US3367127A - Hydraulic icemaker - Google Patents

Description

F. M. WALKER Feb. 6, 1968 HYDRAULIC ICEMAKER 2 Sheets-Sheet Filed Dec.

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INVENTOR. FPAA/K M MAKE-Q Feb. 6, 1968 F. M. WALKER 3,367,127

HYDRAUL I C I CEMAKER 1965 2 Sheets-$heei 2 INVENTOH. P A/w M MLA FE ited States Patent was... .v...

ABSTRACT OF THE DISCLGSURE This invention discloses a hydraulic icemaker having a metal tubular shaped vertically oriented mold, open at the upper end and containing water to be frozen into a piston shaped ice body. A transverse groove on the inner periphery of the mold near the upper open end thereof, contains an O-ring of suitable resilient material, fitted to the groove and having the inner periphery thereof extending slightly beyond the inner periphery of the mold surface to form a pressure friction seal between the mold surface and the ice piston surface, respectively, during the ejection of the ice body from the mold by water pressure. Thus, when heat is applied to the outer periphery of the mold to loosen the ice piston from the mold, and water pressure is simultaneously applied to the surface of the ice piston below the O-ring seal, the ice body is forced from the mold and against an oblique surface spaced from the end of the mold to develop hydraulic stress between the ice body and the mouth of the mold to shear off the portion of the ice body in said space and leave the portion of the ice body still within the mold to remain therein during the freezing of the succeeding ice body. The above combination, together with suitable controls therefore, as disclosed, provide an apparatus for automatically producing successive ice bodies, utilizing a source of water under pressure as the primary means of power for the icemaker in the course of filling the mold with water for the next ice body.

This invention relates to automatic icemakers and more particularly to a small icemaker for use in domestic refrigerators or freezers.

Among the objects of this invention are:

(A) To provide a simple automatic icemaker with no moving parts in the power sense, and only a few parts in the control sense.

(B) To provide an icemaker which requires very little space in the freezing compartment of the refrigerator or freezer as compared to the conventional type using mechanical means to eject the ice from the mold by the use of ejector blades operated by an electric motor, all of which are located in the freezer compartment, taking up valuable space therein needed for storage of frozen foods.

(C) To provide an icemaker that will produce ice pieces of small size for domestic use.

(D) To provide an icemaker that feeds water to the freezing mold automatically without the use of a pump or metering tank.

(E) To provide a simple means of controlling the ice producing activity of the icemaker both, automatically or manually.

(F) To provide an icemaker that automatically limits the heat level produced in the mold by the ice loosening electric heater, thus eliminating the necessity of having an additional heat limiting switch.

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawings, in which similar characters of reference indicate similar parts throughout.

Referring to the drawings, of which there are four figures on two sheets,

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FIG. 1 is a diagrammatic view of the preferred form of this invention shown as installed in the wall of a house hold refrigerator.

FIG. 2 is a fragmentary view of the lower end of the mold shown in FIG. 1 containing another species of the compression element therein.

FIG. 3 is a wiring diagram of the circuits according to this invention.

FIG. 4 is another species of the invention shown as installed in the wall of a household refrigerator.

Referring to FIG. 1, the icemaker is generally designated and is mounted so as to project into the freezer area 11 of a refrigerator or freezer maintained at a temperature of 10 F. or lower by a refrigeration system (not shown). The interior wall 12 is separated from the exterior wall 13 by an insulated area 14. The icemaker 10 is mounted by lugs 15 to the interior wall 12 by screws.

The icemaker 10 comprises a mold 16 formed from metal of tubular shape having good thermal characteristics, such as brass or aluminum or stainless steel. The mold 16 is mounted at an inclined angle from horizontal with the open upper end extending out into the refrigerated space 11 and the lower closed end extending into the insulated space 14. The upper end of the mold 16 has a section having the lower half cut away with the top end thereof covered by a surface 17 forming a surface having an average plane thereof oblique to the longitudinal axis of the mold 16. The lower closed end of the mold 16 has a hole therein receiving tube 43 connecting the outlet of check valve 18 thereto, permitting flow into the mold 16 but precluding reverse flow therethrough. The inlet of check valve 18 is connected to the outlet of a solenoid valve 20 of conventional type by a tube 19. The solenoid valve 20 is fastened to the exterior wall 13 of the refrigerator or freezer by any conventional means. The tube 19 contains a metering orifice 21 of small diameter restricting the flow of water therethrough during the energizing of solenoid valve 20 in accordance with a predetermined flow rate. An interior groove in the mold 16 receives an O-ring 23 made of a resilient material, such as rubber, or neoprene. An exterior groove in the mold 16 receives an electric heater 24 of conventional type thermally bonded therein providing good thermal conductivity to mold 16. A thermostatic switch 25 of conventional bi-metallic actuated type is thermally bonded to the exterior surface of mold 16 and controls the electric heater 24 in response to temperature changes of mold 16. The thermostatic switch 25 closes the circuit therethrough at 18 F. and opens the circuit therethrough at 50 F. A micro-switch 26 of conventional type is fastened to the upper end of the mold 16 at the lower side thereof and has an actuating arm 27 extending up slightly into the path of the projected ice from mold 16. A compression element 28 is in the bottom of the closed end of mold 16. Although the preferred form of compression element 28 is shown as being made from a piece of compressible material, such as Buna-N rubber, it is to be understood that it could be made in many forms, one other of which is shown in FIG. 2, where a sealed rubber bellows 40 is held expanded by a spring 42 inside pressing the bellows 40 outward to a maximum expansion allowed by retainer 41. Another form (not shown) could be a diaphragm closing the bottom of mold 16 and held inward by an external spring. An electric heater 29 is surrounding tube 19 and is constantly energized to prevent water from freezing in the tube 19, check valve 18, tube 43, and the extreme bottom of mold 16 by conductance aided by being insulated from the freezing area 11.

Referring to FIG. 1, and FIG. 3, the operation of the icemaker is as follows: The solenoid valve 20 is connected to a water supply 22 having a normal pressure of to p.s.i.g. present in most distribution systems- An electric supply is applied directly to heater 29; to heater 24, thermostatic switch 25 and shut-off switch 31 in series; and to solenoid valve 20, micro-switch 26 and switch 31 in series. The atmosphere 11 surrounding the icemaker is assumed to be 10 F. or lower. To initiate operation of the icemaker, water is fed into the mold 16 manually depressing actuating arm 27 of switch 26 with the finger. This energizes solenoid valve allowing water to flow through valve 20 from supply 22, then slowly through orifice 21, tube 19, check valve 18, tube 43, and into mold 16 until it overflows at the upper open end thereof, whereupon the actuating arm 27 is released. The water in the mold 16 is up to the level indicated at A, and it starts freezing into ice, first, at the top and inner surfaces of mold 16, then progressively inward and downward as represented by the lines B. Water is prevented from freezing in the bottom of mold 16, as previously explained. This insures a continuous body of water from the bottom side of the ice formed in mold 16 back to the solenoid valve 20 at all times. Inasmuch as the ice in mold 16 and on the outer surfaces of the compression eledownward, a change of state expansion develops a hydrostatic pressure on the remaining water in the bottom of mold 16 and on the outer surface of the compression element 28, also on the tube 43 back to valve seat in the check valve 18. The compression element 28 absorbs the hydrostatic pressure by compressing into a smaller volume, as represented by the dotted line C. This provides a small storage of potential mechanical energy in the compression element 28. When the ice in the mold 16 is subcooled to 18 F., the thermostat switch reacts and completes the circuit therethrough to heater 24, which in turn, warms mold 16 and thaws the surface of the ice in contact with the mold 16. This forms a film of water between the ice and the mold 16, releasing the ice from the mold 16.

This action allows the stored energy in the compression element 28 to expand to normal shape, forcing the ice to move up slightly in mold 16 and project out enough to contact and depress actuating arm 27, as indicated by the dotted line B, effecting completion of the circuit through micro-switch 26 to energize solenoid valve 20. Energized solenoid valve 20 opens and allows water to flow from supply 22 through valve 20, then slowly bleed through orifice 21, tube 19, check valve 18, tube 43, and into the bottom of mold 16, thereby displacing the ice therein. As the ice is being slowly displaced from mold 16, the surface of the projected ice will refreeze and prevent it from sticking to ice already harvested. The ice thus projected from mold 16 moves toward surface 17. On striking surface 17, the projection of the ice is halted. Immediately, a hydraulic force is developed on the ice equal to the supply water pressure at 22. To insure a positive hydraulic force on the ice, a resilient O-ring 23 provdes a liquid seal between the surfaces of the ice and the mold 16. Therefore, the hydraulic pressure thus developed presses the ice against the oblique surface 17 sulficiently to set up a stress between the projected and the unprojected ice due to the deflection action of surface 17 on the ice. The point of greatest stress on the ice is developed at the bottom lip of the open end of mold 16, indicated by the letter D, and radiates outwardly therefrom. This force causes the projected ice to shear off from the unprojected ice at point D and fall into storage bin 30. This automatically releases actuating arm 27, opening the circuit through switch 26, deenergiziug solenoid valve 20 and stopping the flow of water into mold 16. This completes the cycle of the icemaker and it will repeat the cycle until bin is full of ice pieces.

Although I have shown the preferred embodiment of the invention in FIG. 1, another species of the invention is shown in FIG. 4. In this species, the compression element 28 used in FIG. 1 is eliminated. The operation of the icemaker shown in FIG. 4 is as follows: The solenoid valve 20 is connected to a water supply 22 having a normal pressure of to p.s.i.g. present in most distribution systems. An electric supply is applied directly to heater 29, to heater 24, thermostatic switch 25 and shutoff switch 31 in series; and to solenoid valve 20, microswitch 26 and switch 31 in series. The atmosphere 11 surrounding the icemaker 10 is assumed to be 10 F. or lower. To initiate the operation of the icernaker, the actuating arm 27 of switch 26 is manually depresed by the finger to flow water into the mold 16 by energizing solenoid valve 20, allowing water to flow through solenoid valve 20, tube 19, orifice 21, check valve 18, tube 43, and fill mold 16 to overflowing, whereupon the actuating arm 27 is re leased. With water in the mold 16 up to the level indicated by the line A, it will start freezing into ice, first on the outer surfaces next to the mold 16, then inwardly to the center thereof. Due to the change of state expansion, the ice will be forced out from the open end of the mold 16 and project out slightly, as indicated by the dotted line E. This slight projection of the ice from the mold 16 contacts and depresses the actuating arm 27, effecting completion of the circuit through micro-switch 26 to energize solenoid valve 20, opening solenoid valve 20 and allowing water to develope a hydraulic pressure on the bottom of the ice at some point in tube 43 through tube 19, orifice 21, check valve 18, and tube 43. This hydraulic pressure alone is not sufficient to eject the ice from the mold 16 and merely remains dormant until the temperature of the ice in mold 16 is sub-cooled to 18 F. At this point the thermostat switch 25 reacts and closes the circuit therethrough to the heater 24 which then heats the mold 16 thawing and releasing the ice from the surface of mold 16. The hydraulic force already present, as explained above, now forces the ice in mold 16 to project from the mold 16 toward the oblique surface 17. On striking surface 17, projection of the ice is halted. Immediately, a new bydraulic force is developed on the ice equal to the supply water pressure at 22. To insure a positive hydraulic force on the ice, a resilient O-ring 23 provides a liqud seal between the surfaces of the ice and the mold 16. The hydraulic pressure thus developed presses the ice against surface 17 sufficiently to set up a stress between the projected ice and the unprojected ice due to the deflection force of the oblique surface 17 on the ice. The point of greatest stress on the ice is developed at the bottom lip of the open end of mold 16, indicated by the letter D, and radiates outwardly therefrom. This force causes the projected ice to shear off from the unprojected ice at point D and fall into the bin 30. This automatically releases actuating arm 27, opening the circuit through switch 26, deenergizing a solenoid valve 20 and stopping the flow of water into the mold 16. This completes the cycle of the icemaker and it will repeat the cycle until bin 30 is full of ice pieces. Although the species shown in FIG. 4 appears to be an improvement over the species shown in FIG. 1, it has some disadvantages. First, the wall of the mold must be thicker to withstand the high hydrostatic pressure developed in the mold 16 during the change of state expan-v sion therein. The thicker wall of mold 16 requires a greater amount of heat from the heater 24 before a temperature is reached to thaw the surface of ice for release therefrom. Therefore, at the end of the cycle, a greater amount of residual heat must be removed from the thicker wall of mold 16 before it is low enough to start freezing the water in the mold 16. Secondly, the thicker wall of mold 16 adds to the cost of production of the icemaker. Therefore, it is shown that the species in FIG. 4 would not be as efficient as the species shown in FIG. 1.

A shutoff switch 31 attached to the mold 16 has a lever arm 32 pivotally held upward by a spring 34 completing the circuit therethrough to both switch 25 and switch 26. As the harvested ice falls downward from mold 16, the arm 32, being in the path of fall, is de fiected downward temporarily. However, when the bin 30 becomes full of harvested ice pieces, the last harvested piece will lodge the arm 32 down between it and the supporting ice thereunder, thereby breaking the circuit through switch 31 and deenergizing the icemaker completely except for heater 29. When ice is removed from the bin 30, allowing the arm 32 to return to a. normal position by action of the spring 34, the icemaker is again energized to resume normal automatic harvesting of ice pieces. If the user wishes to de-activate the icemaker, the rubber grommet 33 is moved up on the lever arm 32 wedging the lever arm 32 down to deenergize the icemaker.

Although I have shown the preferred arrangement of the invention in the drawings and the description, they are used merely for simplicity of description and are not meant to limit the spirit or scope of the invention. Also, while I have shown but two embodiments of the invention as herein illustrated and described, it will be understood that modifications may be made in the construction and arrangement of elements Without departing from the spirit or scope of the invention. Therefore, without limitation in this respect, the invention is defined by the following claims.

I claim:

1. A hydraulic icemaker for producing successive ice bodies from a source of water under pressure, comprismg:

a tubular shaped vertically oriented mold for containing the water to be frozen;

means for freezing the water in the upper end of the mold into an ice body;

a heater thermally associated with the mold to partially thaw and release the ice body from the surface of the mold;

force applying means associated with the mold for utilizing the pressure of said source of water, to partially eject the ice body from the mold subsequent to said release, and to harvest the partially ejected portion of the ice body;

liquid pressure sealing means in the mold between the inner periphery of the mold and the outer periphery of the ice body therein to form a friction pressure seal therebetween during said partial ejection of the ice body from the mold;

a major control means including a main electric cir- Cuit for controlling the icemaker to produce successive ice bodies, and main electric circuit including:

a first minor control means arranged on the mold and being operable responsive to expansion of water in the mold as the water freezes to control the force applying means, and a second minor control means arranged on the mold and being operable responsive to the temperature of the mold to control the heater, to thereby harvest the ice body and refill the mold with water.

2. A hydraulic icemaker as defined in claim 1 wherein the said force applying means comprise:

conduit means for conducting a metered flow of said source of water under pressure to the lower end of the mold, said conduit means including; a conduit connected between the said source of water and the lower end of the mold, a solenoid valve in said conduit, a check valve in the conduit between the solenoid valve and the mold, and a flow restriction means in the conduit between the solenoid valve and the check valve;

a fixed surface spaced from the mouth of the mold and arranged oblique to the axis of the mold to provide stress development between the ejected ice body and the mold to shear off the ejected portion of the ice body substantially at the mouth of the mold; and

wherein said liquid sealing means comprise:

a transverse groove in the inner periphery of the mold;

and

a resilient O-ring mounted in the groove and arranged to be under mechanical pressure between a mold surface and the ice body surface during movement of the ice body in the mold.

3. A hydraulic icemaker as defined in claim 1 wherein said first minor control means include:

a first electric branch circuit including the coil of the solenoid valve;

a normally open switch in said circuit mounted and arranged adjacent the mouth of the mold to be closed by pressure exerted thereon by the ice body emerging from the mouth of the mold, to thereby energize the coil of the solenoid valve to open the valve, and, alternately, to be opened by the absence of pressure thereon, to thereby dc-energize the coil of the solenoid valve to close the valve;

a compressible means in the lower end of the mold for storing change of state expansion energy generated during the freezing of the water in the mold, said compressible means releasing said energy subsequent to said ice body release, to thereby partially eject the ice body from the mold sufficient to close the said switch; and

wherein said second minor control means include:

a second electric branch circuit including the said heater;

a thermostatically operated switch positioned and arranged in thermal transfer relation with the mold and being operable responsive to a first temperature of the mold to close said second branch circuit to energize said heater, and, alternately, operable responsive to a higher temperature of the mold to open said second branch circuit and de-energize said heater.

4. A hydraulic icemaker as defined in claim 1 further characterized to include a normally closed bin switch in the said main control means, said bin switch being arranged adjacent to the mold and actuated by means including ice accumulated adjacent the icemaker to open the switch and de-energize the main control means, to thereby de-activate the icemaker until said accumulated ice is removed.

5. A hydraulic icemaker as defined in claim 3 wherein the said compressible means in the mold comprise:

a housing in the lower end of the mold;

a hermetically sealed compressible capsule in the housa spring in the capsule arranged to urge the capsule outward against the housing.

6. A hydraulic icemaker as defined in claim 3 wherein the said compressible means in the mold comprises a piece of resilient material impervious to water.

7. A hydraulic icemaker as defined in claim 3 wherein the said compressible means in the mold comprises a portion of the force applying means being resilient relative to interior and exterior pressures exerted thereon.

References Cited UNITED STATES PATENTS 2,471,655 5/ 1949 Rundell 62-7l 2,994,205 8/1961 Brubaker et al. 62344 X 3,008,301 11/1961 Baillif et a1 62353 X 3,039,277 6/1962 Frei et al. 62---7l 3,228,202 1/1966 Cornelius 62347 X ROBERT A. OLEARY, Primary Examiner.

W. E. WAYNER, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,367,127 February 6, 1968 Frank M. Walker It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 21, strike out "and on the outer surfaces of the compression ele" and insert instead is formed at the top first and then progressively Signed and sealed this 15th day of April 1969.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

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