Liquid purification or separation – With alarm – indicator – register – recorder – signal or...
Reexamination Certificate
2000-06-28
2002-04-23
Drodge, Joseph W. (Department: 1723)
Liquid purification or separation
With alarm, indicator, register, recorder, signal or...
C210S094000, C210S087000, C210S138000, C210S175000, C222S032000, C222S189060, C340S607000, C062S318000
Reexamination Certificate
active
06375834
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a water filtration system for a refrigerator and more particularly to an indicator for notifying a user when to change the filter.
2. Description of the Related Art
Many refrigerators, and especially those using a side-by-side configuration wherein the fresh food compartment is located to one side of the frozen food compartment, include integrated ice and water delivery systems. Typically, such systems deliver water and ice through the door of the frozen food compartment to an ice and water station recessed in the door.
Increasingly such systems incorporate a filtration system with a replaceable filter element or cartridge so as to improve the quality of the ice and water delivered to the user of the refrigerator.
Examples of such systems can be seen in U.S. Pat. No. 5,907,958 issued Jun. 1, 1999 to Coates, et al. and entitled “Refrigerator water filter”; U.S. Pat. No. 5,813,245 issued Sep. 29, 1998 to Coates, et al. and entitled “Pressure relief circuit for refrigerator contained water filter”; U.S. Pat. No. 5,715,699 issued Feb. 10, 1998 to Coates, et al. and entitled “Refrigerator water filter”; U.S. Pat. No. 5,707,518 issued Jan. 13, 1998 to Coates, et al. and entitled “Refrigerator water filter”; U.S. Pat. No. 5,135,645 issued Aug. 4, 1992 to Sklenak, et al. and entitled “Refrigerator water filter”; and U.S. Pat. No. 3,982,406 issued Sep. 28, 1976 to Hanson, et al. and entitled “Refrigerator water storage and dispensing system with water filter”.
Since the filters must be periodically replaced to maintain the quality of the water, various methods and apparatus could be used to notify the user of the need to change the filter. However, such many potential approaches would be costly, complex and inflexible as to substitution of different types of filters having different useful lives. Furthermore, in an effort to such reduce cost, many such approaches fail to give the user advance warning that the filter will soon need to be replaced. Additionally, the controls might be used on more than one model of refrigerator in conjunction with more than one type of filtration media.
What is needed, therefore, is a filter monitoring and indicating system that is flexible enough to permit its use with different types of filters. It would be most beneficial if the system doesn't add the cost of requiring an additional switch or sensor for detecting the type of filter being used but instead relies on existing components, where possible.
What is further needed is an inexpensive filter monitoring and indicating system that not only informs the user that a filter needs to be replaced, but provides earlier warning that the filter will need to be replaced soon and therefore a new filter needs to purchased.
SUMMARY OF THE INVENTION
The present invention is directed to a low cost method and apparatus for monitoring the operation of a water and ice delivery system for a refrigerator and indicating when to replace a water filter used in the water and ice delivery system.
The water filter monitoring and indicating method and apparatus of the present invention relies on components existing in many conventional water and ice delivery systems and refrigerators to reduce complexity and number of components. It senses the operational condition of the fresh food compartment door and the valves regulating the water flow into the ice maker and the water dispenser of the refrigerator. The method and apparatus monitors and tracks the duration of valve openings to estimate water consumption since the filter has been changed. Furthermore, it tracks the amount of time that has passed since the last time the filter has been changed. The method and apparatus further tracks user inputs to the fresh food compartment door switch to determine when a filter has been replaced.
The water filter monitoring and indicating method and apparatus of the present invention determines when the filter needs to be changed by comparing the water usage and filter age data with a first set of pre-selected standards for the type of filter being used and further determines when a new filter should be ordered by comparing the water usage and filter age data with a second set of pre-selected standards for the type of filter being used, the second set of pre-selected standards being more stringent than the first set. The method and apparatus then uses a tri-color light emitting diode to display one color when the filter should be replaced, a second color when a filter should be ordered and a third when the filter is good.
In the preferred embodiment of the present invention, the water filter monitoring and indicating system uses a low cost microprocessor to compare the water usage and filter age data with the first and second sets of pre-selected standards, to generate and track a conclusion of a status of “good”, “order” (or alternatively, “warn”) or “change” (or alternatively, “used”) for the filter based on such comparison, and to illuminate the light emitting diode in pre-selected color corresponding to that conclusion of status.
The microprocessor of the water filter monitoring and indicating system of the present invention preferably includes a built-in memory to retain water usage and other data during a power outage.
The light emitting diode of the water filter monitoring and indicating system preferably is illuminated green for a filter status of “good”, yellow for a filter status of “order” or “warn” and red for a filter status of “change” or “used”.
In the preferred embodiment, the indicator warns the user that the filter will soon be past its rated capacity and therefore that a new filter should be ordered when the filter has reached 90% of its rated age or rated water capacity. This increases the likelihood that a user will have a filter available when one is needed and increased the likelihood that the filter will be replaced in a timely manner. Typical settings for filters may be 400 gallons or 200 gallons capacity and warn at 360 gallons or 180 gallons, respectively.
In the preferred embodiment, the microprocessor further tracks the time that the filter has been installed and compares that with the rated life of the filter, which could be typically between 6 months and 12 months. The user will be warned to replace the filter when it has been installed in the refrigerator for more than 90% of its maximum rated installation life or age. The indicator will therefore illuminate green for a status of “good” if the filter is newer than 90% of its maximum rated age and has been used to deliver less than 90% of its rated capacity and will illuminate red for a status of change if it has exceeded 100% of either limit. Otherwise, it will illuminate yellow, for warn, indicating that it is between 90% and 100% for either age or capacity and will shortly need to be replaced.
The water filter monitoring and indicating system preferably further tracks user inputs to the fresh food compartment door switch to determine what type of filter is being used and utilizes a different first and second set of pre-selected standards for each type of filter selectable by the user. This can be accomplished within the microprocessor by changing the age and or capacity limits or by altering the speed of the internal counter.
The microprocessor is provided with programing to detect a first predetermined rapid sequence of depressions of the door switch as a request by the user to reset the age and usage counters to zero because the filter has been changed. The sequence of pulses is selected to be numerous and rapid enough to be unlikely to be accidentally sent during normal door openings and closings. The microprocessor further interprets a second predetermined sequence of depressions of the door switch as a sign that a different type of filter is being used
The light emitting diode of the water filter monitoring and indicating system is preferably located within the fresh food compartment of the refrigerator near the fresh food compartment door switch of the refrigerator
Beard Dale A.
Gotzbach Patrick J.
Guess Ronald W.
Snyder Keith A.
Cecil Terry K
Drodge Joseph W.
Krefman Stephen
Rice Robert O.
Van Winkle Joel M.
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