Abstract:
In an embodiment of the invention, a refrigerator comprising an ice storage bucket and a cooling system in thermal communication with the ice storage bucket is shown. A first transmitter is configured in the ice storage bucket. A first pulse signal is transmitted from the first transmitter. A first receiver is configured in the ice storage bucket and is further configured to receive the first pulse signal. A first pre-signal response from the first receiver is generated before the first pulse signal. A first pulse signal response from the first receiver generated during the first pulse signal.

Description:
FIELD OF THE INVENTION 
     The invention relates to appliances. More specifically the invention relates to appliances that include detectors for determining the volume of ice present in a bucket for a refrigerator icemaker. 
     BACKGROUND OF THE INVENTION 
     In a known appliance, such as a refrigerator, an icemaker delivers ice through an opening in a door of the refrigerator. Such a known refrigerator has a freezer section to the side of a fresh food section. This type of refrigerator is often referred to as a “side-by-side” refrigerator. In the side-by-side refrigerator, the icemaker delivers ice through the door of the freezer section. In this arrangement, ice is formed by freezing water with cold air in the freezer section, the air being made cold by a cooling system that includes an evaporator. 
     Another known refrigerator includes a bottom freezer section disposed below a top fresh food section. This type of refrigerator is often referred to as a “bottom freezer” or “bottom mount freezer” refrigerator. In this arrangement, convenience necessitates that the icemaker deliver ice through the opening in the door of the fresh food section, rather than the freezer section. However, the cool air in the fresh food section is generally not cold enough to freeze water to form ice. 
     In the bottom freezer refrigerator, it is known to pump cold air, which is cooled by the evaporator of the cooling system, within an interior channel of the door of the fresh food section to the icemaker. 
     These prior art arrangements suffer from numerous disadvantages. For example, complicated air ducts are required within the interior of the door for the cold air to flow to the icemaker. Further, ice is made at a relatively slow rate, due to limitations the storage volume for the ice and/or temperature of cold air that can be pumped within the interior of the door of the fresh food section. Another disadvantage is that pumping the cold air to the fresh food compartment during ice production reduces the temperature of the fresh food compartment below the set point. 
     Further, when ice is made and stored in the fresh food compartment of the refrigerator, continued cooling of the ice bucket is required to prevent melting of the ice. The melting of the stored ice is particularly a problem when the user turns off the icemaker. Prior art devices use one of two methods to manage stored ice when the icemaker is turned off. 
     One method eliminates cooling flow to the icemaker. This method has the benefit of reducing energy consumption. However, without cooling flow, the ice melts. The melted ice is typically allowed to drain into the drain pan of the refrigerator for evaporation. However, if a significant volume of ice was in the ice bucket the drain pan overflows onto the floor. 
     The second method used to manage stored ice when the icemaker is turned off is to continue to cool the ice bucket. This method eliminates the melting of the ice and ensuing mess. However this method continues to expend energy cooling the ice bucket even if there is no ice present. 
     SUMMARY OF THE INVENTION 
     Therefore, in an embodiment of the invention, a refrigerator comprising an ice storage bucket and a cooling system in thermal communication with the ice storage bucket is shown. A first transmitter is configured in the ice storage bucket. A first pulse signal is transmitted from the first transmitter. A first receiver is configured in the ice storage bucket and is further configured to receive the first pulse signal. A first pre-signal response from the first receiver is generated before the first pulse signal. A first pulse signal response from the first receiver generated during the first pulse signal. 
     In another embodiment of the invention, a method is used for providing cooling to an ice storage bucket. A first pre-pulse response is received from a first receiver. A pulse signal is transmitted from a first transmitter. The first pulse signal is received as a first pulse response from the first receiver. A first difference is compared between the first signal response and the first pre-signal response. Cooling is enabled where the first difference is greater then a first predetermined difference. 
     In a further embodiment of the invention, a device for detecting ice in an ice storage bucket comprises a first transmitter and a first receiver configured in the ice storage bucket. A first pulse signal is transmitted from the first transmitter. The first receiver is further configured to receive the first pulse signal. A first pre-signal response from the first receiver is generated before the first pulse signal. A first pulse signal response from the first receiver is generated during the first pulse signal. A cooling system is in thermal communication with the ice storage bucket. 
     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
         FIG. 1  is a perspective view of a refrigerator. 
         FIG. 2  is a perspective view of a refrigerator of  FIG. 1  with the doors open. 
         FIG. 3  is a perspective view of an exemplary icemaker incorporated into a refrigerator of  FIG. 1 . 
         FIG. 4  is a schematic representation of the icemaker of  FIG. 3  with incorporated ice in bucket detection means according to an aspect of the invention. 
         FIG. 5  shows the timing of the pulses of the ice in the ice bucket detection means of  FIG. 4 . 
         FIG. 6  shows a calibration sequence according to an aspect of the invention. 
         FIG. 7  is a graph of an ice detection curve. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     It is contemplated that the teaching of the description set forth below is applicable to all types of refrigeration appliances, including but not limited to side-by-side and top mount refrigerators wherein undesirable temperature gradients exist within the compartments. The present invention is therefore not intended to be limited to any particular type or configuration of a refrigerator, such as refrigerator  100 . 
       FIGS. 1 and 2  illustrate a bottom mount freezer refrigerator  100  including a fresh food compartment  102  and freezer compartment  104 . Freezer compartment  104  and fresh food compartment  102  are arranged in a bottom mount configuration where the freezer compartment  104  is below the fresh food compartment  102 . The fresh food compartment is shown with French opening doors  134  and  135 . However, a single door may be used. Door or drawer  132  closes freezer compartment  104 . 
     The fresh food compartment  102  and freezer compartment  104  are contained within an outer case  106 . Outer case  106  normally is formed by folding a sheet of a suitable material, such as pre-painted steel, into an inverted U-shape to form top and sidewalls  230 ,  232  of case  106 . Mullion  114 , shown in  FIG. 2 , is preferably formed of an extruded ABS material. Mullion  114  separates the fresh food compartment  102  and the freezer compartment  104 . 
     Door  132  and doors  134 ,  135  close access openings to freezer and fresh food compartments  104 ,  102 , respectively. Each door  134  and  135  is mounted by a top hinge  136  and a bottom hinge  137  to rotate about its outer vertically oriented edge between an open position, as shown in  FIG. 2 , and a closed position shown in  FIG. 1  closing the associated storage compartment. Door  134  is configured with a dispensing center  108  for through the door ice service. Dispensing center  108  may further contain beverage service, such as for hot or cold water, juices or other beverages. 
     In accordance with known refrigerators, refrigerator  100  also includes a machinery compartment (not shown) that at least partially contains components for executing a known vapor compression cycle for cooling air in the compartments. The components include a compressor (not shown), a condenser (not shown), an expansion device (not shown), and an evaporator (not shown) connected in series and charged with a refrigerant. The evaporator is a type of heat exchanger that transfers heat from air passing over the evaporator to a refrigerant flowing through the evaporator, thereby causing the refrigerant to vaporize. The cooled air is used to refrigerate one or more fresh food or freezer compartments via fans (not shown). Collectively, the vapor compression cycle components in a refrigeration circuit, associated fans, and associated compartments are referred to herein as a sealed system. The construction of the sealed system is well known and therefore not described in detail herein, and the sealed system is operable to force cold air through the refrigerator  100 . 
       FIG. 3  shows a typical arraignment for an ice making and storage compartment  200  mounted on the inside of a door  134  of the fresh food compartment  102 . Ice making and storage compartment  200  has an icemaker  204  and an ice bucket  206 . Ice making and storage compartment  200  may also have an ice chute (shown in  FIG. 4  as  203 ) for through the door beverage and ice serve at a dispensing center  108 . Supplying ice through the door of a refrigerator is known and will not be described in detail. It can be appreciated that the means for cooling the ice making and storage compartment  200  may be any known means, including but not limited to, forced air circulation or a secondary fluid-cooling loop such as a glycol loop in combination with the vapor-compression loop of the refrigerator. 
       FIG. 4  shows an embodiment of the ice in bucket detection for an ice making and storage compartment  200  of the present invention. It should be understood that the term “ice” as used in the description of the present invention is intended to comprise more than water in its frozen state, but shall be broadly construed to comprise any volume of matter in a defined container or volume such as bucket  206 . Ice present in the bucket  206  of the ice making and storage compartment  200  is detected by optical system  300 . The optical system  300  creates invisible infrared (IR) beams  314 ,  324  at infrared transmitters  310  and  320 . The infrared beams  314  and  324  cross the bottom of the ice bucket  206  or in the ice chute  203  to receivers  312  and  322  to detect whether any ice is in the bucket  206 . Slots  211  defined in the sidewalls of the ice bucket  206  and ice chute  203  allow projection of the beams through the ice bucket and ice chute to the receivers  312  and  322 . As shown, more than one beam  314  or  324  may be used to increase the probability of detecting ice. However, one or more than two beams may be used in different location to detect ice within the ice making and storage compartment  200  or chute  203 . When any of the beams  314  or  324  are interrupted, cooling of the bucket  206  is enabled to prevent melting of the ice. If no ice is detected and the ice producing portion  204  of the ice making and storage compartment  200  is off, than bucket cooling is disabled to reduce energy consumption. 
     The use of a transmitter and receiver pair  310 ,  322  and  320 ,  312  on each side of the ice making and storage compartment  200  allows for a common assembly on each icemaker side and increases the chance of detecting a small volume of ice. For a two (or more) channel system, the channels are pulsed independently and alternately, as shown in  FIG. 5 , to avoid interference between the channels. While, the channels are shown pulsed at a 50 second interval per channel, any suitable pulse rate may be used. The method of detection of the present embodiment will be described in greater detail below. The optical system of the present embodiment utilizes light emitting diodes or LED&#39;s as transmitters  310 ,  320  and inferred detectors as receivers  312 ,  322 . 
     At power-up, a calibration procedure is performed to determine the proper drive level for each of the transmitters  310 ,  320  to achieve proper photodiode response when no ice or blockage is present. During calibration, as shown in  FIG. 6 , the current of each transmitter  310 ,  320  is changed, increasingly, until a proper response is received from the receiver  312 ,  322 .  FIG. 6  shows an exemplary calibration of a 2-channel system. The graph of channel  1  indicates the expected response from the receiver  312  is 2.5 volt, shown at  319 . The response  319  need not be 2.5 volt specifically, and may be any value achievable from the receiver  312  for a given transmitter  310 . The current is increased at predetermined increments  316  until the response  319  is achieved. The level  319  of response value identified at five of  FIG. 6  is stored in a memory of a controller (not shown). While the response level five is shown as a single digit integer representing a predetermined current, the actual current or any other designating means may be used. Likewise channel  2  is calibrated in the same manner. As shown each channel may have a different drive level  316 ,  326 . 
     During operation, the transmitters are pulsed at the current determined during calibration. The pulsing transmitters  310 ,  320  can be very occasionally (several seconds or even minutes) and with very short duration (50 micro-seconds or less) to reduce transmitter fatigue. The interval and duration of the pulses need only be sufficient to regularly detect the presence of ice in the bucket  206 . In fact, the ice detection system could remain idle, unless the ice making and storage compartment  200  is switched into an off position. 
     Turning to  FIG. 7 , the output of the receiver is sampled by an analog to digital “A/D” converter before the pulse, identified as segment  340  and during the pulse identified at  342 . By taking two samples ambient IR levels may be removed. The difference in the before  340  and during  342  pulse readings is the “delta”  348  of the output, as shown in  FIG. 7 . It is the delta  348  or voltage  344  (which one? the delta or voltage? need to clarify) subtracted by the voltage  346  that when compared to the calibration responses  319 ,  329  determines if ice is present in the bucket  206 . The delta  348  of  FIG. 7  is 2.5 volts or equal to the calibrated response  319 ,  329 , therefore based on this exemplary data, no ice would be present in the bucket and therefore cooling to the bucket need not be applied. 
     Conversely, if the delta  358  of the during pulse  356  response and the before pulse  340  response is sufficiently small, for example as shown as 0.5 volt, such a voltage would indicate the presence of ice in the bucket  206 , and cooling of the bucket  206  would turned on. 
     If the delta  348  is not equal to the calibrated response  319 ,  329  but is sufficiently smaller than an expected ice in bucket condition recalibration of the detection system may be necessary. 
     As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalence of such meets and bounds are therefore intended to be embraced by the appended claims.