ICE MAKER WITH ICE BIN LEVEL CONTROL
A clear ice maker unit has a clear ice maker mechanism with a cascading water evaporator configured to make clear ice during ice making cycles. A controller uses fuzzy logic to control the clear ice maker and determine whether to initiate a next ice making cycle based on input signals from a thermistor in the ice storage bin. The controller will prevent initiation of an ice making cycle when the ice bin is at or below a threshold temperature. The controller will also prohibit ice making when the ice bin is at or below a second, slightly higher temperature for more than a prescribed period of time. In this way, the clear ice maker can recognize an uneven distribution of ice and maintain an optimal amount of ice in the bin.
This application claims the benefit of U.S. Provisional patent application Ser. No. 60/862,340 filed on Oct. 20, 2006, and entitled “Ice Maker with Ice Bin Level Control,” hereby incorporated by reference as if fully set forth herein.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCHNot applicable.
BACKGROUND OF THE INVENTIONThe present invention relates to the manufacture of ice, and particularly to automated clear ice maker units.
A conventional ice maker forms ice cubes by depositing water in a mold attached to an evaporator and allowing the water to freeze in a sedentary state. Such an approach results in clouded ice cubes resulting from air and impurities present within the frozen water.
It is also known to form ice by flowing water over a freezing surface to allow the air and impurities to separate from the water before freezing layer-by-layer to form the ice cube. This eliminates the clouding associated with sedentary freezing. These “clear ice” makers using such a flowing process have typically been used in commercial applications. One example of a clear ice maker is shown in U.S. Pat. No. 5,586,439, issued Dec. 24, 1996 to Schlosser et al. In that patent, water flows over a vertically disposed evaporator plate whose surface defines pockets. The water flows over the pockets, and an ice cube is formed in each pocket. The ice cubes are harvested by passing hot vaporous refrigerant through the evaporator in place of the cold refrigerant.
It is conventional for harvested ice cubes to fall into an ice bin where the ice cubes are stored until they are used. The ice bin can properly store a certain maximum amount of ice cubes, and ice making must be stopped when the ice bin is full to prevent overfilling the ice bin. Overfilling the ice bin can cause ice to spill out of the ice maker when the ice maker door is opened. Overfilling the ice bin can also lead to ice building up in the ice making assembly which can result in water traveling down the built-up ice into the ice bin thereby melting the ice stored therein.
The ice level in the ice bin can be sensed to control the production of ice and to prevent overfilling the ice bin. If the ice bin is refrigerated, a mechanical arm or a light sensor can sense the ice level in the bin and shut off power to the ice making assembly when the ice reaches a certain level. The mechanical arm is pushed up by the ice thereby throwing a switch that shuts down the ice making assembly. Optical mechanisms can have a light source, light sensor, and/or reflector that shut down the ice making assembly when the path of travel of the light is disrupted by the ice. If the ice bin is not refrigerated, a thermostat located in the ice bin can interrupt the power supply to the ice making assembly when the thermostat drops below a certain temperature.
In some clear ice makers, the ice can fall out of the ice making assembly as slabs of cubes. Usually, the slab falls into the ice bin and breaks into individual cubes when the slab hits the bin or ice stored in the bin. Sometimes, however, the slab does not break apart upon impact with the bin or the stored ice. Slabs tend to fail to break apart when the ice bin is more full, and the slab does not fall very far before hitting the stored ice. The slabs can then stack up to a side of the ice bin so that the ice is not stored uniformly in the ice bin (e.g., a side of the bin is full of stacked slabs and another side is empty). Mechanical arm, optical, and thermostat ice level sensors will detect the improperly stacked ice and prevent more ice from being produced even though storage space in the ice bin is actually available. Thus, the amount of ice produced and the amount of ice stored in the bin is negatively impacted.
SUMMARY OF THE INVENTIONThe present invention provides a clear ice maker with a controller that can determine improperly stacked ice.
Specifically, in one aspect the invention provides an ice maker unit having an ice maker mechanism disposed in an ice maker chamber of an insulated cabinet, the ice maker mechanism being capable of producing ice during a plurality of ice making cycles and depositing the ice into an ice bin within the cabinet. The ice maker unit includes a sensor disposed in the cabinet to sense the temperature at the ice bin and an electronic control having clock circuitry and fuzzy logic programming for controlling the ice maker mechanism. The control is electrically coupled to the sensor to receive an input signal from the sensor associated with a bin temperature. The control uses the fuzzy logic programming to determine whether to initiate a next ice making cycle based on the bin temperature sensed by the sensor. The control initiates the next ice making cycle only if first and second conditions are met. The first condition is that the bin temperature is above a first threshold temperature and the second condition is that the bin temperature is not below a second threshold temperature for a prescribed time period.
The sensor can be disposed at a height corresponding to a maximum ice level in the ice bin. The second condition can correspond to an uneven ice distribution condition in which ice is disposed in the ice bin at or above the maximum ice level at only a portion of the ice bin.
The first threshold temperature can be essentially 33 degrees Fahrenheit and wherein the second threshold temperature can be essentially 34 degrees Fahrenheit.
The prescribed time period can be set according to a time needed to complete a prescribed number of ice making cycles. The prescribed number of ice making cycles can be three.
The ice maker unit can include a user input connected to the controller, wherein the first threshold temperature can be set by the user input.
The ice maker unit can be a clear ice maker unit with a clear ice maker mechanism disposed in the ice maker chamber and capable of cascading water over a vertically disposed evaporator during a plurality of ice making cycles, each ice making cycle resulting in the production of a quantity of clear ice.
The ice bin can not be cooled by a refrigeration system.
In another aspect, the present invention provides a clear ice maker unit with a cabinet defining an ice maker chamber and an ice storage bin. The ice maker includes a clear ice maker mechanism disposed in the ice maker chamber and capable of cascading water over a vertically disposed evaporator during a plurality of ice making cycles, each ice making cycle resulting in the production of a quantity of clear ice. A controller is configured to control the clear ice maker, the controller configured to determine whether to initiate a next ice making cycle. A sensor is connected to the controller and disposed in the ice storage bin for sensing a bin temperature. The controller is configured to prevent the initiation of the next ice making cycle when the bin temperature is not above a first temperature and is less than or equal to a second temperature for a prescribed time period, wherein the second temperature is greater than the first temperature.
The evaporator can have a plurality of pockets therein, and the clear ice maker mechanism can be capable of cascading water over the evaporator during the plurality of ice making cycles and depositing clear ice formed on the evaporator into the ice storage bin.
The sensor can be disposed at a height corresponding to a maximum ice level in the ice bin.
The second temperature can be associated with an uneven ice distribution condition in which ice is disposed in the ice bin at or above the maximum ice level at only a portion of the ice bin.
The prescribed time period can be set according a time needed to complete a prescribed number of ice making cycles.
The first temperature can be essentially 33 degrees Fahrenheit, the second temperature can be essentially 34 degrees Fahrenheit, and the prescribed time period can be essentially one hour.
The clear ice maker can include a user input connected to the control so that the first temperature can be set by the user input.
The sensor can be a thermistor.
The ice storage bin can not be cooled by a refrigeration system.
In another aspect, the present invention provides a method for making clear ice in a clear ice maker unit having a clear ice maker mechanism disposed in an ice maker chamber of an insulated cabinet, the clear ice maker mechanism being capable of cascading water over a vertically disposed evaporator during a plurality of ice making cycles and depositing clear ice formed on the evaporator into an ice bin within the cabinet. The method includes detecting an uneven ice distribution in the ice bin in which ice is disposed in the ice bin at or above a maximum ice level at only a portion of the ice bin and prohibiting a next ice making cycle following detection of an uneven ice distribution condition.
The method can also include sensing an ice bin temperature at a maximum ice level in the ice bin before initiation of the next ice making cycle, prohibiting initiation of the next ice making cycle if the bin temperature is less than or equal to a first temperature, and prohibiting initiation of the next ice making cycle if the bin temperature is less than or equal to a second temperature for more than a prescribed period of time.
These and still other features of the invention will be apparent from the detailed description and drawings.
Referring to
Referring now to
The shroud 72 is formed of a plastic material such as a polypropylene or ABS and is molded about the evaporator grid 70. The shroud 72 has a continuous bulbous edge which engulfs the edges of the evaporator grid 70. The shroud 72 has laterally extending wing portions 76 projecting from each end of the evaporator grid 70. A bib portion 80 of the shroud 72 is disposed beneath the bottom edge of the evaporator grid 70 and contains integral projecting deflector fins 82. Each deflector fin 82 is aligned with the center of a column of pockets in the evaporator grid 70.
The shroud 72 also includes an inclined roof 86 disposed above the evaporator grid 70. A water distributor 88 is attached to the shroud wings 76 above the roof 86. As shown in
An ice maker evaporator 108 is attached to the rear wall 74 of the evaporator grid 70. The ice maker evaporator 108 is a part of the refrigeration system 48 shown schematically in
Referring now to
The hot gas bypass valve 124 is disposed in a line 138 between the outlet of the compressor 120 and the inlet of the evaporator 108. When the hot gas bypass valve is opened, hot refrigerant will enter the evaporator 108, thereby heating the evaporator 108 and evaporator grid 70.
Referring now to
In general operation, water from the sump 140 is pumped by the pump 148 to the distributor 88 which delivers a cascade of water over the surfaces of the evaporator grid 70. When the evaporator 108 is connected to receive liquefied refrigerant from the condenser 126, the water cascading over the surfaces of the evaporator grid 70 will freeze in layers and build up to form cubes of ice in the pockets. The pure water freezes first and impurities in the water will be left in suspension in the flowing water. Once the ice cubes are formed, the hot gas bypass valve 124 is opened and heated refrigerant is delivered to the evaporator 108, thereby warming the surface of the evaporator grid 70 until the ice cubes dislodge from the evaporator plate grid 70. The dislodged ice cubes will fall into the bin 50 and are directed away from the trough portion 142 of the sump 140 by the fins 82. Not all water cascading over the surface of the evaporator plate will freeze. The excess water is collected in the trough 142 and returned to the well 144 where it is re-circulated to the distributor 88 by the pump 148. During ice harvest (after each freezing cycle), a charge of fresh water is delivered to the sump 140 by the water fill valve to dilute the water and flush impurities through the overflow pipe 152 and out the drain.
Referring now to
Upon initial start-up or restarting with the temperature of the bin thermistor 172 above 35 degrees Fahrenheit, the controller 46 energizes the hot gas bypass solenoid 172 and the water inlet valve solenoid 174 for a period of time. This will fill the sump 140 with fresh water to the level of the overflow pipe 152. Thereafter, the compressor 120, the condenser fan 128 and the water circulation pump 148 are energized. After a short period of time, such as ten seconds, the water fill inlet valve solenoid 174 and the hot gas bypass solenoid 172 are de-energized. The ice maker 30 is now in a freeze cycle of an ice making cycle.
After a certain predetermined period of time into the freeze cycle, such as four minutes, a reading of the liquid refrigerant temperature sensed by the thermistor 178 is taken. This temperature reading will determine the remaining length of time for the freeze cycle and may also be used to set or adjust the duration of the ice harvest cycle. The higher the temperature of the liquid refrigerant, the longer the freeze cycle. For example, if the liquid refrigerant temperature is 80 degrees Fahrenheit, the total freeze time will be about 14 minutes. If the sensed temperature is 100 degrees Fahrenheit, the total freeze time will be about 22 minutes. At a temperature of 120 degrees Fahrenheit, the freeze time will be about 30 minutes.
The controller 46 is programmed so that once an ice making cycle has been initiated, the ice making cycle will continue to completion through ice harvest regardless of the temperature reading of the bin thermistor 176. This prevents the ice making cycle from terminating prematurely thereby ensuring that full-sized ice cubes are formed. When the freeze time has elapsed, controller 46 causes the clear ice maker 30 to enter ice harvest mode in which the compressor 120 remains energized while the water pump 148 and condenser fan 128 are de-energized and the solenoids for the hot gas bypass valve 124 and the water inlet valve 160 are energized. The hot refrigerant gas flowing through the ice maker evaporator 120 will loosen the ice formed in the pockets of the evaporator grid 70 so that the ice can fall into the ice bin 50. A typical harvest cycle lasts approximately 2-3 minute. The length of the ice harvest cycle can be dependent upon the reading of the liquid line thermistor 178. The length of the harvest cycle would thus be adjusted inversely based upon the first sensed temperature of the liquid line thermistor. For example, if the sensed temperature of the liquid line thermistor 178 is 80 degrees Fahrenheit, a harvest cycle of 2 minutes would be used. If the temperature is 100 degrees Fahrenheit or above, the harvest cycle will be reduced in time to 1.5 minutes. The harvest cycle can also be made constant for a range of temperatures or entirely independent of the temperature of liquid line thermistor 178.
At the conclusion of the harvest cycle, the controller 46 determines whether to initiate another ice making cycle based on the temperature of the ice bin thermistor 176, which indicates the level of the ice in the ice bin 50. The ice bin 50 is not cooled by the refrigeration system 50; therefore, the temperature of the ice bin thermistor 176 is determined by the ice in the ice bin 50. As the ice fills the ice bin 50, the ice approaches the bin thermistor 176, which causes the bin thermistor 176 to be cooled. When ice is adjacent to the ice bin thermistor 176 and the bin 50 is uniformly filled with ice, the temperature of the ice bin thermistor 176 will be at its lowest. Thus, the temperature of the ice bin thermistor 176 can be used to control the height of the ice in the ice bin 50 by stopping the production of ice when the temperature of the ice bin thermistor 176 indicates that ice is adjacent to the bin thermistor 176. The ice bin thermistor height 180 can be set to equal the maximum desired ice level in the bin 50 in order to ensure that the bin 50 is not overfilled and to maximize ice production.
Referring to
Referring now to
During operation of the ice maker 30, the controller 46 monitors the temperature TB of the ice bin thermistor 176, and logs into memory the temperature TB of the ice bin thermistor 176, and the time the temperature reading was taken so that the controller 46 can analyze the historical temperature data to calculate the time that the temperature TB of the ice bin thermistor 176 is below temperature T2. Alternatively, the controller 46 can be configured to track the period of time that the temperature TB of the ice bin thermistor 176 is below temperature T2.
In order to adapt the ice maker 30 to different environments, running conditions and user preferences, the temperature T1 can be set by a user. For example, the ice maker 30 can be run until the ice bin 50 has a user desired level of ice. The user can then access the current temperature TB of the bin thermistor 176 and set temperature T1 to be equal to the current temperature TB of the bin thermistor 176. The controller 46 is configured so that the user can set temperature T1 through the control unit 182. The user can access current temperature TB of the bin thermistor 176 through the control unit 182. Temperature T2 can be set to equal temperature T1 plus two degrees. Alternatively, the user can also set temperature T2.
It should be appreciated that merely a preferred embodiment of the invention has been described above. However, many modifications and variations to the preferred embodiment will be apparent to those skilled in the art, which will be within the spirit and scope of the invention. Therefore, the invention should not be limited to the described embodiment. To ascertain the full scope of the invention, the following claims should be referenced.
Claims
1. An ice maker unit having an ice maker mechanism disposed in an ice maker chamber of an insulated cabinet, the ice maker mechanism being capable producing ice during a plurality of ice making cycles and depositing the ice into an ice bin within the cabinet, the ice maker unit comprising:
- a sensor disposed in the cabinet to sense the temperature at the ice bin; and
- an electronic control having clock circuitry and fuzzy logic programming for controlling the ice maker mechanism, the control being electrically coupled to the sensor to receive an input signal from the sensor associated with a bin temperature, the control using the fuzzy logic programming to determine whether to initiate a next ice making cycle based on the bin temperature sensed by the sensor, wherein the control initiates the next ice making cycle only if first and second conditions are met, wherein in the first condition the bin temperature is above a first threshold temperature and in the second condition the bin temperature is not below a second threshold temperature for a prescribed time period.
2. The ice maker unit of claim 1, wherein the sensor is disposed at a height corresponding to a maximum ice level in the ice bin.
3. The ice maker unit of claim 2, wherein the second condition corresponds to an uneven ice distribution condition in which ice is disposed in the ice bin at or above the maximum ice level at only a portion of the ice bin.
4. The ice maker unit of claim 1, wherein the first threshold temperature is essentially 33 degrees Fahrenheit and wherein the second threshold temperature is essentially 34 degrees Fahrenheit.
5. The ice maker unit of claim 1, wherein the prescribed time period is set according to a time needed to complete a prescribed number of ice making cycles.
6. The ice maker unit of claim 5, wherein the prescribed number of ice making cycles is three.
7. The ice maker unit of claim 1, further comprising a user input connected to the control, wherein the first threshold temperature can be set by the user input.
8. The ice maker unit of claim 1, wherein the ice maker unit includes a clear ice maker mechanism disposed in the ice maker chamber and capable of cascading water over a vertically disposed evaporator during a plurality of ice making cycles, each ice making cycle resulting in the production of a quantity of clear ice.
9. The ice maker unit of claim 1, wherein the ice bin is not refrigerated.
10. A clear ice maker unit, comprising:
- a cabinet defining an ice maker chamber and an ice storage bin;
- a clear ice maker mechanism disposed in the ice maker chamber and capable of cascading water over a vertically disposed evaporator during a plurality of ice making cycles, each ice making cycle resulting in the production of a quantity of clear ice;
- a controller configured to control the clear ice maker, the controller configured to determine whether to initiate a next ice making cycle; and
- a sensor connected to the controller and disposed in the ice storage bin for sensing a bin temperature;
- wherein the controller is configured to prevent the initiation of the next ice making cycle when the bin temperature is not above a first temperature and is less than or equal to a second temperature for a prescribed time period, wherein the second temperature is greater than the first temperature.
11. The clear ice maker unit of claim 10, wherein the evaporator has a plurality of pockets therein, and wherein the clear ice maker mechanism is capable of cascading water over the evaporator during the plurality of ice making cycles and depositing clear ice formed on the evaporator into the ice storage bin.
12. The clear ice maker unit of claim 11, wherein the sensor is disposed at a height corresponding to a maximum ice level in the ice bin.
13. The clear ice maker unit of claim 12, wherein the second temperature is associated with an uneven ice distribution condition in which ice is disposed in the ice bin at or above the maximum ice level at only a portion of the ice bin.
14. The clear ice maker unit of claim 13, wherein the prescribed time period is set according to a time needed to complete a prescribed number of ice making cycles.
15. The clear ice maker unit of claim 14, wherein the first temperature is essentially 33 degrees Fahrenheit, the second temperature is essentially 34 degrees Fahrenheit and the prescribed time period is essentially one hour.
16. The clear ice maker unit of claim 10, further comprising a user input connected to the controller, wherein the first temperature can be set by the user input.
17. The clear ice maker unit of claim 10, wherein the sensor is a thermistor.
18. The clear ice maker unit of claim 10, wherein the ice storage bin is not refrigerated.
19. A method for making clear ice in a clear ice maker unit having a clear ice maker mechanism disposed in an ice maker chamber of an insulated cabinet, the clear ice maker mechanism being capable of cascading water over a vertically disposed evaporator during a plurality of ice making cycles and depositing clear ice formed on the evaporator into an ice bin within the cabinet, the method comprising:
- detecting an uneven ice distribution in the ice bin in which ice is disposed in the ice bin at or above a maximum ice level at only a portion of the ice bin; and
- prohibiting a next ice making cycle following detection of an uneven ice distribution condition.
20. The method of claim 19, further including:
- sensing an ice bin temperature at a maximum ice level in the ice bin before initiation of the next ice making cycle;
- prohibiting initiation of the next ice making cycle if the bin temperature is less than or equal to a first temperature; and
- prohibiting initiation of the next ice making cycle if the bin temperature is less than or equal to a second temperature for more than a prescribed period of time.
Type: Application
Filed: Mar 5, 2007
Publication Date: Apr 24, 2008
Inventors: Andrew J. Doberstein (Hartford, WI), Thomas W. Rand (Cedarburg, WI)
Application Number: 11/681,963
International Classification: F25C 1/12 (20060101);