IL289645A

IL289645A - Home slush maker

Info

Publication number: IL289645A
Application number: IL289645A
Authority: IL
Inventors: Nissim Levy; Arnon Lewinstein; Itay Shafir
Original assignee: Nissim Levy; Arnon Lewinstein; Itay Shafir
Priority date: 2022-01-05
Filing date: 2022-01-05
Publication date: 2023-08-01
Also published as: WO2023131944A1

Description

43280/21 - 1 - HOME SLUSH MAKER Field of the InventionThe present invention relates to the field of beverage preparing apparatus. More particularly, the invention relates to a home slush maker. Background of the InventionSlush products based on a desired liquid that is cooled close to the freezing point have an appeal not only for children, but also for adults who enjoy consuming various drinks such as iced coffee and slush cocktails. Slush generally has a semi-solid composition of ice crystals surrounded by liquid. Crystals are formed when heat is released from a liquid at such conditions that the liquid temperature is sufficiently below the freezing point of the liquid to be supercooled and to absorb the energy release during crystal nucleation without causing the temperature to rise above the freezing point. Most slush makers are expensive commercial machines. Common home slush makers are devices such as a blender that require the desired liquid to become agitated together with ice cubes, inducing crystal formation in the liquid as its temperature drops significantly. Operations related to preparing and handling ice cubes prior to being introduced into the interior of a prior art home slush maker are uncomfortable. For many home slush makers, the slush preparation is a time consuming procedure. It is an object of the present invention to provide a cost effective home slush maker that does not require the introduction of ice in order to produce a slush product of substantially uniform consistency. It is an additional object of the present invention to provide a home slush maker that can speedily produce a slush product. Other objects and advantages of the invention will become apparent as the description proceeds. 43280/21 - 2 - Summary of the InventionA home slush maker comprises an internal cavity within which a desired liquid is introducible, and an activation unit, when positioned in fluid communication with a source of chilled air, for generating a stream of said chilled air by forced convection that is in heat exchanger relation with a wall of the internal cavity for a sufficient duration to cause the introduced liquid to undergo sufficient rapid cooling that is suitable to produce a slush product. A slush product is accordingly able to be produced when the introduced liquid is subjected to rapid cooling by the chilled air, generally within in a small fraction of hour after the desired liquid has been introduced into a vessel. As referred to herein, a "slush product" is one in which suspended ice crystals form in the introduced liquid or one, such as an ice cream product having a smooth and creamy texture that is made from milk or cream with added ingredients for flavor and texture, whose viscosity is increased relative to that of the initially introduced liquid as a result of the rapid cooling. In one aspect, the activation unit is configured to cause a phase change in the introduced liquid to produce the slush product. In one aspect, the activation unit comprises a housing configured with an annular passageway and a fan retained at a proximal end of the housing that is in fluid communication with the source of chilled air, the generated stream of chilled air flowable through said passageway to the wall of the internal cavity. A vessel configured with the internal cavity within which the desired liquid is introducible is preferably releasably coupleable with the housing. In one aspect, the home slush maker further comprises a stirrer for stirring the introduced liquid which is receivable within the vessel, wherein a stirrer motor for rotatably driving the stirrer is retained in the housing. In one aspect, the activation unit comprises control circuitry for controlling operation of the stirrer and fan until the slush product is produced. The control circuitry may be configured to cause the stirrer or fan to be intermittently operated after the slush product is produced to retain a desired consistency. 43280/21 - 3 - In one aspect, the activation unit is configured to output an indication, such as a remotely transmitted indication, following completion of a slush making operation. In one aspect, the home slush maker is sufficiently small to be hand held, yet is compactly housed with the stirrer, fan and control circuitry and is sufficiently insulated to operate within a freezer. Brief Description of the DrawingsIn the drawings: - Fig. 1 is a perspective of an embodiment of a home slush maker, when assembled; - Fig. 2 is an exploded view of an activation unit used in conjunction with the home slush maker of Fig. 1; - Fig. 3 is a schematic illustration of the activation circuitry used in conjunction with the activation unit of Fig. 2; - Fig. 4 is an exploded view of the home slush maker of Fig. 1; and - Fig. 5 is a cross sectional view of the home slush maker of Fig. 1, cut along the longitudinal axis. Detailed Description of the InventionThe home slush maker is a portable, hand held and cost effective device that utilizes the cooling ability of a domestic freezer to produce a slush product. The dimensions of the home slush maker are significantly smaller than those of a bulky commercial slush maker, which requires a refrigerant as well as a compressor and condenser through which the refrigerant flows in a refrigeration cycle to generate the needed cold for preparing a slush product. Despite the lack of a refrigeration system, the home slush maker is advantageously able to speedily produce the slush product in a small fraction of hour, after a desired liquid is introduced into an internal cavity outside of the freezer and then the slush maker is placed within the freezer and activated. The speedy slush production process is made possible by means of forced convection whereby cold air from the freezer interior is drawn into the internal cavity of slush maker and causes the introduced liquid to become significantly cooled. Fig. 1 illustrates an embodiment of a home slush maker 10. The external structure of home slush maker 10 is shown to include two members, the first being the activation unit housing 5 provided with a lower, substantially horizontal support surface 7 and the second being a cylindrical holder 14 43280/21 - 4 - that is shown to be coupled with activation unit housing 5 and to rest on top of support surface 7. Holder 14 may be configured to be coupled with activation unit housing 5 without resting on the support surface. The activation unit is able to both induce generation of the forced convection for producing the slush product and to output an indication when a slush product of substantially uniform consistency has been produced. Fig. 2 illustrates an exploded view of various components of activation unit 12 which are retained within activation unit housing 5. As shown, activation unit 12 comprises a fan 16, generally an axial fan, but which can be a radial fan or any other suitable type of fan having a built-in motor for generating an air flow from the freezer interior through an annular passageway 6 formed radially inwardly to the outer cylindrical wall 8 of activation unit housing 5, in a direction that is generally parallel to the fan axis. Fan 16 is covered by a grille 18 to prevent injury to the user if the home slush maker has been inadvertently activated when being repositioned. Electric motor 22 provided with gearbox 23 which is configured with reduction gearing is housed within a motor chamber of housing that is provided radially inwardly to annular passageway 6 and is axially spaced from another chamber within which fan 16 is housed. The motor chamber has an end plate 26, which is recessed from the terminal end 17 of inner housing wall 9 that defines passageway 6, is formed with an aperture 27 through which motor output shaft 28 axially extends. Output shaft 28 is connected to adapter 31, which is adapted to be coupled with the stirrer and may be fluted. Activation unit housing 5 may be configured with a secondary housing 11 that radially protrudes from one circumferential region of outer wall 8. Secondary housing 11, which is attached to, or integrally formed with, outer wall 8, houses the activation circuitry needed to perform a slush making operation. The upper surface 7 of secondary housing 11, i.e. the support surface, may be concave to accommodate cylindrical holder 14 (Fig. 1) and may axially protrude from the terminal end 19 of outer housing wall 8, which generally axially protrudes from the terminal end 17 of inner wall 9. Activation unit housing 5 and secondary housing 11 are sufficiently isolated to prevent damage to the activation circuitry if the home slush maker inadvertently remains in the freezer for an extended period of time. As shown in Fig. 3, activation circuitry 35 comprises a microcontroller 41 for commanding operation of the fan and the stirrer. Microcontroller 41, which has a processor that is factory programmed or alternatively is programmed by means of a dedicated application 43 running on a computerized 43280/21 - 5 - device 47 such as a smartphone, selectively transmits command signals C to the stator of the fan motor 24 and of the stirrer motor 22 upon demand, whether wirelessly or through a wired connection. One or more batteries 37 power microcontroller 41 and the stator of the fan motor and of the stirrer motor. Each battery 37 may be rechargeable, and the activation circuitry may also comprise a battery charger. An exemplary axial fan has a fan motor provided with dimensions of 70mm X 20mm and an average speed of 3800 RPM, generates an average volumetric airflow of 35.5 CFM, and requires a power supply of 12V (DC) and 0.5A, usually by means of one or more batteries. The fan motor is preferably configured with speed control to control the flow rate of the chilled air. An exemplary stirrer motor has a high torque gearbox that outputs 50 RPM, is equipped with a Hall encoder with speed measurement, a driver by which the speed is controlled, and requires a power supply of 12V (DC), usually by means of one or more batteries. Both the fan motor and the stirrer motor are preferably configured with a current sensor for determining an instantaneous load. When factory programmed, microcontroller 41 may be activated by a manually activated activation switch 46, for example when pressed for a time period longer than a predetermined duration, whereupon the control signals C are transmitted. A first control signal for activating the fan and stirrer may be transmitted following activation of microcontroller 41, and a second control signal for deactivating the fan and stirrer may be transmitted following a second predetermined duration after activation of microcontroller 41, in response to operation of timer 44. If so desired, more than one activation switch 46 may be provided and indicated accordingly, to select a slush making operation for one of a plurality of predefined liquids, the duration of each operation generally being different. The duration of the slush making operation is generally the average time to produce a slush product provided with ice crystals for the volume of the given liquid that is able to be introduced within the internal cavity, as based on the speed of the fan motor and the stirrer motor. For example, the typical duration of a slush making operation will be no more than 12 minutes for a liquid mixture provided with a concentration of ⅔ milk and ⅓ water for the preparation of iced coffee, from the time the home slush maker containing this liquid mixture has been removed from the refrigerator at which it has been cooled to a temperature of 4°C until the liquid mixture has been converted to iced coffee with a slushy consistency. An LED light 52 may illuminate and an enunciator 53 may emit a distinctive sound at the completion of the duration of the slush making operation. 43280/21 - 6 - Alternatively, the duration of a slush making operation may be determined electronically, by monitoring the instantaneous speed and current associated with the stirrer motor as being indicative of the mechanical resistance of the introduced liquid to agitation. The motor speed may be determined by a speed sensor 56 that detects the shaft speed and the direction of rotation, or by means of pulse width modulation whereby the duty cycle is varied, and a current sensor 57 may be used to detect the current in the motor. Microcontroller 41 is programmed to transmit a deactivation signal C when one or both of speed sensor 56 and current sensor 57 detect a predetermined high value that is indicative of a corresponding slush consistency, and to output one or more indications upon completion of the slush making operation. The fan motor and stirrer motor may be controlled separately. For example, when the predetermined high value indicative of a slush consistency is sensed by the current sensor of the stirrer motor, the speed of the stirrer is first decreased and then the fan speed is decreased to prevent the transformation of the desired liquid into a single ice block. When the dedicated application 43 is used, the entire slush making operation may be monitored through interaction with the application. By means of application 43, the user is able to transmit an input signal IN that is indicative of the type of liquid that has been introduced and an activation signal ACT to initiate the slush making operation, and is also able to receive an indication upon completion of the slush making operation in conjunction with one or both of speed sensor 56 and current sensor 57. This completion indication COM received by the application may be in addition to or in lieu of an indication provided by LED light 52 and enunciator 53. Input signal IN may also be indicative of a desired duration of a slush making operation or a desired temperature to which the introduced liquid is to be rapidly cooled. Input signal IN, activation signal ACT and completion indication signal COM are able to be remotely transmitted by a Bluetooth module 58 or by a WiFi module 59. Of course, the slush making operation may be terminated by depressing activation switch 46. Application 43 may be provided with instructions for preparing slush products with one or more liquids and also facilitates ordering various liquids or other edible items when inventory is low. Fig. 4 illustrates an exploded view of home slush maker 10. 43280/21 - 7 - As shown, stirrer 25 is coupled to motor 22 by means of output shaft 28 and adapter 31, the latter being frictionally engaged with a circular head plate 29 at the proximal end of stirrer 25. Stirrer 25 in turn is received in the internal cavity defined by cylindrical cup 36 within which the desired liquid is also introducible, and is rotatable about the longitudinal axis of cup 36. Receiving cup 36 may be configured with a heat sink 38, which may be embodied by a plurality of axially extending and circumferentially spaced fins that are attached at one radial end with the outer wall of cup 36. Alternatively or additionally, heat sink 38 may be embodied by a Peltier device, for example attached to the outer wall of cup 36. Holder 14 having a proximally located neck 39 of an enlarged radial dimension encircles cup 36 to provide an air gap therebetween and is coupled with the outer wall of activation unit housing 5 via neck 39 by threading 34, or by any other suitable coupling means well known to those skilled in the art. A proximally located neck of cup 36 in turn is coupled to an inner wall of activation unit housing 5 by threading 49. Although the distal end of cup 36 is solid to retain the introduced liquid and the slush product to be produced within its internal cavity, the distal end of holder 14 is configured with a plurality of air discharge openings 61, each of which defined by two adjacent circumferentially spaced and axially extending rod elements 63 that distally extend from a surface in contact with the distal end of cup 36. Rod elements 63 may serve to restrict the passage of foreign particles and ice from the freezer into the interior of holder 14. Stirrer 25 is an elongated member that is adapted to axially extend substantially throughout the interior of cup 36. In one embodiment, stirrer 25 is configured with two angled plates 42 and 48, e.g. angularly separated by 135 degrees, which radially extend from central stirrer shaft 45 that has an axial length significantly less than plates 42 and 48, for example one-half of their length, without radially protruding from head plate 29. Each of angled plates 42 and 48 is configured with a plurality of triangular apertures 51 throughout its length, through which formed ice crystals are able to pass when being agitated so as not to accumulate along the wall of cup 36 and reduce the temperature of the slush product below a desired value. In other words, stirrer 25 mixes the liquid to create a desired texture and to remove heat from the liquid due to the generation of an internal forced convection within cup 36. The operation of stirrer 25 accelerates the heat removal from the liquid using the generated internal forced convection. 43280/21 - 8 - Fan 16 is shown to be surrounded by a perforated cylindrical casing 21 that has a plurality of circumferentially spaced openings 32, in order to direct the drawn freezer air in specific radial directions. Fig. 5 illustrates a cross sectional view of home slush maker 10 when adapter 31 is coupled with both motor output shaft 28 and stirrer 25 and when fan 16 and stirrer 25 are operating during a slush making operation. Stirrer 25 may be conveniently detached from motor output shaft 28 when it is desired to replaced one type of stirrer with a different type, depending on the selected slush product that is to be prepared. As shown, the neck 39 of holder 14 is coupled to the distal end of the outer wall 8 of activation housing 5, and the neck 33 of cup 36 is coupled to the distal end of inner wall 9 of activation housing 5. An O-ring 54, or any other suitable sealing element, may be provided at the inner wall distal end of activation housing 5 to prevent any seepage of the slush product to annular passageway 6 or to motor 22. Cup neck 33 may also be coupled to a rotatable sealing element. The forced convection induced by the rotation of the blades of fan 16 draws the cold freezer air 64, e.g. at a set temperature of -18°C and at a volumetric flow rate of 1 m/min, through grille 18, shroud 21, annular passageway 6 formed in activation unit housing 5, air gap 66 provided between holder and cup 36, and through discharge openings 61 defined by rod elements 63. The air temperature after being discharged from openings 61 is slightly higher than that at the inlet of grille 18, e.g. -15°C. An additional cooling cycle is initiated within the freezer compartment to maintain the set temperature once the detected air temperature rises above a predetermined threshold. This forced convection arrangement optimally chills the liquid that has been introduced within the cavity of cup 36 by supercooling and facilitates the formation of small ice crystals that are characteristic of a slush product without having to deal with the bother of preparing ice cubes, handling them and introducing them into the internal cavity together with the desired liquid. The flow of cold freezer air 64 across the wall of cup 36 provides a relatively high rate of heat transfer from the introduced liquid and would normally cause the liquid to freeze to a solid block. The mechanical agitation provided by stirrer 25 causes the liquid temperature within the cup interior to be more uniform, and consequently inhibits crystal growth that would otherwise occur at the wall of 43280/21 - 9 - cup 36 where heat is typically being transferred out of the liquid. The small crystals that have already been formed remain suspended in the agitated liquid and produce the slush. Another cause for a reduction in the rate of heat transfer from the introduced liquid is the presence of the heat sink. After home slush maker 10 has been repositioned from outside to inside the freezer, the heat sink is at a temperature approximately equal to room temperature, and therefore reduces the rate of heat transfer from the introduced liquid. Also, the presence of sugar within the introduced liquid reduces the initial freezing point of the liquid and mitigates the bonding together of water molecules that would normally promote the formation of larger crystals and eventually solid ice. Since a sugar molecule is not integrated into the crystalline structure, the concentration of sugar in the remaining liquid increases as the percentage of the small crystal formations likewise increases, thus further reducing the freezing point of the remaining liquid. When a slush making operation is performed in conjunction with a current sensor and a speed sensor, the values detected by these sensors, as well as by temperature sensor 68 for detecting the temperature of the introduced liquid and temperature sensor 69 for determining the temperature of the incoming surrounding air, generally freezer air, are continually monitored throughout the slush making operation to determine whether the predetermined consistency has been produced. For purposes of troubleshooting, the current of the fan motor may be monitored throughout the slush making operation to determine whether the fan motor has become overloaded, for example due to blockage of the air outlet at discharge openings 61 that would seriously reduce the effectiveness of the forced convection and of the slush making operation. Before commencement of a slush making operation, the state of charge of the battery may be acquired in order to determine whether the battery is sufficiently charged to power the slush making operation. Upon determining that the slush product is ready to be consumed in accordance with a combination of various factors as defined in instruction stored in the processor of the microcontroller, including a predetermined temperature depending on the type of slush product that is being prepared and its sugar concentration and on the predetermined consistency of the slush product that is being produced, the microcontroller transmits a command to adjust the fan speed, depending on whether the slush temperature increases or decreases. At times, the microcontroller determines, when the temperature of the incoming surrounding air is equal to room temperature, that the slush product has achieved the predetermined set temperature

Claims

1./21 - 11 - CLAIMS1. A home slush maker, comprising an internal cavity within which a desired liquid is introducible, and an activation unit, when positioned in fluid communication with a source of chilled air, for generating a stream of said chilled air by forced convection that is in heat exchanger relation with a wall of the internal cavity for a sufficient duration to cause the introduced liquid to undergo sufficient rapid cooling that is suitable to produce a slush product.

2. The home slush maker according to claim 1, wherein the activation unit is configured to cause a phase change in the introduced liquid to produce the slush product.

3. The home slush maker according to claim 1, wherein the activation unit comprises a housing configured with an annular passageway and a fan retained at a proximal end of the housing that is in fluid communication with the source of chilled air, the generated stream of chilled air flowable through said passageway to the wall of the internal cavity.

4. The home slush maker according to claim 3, wherein a vessel configured with the internal cavity within which the desired liquid is introducible is releasably coupleable with the housing.

5. The home slush maker according to claim 4, further comprising a stirrer for stirring the introduced liquid which is receivable within the vessel, wherein a stirrer motor for rotatably driving the stirrer is retained in the housing.

6. The home slush maker according to claim 5, wherein the activation unit comprises control circuitry for controlling operation of the stirrer and fan until the slush product is produced.

7. The home slush maker according to claim 6, wherein the control circuitry is configured to cause the stirrer or fan to be intermittently operated after the slush product is produced to retain a desired consistency.

8. The home slush maker according to claim 5, which is suitable to produce a slush product in a small fraction of hour, after the desired liquid has been introduced into the vessel. 43280/21 - 12 -

9. The home slush maker according to claim 2, wherein the activation unit is configured to output an indication following completion of a slush making operation.

10. The home slush maker according to claim 9, wherein the activation unit is configured to output a remotely transmitted indication following completion of a slush making operation.

11. The home slush maker according to claim 1, which is sufficiently small to be hand held.