Dishwasher with dynamically controlled cycle of operation

Patent metadata

Field	Value
Publication number	US-9420937-B2
Application number	US-64068909-A
Country	US
Kind code	B2
Filing date	Dec 17, 2009
Priority date	Dec 17, 2009
Publication date	Aug 23, 2016
Grant date	Aug 23, 2016

Abstract

A method of controlling the operation of an automatic dishwasher having at least one cycle of operation and a sensor that indicates a degree of turbidity of liquid in the dishwasher includes repeatedly determining a correction value for the sensor related to the scaling of the sensor and executing a de-scaling cycle of operation based thereon.

First claim

What is claimed is:

1. A method of controlling operation of a dishwasher having at least one cycle of operation and a sensor outputting a signal indicative of a degree of turbidity of liquid within the dishwasher and where soils build up on the sensor to form scaling, the method comprising:
repeatedly determining a correction value for the sensor of the dishwasher related to scaling of the sensor where the sensor is in contact with wash liquid within a wash chamber or liquid system within a cabinet of the dishwasher;
determining a rate of change of the correction value based on the repeated determinations of the correction value; and
executing a de-scaling cycle of operation of the dishwasher based on the determined rate of change of the correction value.

2. The method of claim 1 , further comprising comparing the determined rate of change of the correction value to a threshold value and executing the de-scaling cycle of operation if the determined rate of change of the correction value satisfies the threshold value.

3. The method of claim 1 , wherein determining the rate of change of the correction value comprises at least one of:
comparing each determined correction value to a predetermined threshold value over a predetermined number of cycles;
comparing each determined correction value to a previously determined correction value over a predetermined number of cycles;
determining a moving average of a predetermined number of the repeatedly determined correction values and comparing the moving average to a previously determined threshold value; or
determining a moving average of a predetermined number of the determined correction values and comparing the moving average to a previously determined moving average.

4. The method of claim 1 , further comprising determining water hardness based on the determined rate of change of the correction value.

5. The method of claim 4 , wherein the water hardness is determined from a table lookup of water hardness and rate of change.

Assignees

• Deweerd Brent A
• Lau Brooke L
• Pinkowski Robert J
• Rolek Robert J
• Whirlpool Co

Inventors

• Deweerd Brent A
• Lau Brooke L
• Pinkowski Robert J
• Rolek Robert J

Classifications

• A47L2501/07

  Consumable products, e.g. detergent, rinse aids or salt · CPC title

• A47L15/4297

  Arrangements for detecting or measuring the condition of the washing water, e.g. turbidity · CPC title

• A47L15/4229 Primary

  Water softening arrangements · CPC title

• A47L15/0057 Primary

  Cleaning of machines parts, e.g. removal of deposits like lime scale or proteins from piping or tub · CPC title

• A47L2501/11

  Air heaters · CPC title