US2419954A - Freezing machine - Google Patents

Description

y 6, N. J. SCHAAL FREEZING MACHINE Filed s pt. 19, 1939 3 Sheets-Sheet 1 m mg ON Q M 6, 1947- N. SCHAAL 2,419,954

FREEZING MACHINE Filed Sept. 19, 1939 s Sheets-Shet 2 INVENTOR.

y 1947. N. J. SCHAAL FREEZING MACHINE 7 Filed Sept. 19, 1939 3 Sheets-Sheet 5 Patented May 6, 1947 uNi'rEp STATES PATENT or ies FREEZING MACHlNE Norbert J. Schaal, Riverton Heights, Wash.

Application September 19, 1939, Serial No. 295,614

Claims.

My invention relates to improvements in freezing machine for making crystalline laminae of frozen liquid, for use in the icing of food products, the cooling of liquids, and other purposes.

Referring to the accompanying drawings, Figure 1 is a view of a portion of one of the crystalline laminae made on my machine. Figure 2 is a longitudinal cross-section view of my machine for the production of said laminae, Figure 3 is a transverse section of the same machine. Figure 4 is a view of a part of the machine in the area surrounding one of the adjustable bearings. Figure 5 is a cross-section of a portion of the frozen lamina after it has been stripped from the drum and before removing the embedded wires. Figure 6 is a greatly enlarged section of a portion of the roll and a lamina and-wire at the time when the wire leaves the lamina. Fig. 7 is a systematic diagram showing safety stops and means for controlling the temperature and thickness of the ice layer.

When food products have been packed in crystalline fragments made by freezing water or other liquid, or when such crystalline material has been stored in bins or piles and subjected to the action of warm air, it has been found that the crystalline material lasted longer if it was in a form having relativelylow thermal conductivity.

The thermal conductivity of a, mass of the crystalline material is lowest when the percentage of voids is high, when the heat must pass through a maximum number and area of solid-air interfaces per inch of travel, and when the contact area between surfaces of adjacent fragments is a minimum.

Heretofore, laminae made for the above purposes have been in the form of almost flat flakes of very slight curvature. Such flakes possess relatively little strength and are therefore I easily pressed into good contact with one another, thus reducing the percentage of voids, reducing the number and area of solid-air interfaces through which the heat must pass, and increasing the contact area between surfaces of adjacent fragments.

Lamina made on the machine of the present invention is of such form that it cannot easily be pressed into intimate contact, over any relatively large portion of its surface, with adjacent laminae. Therefore, even for a given thickness of laminae, a mass of these new laminae has lower thermal conductivity than a mass of the previous type. However, due to its greater strength and frozen. The matrix is kept at a temperature be- 7 more effective use of material in resisting distortion, this new form of lamina may be produced than was found most effective inthe former type.

The use of this smaller thickness naturally results in a still further decrease in the thermal conductivity of a mass of these laminae. I

A very much enlarged view of a portion of a lamina made on the present machine is shown in Figure 1. Protuberances in the form of ridges on the top and bottom surfaces of the lamina act as fenders to prevent the close contact of more than a minimum proportion of the area of an adjacent lamina, thus ensuring a large percentage of voids. .Also, the ridges act as reinforcements, tending to resist breakage of the lamina.

Another advantage of the lamina is the fact that, due to the plurality of ridges and depressions, the total surface area is relatively large, thus increasing the speed with which heat is absorbed from a liquid into which the lamina is immersed for the purpose of coolin such liquid.

In the production of the above described laminae, I place narrow wires in contact with a freezing matrix of high thermal conductivity, high density and high specific heat, having a surface layer with very little affinity for the liquid to be low the freezing point of the liquid to be frozen to make the laminae. Liquid is then applied to the matrix and wires are allowed to freeze, thus forming a reinforced lamina of brittle frozen material, strongly reinforced by the wires. The wires are then used to strip this reinforced lamina from the matrix.

It has been found that a similar layer of frozen liquid, namely water ice, formed without the reinforcements, resists removal by chipping or scraping, due to the fact that the edges of the lamina often break off before sufiicient force can be applied to strip off the main body of the lamina.

After the reinforced lamina has been stripped from the surface of the matrix, the wires must be removed from the lamina. This may be done by stretching the wires to a rigid condition and then applying force to the lamina in such amount and direction as to sever the bond between the wires and the surface of the lamina.

My experiments prove that for best results the wires should be continuous in their contact over the entire portion of their length that happens to be in order that the neutral axis of the reinforced lamina, considered as a beam, may be close to the surface on the side toward the matrix, so that practically no stretching of any part of the frozen liquid, with its low tensile strength, may occur during the flexure which is necessary in order to remove the lamina from the surface. In my experiments with wire mesh in place of single parallel wires, I found that due to the greater thickness of the mesh, caused by the necessary crossing of the wires, for a given gauge of wire, the neutral surface of the reinforced lamina was at a greater distance from the face of-the lamina toward the matrix. Consequently, the brittle material of the lamina was subjected to tension at the face toward the matrix, at the time of stripping, resulting in an inferior product.

Since the crystalline lamina is to be flexed in only one direction, it is necessary to reinforce it in only one direction, and wires tending to reinforce it in any other direction would be superfluous and in the way. I therefore find it best to use parallel and mutually independent wires.

I prefer to form such laminae by means of mechanism illustrated in the accompanying drawings.

Drum I is designed to be rotated about aline through centers of bearings 2 and 3. Shaft 4 carries drive sprocket 5. Shaft 6 is h'ollow to allow of the pumping of refrigerating liquid to and from the interior of drum I. Cooling fluid enters fitting I and is distributed to the interior of drum I by pipe 8. The cooling fluid leaves drum I by means of annular space between 6 and roll I8 in the manner of a multiple rope drive.

Water passes into the apparatus through magnetic valve 23 and float valve 24. The water is compelled by baflle 25 to pass by the refrigerating coils I6 before coming in contact with the drum I and belts l'I.

The rotation of drum I, clockwise in Figure 3, causes successive portions of the wires I1 to be pressed into intimate contact with the surface of the drum I.

The more or less cylindrical shell of the refrigerated drum I may be made from hard copper, which has the capacity to absorb a great deal of heat for a given temperature rise, and

8, and is kept from leaking out by means of pack- Drum I is insulated at the ends by sealed in-' sulation discs, I3, I3, held in place by metal discs I4, I4.

Drum I dips into water in insulated tank I5, which is provided with cooling coils I6 for precooling of the water.

The drum I is grooved on its outer surface to form a suitable matrix for the ice which is to be formed and to guide the endless wires I'I. As illustrated in Fig. 1, one side of the ice particle conforms to the irregular, grooved surface of the drum against which it was frozen or cast. If the thickness of the lamina is very small as compared to the dimensions of the grooves, then the opposite surface of the lamina also conforms quite closely to the form of the drum surface.

metal mandrel I9 whose ends terminate in journals 20, mounted in adjustable bearings 2i, con trolled by set screws 22.

The endless wires are mounted on drum I and Fig. 1 reprehas a very high thermal conductivity. The outer surface of the drum may be coated with chromium, whose exposed surface, in contact with the atmosphere, becomes coated with a material not easily wet by water.

As the drum turns, the ice lamina 26, together with the embedded wires I1, is carried up and out of the water and exposed to the cold air of the refrigerated room in which this apparatus is to be used. Heat continues to be absorbed from the water-ice 26 and it arrives at the top of the drum I at a temperature considerably below its freezing point.

It will be noted that the layer of ice, in combination with the embedded wires, forms a reinforced beam. That portion which is next to the surface of the drum I is, as a result of the reinforcing wires I1, very strong in tension. Without the wires, the ice would naturally be very weak in tension. The remaining portion of the crosssection of this reinforced beam is strong in compression. It will be seen that the conditions are ideal for the resisting of force tending to bend this reinforced beam away from the drum I. Consequently, the portion of this reinforced beam between the points of tangency 21 and 28 acts, as a lever in stripping itself loose from drum I at point of tangency 21.

The cross-section of the ice and wires II, at a point intermediate between 21 and 28, is shown in Figure 5. The lower surface of this section, naturally has the form of the grooved surface of drum I.

The surface of roll I8 is also grooved in a similar manner, except that the central portionof each groove is made slightly deeper and the surface between the grooves is releaved, eliminating the cross grooves entirely, as shown in very much enlarged section in Figure 6.

The wires I! are maintained at sufficient tension to ensure that they are substantially straight at all points between 21 and their point of tangency 28 on roll I8. The belts therefore continue in a straight line toward their seats in the bottom of grooves in roll I8, while the ice lamina is gently forced upward by the remaining portions of the sides of the grooves on roll- I8, thus freeing the belts from the under surface of the ice lamina 29] and allowing this lamina to be discharged over the top of roll I8.

Roll surface I8 is made fromelastic material to allow for individual differences in the lengths of the endless wires I1 and to aid in freeing the surface of roll I8 of small pieces of ice which break loose from the under side of the lamina 29, next to the wires I1, as shown in Figure 6. Also, said elastic material is used in order that the wires Il may sink into the surface of roll I8 an amount depending upon their tension, making it possible, by changing the tension of the wires, to regulate the pressure exerted in the removal of the ice lamina from the wires I'I.

Angle iron scraper 30 is designed to prevent small pieces of ice from dropping down and lodging between the wires I1 and the face of the drum I, thus straining wires I1. The scraper 30 is adjustably mounted on arms 3| and pivots about axis of shaft 32. This pivoting is resisted by spring 33, and is provided to prevent breakage of a wire I! if a projecting joint thereof becomes jammed against scraper 30. Screw 34 is used in the adjusting of the normal position of scraper 30.

Power for'rotating drum I is supplied from mains 35, 35, 35, through magnetic switch 36 to motor 31. Magnetic switch 35 is controlled by means of push-button switch 38 and contact lever 39. Motor 3'! drives sprocket 5 through variable speed transmission 45, worm reducer 4| and chain 42.

At all times it is desirable to produce laminae of uniform thickness. Accordingly, gauging finger 43 is pressed against the surface of the ice through the action of the spring 44. Excessive thickness of the ice 26 causes the contact lever 45 to touch contact 46. Lever 44 and contacts 46 and 41 are connected to reversing magnetic switch 48, which controls the direction of rotation of motor 49, which operates the control screw 50 of the variable speed transmission 40 through gears-5| and 52. The relationship of contacts 46 and 41, switch 48 and motor 49, along with mechanical relationships in the speed changer 40 are srarranged that a reduction in the thickness of vne ice, beyond a certain point, causes the drum I to decrease its speed, while if the ice is too thick, the speed of the drum I will be increased.

Thermostat I2 is electrically connected to the magnetic intake valve 23. This valve is so constructed and adjusted that liquid is allowed to pass only when current flows through its windings. the current to flow to magnetic valve 23 whenever the cooling fluid passing through said thermostat is cold enough to indicate that suificient cooling of drum I is taking place to warrant the application of water to its surface.

If at any time, for any cause, the rotation of the drum I is stopped, or the action of the refrigerating system stops, it becomes necessary to drain the tank I5 and. prevent the entry of further'water, so as to prevent the formation of an excessive layer of ice in the tank I 5. Magnetic valve 53 is constructed and adjusted so as to allow liquid to flow only when there is no current supplied to its windings. When shutting down the machine, the opening of magnetic switch 36 shuts off the supply of current to magnetic valve 53 and magnetic intake valve 23, draining tank I5 and preventing further intake of water through magnetic intake valve 23.

Gear pump 54 is driven by worm reducer 4I. As a result of the action of pump 54, pressure is built up in tank 55, making contact in pressurestat 56, thus not interfering with the action of magnetic valves 23 and 53. However, if worm drive M, and consequently drum I, stops, the pressure in 55 is soon lost through valve 51 and contact is broken in pressurestat 55, thus preventing the flow of current to magnetic valves 23 and 53 and so emptying tank l5 and preventing further water from entering until repairs or corrections are made.

The pressurestat 58 is connected to the suction line of the refrigerating compressor which sup- During operation the thermostat I2 allows ice will stick to the tops of the ridges on drum I and will be carried around to contact lever 39', breaking the contact and so shutting off the current supply through the action of magnetic switch 36.

Pipe 59 is used in supplying a small quantity of low freezing point oil to the surface of drum I. This oil has a greater wetting tendencytoward chromium than water has, and will displace water on the surface of that metal.

I claim:

1. A machine for the freezing of ice comprising a rigid rotatable refrigeratable drum adapted to contain a refrigerating medium, said drum formed with encircling grooves in spaced relationship therealong, wires disposed about and in contact with only a portion of the drum within said grooves, means for applying liquid to the surface of thedrum for freezin over said wires, and means for rotating the drum whereby the wires will efiect the separation of formed ice from the drum surface.

2. A machine for the production of crystalline laminae of frozen liquid comprising a rigid rotatable refrigeratable drum adapted to contain a refrigerating medium, said drum formed with circumferential grooves in spaced relationship therealong, a rotatably mounted, roll separate from the drum, a plurality of wire belts applied about the roll and drum within the grooves of the latter, means for applying a liquid to a portion of the periphery of said drum as it rotates for freezing thereon over said belts, and means for rotating the drum.

3. A machine for the production of crystalline laminae of frozen liquid comprising a rigid rotatable refrigeratable drum adapted to contain a refrigerating medium, a plurality of separate unconnected parallel endless single wire belts drawn taut and operating about a portion of the periphery of said drum, means for applying liquid to a portion of the periphery of said drum for freezing thereon over said wires, means for rotating the drum for the progressive freezing of ice about its surface and for the separation of the ice from the surface by the wire belts, and means for the separation of the ice from said wires.

4. A machine for the production of frozen liquid, comprising: a rigid rotatable refrigeratable drum adapted to contain a refrigerant, a roll spaced from and parallel to said drum, placed about said drum and roll a plurality of spaced apart separate unconnected parallel endless single wire belts, means for refrigerating said drum, means for rotating said drum, and means for supplying a liquid to the surface of said drum for freezing thereon and stripping therefrom by said belts.

5. A machine for the production of frozen liquid, comprising: a rigid rotatable refrigeratable drum adapted to contain a refrigerant,'-a roll spaced from and parallel to said drum, wire placed about said drum and roll in a plurality of runs to form a belt extending around but not contacting the whole of the circumference of said 7- drum, said wire being not cross connected. means for refrigerating said drum, means for rotating said drum, and means for supplying a liquid to the surface of said drum for freezing thereon and stripping therefrom by said belts.

NORBERT JAMES SCHAAL.

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

UNITED STATES PATENTS Number Name Date 2,005,736 Field June 25, 1935 2,025,711 Bemis Dec. 31, 1935 2,149,912 Fuss Mar. 7, 1939 607,764 Rankin July 19, 1898 Number Number Name Dlte Kallander July 28, 1931 Barrett Feb. 25, 1936 Short Sept. 15, 1936 'I'hllenius Mar. 14, 1939 Swab Mar. 28, 1940 Bennett Jan. I, 1930 Hathorne Oct, 31, 1933 Field June 25, 1935 Anderson Nov. 1, 1938 Field June 10, 1941 Field Apr. 17, 1923 FOREIGN PATENTS Country Date Swiss Aug. 1, 1934

Images