Ice Maker Heater Assembly

Abstract

The ice maker includes an ice mold having an inner surface and an outer surface. The inner surface of the ice mold is configured to hold water for forming ice cubes within the ice mold. The ice mold includes a plurality of ice lobes, each shaped to form a respective ice cube within the ice mold. A heater assembly is disposed on the outer surface of the ice mold. In some embodiments, each of a plurality of heating elements of the heater assembly is aligned with a corresponding lobe of the plurality of lobes to supply heat to the ice cubes formed within the lobe to release the ice from the ice mold. In some embodiments, the heater assembly includes a heater having a ceramic substrate and one or more electrically resistive traces and conductive trace thick films printed on the ceramic substrate.

Description

[Technical Field]

[0001] The present disclosure relates to an ice making heater assembly. [Background technology]

[0002] Conventional ice makers, such as those installed in or built into refrigerators and freezers, include a heater assembly located below the ice maker that supplies heat to the bottom of the ice mold to loosen the ice from the mold's surface after it has formed and enable its removal from the mold, for example, by one or more ejector blades driven by a motor. Existing ice makers often include a Calrod®-type heating element, available from General Electric Company (Schenectady, New York), located along the exterior surface of the bottom of the ice mold. The Calrod®-type heating element includes a coiled nichrome wire, acting as a resistance heating element, within a metal (steel alloy) sheath, surrounded by magnesium dioxide, acting as a heat transfer element. These Calrod®-type heater assemblies have relatively low thermal efficiency, resulting in ice-making cycle times of 250 minutes or longer. Summary of the Invention [Problem to be solved by the invention]

[0003] Therefore, what is desired is a heater assembly for an ice maker that has improved thermal efficiency to allow for shorter cycle times for faster ice making. [Means for solving the problem]

[0004] An ice making machine according to one exemplary embodiment includes an ice mold having an inner surface and an outer surface. The inner surface of the ice mold is configured to hold water for forming ice cubes within the ice mold. The ice mold includes a plurality of ice lobes, each shaped to form a respective ice cube within the ice mold. A heater assembly is disposed on the outer surface of the ice mold. The heater assembly includes a plurality of heating elements. Each of the plurality of heating elements is aligned with a corresponding lobe of the plurality of lobes to provide heat to ice cubes formed in the lobe to release the ice cubes from the ice mold. The heater assembly includes a plurality of conductors extending between the plurality of lobes and electrically connecting the plurality of heating elements. In some embodiments, the heater assembly is disposed along the underside of the ice mold. Embodiments include embodiments in which the heater assembly includes a heater having a ceramic substrate, and the plurality of heating elements of the heater assembly are formed by a plurality of electrical resistance traces printed on the ceramic substrate of the heater. In some embodiments, the plurality of conductors are formed by a plurality of conductive traces printed on the ceramic substrate of the heater.

[0005] An ice making machine according to another exemplary embodiment includes an ice mold having an inner surface and an outer surface. The inner surface of the ice mold is configured to hold water for forming ice cubes within the ice mold. A heater assembly is disposed on the outer surface of the ice mold to supply heat to ice cubes formed in the ice mold to release the ice cubes from the ice mold. The heater assembly includes a heater having a ceramic substrate. The ceramic substrate has at least one thick-film electrically resistive trace printed on the ceramic substrate and at least one thick-film electrically conductive trace printed on the ceramic substrate. The heater is configured to generate heat when an electric current is supplied to the at least one thick-film electrically resistive trace.

[0006] An ice making machine according to another exemplary embodiment includes an ice mold having an inner surface and an outer surface. The inner surface of the ice mold is configured to hold water for forming ice cubes within the ice mold. The ice mold includes a plurality of ice lobes, each shaped to form a respective ice cube within the ice mold. A heater is disposed on the outer surface of the ice mold. The heater includes a ceramic substrate having a plurality of electrical resistance traces disposed thereon and a plurality of conductive traces disposed thereon. The heater is configured to generate heat when an electric current is supplied to the electrical resistance traces. The plurality of electrical resistance traces are spaced along a length of the ceramic substrate such that each of the plurality of electrical resistance traces is aligned with a corresponding lobe of the plurality of lobes to supply heat to ice cubes formed within the lobe to release the ice cubes from the ice mold. The plurality of conductive traces extend between respective pairs of the plurality of lobes and electrically connect the plurality of electrical resistance traces.

[0007] According to another exemplary embodiment, an ice making machine includes an ice mold having an inner surface and an outer surface. The inner surface of the ice mold is configured to hold water for forming ice cubes within the ice mold. The ice mold includes a plurality of ice lobes, each shaped to form a respective ice cube within the ice mold. A plurality of heaters are disposed on the outer surface of the ice mold. Each heater of the plurality of heaters includes a ceramic substrate having at least one electrical resistance trace disposed thereon. Each heater of the plurality of heaters is configured to generate heat when an electric current is supplied to the at least one electrical resistance trace. The at least one electrical resistance trace of each heater is aligned with a corresponding lobe of the plurality of lobes to supply heat to ice cubes formed in the lobe to release the ice cubes from the ice mold.

[0008] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of an ice making machine according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram of the ice making machine of FIG. [Figure 3] FIG. 3 is a perspective view of the bottom of an ice mold of an ice maker according to an example embodiment. [Figure 4] FIG. 4 is a perspective view of the bottom of an ice mold of an ice maker having a heater assembly in an example of the first embodiment. [Figure 5] FIG. 5 is an exploded view illustrating additional features of the ice mold and heater assembly of FIG. 4, in an example embodiment. [Figure 6] FIG. 6 is a plan view of the heater of the heater assembly shown in FIGS. 4 and 5, in one example embodiment. [Figure 7] FIG. 7 is a bottom view of the ice mold and heater assembly of FIG. 4, according to an example embodiment. [Figure 8] FIG. 8 is a perspective view of the bottom of an ice mold of an ice maker having a heater assembly in a second example embodiment. [Figure 9] FIG. 9 is a plan view of the heater of the heater assembly shown in FIG. 8 according to one exemplary embodiment. [Figure 10] FIG. 10 is a bottom view of the ice mold and heater assembly of FIG. 8, according to an example embodiment. [Figure 11] FIG. 11 is a perspective view of the bottom of an ice mold of an ice maker having a heater assembly in a third embodiment. [Figure 12] FIG. 12 is a top view of the heater of the heater assembly shown in FIG. 11, in one example embodiment. [Figure 13] FIG. 13 is a bottom view of the ice mold and heater assembly of FIG. 11, in an example embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] In the following description, reference is made to the accompanying drawings, in which like numbers represent like elements. The embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure. It is to be understood that other embodiments may be utilized, and process, electrical, and mechanical changes, and the like, may be made without departing from the scope of the disclosure. The examples merely represent possible variations. Portions and features of some embodiments may be included in or substituted for others. Therefore, the following description is not to be taken in a limiting sense, and the scope of the disclosure is defined only by the appended claims and their equivalents.

[0011] FIG. 1 illustrates an ice maker 100 according to an example embodiment. Ice maker 100 may be installed or incorporated into, for example, a refrigerator, a freezer, etc. Ice maker 100 includes ice molds 102. Ice molds 102 include an interior surface configured to hold water supplied to ice maker 100 and to form ice cubes when the water held within ice molds 102 freezes. Typically, a refrigeration unit of the refrigerator or freezer in which ice maker 100 is installed provides chilled air to maintain a temperature below freezing to freeze the water within ice molds 102. Although the term "cube" is used, it is understood that ice cubes may be formed in a variety of shapes other than true geometric cubes, including, for example, cubes, half cubes, crescents, nuggets, flakes, etc. In some embodiments, the ice mold 102 is constructed from a thermally conductive material to facilitate efficient cooling of the water within the mold 102 to form ice cubes, and to efficiently heat the ice cubes formed within the mold 102 to aid in removing the ice cubes from the mold 102, as described below. In some embodiments, aluminum is advantageous due to its relatively high thermal conductivity and relatively low cost. Hot-forged aluminum into a desired shape is often preferred over casting aluminum due to the higher thermal conductivity of forged aluminum.

[0012] Ice making machine 100 may include a lid or cover 104 that is positioned over and covers a portion of ice molds 102. Ice making machine 100 may also include one or more ejector blades (or other forms of extensions) that extend outward from rotatable shaft 108 ( FIG. 2 ) and are positioned to move ice cubes from molds 102 to bin 110 (or other area for holding ice cubes) after they have been formed and frozen. Cover 104 may include a series of slits 112 (or other forms of openings) through which ice cubes exit molds 102 and through which ejector blades driven by shaft 108 pass during rotation of shaft 108. Ice making machine 100 may also include a housing 114 located at one end of ice making machine 100 that houses various components, including, for example, a motor that drives shaft 108, control circuitry for ice making machine 100, and other electrical and / or mechanical components.

[0013] The basic operation of an ice making machine, such as ice maker 100, is well known and will therefore only be briefly described herein. Referring to FIG. 2, ice maker 100 includes a control circuit 120 that controls the operation of ice maker 100. In one example, to initiate an ice making cycle, control circuit 120 opens a valve 122 (e.g., a solenoid valve) that allows water to enter ice molds 102 from a water supply 123. Water is typically supplied to ice maker 100 via a plumbing line to a refrigerator / freezer in which ice maker 100 is installed. Valve 122 is opened for a predetermined time sufficient to fill molds 102 with a desired amount of water, after which valve 122 is closed to stop the flow of water to molds 102. A cooling unit in the refrigerator / freezer, for example, cools the water in molds 102. A temperature sensor 124, such as a thermistor, thermostat, or the like, located proximate to molds 102 can provide temperature data to control circuit 120. When the water temperature in the molds 102 drops below a predetermined value, indicating that the water is sufficiently frozen, the control circuit 120 switches on the heater assembly 150 for a predetermined time (or until a predetermined temperature is reached) to provide heat to the ice in the molds 102 to loosen the ice cubes from the interior surfaces of the molds 102. The control circuit 120 activates (e.g., simultaneously with or immediately after activation of the heater assembly 150) the motor 126, which provides rotational motion to the shaft 108, to rotate the shaft 108, thereby rotating the ejector blades, which can push the ice cubes out of the molds 102 and into the bin 110. The control circuit 120 causes the motor 126 to rotate a predetermined amount sufficient to remove the ice from the molds 102. The rotation of the motor 126 and the shaft 108 can also lift a shutoff arm 128, which is pivotally mounted to the ice maker 100. Further rotation of motor 126 and shaft 108 allows blocking arm 128 to fall via gravity until blocking arm 128 either (a) rests against the top surface of the ice in container 110, or (b) the blocking arm 128 reaches a downward rotation stop. Blocking arm 128 is operably connected to a switch 130, such as a mechanical or electronic switch.

[0014] After motor 126 completes its rotation, control circuit 120 checks the state of switch 130 connected to shutoff arm 128. If switch 130 is in a first state, indicating that shutoff arm 128 is positioned below a predetermined point such that bin 110 has additional capacity available for ice, control circuit 120 initiates another ice-making cycle by opening water valve 122. On the other hand, if switch 130 is in a second state, indicating that shutoff arm 128 is positioned above a predetermined point such that bin 110 is full, control circuit 120 delays the next ice-making cycle until switch 130 changes from the second state to the first state, i.e., until the position of shutoff arm 128 has dropped below the predetermined point, indicating that bin 110 has sufficient capacity to receive additional ice. Delaying the next ice making cycle can include delaying the opening of valve 122 to fill mold 102 with water, or can include opening valve 122 and filling mold 102 with water but delaying the removal of ice from mold 102 by heater assembly 150 and ejector blades on shaft 108 until bin 110 has sufficient capacity to receive additional ice.

[0015] FIG. 3 shows the underside 130 of the ice mold 102 in one example embodiment. The ice mold 102 includes an outer surface 132 and an inner surface 134. The inner surface 134 contacts the water held within the ice mold 102 during ice formation. The outer surface 132 is disposed opposite the inner surface 134. The inner surface 134 of the ice mold 102 includes a plurality of individual cavities or lobes 136 formed therein. Each lobe 136 is shaped and positioned to form a respective ice cube when the water held within the mold 102 is frozen. In the illustrated embodiment, the lobes 136 are formed to correspond to the outer surface 132 and the inner surface 134 of the mold 102. In some embodiments, the thickness of the walls forming the mold 102 is thinner at the heating location 137 of each lobe 136 than the portion of the walls forming the mold 102 away from the heating location 137 of the lobe 136. A corresponding heating element is located at heating location 137 for each lobe 136, as will be described in more detail below.

[0016] FIG. 4 shows a heater assembly 150 of ice making machine 100 according to one exemplary embodiment. In the illustrated embodiment, heater assembly 150 includes a single heater 152 disposed on outer surface 132 of mold 102 along underside 130 of mold 102. Heater 152 has an inner surface 154 facing outer surface 132 of underside 130 of mold 102 and an outer surface 156 facing away from outer surface 132 of underside 130 of mold 102. As described in more detail below, heater 152 includes a ceramic substrate 160 (e.g., a commercially available 96% aluminum oxide ceramic) having a series of one or more electrical resistive traces 162 and conductive traces 164 disposed on ceramic substrate 160. Resistive traces 162 include a suitable electrical resistor material, such as, for example, silver-palladium (e.g., a 70 / 30 silver-palladium blend). Heat is generated when an electric current passes through resistive trace 162. The conductive traces 164 comprise a suitable electrical conductor material, such as, for example, silver-platinum. The conductive traces 164 provide electrical connection between the resistive traces 162. In the illustrated embodiment, one or more resistive traces 162 are disposed on or aligned with each lobe 136 of the mold 102 to efficiently supply heat to each lobe 136 from the inner surface 134 of the mold 102 to release ice cubes formed in the lobe 136 upon activation of the heater assembly 150 by the control circuit 120. The conductive traces 164 extend between the lobes 136 of the mold 102 to electrically connect the electrical resistive traces 162 of adjacent lobes 136. The conductive traces 164 also form a pair of terminals 166, 167 of the heater 152. A voltage connector can be connected to terminals 166, 167 to electrically connect resistive trace 162 and conductive trace 164 to a voltage source of ice maker 100 (e.g., a voltage source of a refrigerator or freezer in which ice maker 100 is installed), and control circuit 120 selectively closes the circuit formed by resistive trace 162 and conductive trace 164 to generate heat.

[0017] 5, heater assembly 150 includes a voltage connector 138 that electrically connects a voltage source of ice maker 100 and control circuit 120 to terminals 166, 167 of heater 152. In the exemplary embodiment shown, a single voltage connector 138 is used having a pair of electrical contacts (e.g., spring-loaded electrical contacts) that each contact a respective terminal 166, 167 of heater 152. In other embodiments, a separate voltage connector electrically contacts each terminal 166, 167. While the exemplary embodiment shown includes a voltage connector 138 that facilitates an electrical connection between heater 152 and a voltage source of ice maker 100 and control circuit 120, it will be understood that the electrical connection may be established by any suitable means desired, including, for example, soldering or welding wires, cables, bus bars, or other forms of electrical contacts to each terminal 166, 167.

[0018] In the illustrated exemplary embodiment, the heater assembly 150 includes a cover 140 that substantially covers an outer surface 156 of the heater 152. The cover 140 provides electrical and thermal insulation for the heater 152. The cover 140 may be constructed from a suitable plastic material, such as, for example, polyphenylene sulfide (PPS) plastic, liquid crystal polymer (LCP) plastic, polyethylene terephthalate (PET) plastic, or polyether ether ketone (PEEK) plastic. If desired, an insulating pad or other form of insulation (e.g., silicone rubber or silicone foam) may be applied to the outer surface 156 of the heater 152 (e.g., between the cover 140 and the outer surface 156 of the heater 152 and / or on the outer surface of the cover 140) to reduce heat loss and improve heat transfer from the heater 152 to the mold 102. Heat transfer from the heater 152 to the mold 102 may also be improved by attaching the heater 152 to the ice mold 102 using thermally conductive, high temperature resistant double sided tape or thermally conductive adhesive or gap filler 142 disposed between the inner surface 154 of the heater 152 and the outer surface 132 of the mold 102. If desired, a spring or other biasing mechanism may be used to urge the heater 152 toward the outer surface 132 of the mold 102 to improve heat transfer.

[0019] FIG. 6 illustrates the outer surface 156 of the heater 152 according to one exemplary embodiment. In the illustrated embodiment, the inner surface 154 and outer surface 156 of the heater 152 are bounded by four sides or edges (including side edges 170 and 171 and longitudinal edges 172 and 173), each having a smaller surface area than the inner surface 154 and outer surface 156. In this embodiment, the inner surface 154 and outer surface 156 are rectangular, although other shapes (e.g., other polygons, such as squares) may be used as desired. In the illustrated embodiment, the heater 152 includes a longitudinal dimension 174 extending from the lateral edge 170 to the lateral edge 171 and a lateral dimension 175 extending from the longitudinal edge 172 to the longitudinal edge 173. The heater 152 also includes an overall thickness measured from the inner surface 154 to the outer surface 156.

[0020] As described above, heater 152 includes one or more layers of ceramic substrate 160. Ceramic substrate 160 includes an outer surface 157 oriented toward outer surface 156 of heater 152 and an inner surface oriented toward inner surface 154 of heater 152. Outer surface 157 and the inner surface of ceramic substrate 160 are disposed on an outer portion of ceramic substrate 160, such that, when two or more layers of ceramic substrate 160 are used, outer surface 157 and the inner surface of ceramic substrate 160 are disposed on opposing outer surfaces of ceramic substrate 160, rather than on an inner or intermediate layer of ceramic substrate 160.

[0021] In the illustrated exemplary embodiment, the inner surface 154 of the heater 152 is formed by the inner surface of the ceramic substrate 160. In this embodiment, the outer surface 157 of the ceramic substrate 160 includes a series of one or more electrical resistive traces 162 and conductive traces 164 disposed thereon, as described above. In the illustrated embodiment, the resistive traces 162 and conductive traces 164 are applied to the ceramic substrate 160 by thick film printing. For example, the resistive traces 162 may include a resistive paste having a thickness of 10 to 13 microns when applied to the ceramic substrate 160, and the conductive traces 164 may include a conductive paste having a thickness of 9 to 15 microns when applied to the ceramic substrate 160. The resistive traces 162 form respective heating elements 176 of the heater 152, and the conductive traces 164 provide electrical connections between the resistive traces 162 to supply current to each resistive trace 162 to generate heat.

[0022] In the illustrated exemplary embodiment, the terminals 166, 167 are positioned adjacent to one another along the longitudinal edges 172 of the heater 152 near the lateral edges 170. In the illustrated embodiment, the resistive traces 162 and the conductive traces 164 extend in an alternating pattern along rectangular paths on the exterior surface 157 of the ceramic substrate 160. The heating elements 176 formed by the resistive traces 162 are positioned to align with corresponding lobes 136 of the ice mold 102 when the heater 152 is installed on the ice mold 102. In the illustrated embodiment, the heating elements 176 are positioned in a spaced-apart relationship from one another along the vertical dimension 174. In this embodiment, each heating element 176 includes a first resistive trace 162a located along the longitudinal edge 172 and a second resistive trace 162b located along the transverse edge 173. The conductive traces 164 extend along the longitudinal edges 172, 173 and lateral edges 170, 171 to electrically connect adjacent resistive traces 162 and complete the circuits formed by the conductive traces 164 between the resistive traces 162 and the terminals 166, 167. In this embodiment, the resistive traces 162 extend generally parallel to each other and to the longitudinal edges 172, 173 of the heater 152. The conductive traces 164 at the lateral edges 170, 171 of the heater 152 extend generally perpendicular to the resistive traces 162 and parallel to the lateral edges 170, 171 of the heater 152. The remaining conductive traces 164 extend generally parallel to the resistive traces 162 and the longitudinal edges 172, 173 of the heater 152.

[0023] In the illustrated embodiment, heater 152 includes one or more layers of printed glass 180 on the outer surface 157 of ceramic substrate 160. In the illustrated embodiment, glass 180 covers resistive traces 162 and conductive traces 164, except for the portions of conductive traces 164 that form terminals 166, 167, to electrically insulate such features to prevent electric shock or arcing. The boundaries of glass layer 180 are indicated by dotted lines in Figures 4-7. The overall thickness of glass 180 may be in the range of 70-80 microns, for example.

[0024] The heater 152 can be constructed by thick-film printing. For example, in one embodiment, the resistive trace 162 is printed onto a fired (not unfired) ceramic substrate 160, which involves selectively applying a paste containing resistor material to the ceramic substrate 160 through a patterned mesh screen, such as with a squeegee. The printed resistor is then deposited onto the ceramic substrate 160 at room temperature. The ceramic substrate 160 with the printed resistor is then heated to, e.g., about 140-160°C, for a total of about 30 minutes, including about 10-15 minutes at peak temperature, with the remaining time ramping up to and down from the peak temperature, to dry the resistive paste and temporarily fix the resistive trace 162 in place. The ceramic substrate 160 with the temporary resistive trace 162 is then heated to, e.g., about 850°C, for a total of about 1 hour, including about 10 minutes at peak temperature, with the remaining time ramping up to and down from the peak temperature, to permanently fix the resistive trace 162 in place. Conductive traces 164 are then printed onto the ceramic substrate 160, which involves selectively applying a paste containing conductor material in the same manner as resistor material. The ceramic substrate 160 with the printed resistor and conductors is then sunk, dried, and fired in the same manner as described above for the resistor traces 162 to permanently fix the conductive traces 164 in place. A glass layer 180 is then printed in substantially the same manner as the resistor and conductors, including sunk, drying, and firing the glass layer 180. In one embodiment, the glass layer 180 is fired at a peak temperature of approximately 810° C., slightly lower than the resistor and conductor.

[0025] The thick film printed resistive traces 162 and conductive traces 164 on the fired ceramic substrate 160 provide more uniform resistive and conductive traces compared to conventional ceramic heaters that include resistive and conductive traces printed on green state ceramic. The improved uniformity of the resistive and conductive traces 162 and 164 provides more uniform heating across the inner surface 154 of the heater 152, as well as more predictable heating of the heater 152.

[0026] 4-7 includes resistive trace 162 and the heating element 176 formed thereby that is positioned on the exterior surface 157 of ceramic substrate 160; in other embodiments, resistive trace 162 and the heating element 176 formed thereby may be positioned on the interior surface of ceramic substrate 160, with corresponding conductive traces as needed to establish electrical connection thereto. Glass 180 may cover the resistive traces and conductive traces on exterior surface 157 and / or the interior surface of ceramic substrate 160, as desired, to electrically insulate such features.

[0027] 7 shows the underside 130 of the ice mold 102 with the heater 152 attached. As mentioned above, in the illustrated embodiment, the heating elements 176 of the heater 152 are aligned with the corresponding lobes 136 of the mold 102 to efficiently supply heat to each lobe 136 and release ice cubes formed in the lobes 136 from the inner surface 134 of the mold 102 upon activation of the heater assembly 150 by the control circuit 120. In the illustrated embodiment, each heating element 176 includes a pair of resistive traces 162 aligned with the respective lobe 136 of the mold 102. However, in other embodiments, each heating element 176 can include a single resistive trace 162 or two or more resistive traces 162, as desired. Conductive traces 164 extend between the lobes 136 of the mold 102 to electrically connect each heating element 176.

[0028] FIG. 8 shows a heater assembly 250 of the ice making machine 100 according to another exemplary embodiment. In the illustrated embodiment, the heater assembly 250 includes a single heater 252 disposed on the outer surface 132 of the mold 102 along the lower surface 130 of the mold 102. The heater 252 has an inner surface 254 facing the outer surface 132 of the lower surface 130 of the mold 102 and an outer surface 256 facing away from the outer surface 132 of the lower surface 130 of the mold 102. Similar to the heater 152 described above, the heater 252 includes a ceramic substrate 260 having a series of one or more electrical resistive traces 262 and conductive traces 264 disposed thereon. Upon activation of the heater assembly 250 by the control circuit 120, heat is generated when an electrical current is passed through the resistive traces 262 to release ice cubes formed in the lobes 136 from the inner surface 134 of the mold 102. The conductive traces 264 provide an electrical connection between the resistive traces 262. The conductive trace 264 also forms a pair of terminals 266, 267 (FIG. 9) of the heater 252.

[0029] In this embodiment, each voltage connector 238, 239 is connected to a respective terminal 266, 267 to electrically connect resistive trace 262 and conductive trace 264 to a voltage source in ice maker 100, and control circuit 120 selectively closes the circuit formed by resistive trace 262 and conductive trace 264 to generate heat. Each voltage connector 238, 239 includes a respective electrical contact (e.g., a spring-loaded electrical contact) that contacts a corresponding terminal 266, 267 of heater 252. As noted above, although a pair of voltage connectors 238, 239 is illustrated, electrical connection to terminals 266, 267 may be established by any suitable means as desired.

[0030] 8, the heater assembly 250 can include a cover and insulation as desired. Additionally, thermal tape, adhesive, or gap filler can be placed between the inner surface 254 of the heater 252 and the outer surface 132 of the mold 102 to improve heat transfer as desired, and a spring or other biasing mechanism can urge the heater 252 toward the outer surface 132 of the mold 102 as desired.

[0031] FIG. 9 illustrates an outer surface 256 of a heater 252 according to one exemplary embodiment. In the illustrated embodiment, the inner surface 254 and outer surface 256 of the heater 252 are bounded by four sides or edges (including lateral edges 270 and 271 and longitudinal edges 272 and 273), each having a smaller surface area than the inner surface 254 and outer surface 256. In this embodiment, the inner surface 254 and outer surface 256 are rectangular, although other shapes (e.g., other polygons, such as squares) may be used as desired. In the illustrated embodiment, the heater 252 includes a longitudinal dimension 274 extending from the lateral edge 270 to the lateral edge 271 and a lateral dimension 275 extending from the longitudinal edge 272 to the longitudinal edge 273. The heater 252 also includes an overall thickness measured from the inner surface 254 to the outer surface 256.

[0032] As described above, heater 252 includes one or more layers of ceramic substrate 260. Ceramic substrate 260 includes an outer surface 257 oriented toward outer surface 256 of heater 252 and an inner surface oriented toward inner surface 254 of heater 252. Outer surface 257 and the inner surface of ceramic substrate 260 are disposed on an outer portion of ceramic substrate 260, and if more than one layer of ceramic substrate 260 is used, outer surface 257 and the inner surface of ceramic substrate 260 are disposed on opposing outer surfaces of ceramic substrate 260, rather than on an inner or intermediate layer of ceramic substrate 260.

[0033] In the illustrated exemplary embodiment, the inner surface 254 of the heater 252 is formed by the inner surface of a ceramic substrate 260. In this embodiment, the outer surface 257 of the ceramic substrate 260 includes a series of one or more electrically resistive traces 262 and conductive traces 264 disposed thereon, as described above. The resistive traces 262 and conductive traces 264 may be applied to the ceramic substrate 260 by thick film printing, as described above.

[0034] In the exemplary embodiment shown, terminals 266, 267 are positioned at opposite ends of heater 252 along longitudinal dimension 274, such that terminal 266 is positioned adjacent lateral edge 270 and terminal 267 is positioned adjacent lateral edge 271. Positioning terminals 266, 267 at opposite ends of heater 252 allows for a narrower overall width of heater 252 along lateral dimension 275, as compared to the width of heater 152 along lateral dimension 175 where, for example, electrical connections to both terminals 166, 167 are made near one end of heater 152. Reducing the width of heater 252 helps reduce the thermal mass of heater 252 to improve the thermal efficiency of heater assembly 250.

[0035] In the illustrated embodiment, the resistive traces 262 and conductive traces 264 form an alternating row-by-row pattern on the outer surface 257 of the ceramic substrate 260 extending along a longitudinal dimension 274 from terminal 266 to terminal 267. The resistive traces 262 form respective heating elements 276 of the heater 252. The heating elements 276 are positioned to align with corresponding lobes 136 of the ice mold 102 when the heater 252 is installed on the ice mold 102. In the illustrated embodiment, the heating elements 276 are positioned in a spaced-apart relationship from one another along the longitudinal dimension 274. In the illustrated exemplary embodiment, each heating element 276 includes a single resistive trace 262. The conductive traces 264 extend between and electrically connect adjacent resistive traces 262 to complete the circuit formed by the resistive traces 262 and the conductive traces 264 between the terminals 266, 267. In the illustrated embodiment, the resistive traces 262 and conductive traces 264 extend parallel to one another and generally parallel to the longitudinal edges 272, 273 of the heater 252. In the illustrated embodiment, for each conductive trace 264, the central portion 265 of each conductive trace 264 has a width along the lateral dimension 275 that is smaller than the width of the resistive trace 262, and tapers inward along the lateral dimension 275 away from the longitudinal edges 272, 273 as the conductive trace 264 extends away from the respective resistive trace 262 with which it is in contact, such that the width of the conductive trace 264 along the lateral dimension 275 is smaller than the width of the resistive trace 262 along the lateral dimension 275. The reduced width of the central portion 265 of the conductive trace 264 also aids in reducing the thermal mass of the heater 252.

[0036] In the illustrated embodiment, heater 252 includes one or more layers of printed glass 280 on the outer surface 257 of ceramic substrate 260, as described above. In the illustrated embodiment, glass 280 covers resistive traces 262 and conductive traces 264, except for portions of terminals 266, 267, to electrically isolate such features. The boundaries of glass layer 280 are indicated by dotted lines in Figures 8-10.

[0037] 8-10 includes resistive trace 262, and in other embodiments, as described above, the heating element 276 formed thereby disposed on the outer surface 257 of ceramic substrate 260. Resistive trace 262 and the heating element 276 formed thereby may be disposed on the inner surface of ceramic substrate 260, along with corresponding conductive traces as needed to establish electrical connection thereto. Glass 280 may cover the resistive and conductive traces on outer surface 257 and / or the inner surface of ceramic substrate 260, as desired, to electrically insulate such features.

[0038] 10 shows the underside 130 of the ice mold 102 with the heater 252 attached. The heating elements 276 of the heater 252 are aligned with the corresponding lobes 136 of the mold 102 to efficiently supply heat to each lobe 136 and release ice cubes formed in the lobes 136 from the inner surface 134 of the mold 102 upon activation of the heater assembly 250 by the control circuit 120. In the illustrated embodiment, each heating element 276 includes a resistive trace 262 aligned with the respective lobe 136 of the mold 102. However, in other embodiments, each heating element 276 can include two or more resistive traces 262, as desired. Conductive traces 264 extend between the lobes 136 of the mold 102 to electrically connect each heating element 276.

[0039] FIG. 11 shows a heater assembly 350 of ice making machine 100 according to another exemplary embodiment. In the illustrated embodiment, heater assembly 350 includes a plurality of heaters 352 disposed on outer surface 132 of mold 102 along lower surface 130 of mold 102. Heaters 352 are spaced along outer surface 132 of mold 102 for selectively applying heat to mold 102 upon activation of heater assembly 350 by control circuit 120. Each heater 352 has an inner surface facing outer surface 132 of lower surface 130 of mold 102 and an outer surface 356 ( FIG. 12 ) facing away from outer surface 132 of lower surface 130 of mold 102. Similar to heaters 152 and 252 described above, each heater 352 includes a ceramic substrate 360 ​​( FIG. 12 ) having a series of one or more electrically resistive traces 362 ( FIG. 12 ) and conductive traces 364 ( FIG. 12 ) disposed thereon. Upon activation of the heater assemblies 350 by the control circuit 120, heat is generated when current flows through the resistive traces 362 of the heaters 352 to release ice cubes formed in the lobes 136 from the inner surface 134 of the mold 102. The conductive traces 364 provide electrical connections between the resistive traces 362 of each heater 352. The conductive traces 364 also form a pair of terminals 366, 367 (FIG. 12) for each heater 352.

[0040] The heaters 352 are electrically connected to each other, e.g., in series, by cables, wires, bus bars, or other forms of electrical connection to provide voltage to each heater 352 and facilitate control of the heaters 352. In the illustrated exemplary embodiment, a voltage connector 338 is disposed at a first end of the mold 102 and is electrically connected to a pair of bus bars 342, 343 that extend from the voltage connector 338 along the underside 130 of the mold 102. In this embodiment, the bus bar 342 is electrically connected to a first terminal 366 of each heater 352, and the bus bar 343 is electrically connected to a second terminal 367 of each heater 352 to electrically connect the heaters 352 to respective electrical contacts of the voltage connector 338. In the illustrated embodiment, a conductive tab 344 is welded (e.g., laser welded or resistance welded) directly to each terminal 366, 367 and then welded or soldered directly to the corresponding bus bar 342, 343 to electrically connect the bus bar 342, 343 to the terminal 366, 367 of each heater 352. In the illustrated embodiment, a mount 339 is located on the end of the mold 102 opposite the voltage connector 338. The mount 339 receives the respective ends of the bus bars 342, 343 to provide additional physical support for the bus bars 342, 343, although in the illustrated embodiment, the mount 339 does not electrically connect the bus bars 342, 343. A voltage connector 338 and bus bars 342, 343 electrically connect each heater 352 to a voltage source in ice maker 100, and control circuit 120 selectively closes circuit-forming heaters 352 and bus bars 342, 343 to generate heat from resistive traces 362 of heaters 352. Voltage connector 338 includes a pair of electrical contacts that respectively contact each bus bar 342, 343.

[0041] 11, heater assembly 350 may include a cover and insulation as desired. Additionally, thermal tape, adhesive, or gap filler may be placed between the inner surface of each heater 352 and the outer surface 132 of mold 102 to improve heat transfer as desired, and a spring or other biasing mechanism may bias each heater 352 toward the outer surface 132 of mold 102 as desired.

[0042] FIG. 12 shows the outer surface 356 of the heater 352 according to one exemplary embodiment. In the illustrated embodiment, the inner surface of the heater 352 and the outer surface 356 of the heater 352 are square, although other shapes (e.g., other polygons, such as a rectangle) may be used if desired. The heater 352 includes one or more layers of a ceramic substrate 360, as described above. The ceramic substrate 360 ​​includes an outer surface 357 oriented toward the outer surface 356 of the heater 352 and an inner surface oriented toward the inner surface of the heater 352. In the illustrated exemplary embodiment, the inner surface of the heater 352 is formed by the inner surface of the ceramic substrate 360. In this embodiment, the outer surface 357 of the ceramic substrate 360 ​​includes an electrically resistive trace 362 and a pair of conductive traces 364 a, 364 b located thereon. The resistive trace 362 forms the heating element 376 of the heater 352. The resistive trace 362 and conductive traces 364a, 364b may be applied to the ceramic substrate 360 ​​by thick film printing as described above.

[0043] In the illustrated exemplary embodiment, resistive trace 362 extends from near first edge 370 of heater 352 toward second edge 371 of heater 352, substantially parallel to third edge 372 and fourth edge 373 of heater 352. In this embodiment, resistive trace 362 is disposed midway between edges 372, 373 of heater 352. Conductive traces 364a, 364b each constitute a respective terminal 366, 367 of heater 352. Conductive trace 364a directly contacts a first end of resistive trace 362 near edge 371 of heater 352, and conductive trace 364b directly contacts a second end of resistive trace 362 near edge 370 of heater 352. The portion of resistive trace 362 hidden beneath conductive traces 364a, 364b in FIG. 12 is indicated by dashed lines.

[0044] In the illustrated embodiment, heater 352 includes one or more layers of printed glass 380 on an outer surface 357 of ceramic substrate 360. In the illustrated embodiment, glass 380 covers portions of resistive trace 362 and conductive traces 364a, 364b, but not portions of terminals 366, 367, to electrically isolate such features. The boundaries of glass layer 380 are indicated by dashed lines in Figures 12 and 13.

[0045] 11-13 includes resistive trace 362, and in other embodiments, as described above, the resistive trace 362 and the heating element 376 formed thereby disposed on the outer surface 357 of the ceramic substrate 360. The resistive trace 362 and the heating element 376 formed thereby may be disposed on the inner surface of the ceramic substrate 360, along with corresponding conductive traces as needed to establish electrical connection thereto. Glass 380 may cover the resistive traces and conductive traces on the outer surface 357 and / or the inner surface of the ceramic substrate 360, as desired, to electrically insulate such features.

[0046] 13 shows the underside 130 of the ice mold 102 with a heater 352 attached. The heater 352 is aligned with the corresponding lobe 136 of the mold 102 so that, upon activation of the heater assembly 350 by the control circuit 120, the heating element 376 supplies heat to each lobe 136 to release ice cubes formed in the lobe 136 from the inner surface 134 of the mold 102. Bus bars 342, 343 extend between the lobes 136 of the mold 102 to electrically connect each heater 352 to a voltage connector 338, electrically connecting the heater 352 to the voltage source and control circuit 120 of the ice maker 100.

[0047] The heater embodiments of ice making machine 100 illustrated and described above with respect to Figures 4-13 are intended as examples and are not exhaustive. Heaters of the present disclosure can include many different patterns, layouts, geometries, shapes, positions, sizes, and inventive resistive and conductive traces as desired, including resistive traces on the outer surface of each heater, the inner surface of each heater, and / or intermediate layers of the ceramic substrate of each heater. Other components (e.g., thermistors and / or thermal cutoffs) may be disposed on or adjacent to the surface of each heater as desired. As noted above, the ceramic substrate of the heater may be provided in a single layer or multiple layers, and ceramic substrates of various shapes (e.g., rectangular, square, or other polygonal faces) and sizes may be used as desired. Curved shapes may also be used but are typically more expensive to manufacture. Printed glass may be used on the outer and / or inner surfaces of each heater to provide electrical insulation as desired.

[0048] The heaters of the present disclosure are preferably fabricated in arrays for cost efficiency, e.g., each heater is fabricated in a specific array with substantially the same structure. Preferably, each array of heaters is separated into individual heaters after construction of all heaters in the array is complete, including firing of all components and any applicable finishing operations. In some embodiments, individual heaters are separated from the array by fiber laser scribing. Fiber laser scribing tends to provide a more uniform singulation surface with fewer microcracks along the separated edges compared to traditional carbon dioxide laser scribing. In some embodiments, the ceramic substrate for each heater is tape-cast and laminated into two green-state layers, which are compressed together, dried, and oriented to have opposing concave curvatures when fired. The thickness of each layer of the ceramic substrate may range, for example, from 0.3 mm to 2 mm. For example, commercially available ceramic substrate thicknesses include 0.3 mm, 0.635 mm, 1 mm, 1.27 mm, 1.5 mm, and 2 mm.

[0049] The present disclosure provides ceramic heaters with low thermal mass compared to conventional ceramic heaters. In some embodiments, thick-film printed resistive traces on the exterior (exterior or interior) surface of a ceramic substrate provide reduced thermal mass compared to resistive traces disposed internally between multiple sheets of ceramic. In some embodiments, thick-film printing of resistive and conductive traces on a fired ceramic substrate provides more uniform and predictable resistive and conductive traces compared to resistive and conductive traces printed on green-state ceramic due to the relatively large variation in the amount of ceramic shrinkage during firing of the green-state ceramic. The low thermal mass of the ceramic heaters of the present disclosure allows the heater(s) to heat up to an effective temperature for use in a few seconds (e.g., less than 5 seconds, or less than 20 seconds) significantly faster than conventional heaters in some embodiments. The low thermal mass of the ceramic heaters of the present disclosure also allows the heater(s) to cool to a safe temperature after use in a few seconds (e.g., less than 5 seconds, or less than 20 seconds) in some embodiments, again significantly faster than conventional heaters. Additionally, ceramic heater embodiments of the present disclosure operate at more precise and uniform temperatures than conventional heaters due to the relatively uniform thick-film printed resistors and conductive traces. The low thermal mass and improved temperature control of ceramic heaters allows for greater energy efficiency compared to conventional heaters.

[0050] The relatively low thermal mass of the heater of the present disclosure allows the heater assembly of the ice making machine 100 to heat and cool significantly faster than conventional ice making machine heaters. As a result, the heater of the present disclosure can reduce ice making cycle times to a fraction of the time of conventional ice making machines. By aligning the heating elements of the heater with the lobes 136 of the ice molds 102 of the ice making machine 100, heat can be delivered precisely where ice cubes need to be released from the molds 102. This further reduces the heating time required to release ice cubes from the molds 102, which in turn further reduces ice making cycle times. Aligning the heating elements of the heater with the lobes 136 of the molds 102 of the ice making machine 100 also improves the thermal efficiency of the ice making machine 100 by directing heat only to the portions of the molds 102 that require heat to remove ice cubes from the surface of the molds 102.

[0051] As mentioned above, the heater assembly of ice making machine 100 can include a single heater (e.g., heater 152 or 252) or multiple heaters (e.g., heater 352). When multiple heaters are used, each heater can include a heating element aligned with a single lobe 136 of ice mold 102 (as in the exemplary embodiment shown in FIGS. 11-13), or each heater can include multiple heating elements each aligned with a respective ice lobe 136 of ice mold 102, such that each heater supplies heat to multiple ice lobes 136.

[0052] The heater assembly of the present disclosure can be further tailored to meet the heating requirements of each individual ice lobe 136. For example, it may be preferable to provide additional heating to the two outermost ice lobes 136a, 136b shown in FIG. 3, which have the highest thermal mass, and further, in the exemplary embodiment shown in FIGS. 4-6, it may be preferable to provide the most heat to the outermost ice lobe 136b shown in FIG. 7, which is furthest from the heater 152 and terminals 166, 167 of the voltage connector 138 and has the highest thermal mass. In embodiments including a single heater, the heating element of the heater can be tailored to have a desired power depending on the heating requirements of the particular lobe 136 to which the heating element is aligned. For example, the heating elements 176a, 176b shown in FIG. 7 of the heater 152 aligned with the end lobes 136a, 136b may be printed to have a lower resistance (and therefore a higher current and power at a given voltage) than the other heating elements 176 of the heater 152 (e.g., the heating element 176c aligned with the central lobe 136c) to supply more heat to the lobes 136a, 136b. Lower resistance may be achieved, for example, by increasing the cross-sectional area (by increasing the thickness and / or width) of the resistive trace forming the heating element, by decreasing the length of the resistive trace, and / or by forming the resistive trace from a material with a lower resistivity. In embodiments including multiple heaters, the heating elements of each heater can be adjusted to have a desired power depending on the heating requirements of the lobe 136 in which the heater is located. For example, the heater 352a shown in FIG. 13 aligned with the end lobe 136b is furthest from the voltage connector 338 and may be printed to include a heating element 376a with a lower resistance than the heating elements 376 of the other heaters 352 in the heating assembly 350 (such as the heating element 376b aligned with the central lobe 136c) in order to provide more heat to the lobe 136b, which has the highest thermal mass.

[0053] The heater assembly of the present disclosure can also be easily scaled to accommodate the size of the ice molds 102 in a particular ice maker 100. Larger or smaller ice molds 102 may be required in different applications depending on the amount of ice production required. In embodiments including multiple heaters, more or fewer heaters can be used as needed depending on the size of the ice molds 102. In embodiments including a single heater, the heater's substrate can be lengthened or shortened as needed depending on the size of the ice molds 102, and the size and position of the heater's heating element can be adjusted by adding, removing, or repositioning resistive traces on the substrate.

[0054] The foregoing description illustrates various aspects of the present disclosure. It is not intended to be exhaustive. Rather, it is chosen to illustrate the principles of the present disclosure and its practical application so as to enable those skilled in the art to utilize the disclosure, including various modifications thereof that naturally follow. All modifications and variations are contemplated within the scope of the present disclosure, as determined by the appended claims. Relatively obvious modifications include combining one or more features of various embodiments with features of other embodiments.

Claims

1. an ice mold having an inner surface and an outer surface, the inner surface of the ice mold configured to hold water so that ice cubes are formed within the ice mold, the ice mold having a plurality of ice lobes shaped to form respective ice cubes within the ice mold; a heater assembly disposed in the ice mold, the heater assembly including a plurality of heating elements, each of the plurality of heating elements aligned with a corresponding one of the plurality of ice lobes to supply heat to ice cubes formed in the ice lobe to release the ice cubes from the ice mold, and including a plurality of conductors extending between the plurality of ice lobes and electrically connecting the plurality of heating elements; Equipped with a power at a given voltage of a first heating element of the plurality of heating elements aligned with a first ice lobe of the plurality of ice lobes is greater than a power at the given voltage of a second heating element of the plurality of heating elements aligned with a second ice lobe of the plurality of ice lobes; Ice maker.

2. the heater assembly is positioned along the bottom surface of the ice mold; The ice maker of claim 1.

3. the heater assembly includes a heater having a ceramic substrate; the plurality of heating elements of the heater assembly are formed by a plurality of electrical resistive traces printed on the ceramic substrate of the heater; The ice maker of claim 1.

4. the plurality of electrical conductors are formed by a plurality of conductive traces printed on the ceramic substrate of the heater; The ice making machine of claim 3.

5. the heater assembly includes a plurality of heaters, each having a ceramic substrate; each of the plurality of heaters includes at least one electrically resistive trace printed on the ceramic substrate of each of the plurality of heaters; the plurality of heating elements of the heater assembly are formed by the electrical resistive traces printed on the ceramic substrate of the plurality of heaters; The ice maker of claim 1.

6. the plurality of conductors include a plurality of conductors electrically connecting the plurality of heaters; The ice making machine of claim 5.

7. the first ice lobe is an end ice lobe of the plurality of ice lobes, and the second ice lobe is a central ice lobe of the plurality of ice lobes; The ice making machine of claim 1 .

8. an ice mold having an inner surface and an outer surface, the inner surface of the ice mold configured to hold water such that ice cubes are formed within the ice mold; a heater assembly disposed on the exterior surface of the ice mold for supplying heat to ice cubes formed in the ice mold to release the ice cubes from the ice mold, the heater assembly including a heater having a ceramic substrate, the ceramic substrate having a plurality of thick-film electrically resistive traces printed on the ceramic substrate and at least one thick-film electrically conductive trace printed on the ceramic substrate, the heater configured to generate heat when an electric current is supplied to at least one of the thick-film electrically resistive traces; Equipped with the ice mold includes a plurality of ice lobes shaped to form respective ice cubes within the ice mold, each of the plurality of electrical resistance traces being aligned with a corresponding one of the plurality of ice lobes to supply heat to ice cubes formed within the ice lobe to release the ice cubes from the ice mold; a power at a given voltage of a first one of the plurality of electrical resistive traces aligned with a first ice lobe of the plurality of ice lobes is greater than a power at the given voltage of a second one of the plurality of electrical resistive traces aligned with a second ice lobe of the plurality of ice lobes; Ice maker.

9. the heater assembly is positioned along the bottom surface of the ice mold; The ice making machine of claim 8.

10. the first ice lobe is an end ice lobe of the plurality of ice lobes, and the second ice lobe is a central ice lobe of the plurality of ice lobes; The ice making machine of claim 8.

11. an ice mold having an inner surface and an outer surface, the inner surface of the ice mold configured to hold water so that ice cubes are formed within the ice mold, the ice mold having a plurality of ice lobes shaped to form respective ice cubes within the ice mold; a heater disposed on an exterior surface of the ice mold, the heater including a ceramic substrate having a plurality of electrical resistance traces disposed thereon and a plurality of conductive traces disposed thereon, the heater configured to generate heat when an electric current is supplied to the electrical resistance traces, the plurality of electrical resistance traces being spaced along a length of the ceramic substrate such that each of the plurality of electrical resistance traces is aligned with a corresponding ice lobe of the plurality of ice lobes to supply heat to ice cubes formed within the ice lobes to release the ice from the ice mold, and the plurality of conductive traces being spaced apart along a length of the ceramic substrate such that each of the plurality of electrical resistance traces is aligned with a corresponding ice lobe of the plurality of ice lobes to supply heat to ice cubes formed within the ice lobes to release the ice from the ice mold, a heater extending and electrically connecting the plurality of electrical resistive traces; Equipped with a power at a given voltage of a first one of the plurality of electrical resistive traces aligned with a first ice lobe of the plurality of ice lobes is greater than a power at the given voltage of a second one of the plurality of electrical resistive traces aligned with a second ice lobe of the plurality of ice lobes; Ice maker.

12. The heater is disposed along the lower surface of the ice mold. The ice making machine of claim 11.

13. 12. The ice making machine of claim 11, wherein the heater includes a first terminal disposed along a length of the ceramic substrate at a first end of the ceramic substrate and a second terminal disposed along a length of the ceramic substrate at a second end of the ceramic substrate, the first terminal and the second terminal providing electrical connections to the heater for electrically connecting the heater to a voltage source.

14. the plurality of electrically resistive traces are interleaved with the plurality of electrically conductive traces in a line arrangement along the length of the ceramic substrate; The ice making machine of claim 11.

15. a width of at least a portion of each conductive trace connecting a respective pair of resistive traces along the width of the ceramic substrate that is less than a width of the respective pair of resistive traces along the width of the ceramic substrate; The ice making machine of claim 14.

16. the first ice lobe is an end ice lobe of the plurality of ice lobes, and the second ice lobe is a central ice lobe of the plurality of ice lobes; The ice making machine of claim 11.

Images