is used over the rectifier to minimize loss of lubricant carried off by the escaping steam.

HYDRAULIC TRACKING SYSTEM FIGURE 4 is a diagrammatic representation of the hydraulic tracking system which automatically keeps belt 39 centered on evaporators 1a and 1b and drive pulley 19 and idler pulley 37 as it runs. A reservoir 205 holds a supply of hydraulic fluid. Pump 207 (driven by sprocket 73 in FIGURE 7) draws fluid from reservoir 205 to build up pressure in pressure line 209, limited by a pressure regulator 211 Which bleeds into a drain line 213 to return spent fluid to reservoir 205. Each of the two belts in this embodiment is tracked by using this pressure in the following manner: a control valve 215 is operated by a roller arm 217 which follows the molded edge 49 of belt 39. When belt 39 starts to the left of center it causes arm 217 to turn control valve 215 so as to permit more fluid into cylinder 47 increasing the tension slightly in the left side of the belt 39 which moves the belt back to the center position. When belt 39 starts to the right of center it causes arm 217 to turn control valve 215 so as to vent fluid from cylinder 47 decreasing the tension slightly in the left side of the belt 39 which moves the belt back to the center position. Spring 45 maintains a practically constant preset tension on the right side of the belt. The changes in tension on the left side of the belt required for tracking are referenced to this tension and are so slight that they have no noticeable effect on the belt. A check valve 221 is provided between the control valve 215 and the cylinder 47. This valve remains open as long as there is pressure in line 209. When the pump stops and its pressure falls, check valve 221 closes to hold cylinder 47 in the proper position for restarting without excessive tracking movement.

THE WATER SYSTEM Identical systems apply the water (or other liquid or fluid) to be solidified to the refrigerated portions of each of the two belts 39. One of these, therefore, will be described with reference to :FIGURES 1 and 3. The liquid enters through tube 223 controlled by float valve 225 which maintains a level 227 in sump 229. It is circulated by pump 231 from the sump through tube 233 to T 235. To supply the upper freezing portion of the belt, the liquid rises from T 235 through tube 237 to the high end of upper precooler trough 239, down this trough and then down a second precooler trough 241 on to the belt 39. It

is distributed across the belt by a corrugated weir 243 at the end of trough 241. Cooling coils 244 and 246 are brazed to the underside of troughs 239 and 241, respectively. The excess liquid that is not froozen as it flows downward and to the left, over the upper refrigerated portion of belt 39 returns to the sump after flowing over drive pulley 19. It is prevented from enterng ice chute 245 by an air curtain from a row of nozzles 247 in a. header 249. To supply the lower portion of the belt the liquid passes through tube 251 to four sprinkler nozzles 253 connected to tube 251 by TS 255. Nozzles 253 are so located that they produce complete coverage of the lower freezing portion of belt 39. The nozzles 253 and tube 251 are secured into a run-down pan 257 which has sides curved to fit the belt. vRubber edges 259 on these sides form a splash seal against the rubber edges of belt 39. Another rubber strip 261 across the belt at the top of the upper end of run-down pan 257 forms a splash seal at this point. An air curtain from a row of nozzles 263 in header 265 prevents any unfrozen liquid from following down the belt into ice chute 245. Hence it is all deflected into run-down pan 257 and returns to sump 229 at point 267. A finned cooling coil 269 is submerged in the liquid in sump 229 for precooling the returned unfrozen liquid and the make-up from the float valve 225. A blower 271, direct-driven by motor 273 provides the air for the air curtains. Its discharge is divided into four tubes 275. The two shown supply headers 247 and 265. The two behind them supply the air curtains for the other belt. A splash pan 2'62 fits snugly on top of sump 229. It has an ice chute 245 built into it and also has a support trough for air header 249 and run down trough for the excess unfrozen liquid from the upper freezing surface. A lower extension 245A of the ice chute is built into sump 229 to guide the ice harvested from the lower cooling surface through the bottom of the ice maker out of contact with the unfrozen liquid.

PREC-OC-LER REFRIGERATION As has been indicated above, the liquid to be frozen is precooled by cooling coils on upper troughs 239 and 241 and finned lower coils 269 immersed in the lower sumps 29. These coils are cooled by the evapoartion of a refrigcrant in a system in conformity with general practice diagrammed in FIGURE 10. The liquid refrigerant flows from the receiver 277 under control of solenoid valve 279. Its flow is properly distributed between the four evaporators by means of four adjustable needle valves 281. The bulb 283 of thermal switch 285 is secured at one of the upper precooler troughs 241 so that it is in contact with the liquid as it fiows onto the belt. The switch 285 controls solenoid valve 279. Thus the amount of cooling is regulated by the temperature of the precooled liquid to be frozen.

GENERAL ARRANGEMENT As may be seen in FIGURES 1 and 3, the cold portions of the ice maker are enclosed in a cabinet 287 which is comprised of readily removable insulated panels joined at their edges by angle strips 289. Thus the front, rear, and sides of this cabinet may each be removed in one piece for ready service access. Since the slant portions of frame 5 are cantilevered, replacement of belt 39 is simple after removal of the side and rear cabinet sections, the run-down pan 257, and the splash-pan 262. Disconnecting rods 43 permits bearing blocks 31 to slide downward and to the left along with idler pulley 37 producing clearance for removal of belt 39. A thin section of the cabinet projects at the lower front center so that gear motor 291 may be mounted outside the insulated space. Its output shaft 61 projects through the panel with drive sprocket '59 on the inside. Thus the motor heat is excluded.

What is claimed is:

1. In congealing apparatus a combination of an endless metal belt having an outer surface upon which ice may be formed and having dam means at its edges which protrude from the opposite side to form continuous rims, mounting means for said belt which support said belt with two runs which extend between end portions, drive means to drive said belt at one of said end portions, a pair refrigerated plates presenting grooved surfaces respectively along said runs between said rims with said belt moving along said surfaces when it is driven, one of said end portions of said belt being at higher elevation than the other whereby one of said runs is an upper run along which said belt moves upwardly and the other run is a lower run along which said belt moves downwardly,

means to supply heat conducting lubricant between said belt and said surfaces, and means to collect and remove said lubricant from between said rims at the lower end of said lower run, said means to collect and remove lubricant comprising cup means which is mounted to move with said belt from the lower end of said lower run and to receive and raise the lubricant and means to discharge the lubricant from said cup means.

2. Apparatus as described in claim 1 which includes means to rectify the lubricant after it has been removed.

3. Apparatus as described in claim 1 wherein said belt is work-hardened Monel metal.

4. In congealing apparatus a combination of an endless metal belt having an outer surface upon which ice may be formed and having dam means at its edges which protrude from the opposite side to form continuous rims, mounting means for said belt which support said belt with two runs which extend between end portions, drive means to drive said belt at one of said end portions, a pair of refrigerated plates presenting grooved surfaces respectively along said runs between said rims with said belt moving along said surfaces when it is driven, each of said refrigerated plates having a surface in contact with said belt Which is formed of sprayed molybdenum having pores in which heat conducting plastic has been placed, one of said end portions of said belt being at a higher elevation than the other whereby one of said runs is an upper run along which said belt moves upwardly and the other run is a lower run along which said belt moves downwardly, means to supply heat conducting lubricant between said belt and said surfaces, and means to collect and remove said lubricant from between said rims at the lower end of said lower run.

5. Apparatus as described in claim 4 wherein each of said refrigerated plates has grooves along said surfaces, means for supplying the heat conducting lubricant to the bottom side of said belt as it starts along each of said runs, and wherein said apparatus includes a drum constituting the mounting means between the bottom ends of said runs, groove means in said drum within which the lubricant collects, and wherein said means to remove the lubricant comprises cup means mounted within said drum and positioned to dip lubricant from said groove means and to lift the lubricant upwardly, and means to receive the lubricant from said cup means at an elevated level.

=3. Apparatus as described in claim 5 wherein said means to receive the lubricant comprises tube means mounted upon said cup means and extending radially inwardly, stationary means to receive the lubricant from said tube means, and means to return the lubricant to a lubricant supply means.

7. In congealing apparatus a combination of an endless metal belt having an outer surface upon which ice may be formed and having dam means atits edges which protrude from the opposite side to form continuous rims, mounting means for said belt Which support said belt with two runs which extend between end portions, drive means to drive said belt at one of said end portions, a pair of refrigerated plates presenting grooved surfaces respectively along said runs between said rims with said belt moving along said surfaces when it is driven, one of said end portion of said belt being at a higher elevation than the other whereby one of said runs is an upper run along which said belt moves upwardly and the other run is a lower run along which said belt moves downwardly, means to supply heat conducting lubricant between said belt and said surfaces, pulley means providing the mounting means for one end of said belt, adjustable spring means providing tension at one side of said pulley means, hydraulic means providing tension at the other side of said pulley means, and control means to control said hydraulic means and thereby guide said belt.

8. In congealing apparatus the combination of means providing a moving surface upon which a product is congealed, and means to impel a stream of air against the surface of the congealed product Within a predetermined zone of the movement of said surface thereby to limit the zone of uncongealed liquid, said moving surface being that References Cited UNITED STATES PATENTS 1,046,307 12/1912 Kind 62345 X 2,990,199 6/1961 Field 6272 3,037,366 6/1962 Field 62345 3,356,182 12/1967 Robinson et a1. 1846 WILLIAM E. WAYNER, Primary Examiner US. Cl. X.R.

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