US2691275A - Ice making - Google Patents

Description

Oct. 12, 1954 M. ANDREWS ICE MAKING Filed July 1'7, 1950 3 Sheets-Sheet l INVENTOR Jo/in M. Andrews BY MM? ATTORN 1954 J. M. ANDREWS 2,691,275

ICE MAKING Filed July 17, 1950 3 Sheets-Sheet 2 INVENTQR ohn Mflndrews Patented Oct. 12, 1954 ICE MAKING John M.- Andrews, York, Pa., assignor to Flakice Corporation, Brooklyn, N. Y., a corporation of Delaware Application July 17, 1950, Serial No. 174,301

11 Claims.

This invention relates to refrigeration, and more in particular to the operation and control of ice-making machines such as those disclosed in the following copending applications of Meldon Gerald Lesson: Serial No. 573,939, filed January 22, 194.5, now Patent No. 2,524,815; Serial No. 685,021, filed January 24, 1946, now Patent No. 2,549,747; and Serial No. 83,803, filed March 26, 1949, now Patent No. 2,633,004. In some respects the present invention may be considered an improvement upon or a species of the invention disclosed in the last-mentioned application. The present invention is also related to that disclosed in the copending application of William M.

Grandia, Serial No. 58,158, filed October 29, 1948,

now Patent No. 2,593,874.- and certain aspects of the inventions disclosed in the two applications are closely related.

In the above-identified copending applications a number of ice-making units or machines are disclosed by means of which ice is made in the form of cubes or the like. Machines of this character are being manufactured as package units on a mass production basis, and are sold and installed throughout this country and abroad. The installation of such a unit involves connecting it to a source of electric power to operate it, and connecting it to a source of water such as city mains or individual wells and also to a drain for waste water.

In the above-identified application of William M. Grandia a control arrangement is provided for machines of the above character. These machines freeze columns of ice in vertical tubes while the water flows down the inside tube surfaces at a sufficiently rapid rate to insure that the ice is of high quality. The ice-forming operation is stopped and the harvesting operation is started whenever the flow of water through one or more of the freezing tubes is restricted. In the illustrative embodiment this mode of control is obtained by providing an overflow discharge from the top of each tube which carries cold water from that tube whenever the water flow is restricted. This cold water is directed over the bulb of a thermostatic switch which is so arranged and adjusted that the switch is opened when cold water flows over the bulb, and the opening of the switch then initiates the harvesting operation as explained above. present invention relates to the overflow control features of the arrangement just discussed.

As discussed in application Serial No. 83,603, the characteristics of the available water varies greatly, particularly in its content of dissolved The solids, i. e., its hardness. During the operation of the machines of the above character, these dissolved solids are rejected within the freezing zone and are not trapped in the ice, but rather remain in the rather substantial stream of water which returns to the sump tank from the bottoms of the freezing tubes.

In accordance with the teaching of application Serial No. 83,603, the concentration of dissolved solids is kept within permissible limits; specifically, by removing a predetermined quantity of the water during each cycle of operation and replacing the water removed with feed water. The amount of Water removed during each cycle is regulated in accordance with the condition of the feed water being supplied to that machine; for example, with very hard water a relatively large amount of water is discharged during each cycle, Whereas with a lesser degree of hardness a correspondingly lesser amount of water is removed.

It is an object of the present invention to provide for the improved operation of equipment such as that discussed above. It is a further object to provide apparatus of the above character which will operate at high efiiciency and produce maximum quantities of commercially acceptable ice even under widely varying conditions of use. Itis a further object to accomplish the above with apparatus which is inexpensive to manufacture and maintain, dependable in operation, and which may be installed and will then operate satisfactorily without the attention of highly skilled operators or engineers. It is a further object to provide for improved operation of machines of the above character while at the same time providing for flexibility in use. These and other objects will be in part obvious and in part pointed out below.

The invention accordingly consists in the features of construction, combinations of elements, arrangements of parts and in the several steps and relation and order of each of the same to one or more of the others, all as will be illustratively described herein, and the scope of the application of which will be indicated in the following claims.

In the drawings:

Figure 1 is a somewhat schematic View of an ice-making machine of the above character incorporating the present invention;

Figure 2 is a View similar to the right-hand portion of Figure l and showing another embodiment of the invention;

Figure 3 is a side elevation of an ice-making machine incorporating the embodiment of the invention of Figure 2; and,

Figure 4 is a rear elevation of the unit of Figure 3.

In describing the illustrative embodiments of the present invention, only those details are discussed which are pertinent to the understanding of the present invention, and reference may be had to the above-mentioned copending applications for'more details of the various features. Referring particularly to Figure 1 of the drawings, a bank 2 of freezing tubes 3 is cooled by a refrigerant system, which is represented schematicallyand which comprises, a compressor 4 driven by an electric motor 6, a water-cooled condenser 8 (which also acts as a receiver), andan evaporator H! which is formed by two parallel tube sections (only one of which is shown) positioned on the opposite sides of the bank of freezing tubes. A capillary restrictor tube I2 is in a pipe l3 connecting the condenser to the evaporator, and this tube provides the pressure drop to the evaporator. A gas return pipe extends from the evaporator to the compressor. Water to condense the refrigerant is supplied from a source of feed water and flows through a pipe 15 and is discharged to a drain. Pipe It has a valve [3 therein which is controlled by the refrigerant pressure in the condenser transmitted through a pressure tube IT. The arrangement is such that the water flow is increased whenever the condenser pressure rises so that water issupplied to the condenser in sufiicient quantity at all times to condense the refrigerant and maintain the desired condenser pressure.

Water to be frozen is supplied to a sump tank through a, pipe 22 under the control of a float valve 24 which maintains a predetermined water level in the tank. At the right-hand end of tank 20,, a centrifugal pump 23, driven by an electric motor 28, pumps water upwardly through a pipe 38 to a header 32. From header 32 the water is directed downwardly by a plurality of nipples into the tops of tubes 3 so as to cover the inner surfaces of the tubes with fast moving sheets or streams of the water. Tubes 3 are cooled sufficiently during the freezing cycle to freeze some of the water on the inner surfaces of the tubes, and the rate of. flow of the water is sufficiently rapid to cause clear, hard ice of high quality to be formed. Water is supplied to the tubes in an amount which is in excess of the amount which is frozen, and. the excess returns to the sump tank 20 for recirculation.

As is explained in detail in thecopending applications referred to above, ice is produced by this apparatus in accordance with a predetermined cycle of operations. The cycle is started by starting pump 26 and compressor 4 so that tubes 3 are cooled as water flows through them and ice is formed therein. When ice of the desired thickness has been formed, the freezing operation is discontinued and the ice is harvested. In this embodiment the freezing operation is continued until ice fills substantially the entire space within the tubes, and the ice columns or bodies have only small cylindrical openings therethrough. The ice harvesting operation is performed by supplying hot refrigerant gas to the evaporator, all in a manner tobemore fully described below.

The electrical circuit is represented schematically in Figure 1, and will now be described in detail.

Motor 6 is connected directly to a pair of lines 40 and 42 which constitute a supply of electric power, and motor 28 Of'DLlIllUZF'lS connected'at 4 one side to line 42, and at the other side through a line 44 and the armature 45 of a time-delay relay switch 46 to line 40. Line 40 is also connected to the armature 41 of a relay switch 48 and to the armature 49 of a normally closed thermostatic relay 5!). The other side of relay 50 is connected to one side of a thermostatic relay 52 having an armature El, and also to one side of the solenoid 54 of relay 48. The other side of relay 52 is connected to the upper contact 53 of relay 48. Relay 48 has a lower contact 56 which is connected through a line 62 to the solenoid of a valve 64; the other side of this solenoid is connected to line 42. Valve 64 is in a bypass pipe 65 which extends between the top of the condenser 3 and evaporator l0. Valve 64 is normally closed, but when its solenoid is energized, the valve is opened so as to provide for free passage of hot gas from the condenser receiver to the evaporator, and this initiates the harvesting operation by freeing the ice.

Contact 56 of relay 48 is also connected to one side of solenoid 68 of relay 46, the other side of which is connected to line 42. The lower contact of relay 46 is connected to motor 28, and the upper contact is connected through a line 18 to an ice cutter or breaker motor 72, the other side of which is connected to line 42. The bulb 14 of thermostatic relay 50 is positioned in heat exchange relationship with evaporator H3 and this relay is so adjusted that its switch is opened when the evaporator temperature falls below 32 F.

As will be discussed below, the thermostatic relay 52 has its bulb It so positioned that the bulb is cooled toterminate the freezing operation and to initiate the harvesting operation. Accordingly, the switch of relay 52 remains closed until this bulb is cooled; specifically, until the bulb temperature is reduced to 38 F.

As indicated above, the present invention is concerned with improved control of this machine as well as an improved arrangement for discharging water having high concentrations of dissolved.

solids. Accordingly, the machine includes a water overflow header 8B which extends parallel to the water inlet 32 and has inverted U tubes 62 connecting the upper side of the overflow header individually with the top of each of the freezing tubes. Specifically, at the top center of each of the freezing tubes there is a water discharge nozzle and above the level of this nozzle there is an overflow connection so that when the water level rises in the freezing tube the water overflows into header 89.

Header 88 extends to the right and thence downwardly to the top of a water collector 84 which is in the form of a vertical pipe or cylinder and has near its lower end a perforated divider wall 86 havingan opening 88 therethrough. This wall 86 divides the collector into a large upper chamber 90 and a smaller lower chamber Q2. These two chambers are connected by opening 82 and they are also connected by a bypass pipe 914 which has its upper end connected slightly above the center of chamber 96 and its lower end connected to, the central portion of chamber 92. Chamber 92 has connected to it an inverted hairpin trap llfiwhich is formed by two vertical portions or pipes 95 and 97 and a top U bend 9B. The lowerend of pipe 95 is connected to chamber 92 and the lower end of pipe 91 is connected to a water discharge or waste outlet connection 99.

A horizontal pipe I00 is connected to pipe 91 at a level slightly below sump tank 20 and the left-hand end of pipe I00 isconnected to two siphons, a main siphon I02 and an auxiliary siphon I04 which extend from pipe I upwardly along the side of tank 20 and thence downwardly over the edge of the tank as shown. The upward leg I05 of siphon I02 extends to substantially the bottom wall of the sump tank whereas the upward leg I90 of siphon I04 extends to substantially midway of the vertical wall. The lower end of leg I08 has an adjustable sleeve extension I0! which is threaded and may be turned to move it up and down to vary the heighth of the lower end of this leg for a purpose to be discussed later. Siphon I02 has an enlarged chamber I09 at the top of its downward leg I I0 Within which bulb I0 of switch 52 is positioned. Thus, bulb it is maintained at the temperature of the surrounding air, except when water is flowing through siphon 02 at which time it is subjected to the temperature of the water.

During the freezing operation, ice builds up on the inner surfaces of the freezing tubes soas to form hollow columns or bodies of ice. Water is supplied to each of these tubes at a fairly rapid rate, and it flows freely down through the center of the ice formation. However, as the end or" a freezing or ice-making operation is approached the size of the hole through each of the ice bodies is reduced sufiiciently to tend to restrict the water flow, and the water tends to back up at the top of the freezing tube. that when the flow of water through any freezing tube is materially interfered with, then the water is diverted into the header tube 00 and it flows down into chamber 90 of the water collector 04.

Chamber 92 as well as chamber 90 and pipes 94 and 95 are filled with water to the level indicated as a result of prior operation and, therefore, as water flows into chamber 90 the level in this chamber and the two connected pipes rises. This level eventually covers the upper end of pipe 94 and continues to rise to the level indicated by the broken line I I2 at which time water starts to run from pipe 95 over the inverted U- bend 98 and down pipe 9'! and starts a siphon action in pipe 95. This converts the trap 95 into a siphon, which connects chamber 92 with the waste outlet connection 99, the water flowing out of chamber 92 and causing water to flow therein from chamber 90 through the restricted opening 88 and pipe 94.

The flow through trap 96 is relatively unrestricted so that the flow down pipe 91 past the end of pipe I00 has a Venturi effect which draws a suction on pipe I00 and causes water from the sump tank to flow into the siphons I02 and I04 with the result that these siphons are set into operation and water starts to flow from the sump tank through both of these siphons and pipe I00 and thence downwardly through the lower end of pipe 91 to the waste outlet connection 99. The water flowing through siphon I02 immerses bulb I6 and this stops the freezing operation and initiates the ice harvesting operation, all in a manner to be more fully discussed below.

The flow of water through the siphon formed by trap 96 is sufficiently rapid to cause the liquid level to drop even though there is a continued supply of water through header 80. When this water level drops to the upper end of the pipe 94 air enters the upper end of the pipe 94 and thereafter chambers 90 and 92 are interconnected only by opening 80 in the divider wall 95. This opening provides a sufiicient restriction to the flow so that the siphon i starved with the result that the water level in pipe 94 falls and air is The arrangement is such passed down pipe 94 into chamber 92 and thence into pipe 95. This air accumulates at the inverted U-bend 98 and breaks the siphon thus stopping the water flow.

However, siphons I02 and I04 continue unbroken with siphon I02 drawing water at a fairly rapid rate from the bottom of the sump tank and with siphon I04 drawing water at a lower rate from the central portion of the tank. This flow continues until the water level in the sump tank falls to the level of the opening into the bottom of the upward leg I00 of siphon I04. When this water level is reached air enters siphon I04 and breaks this siphon and it also flows through this siphon into the bottom of siphon I02 so as to break that siphon also. The water then drains from pipe 9'! and in the meantime the flow from header is stopped. Therefore, the water in chamber and pipes 94 and levels off as shown and remains unchanged until the end of the next freezing operation.

As indicated, the lower end of the upward leg I08 of siphon I04 has a sleeve I01 threaded thereon which may be adjusted to change the level of its lower end which is the inlet into the siphon I04. This changes the level at which the siphoning operation from the sump tank is stopped. In this way, the amount of water discharged from the sump tank at the end of each freezing operation may be regulated. In this embodiment, valve 24 is opened to admit feed water at the time that the water level starts to fall, but the rate of water flow from the tank through the siphons is greatly in excess of the flow into the tank through valve 24, and therefore the siphoning operation is completed rapidly.

The cycle of operation will now be outlined, it being assumed that there is a sufiicient acquaintance with the details of construction from the above discussion and from reference, if necessary, to the copending applications referred to above.

Assuming that the apparatus has just started a freezing operation, with motor 6 driving compressor 4 and motor 28 driving the water pump 26, the evaporator is still at a relatively high temperature, and relay 50 is still closed so that solenoid 54 of relay 48 is connected directly to lines 40 and 42. Thus, solenoid 54 is energized so that armature 41 is raised away from contact 50; therefore, solenoid 58 of relay 46 is deenergized and line 40 is connected through relay 46 to the pump motor 28. Furthermore, the solenoid of the by-pass refrigerant valve 64 is deenergized by virtue of contact 55 being disconnected from line 40. As the operation continues, the evaporator temperature drops, and relay 50 opens, but solenoid 54 remains energized because relay 52 is closed at this time so that it forms an interlock circuit for solenoid 54 through the upper contact 53 of relay switch 48 to line 40.

When ice of the desired thickness has been formed inthe freezing tubes, water is diverted from the top of one or more of the freezing tubes through header 90 into chamber 90. This initiates the siphoning operation described above, whereby water is siphoned from the sump tank. During this operation the water flowing through siphon I02 immerses and cools bulb I0 so that relay 52 is opened. This deenergizes solenoid 54 so that its armature drops against contact 50. This connects line 40 through armature 47 to contact 55 and thence through line 02 to the solenoid of valve 64, with the result that this solenoid is energized and its valve is opened and hot refrigerant gas is supplied to the evaporator.

7. This melts the ice bodies free so that they fall from the freezing tubes.

The dropping of armature 41 also energizes solenoid 68 of relay 46 but armature 45 is not lifted immediately, because ofv a time delay characteristic of this relay, whereby its armature is not lifted for a predetermined time after the energization of its solenoid. Therefore, the pump motor 23 continues to operate and water is still pumped upwardly through pipe 3.0. After the predetermined time, the armature 45 of relay 46 is lifted with the result that motor 28 is deenergized and water is no longer pumped upwardly through pipe 30.

Simultaneously with the above operations the water from header 80 having initiated the siphoning of water from the sump tank, the siphoning operation continues until the water. in the sump tank falls to the predetermined level as discussed. above. Thus, a predetermined amount of water is removed from the sump tank and replaced with feed water through valve 24 at the end of each ice-making operation. A relatively constant quantity of ice is produced during each freezing operation and, therefore, a relatively constant and determinable amount of water must be removed at the end of each freezing operation to maintain acceptable water conditions. In other words, freezing of a predetermined amount of water into pure ice tends to build up the concentration of dissolved solids a predetermined amount and, therefore, a determinable amount of water is discharged and replaced with feed water in order to avoid the possibility of producing inferior ice.

The raising of armature 45 connects line 40 through this armature, the upper contact and line ill to the ice cutter motor 72 and, as disclosed more fully in the copending applications referred to above, this cuts the columns of ice in predetermined lengths to form ice cubes. When all of the ice has been discharged from the freezing tubes, the temperature of bulb i4 rises so that relay 49 is reclosed and, in the meantime, the flow of water over bulb is has been discontinued so that the temperature of this bulb is such that relay 52 is reclosed. Therefore, the circuit is restored to the condition of Figure l, and the cycle is completed.

It is thus seen that the machine carries on the ice-making and harvesting cycles in an efficient and dependable manner. The harvesting operation is not started until after the siphoning operation is started whereby the desired quantity of water is removed from the'sump tank. It has been indicated above that the main siphon 102 is larger than the auxiliary siphon HM and the main siphon extends to the bottom of the tank. Thus, the major portion of the water is discharged from the. bottom of the tank so that it carries with it any accumulated solids which have settled in the tank. The water in the sump tank at the end of the freezing operation is substantially at 32 F. and, therefore, the thermostatic bulb '46 is cooled immediately by the water flow through the siphon so that the harvesting cycle is started without delay.

Referring to Figure 3 of the drawings, an icemaking machine H2 has at the. bottom an ice storage compartment H3 and at the top an icemaking unit H4 which includes a sump tank 20. At the top of; the ice-making unit there is a Water header 32 and an overflow discharge header 80 through. which water flows from the tops ofthe tubes at. the end. of. the freezing 8;. operation. Positioned on: the side wall of. the unitis an accumulator and trap assembly H5 (see also Figure 4) and beneath this a vented drain connection H6. Mounted at the level of the sump tank 2|) is a siphon assembly H1 (Figure 3). The relative heighths and sizes of the various parts are shown in Figures 3 and 4 but certain details are shown better in Figure 2. Therefore. the details will now be described and then the operation will be explained by reference to Figures 3 and 4.

Referring now to Figure 2 of the drawings, the siphon assembly includes a main siphon H8 having at the right a downward leg H9 and at the left an upward leg I20 which projects downwardly into the sump tank to near the bottom thereof. The siphon assembly also includes an auxiliary siphon l2! having at the left an upward leg I22, the top of which is connected through ahorizontal tube 123 of reduced size to a downward. leg 525-, the lower end of which is connected through. a horizontal portion to the downward leg I I9 of the main siphon.

The upward leg 220 of the main siphon is connected to the horizontal tube i255 through a T I24 from which a thermostat bulb entry tube 128 extends to the left. The left hand end of this tube is flared and is sealed by a rubber stopper E30 which has a central opening therethrough for the tube B2 of a thermostat bulb 134i. Bulb H4 is thus positioned directly over the top of upward leg 20 and its tube 132 extends through the sealed opening to the left to a thermostatic switch (not shown) which is identical with relay 52 of the embodiment of Figure l.

The lower end of leg. H9 is connected through a T R56 to a water discharge pipe l38 which (see Figures 3 and- 4) is a portion of the water discharge assembly !6. Pipe 138 extends into the top of a vent chamber I40. which has its lower end connected to the waste connection 99. The top of vent chamber M0 is-connected through a vent tube 142 which extends upwardly and is open to atmosphere through an inverted: U. portion or gooseneck M4.

The T I36- provides the horizontal connection at M5 to the bottom of th accumulator and trap portion H5 which includes a vertical accumulator I48 (Figure 3) which is vented at the top and is connected toreceive the overflow water from pipe 80 through an overflow pipe I58. Accumulator M8 isan unobstructed vertical pipe which extends downwardly to substantially the level of the bottom of sump tank 29 and the bottom end of the accumulator is connected to a trap tube 152 which extends through an arc of one-hundred eighty degrees and thence upwardly to adjacent to the top of the accumulator where it has a top U bend Hlfl. This U bend is connected to a downwardly extending tube 156, the lower end of which is connected to the horizontal connection N5 of the T 136.

The joints and connections are soldered except where threaded connections are shown and as indicated above the relative proportions and sizes ofparts' are as shown in the drawings. In Figure 2 certain of the straight vertically extending pipesare cut away but the. relative lengths are shown in Figures 3 and 4 and in Figure 2 certain of the parts are modified in order to bringout the structure more clearly. The operation is: similar' to that of the embodiment of Figure 1 Howeven, in the embodiment. of. Figures 2,. 3 and.4 theaccumulator is. of. relatively greater length and of lesser diameter and it has no obstructing baflie and no bypass pipe is provided. Furthermore, the upward leg I22 of the auxiliary siphon is of fixed length and for any particular conditions of operation, the lower end of this leg may be out off to raise the level of the opening into its lower end. This causes the siphoning operation to be discontinued when the water in the sump tank is at a higher level and, therefore, a lesser amount of water is withdrawn during each siphoning operation.

In describing the operation, it is assumed that the ice-making machine of Figures 3 and 4 has reached the end of an ice-making operation and that water has started flowing from the tops of certain of the freezing tubes into the water discharge header I80 and thence through pipe I59 into accumulator I48. The water level in the accumulator rises and simultaneously it climbs in the trap pipe I52. When this water level reaches the level of the U bend I54 the water flows over this U bend and converts this trap into a siphon so that water flows down pipe I56 and thence v through T I36 into the water discharge pipe I38. This water flowing downwardly in pipe I33 draws a partial vacuum at the bottom of the downward leg H9. This partial vacuum condition causes the water to rise in the upward legs of the two siphons and to eventually flow through the horizontal portions of these siphons and thence downwardly to seal the downward leg I 19. Thus, siphon flow is established through the main siphon I I8 and the auxiliary siphon I ZI with the main siphon drawing water from adjacent the bottom of the sump tank and with the auxiliary siphon drawing water at a much lesser rate from a higher level in the sump tank.

During establishing of the siphon flow in the main siphon the cold water comes into contact with bulb I34 and this stops the ice-making operation and initiates the harvesting operation as discussed above. In the meantime, the water level falls in the accumulator I48 because the flow from the bottom of the accumulator is more rapid than the fiow into it from the tops of the freezing tubes. The parts are so proportioned, however, that the siphon flow is established in the siphons I I8 and HI before the water level drops to the bottom of the acumulator. When the water level thus drops, air enters the bottom of trap tube I52 and it is carried upwardly in this tube and it tends to accumulate and form atrap at the top U bend I5 l. When a sumcient quantity of air has accumulated at this U bend a trap is formed so that flow from the accumulator is stopped.

The establishing of the siphons as explained above stops the freezing operation and this stops the flow of water from the tops of the freezing tubes into accumulator I58. However, there is some flow of water into the accumulator after the flow in the siphons has been established and the flow from the accumulator has stopped and, therefore, the water level in the accumulator and the connected trap pipe I52 may rise to a relatively high level where it remains until the end of the next freezing operation. If for any reason the siphon flow is not established in the main siphon H8 prior to the time that the flow from the accumulator is stopped, the bulb B35 will not be cooled sufficiently to stop the freezing operation. Under such circumstances, the freezing operation continues until the siphon flow from the accumulator is reestablished. The reestablishing of this siphon flow sets up conditions 10' again tending to establish the siphon flow through the siphons I I8 and IZI.

As indicated above, the bottom end of the auxiliary siphon opens into the sump tank at the level at which it is desired that the siphoning operation be discontinued. At such time as the water falls to this level air enters the auxiliary siphon and passes over to the downward leg II9 of the main siphon. This air accumulates in the horizontal portion of the main siphon so that the siphon flow in the main siphon is broken.

I claim:

1. In ice-making apparatus, the combination of, a bank of freezing tubes, water feed means to flow water through said tubes, refrigerating means to refrigerate said tubes whereby ice is formed on the walls thereof, water discharge means connected to receive water overflowing from the entrance of one of said tubes whereby water will flow therethrough when there is a. restriction in that tube, accumulator means to ac" cumulate the water which flows through said water discharge means, and means which is effective to flow water from said accumulator means when a substantially predetermined amount of water has flowed into said accumulator means.

2. Apparatus as described in claim 1 which in cludes, a sump tank positioned beneath said freezing tubes and adapted to have water flow therein from said freezing tubes and a watercirculating pump to flow the water from said sump tank to the tops of said freezing tubes, siphon means to discharge water from said sump tank, and means to render said siphon means effective at the end of each freezing operation.

3. Apparatus as described in claim 2 wherein said control means includes, a thermostat bulb positioned in the path of flow of water from said sump tank through said siphon means and the cooling of which terminates the freezing operation.

4. Apparatus as described in claim 3 which includes, an inverted U-trap connecting said accumulator to a waste discharge and which is adapted to operate as a siphon when the water in the accumulator rises to a predetermined level, and wherein said siphon means has its discharge connected to the discharge from said inverted U- trap whereby the flow of water through said inverted U-trap initiates the operation of said si- Dhon means.

5. Apparatus as described in claim 4 wherein said siphon means includes a main siphon which has its water inlet opening adjacent the bottom of the sump tank, and an auxiliary siphon which has its water inlet opening at a predetermined level above the bottom of the sump tank.

6. In ice-making apparatus of the character described, the combination of, a plurality of freezing tubes positioned in parallel side-by-side relationship and adapted to have water flow therethrough at a rapid rate, refrigeration means to cool the freezing tubes and cause ice to form on the walls thereof, a sump tank which is adapt" ed to contain a body of water from which water is flowed through said freezing tubes and to which the water returns which is not frozen within the tubes, siphon means which is adapted to remove water from the sump tank to a predetermined level, and control means to control the operation and to initiate the flow through said siphon means in accordance with a predetermined cycle of operations, said control means including means to divert water from the freez- 131' ing tubes when a predetermined amount of ice is formed, accumulator means 'to accumulate the water thus diverted, and siphon-flow initiating means which utilizes the water in said accumulator means to initiate the flow in said siphon means.

7. Apparatus as described in claim 6 wherein said control means includes means to divert water from the frezing tubes when a predetermined amount of ice is formed, accumulator means to accumulate the water thus diverted, and siphonflow initiating means which utilizes the water in said accumulator .means to initiate the flow in said siphon means.

8. Apparatus as described in claim 6 wherein said accumulator means is an unobstructed vertical pipe extending from substantially the level of the top of the freezing tubes to substantially the level of the bottom of the sump tank, and

whereinsaid apparatus includes a trap which is converted into a siphon to carry water from the bottom of said accumulator whenever the water in the accumulator reaches a predetermined level.

9. Apparatus as described in claim 8 wherein the water from thevaccumulatcr is discharged in a downwardly extending pipe and wherein said siphon means is connected to said downwardly extending pipe, and vent means connected to the lower end of said downwardly extending pipe.

10. In the art of making ice, the steps of, flowing water through a refrigerated passageway at a rapid rate thereby to form ice, diverting water from said passageway when the ice forms an obstruction to the flow, collecting the unfrozen water which has flowed through the passageway to 12 form a body of water, and utilizing the flow :of the water diverted as stated above to initiate automaticallya water discharge operation to discharge a predetermined amount of the-water collected.

11. In ice-making apparatus of the character described, the combination of, a plurality of freezing tubes positioned in parallel side-by-side relationship and adapted to have water flow therethrough at a rapid rate, refrigeration means to cool the freezing tubes and cause ice to form on the walls thereof, a sump tank which is adapted to contain abody of water from'which water is flowed through said freezing tubes and to which the waterreturns which is not frozen within the tubes, siphon means which is adapted to remove the water :from the sump tank-to a predetermined level, said siphon means including a main siphon which withdraws water from the bottom of the sump tank-ata rapid rate and'an auxiliary siphon which withdraws water from the sump tank at a lesser .rate and at a predetermined level and which is adapted'to stop the siphon flow when the water level in the sump tank falls to said predetermined level, and control means to control the operation and to initiate the flow through said siphon means in accordance with a predetermined cycle of opera, tions.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,239,234 Kubaugh Apr. 22, 1941 2,303,000 Ribble Nov. 24, 1942 2,5933% 'Grandia Apr. 22, 1952

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