US3058319A

US3058319A - Ice making machines

Info

Publication number: US3058319A
Application number: US753829A
Authority: US
Inventors: Gerald M Lees
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-08-07
Filing date: 1958-08-07
Publication date: 1962-10-16
Anticipated expiration: 1979-10-16

Description

Oct. 16, 1962 G. M, was 3,058,319

ICE MAKING MACHINES Filed Aug. 7, 1958 4 Sheets-Sheet 1 jlififOfl' fierald 0% lees ,B M MYW Oct. 16, 1962 cs. M. LEES 10s MAKING MACHINES 4 Sheets-Sheet 2 Filed Aug. 7, 1958 Inzntor: @eralci Ml. Lees -wwv/g z m/ Oct. 16, 1962 G. M. LEES ICE MAKING MACHINES 4 Sheets-Sheet 3 72 #6 72 #07 fieralci M lees y/M M, M-

WNW

Filed Aug. 7, 1.958

Oct. 16, 1962 G. M. LEES ICE MAKING MACHINES 4 Sheets-Sheet 4 Filed Aug. 7-, 1958 )luu m 531 N H N W N U \I U \N United States Patent Ofi ice Patented Get. 16, 1962 3,055,319 ICE MAKING MACEHNES Gerald M. Lees, 5909 W. Lake St, Chicago, Ill. Filed Aug. 7, 1958, Ser. No. 753,829 11 Claims. (Cl. 6234S) My invention relates to improvements in ice making machines and, more specifically, to machines for the continuous production of flake ice.

A commercially Well-accepted form of flake ice machine comprises a tubular evaporator shell, down the inside surface of which water flows slowly so as to freeze thereon. A plurality of ice removing blades rotate around the interior of the evaporator shell running in close proximity to the inside surface thereof and continuously flake off the ice formed, which then drops through the tube and into an appropriate receptacle.

My invention arose from and is illustrated in conjunction with a machine incorporating this same tubular evaporator shell. By the practice of my invention, however, far greater efficiency is obtained from the use of the shell and, at the same time, the strains implicit in moving the blades about the inside of the shell for ice removal are greatly minimized so as to make possible considerably lighter bearing structure which at the same time possesses considerably longer life.

I achieve this increased efliciency and production and lessening of bearing strain by employing both the inside and outside surfaces of the evaporator shell as freezing surfaces. The improvement of efficiency will be readily appreciated. From a shell of given size more than twice the quantity of ice can be obtained. Since the dimensions of the evaporator shell determine largely the physical space occupied by the machine, a substantially greater quantity of ice can be produced from a machine occupying a given floor area. The heat exchange surfaces on which the ice is formed are likewise more than doubled, with permits a more efficient utilization of the equipment.

With the conventional machines as described above, there will be some heat absorption through the exterior surface of the shell which represents wasted power. Under my present invention, there is no heat waste from that surface.

Again, with the conventional machine, the above described ice harvesting blades are carried by a blade carrier which in turn is mounted on a shaft extending axially up through the center of the evaporator shell, which is powered for rotation to drive the blades into the continuously formed ice sheet. There will inevitably be a very substantial thrust on the bearings supporting this shaft due to the tendency of the blades to ride out of the ice sheet. I contemplate in the practice of my invention that a common blade carrier be used to detach and flake both the inside and the outside sheets of ice simultaneously across the shell. By having two sets of blades bearing against the opposite freezing surfaces, this thrust is absorbed by the structure of the blade carrier itself and the bearings wholly relieved of this strain.

Again, in the conventional ice machine the ice removing blades are advanced into the ice sheet at an angle to their line of movement so as to obtain a more positive cleaning of the freezing surface and more effective ice detachment which again imposes thrusts on the mounting and driving structure of the blade carriers. My invention provides novel means whereby the driving structure is wholly relieved of this strain.

One problem encountered in previously known ice making machines of this type has been an adequate delivery of water to the freezing surface with, however, a cessation of water flow to any portion of the freezing surface immediately prior to the removal of ice from it so that the water delivered to that portion has an opportunity to freeze wholly and flake off dry. This has been achieved in the past by an annular water chamber delivering water to the freezing surface, flow from which is shut off by a movable dam moving with but preceding the blade carrier. 1 have made novel provision in the present invention for the achievement of this purpose which functions in positive fashion and is not dependent on the movable damming of water flow with its attendant possibilities of leakage.

Other objects and advantages of my invention will be apparent from the following description and drawings, of which:

FIG. 1 is a central sectional view through an ice machine embodying my invention, showing certain portions thereof in elevation;

FiG. 2 is a top plan view of the machine of FIG. 1;

FIG. 3 is a section taken substantially along the line 33 of FIG. .1, looking in the direction of the arrows;

FIG. 4 is a section taken substantially along the line 4-4 of FIG. 3, looking in the direction of the arrows;

FIG. 5 is a section taken substantially along the line 5-5 of FIG. 3, looking in the direction of the arrows;

FIG. 6 is a section taken substantially along the line 6-6 of FIG. 1, looking in the direction of the arrows;

FIG. 7 is a section taken substantially along the line 7-7 of FIG. 6, looking in the direction of the arrows;

FIG. 8 is a section taken substantially along the line 8-S of FIG. 1, looking in the direction of the arrows;

PEG. 9 is an edge elevation of the blade mounting structure shown in section in FIG. 8 and may be regarded as viewing the right hand structure of FIG. 8 from the left side thereof;

FIG. 10 is a side elevation of the blade mounting structure and may be regarded as viewing the structure of FIG. 9 from the right side thereof; and

FIG. 11 is a fragmentary side elevation of the machine taken substantially from the line 1 111 of FIG. 2, looking in the direction of the arrows.

The embodiment of my invention illustrated in the drawings includes a radial four armed base 12 which consists of two

plates

14 and 16 secured together in a T shape, plate 16 meeting the center of plate 14, to stand on their edges and constituting three arms of the base. The fourth arm of the base is a pipe 18 which is welded at one end to the center of plate 14 to extend perpendicularly away therefrom oppositely to plate 16. The other end of the pipe is secured in open communication with rectangular return chamber 26, the bottom 22 of which lies in the same plane as the bottom edges of the

plates

14 and 16, and, with the plates, makes up the base on which the remaining structure rests.

An annular trough 24 having upstanding edges 26 is secured to the top edges of plates 14- and 16 concentric with the center of plate 14. Pipe 18 has a smaller diameter than the height of plates 14- and 16, and a spacer 28 is therefore secured to the top side of the pipe in a position to underlie trough 24 so as to support the trough over the pipe. The trough has an opening 30 in the bottom thereof to one side of pipe 18, and an elbow 32 extends from opening 3t into a port 34 in the side of pipe 18.

Return chamber 20 is in communication with a float valve chamber 36 through a pipe 38. The float valve chamber has a float valve 40 therein to govern the admission of water thereinto from any appropriate supply through pipe 42. Chamber 20 is also connected to the intake side 44 of a pump 46 by means of a tube 48. Pump 46 is driven by a motor 50. The output side 52 of the pump has a pipe 54- connected thereto which extends upwardly outside the machine proper and then extends inwardly to a downwardly directed outlet 56 at a point close to the vertical center line of the machine proper as defined by the intersection of the arms of the base as will be described later.

A post 58 consisting of a large diameter pipe section is secured as by welding at its lower end to the top edges of the base arms to stand upwardly from the center of the base 12. The post may be braced in position by gussets 60. Post 58 has a cap 62 secured thereto at its upper end as by welding. A shaft 64 having a flanged base 66 is secured by bolts 68 to the top 62 of the post to extend axially upward therefrom.

A tubular evaporator shell 70 having an inside freezing wall 72, an outside freezing wall 74, a top annular end wall 76 and a bottom annular end wall 78 is likewise mounted to the base to be concentric with the post 58. The means of mounting the shell to the base consists of legs 80 extending downward from the bottom wall 78 at spaced intervals which are bolted to L-shaped brackets 82 secured as by welding to the bottom of trough 24. It will be appreciated that the width of trough 24 is equal to the width of the evaporator shell or the distance between the inside 72 and outside 74 walls thereof and lies directly under the evaporator shell. The evaporator, of course, is connected to receive liquid refrigerant and exhaust spent refrigerant. A showing and description of such well-known components are, however, believed unnecessary.

I contemplate that both the inside and

outside walls

72, 74 of the evaporator shell be smoothly machined and hard chrome plated. These surfaces, in addition to being the freezing surfaces, are also to serve as guide surfaces for the ice harvesting blades as will be subsequently described and, therefore, an exceedingly durable surface is greatly to be desired. An annular bearing ring 84 is welded to the top wall 76 of the evaporator shell to follow generally the central line thereof.

A relatively wide channel member 86 having outwardly facing flanges extends upwardly from the top of chamber 20 to a point well above the level of the evaporator shell 70. A horizontal shelf 88 extends outwardly from a point near the upper end of the channel member 86 and is appropriately braced by bracket 90 to support a motor 92. A second broad channel member 94, flanges up, is secured at one end as by bolts 96 to the top of channel member 86 and extends inwardly therefrom to be secured at its other end 98 to the top of shaft 64 as by screws 100. The end 98 of channel member 94 may have a sleeve 102 welded to the underside thereof which fits closely over the end of shaft 64. A speed reducing gear box 104 is secured to the side of channel member 94 as by bolts 106. The speed reducer is driven by a V-belt 108 from motor 92 and the output shaft 110 of the speed reducing gear box 104 has a sprocket wheel 112 thereon.

All of the above-described parts of my machine are positionally stationary. The remaining parts thereof now to be described may be characterized generally as a rotor assembly 114 which revolves on shaft 64. The rotor includes a sleeve 116 fitting closely shaft 64 and having bearings 118 at the upper and lower ends thereof for free rotation on shaft 64. The lower bearing is contained between a recess 120 in the lower end of sleeve 116 and a shoulder 122 at the lower end of shaft 64. The upper bearing is contained between a similar recess 124 in the upper end of sleeve 116 and sleeve 102 mounted to the underside of the channel member 94.

Sleeve 116 constitutes the inside wall of an annular water receiving trough 126 which surrounds shaft 64. The floor 128 of the water receiving trough is the central annular portion of a four-armed spider 129 which constitutes essentially the base of the rotor assembly, into the central aperture of which the lower end of sleeve 116 is secured as by welding. The outer wall 130 of the water receiving trough is an annular member secured at its lower end 132 against the outside edge of the trough floor 128 and having an outwardly turned flange 134 at its upper end. A large diameter sprocket wheel 136 is secured against flange 134 by bolts 138 in horizontal alignment with the sprocket wheel 112 of the speed reducer 104. A roller chain 140 extends between

sprocket wheels

112 and 136 to drive sprocket wheel 136 or the rotor assembly generally. Sprocket wheel 136 has a large central aperture 142 therein inside the ring of bolts 138 which leaves the water receiving trough 126 completely open at the top.

Three

arms

143, 144, 145 of the spider 129 extend outwardly from the water receiving trough floor 128 to points overlying the evaporator shell and spaced from each other. A distribution trough 146 amounting to less than a complete annulus is mounted to the ends of the

arms

143, 144, to overlie about 260 of the top wall 76 of the evaporator shell. The arm 144 constitutes the floor or bottom of a delivery trough 148. The lower portion of the outer wall 130 of the water receiving trough 126 is cut away as at 150 where it overlies the arm 144. Delivery trough walls 152 are welded at their inner ends to the edges 154 of the cut-away portion 150 of the outer wall 130 of the water receiving trough and at their lower edges to the arm 144 to define the delivery trough 152.

The distribution trough 146 includes floor 156, upstanding outside 158 and inside 16!) walls and leading and trailing

end walls

161 and 163. The inside wall is broken away as at 166 to define an inlet from the delivery trough 152 into the distribution trough 146, the outer ends of the delivery trough walls 152 and the edges of the break in the inside wall 160 of the distribution trough being welded in water-tight relation.

The outside and inside

walls

158 and 160 of the distribution trough 146 are preforated at closely spaced intervals adjacent the trough floor 156 and nipples 162 are theaded into the perforations. Open ended small diameter pipes 164 in turn are threaded into the nipples at one end and are recurved under the trough 156 so that the pipes leading from the outer wall 158 of the distribution trough overlie the top wall of the evaporator shell outsider the bearing ring 84 and the pipes leading from the inner wall 160 of the distribution trough overlie the top wall of the evaporator shell inside bearing ring 84.

The rotor assembly 114 likewise includes the ice harvesting assembly indicated generally by 170. The fourth arm 172 of the spider 129 is off-set on the hub or annular central portion 128 thereof forwardly relative to the direction of movement of the rotor. It, like the other arms, is a flat horizontal member having, however, a bracing gusset portion 174 interconnecting the base of arm 172 to arm 143 which leads arm 172. A vertical plate 176 is welded to the back edge of arm 172 to extend u-pwardly therefrom and right triangular braces 178 are welded on one edge to arm 172 and on their adjacent edge to plate 176 to support and brace plate 176 in its vertical orientation. Ar-m 172 is shorter than the rest of the arms and overlaps only slightly the top wall of the evaporator shell.

A blade carrier 180 is secured to the rear surface of plate 176 by bolts 181. The blade carrier is a piece of very heavy metal plate formed into an inverted U and having substantial Width both on the

sides

182, 184 and end 186. The depth of the U is such as to receive the length of the evaporator shell within the central opening 188 thereof. rigidity under the strains of ice removal. The upper end of the carrier or the base 186 of the U is built up to still greater width by the addition of supporting plates 190 on the front and back sides thereof so as to strengthen further the carrier at this point.

The facing edges of the sides '182, 184 of the U will be spaced from the inside and outside surfaces 72, 74 of the evaporator shell. To these edges, 1 secure ice harvesting blade racks 192 which support blades 194 in im mediate proximity to the inside and outside freezing

surfaces

72, 74. The blade racks 192 are bored along their outside edges for the reception of bolts 196 by which the The heavy section of this member is to insure plates are secured against the

sides

182, 184 of the blade carrier. The ice removing blades 194 are secured in appropriate slots formed in the inside edges of the racks. The blade racks may be appropriately stiffened as by ribs 198 and gussets 200.

The ice removal blades 194 shown in the drawings are of conventional design and include a leading sharp edge 282 and a trailing portion 294 of greater width. The leading edges score the ice formed on the freezing surfaces into ribbons and the trailing portions 204 thereafter wedge the ice off in flakes.

It will be appreciated, particularly from FIGS. 9 and 10, that the blades are not situated at a right angle to the axis of the blade rack 192 but rather are inclined with the leading edges 202 thereof pointing generally downward relative to the direction of travel of the blades. The obvious effect of a rack of these blades being drawn across a freezing surface would, therefore, obviously be to draw the blade rack spirally downward as it traverses a cylindrical freezing surface. To counteract this effect, I provide a roller bracket 206 secured to the back or trailing side of the upper end 186 of the blade carrier 18%. A roller 268 is secured to the side of bracket 206 by a horizontal bolt 210 which positions the roller over and in bearing relation with the bearing ring 84 secured to the top wall of the evaporator shell 70. A connector plate 212 (FIG. 3) is secured at its inner end to the gusset portion 174 interconnecting

arms

172 and 143 of the rotor. The connector plate extends outward from the rotor at a substantial angle to arm 172 to lead that arm and trail only slightly arm 143. An angle member 214 is connected to the outer end of the connector plate 212 to extend outwardly in alignment therewith and substantially beyond the evaporator shell 70. A first vertical plate 216 is welded about centrally to the front surface of the upper end 186 of the blade carrier 180 and extends angularly inward therefrom so as to pass immediately by the outer leading corner 218 of arm 172. A block 220 is welded to the inside of plate 216 in abutting relation with the leading corner 218 of arm 172. A second vertical plate 222 is welded at its trailing end to the leading free end of plate 216 and at its other end to angle 214, the

plates

216 and 222 together constituting a bridge interconnecting the upper end of the blade carrier and the angle 214. The angle 214 has a vertical plate 224 secured approximately centrally thereto and extending forward therefrom which constitutes a second roller bracket. The plate supports a roller 226 mounted against the bracket by bolt 228 to support the roller in rolling engagement with the top edge of the bearing ring 84.

The blade carrier is additionally supported by a flat brace 236 which is secured at its leading end 232 against the underside of the outer end of the angle 214 and extends therefrom downwardly and rearwardly and on a curvature following the exterior periphery of the evaporator shell to its point of connection 234, as by welding or the like, to the lower portion of the outer arm 184 of the blade carrier. This brace, of course, preserves and strengthens the right angular relation between the blade carrier and what may be termed the carriage as defined by the two

rollers

208 and 226 and their supporting structure.

The blade carrier is also supported on the interior of the evaporator shell by a bearing indicated generally by 236. An inner bearing sleeve 238 surrounds post 58 adjacent the lower end thereof and is fixed thereto by set screws 240. An outer bearing sleeve 242 is secured by a bracket 244 to the lower end of the inner arm 182 of the blade carrier and a bearing 245 is contained be- -tween the two

sleeves

238, 242.

The operation of my ice making machine is as follows. The pumping motor 50 and the driving motor 92 are assumed to be in continuous operation, refrigerant is being continuously delivered to and spent refrigerant exhausted from the evaporator shell and the water supply pipe is connected to deliver water to the machine as demanded.

6 The rotor assembly, driven by the driving motor 92 will be rotating continuously and carrying the water delivery structure and the ice removing blades continuously about the evaporator shell.

Turning particularly to FIGS. 1 and 3, the pump motor is circulating water through pipe 54 and delivering it from the outlet 56 into the water receiving trough 126. Water flows from the trough 126 through the delivery trough 148 into the distribution trough 146 so as to keep the distribution trough filled throughout its length to a level above the nipples 162 in the inside and outside walls of the trough. Water thus will flow slowly through the many tubes 16-4 onto the top wall 76 of the evaporator shell and down the inside 72 and outside 74 walls thereof. The bearing ring 84 effectively maintains the distribution of water to the inside and outside freezing surfaces.

The machine as illustrated in FIGS. 2 and 3 shows the leading end wall 161 of the distribution trough 146 overlying a particular portion of the evaporator shell. The rotor assembly, as indicated, is traveling counterclockwise. Regarding that portion of the evaporator shell then with the rotor at the position indicated in these figures, this portion of the shell will begin receiving water on both the inside and outside surfaces thereof, the water flowing through the set of tubes nearest the leading end of the trough 161 and flowing down both the inside and outside of the evaporator shell. As the rotor continues to rotate, water will be continuously delivered to this area of the shell through the successive tubes 164 until the trailing end wall 163 of the distribution trough overlies this portion of the evaporator shell. As the trailing end wall passes over this portion, the flow of water thereto will be shut off. Should more water flow than the evaporator will freeze, the excess water will run down the inside and outside surfaces of the evaporator shell and drip from the bottom wall thereof into the drip trough 24.

Upon further rotation of the rotor, the freezing will continue in this portion of the evaporator shell and any water which may be present and adhering to the ice sheet formed on the inside and outside freezing surfaces will thus have an opportunity to freeze before thearrival of the ice removal blades. Further rotation of the rotor will bring the blade carrier into this area and the ice removal blades will penetrate the ice sheets formed on the inside and outside freezing surfaces, and by virtue of the in creasing thickness of the blades and by virtue of their inclination relative to the line movement thereof, will wedge the ice from the freezing surface in the form of ice flakes. The ice flakes will then fall from the freezing surfaces outside the trough 24, through the radial fourarmed base 12 and into an appropriate receiver situated under the machine.

Excess water which runs off the freezing surfaces and into the drip trough 24 passes through the trough drain 30, into the pipe 18 and thence into the return chamber 20. From the return chamber, it is again recirculated into the water receiving trough 126 by pump 46. In this fashion, any energy devoted to cooling this recirculated water is effectively scavenged.

The presence of recirculated water in the water return chamber 20* to a predetermined level prevents water inflow from the float valve chamber 36 by maintaining a leyel in that chamberto keep the float valve 40 closed. As water is withdrawn from the water return chamber, however, the water level in the float valve chamber falls and new water is admitted therethrough into the system. -It will be appreciated that by these two chambers I am able to use first the water which may drip from the freezing surfaces and add in only that amount of new, uncooled water necessary to maintain the desired rate of water delivery into the delivery trough 126.

- It will be appreciated from the foregoing description of the structure and operation of this preferred embodiment of my invention that I have devised mechanism whereby the production of any given size of cylindrical evaporator shell may be more than doubled. Nor should my invention be regarded as being limited only to a cylindrical or tubular evaporator shell. The methods of water application and ice harvest as taught by my invention are applicable to a straight as well as to "a circularly curved evaporator. Not only does the concept of freezing ice on both sides of a parallel walled evaporator shell result in a substantial doubling of the capacity thereof, it likewise substantially reduces bearing loading and accuracy requirements in the ice harvesting means. By virtue of my U-shaped ice harvesting blade carrier whereby the ice harvesting blades ride on opposite sides of an evaporator shell, the freezing surfaces themselves constitute a guide for the blades. In the illustrated tubular evaporator, therefore, the ice harvesting means may be regarded as being virtually centerless, being guided by the blades riding against opposite sides of the freezing surfaces, being loaded against the bearing ring 84 by the downward inclination of the ice removing blades and being supported in axially parallel relation to the evaporator shell by the relatively broad based carriage incorporating the two rollers which ride on the bearing ring.

It will be further appreciated that I have made novel and effective provision for distributing water to both sides of a tubular evaporator shell in such fashion as to halt the delivery of water to any given area of the evaporator shell a substantial time interval prior to the arrival of the ice removal blades so as to insure dryness of the detached ice. It will be further appreciated that I have made novel and eifective provision for reclaiming any excess water which may flow to the freezing surfaces and for insuring its return to the freezing surfaces immediately so as to take maximum advantage of whatever pre-cooling it may have had.

It will, likewise, be appreciated that the invention as described above is illustrative only and that many variations as to structural details and application may be employed in the practice of my invention, and I therefore desire that my invention be regarded as being limited only as set forth in the following claims.

I claim:

1. A flake ice making machine comprising an evaporator shell having opposite freezing surfaces equally spaced from each other, ice harvesting means including a U-shaped member straddling a longitudinal edge of said evaporator shell and movable longitudinally of said shell to dislodge ice from each of said surfaces and having arms adjacent and parallel to each of said surfaces and extending transversely of the direction of movement of said member, blades on each of said arms extending to said freezing surfaces for dislodging ice from said surfaces and guiding said member relative to said surfaces, said blades being inclined with respect to the travel of said member to draw said member against said straddled edge, and means on said member to elfect rolling engagement between said edge and said member.

2. The combination as set forth in claim 1 wherein said means for effecting rolling engagement between said U-shaped member and said straddled edge of said evaporator comprises a pair of rollers carried by said member and spaced substantially from each other lengthwise of said edge.

3. The combination as set forth in claim 1 wherein said edge includes a longitudinal rail afixed thereto and said member includes a pair of rollers riding on said rail and spaced substantially away from each other along said rail.

4. A flake ice making machine comprising a vertical tubular evaporator shell having inside and outside freezing surfaces, a trough constituting less than a complete annulus overlying the upper edge of said evaporator shell and rotatable relative thereto, means for delivering water into said trough, means for delivering water from u said trough over the length thereof to both of said freezing surfaces, an ice harvesting member mounted to straddle the upper edge of said evaporator shell and to rotate with said trough about said shell, said ice harvesting member trailing substantially the trailing end of said trough, said member having arms extending downward adjacent each of said freezing surfaces, blades on said arms extending from said arms to said freezing surfaces for removing ice from said freezing surfaces and whereby said member is guided by said surfaces, and means for rotating said trough and said member about said evaporator shell.

5. A flake ice making machine comprising a tubular evaporator shell having inside and outside freezing surfaces, means for delivering water to both of said surfaces, an ice harvesting member including arms parallel to the axis of said evaporator respectively adjacent said inside and said outside freezing surfaces and opposite each other across said evaporator, ice removal means on said arms extending to said respective freezing surfaces, carriage means associated with said ice harvesting means movably engaging one end of said evaporator shell at two spaced points to support said ice harvesting means in said parallel relation to the axis of said evaporator and means for causing relative rotation between said evaporator shell and said ice harvesting means.

6. A flake ice making machine comprising a rigid post, a vertical cylindrical evaporator shell concentric with and surrounding said post and having inside and outside freezing surfaces, means for delivering water to each of said surfaces, a U-shaped ice harvesting member straddling said evaporator shell and having arms parallel to the axis of said evaporator shell extending respectively adjacent said inside and said outside freezing surfaces, ice harvesting blades secured to said arms to extend therefrom to said freezing surfaces, driving means operatively connected to the upper end of said ice harvesting member to move said member around said freezing surfaces, means supporting the lower end of said member from said post for rotational movement thereabout, and carriage means associated with said member and movably engaging one end of said evaporator at spaced points to support said member against displacement from its axially parallel position.

7. The combination as set forth in claim 6 wherein said blades are inclined relative to their direction of travel to urge said carriage against said end of said shell.

8. A flake ice making machine comprising a vertical cylindrical evaporator shell having inside and outside freezing surfaces, a ventical spindle centrally and at the upper end of said evaporator shell, a rotor assembly mounted for rotation on said spindle, means for driving said rotor assembly, a trough constituting less than a complete annulus overlying the upper edge of said evaporator shell secured to said rotor, means for delivering water from said trough over the length thereof to both freezing surfaces, fully annular means inwardly of said trough for receiving water from a source of supply and delivering water to said trough, and ice harvesting means adapted to remove ice from both of said surfaces simultaneously mounted to said rotor assembly to trail substantially the trailing end of said trough.

9. The combination as set forth in claim 8 wherein the upper end of said evaporator shell has an annular wall secured thereto to insure distribution of water to both of said surfaces.

10. The combination as set forth in claim 9 wherein said ice harvesting means includes a carriage movably engaging the upper edge of said wall at spaced points to maintain the angular relation of the ice harvesting means with respect to the axis of said evaporator shell.

11. A flake ice making machine comprising a vertical tubular evaporator shell having inside and outside freezing surfaces, means including a pump for delivering water to the upper portions of both of said surfaces, an annular References Cited in the file of this patent trough underlying said evaporator shell and having side walls exactly aligned with said inside and outside freez- UNITED STATES PATENTS ing surfaces to catch excess water flow over said surfaces, 490,475 Holden 1893 a first chamber receiving water from said trough, means 5 1,020,759 Holden Mali 1912 connecting said chamber to the intake side of said pump 1,623,535 Fefguson P 1927 and a second chamber connected to said first chamber so 2,150,792 wl'llat 16, 1939 as to have a common water level with said first chamber 2,299,414 splegl 1942 above the bottom of both of said chambers and means 2,440,397 Enclfson P 1948 for admitting new water into said second chamber upon 10 2,683,357 A'lbnght y 1954 2,758,451 Lauterbach Aug. 14, 1956 a lowering of the Water level in said second chamber.