RINSE AID RELEASE DETECTION METHOD

• US 20110088724A1
• Filed: 10/21/2009
• Published: 04/21/2011
• Est. Priority Date: 10/21/2009
• Status: Active Grant

• Current Assignee: Whirlpool Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: ALLEN, DOUGLAS T., SZOSTAK, JACEK, KING, JONATHAN D., LAU, BROOKE L.
• Granted Patent: US 8,540,820 B2
• Time in Patent Office: Days
• US Class Current: 134/18
• CPC Class Codes: A47L 15/0034 Drying phases, including dripping-off phases
• CPC Class Codes: A47L 15/0055 Metering or indication of used products, e.g. type or quantity of detergent, rinse aid or salt; for measuring or controlling the product concentration
• CPC Class Codes: A47L 15/4221 Arrangements for redirection of washing water, e.g. water diverters to selectively supply the spray arms A47L15/0078 takes precedence
• CPC Class Codes: A47L 15/4297 Arrangements for detecting or measuring the condition of the washing water, e.g. turbidity
• CPC Class Codes: A47L 2401/023 Quantity or concentration of the consumable product
• CPC Class Codes: A47L 2401/10 Water cloudiness or dirtiness, e.g. turbidity, foaming or level of bacteria
• CPC Class Codes: A47L 2501/03 Water recirculation, e.g. control of distributing valves for redirection of water flow
• CPC Class Codes: A47L 2501/07 Consumable products, e.g. detergent, rinse aids or salt
• CPC Class Codes: A47L 2501/30 Regulation of machine operational steps within the washing process, e.g. performing an additional rinsing phase, shortening or stopping of the drying phase, washing at decreased noise operation conditions

Abstract

A dishwashing machine configured to detect the presence of rinse aid in fluid in a washing chamber of the dishwashing machine. An electronic controller selects the drying stage of the dishwashing cycle based on whether rinse aid is present.

Claims

1. A dishwashing machine, comprising:

a tub defining a washing chamber,

a number of dish racks positioned in the washing chamber,

a pump operable to circulate fluid onto the number of dish racks during a dishwashing cycle,

a turbidity sensor operable to measure turbidity of fluid in the washing chamber and generate an electrical output signal indicative thereof, and

an electronic controller electrically coupled to the turbidity sensor, the controller comprising (i) a processor, and (ii) a memory device electrically coupled to the processor, the memory device having stored therein a plurality of instructions which, when executed by the processor, cause the processor to;

(a) communicate with the turbidity sensor to determine a turbidity level of fluid in the washing chamber,

(b) determine presence of a rinse aid in fluid in the washing chamber based on the turbidity level, and

(c) modify a drying stage of the dishwashing cycle when rinse aid is present in the fluid.

2. The dishwashing machine of claim 1, further comprising:

an electronically-controlled dispenser electrically coupled to the controller, the dispenser having a receptacle formed therein configured receive the rinse aid and a hatch extending over an opening defined in a front surface of the receptacle,

wherein the plurality of instructions, when executed by the processor, further cause the processor to operate the dispenser to open the hatch such that the rinse aid may pass from the dispenser into the washing chamber.

3. The dishwashing machine of claim 2, wherein the plurality of instructions, when executed by the processor, further cause the processor to:

(a) communicate with the turbidity sensor to determine a first turbidity level before the dispenser is operated to open the hatch,

(b) communicate with the turbidity sensor to determine a second turbidity level after the dispenser is operated to open the hatch, and

(c) calculate a difference between the second turbidity level and the first turbidity level.

4. The dishwashing machine of claim 3, wherein the plurality of instructions, when executed by the processor, further cause the processor to determine the rinse aid is present when the difference between the second turbidity level and the first turbidity level is greater than a predetermined threshold value.

5. The dishwashing machine of claim 1, further comprising an electric heating element electrically coupled to the controller, wherein:

the electric heating element is configured to heat fluid in the washing chamber, and the plurality of instructions, when executed by the processor, further cause the processor to;

(a) operate the electric heating element to heat fluid in the washing chamber to a first temperature, and

(b) communicate with the turbidity sensor to determine the turbidity level of fluid in the washing chamber at the first temperature.

6. The dishwashing machine of claim 1, wherein the turbidity sensor is an optical water indicator sensor.

7. The dishwashing machine of claim 1, further comprising:

a lower spray arm positioned below one of the number of dishracks, the lower spray arm being fluidly coupled to the pump to circulate fluid, and

an upper spray arm positioned above the lower spray arm, the upper spray arm being fluidly coupled to the pump to alternately circulate fluid with the lower spray arm,

a diverter valve electrically coupled to the controller and configured to alternately supply fluid to the upper spray arm and the lower spray arm,

wherein the plurality of instructions, when executed by the processor, further cause the processor to;

(a) operate the diverter valve to suspend the supply of fluid to the lower spray arm such that the upper spray arm continuously circulates fluid,

(b) communicate with the turbidity sensor to determine the first turbidity level and second turbidity level while the upper spray arm continuously circulates fluid, and

(c) operate the diverter valve to resume the supply of fluid to the lower spray arm such that the lower spray arm alternately circulates fluid with the upper spray arm.

8. A method of detecting a rinse aid in a dishwashing cycle, comprising:

determining a first turbidity level of fluid in a washing chamber during a rinsing stage of a dishwashing cycle,

generating a control signal to operate a dispenser during the rinsing stage,

determining a second turbidity level of fluid in the washing chamber after generation of the control signal,

determining if a rinse aid is present in fluid in the washing chamber based on the first turbidity level and the second turbidity level, and

selecting a drying stage of the dishwashing cycle based on whether rinse aid is present.

9. The method of claim 8, wherein determining if the rinse aid is present includes:

comparing the second turbidity level to the first turbidity level, and

concluding the rinse aid is not present if the second turbidity level is less than the first turbidity level.

10. The method of claim 8, wherein determining if the rinse aid is present includes:

determining whether the second turbidity level is greater than or equal to the first turbidity level,

calculating a difference between the second turbidity level and the first turbidity level when the second turbidity level greater than or equal to the first turbidity level, and

concluding the rinse aid is present when the difference between the second turbidity level and the first turbidity level exceeds a predetermined threshold value.

11. The method of claim 8, wherein selecting the drying stage of the dishwashing cycle includes selecting a standard drying stage having a standard duration and a standard temperature if the rinse aid is not present in fluid.

12. The method of claim 11, wherein selecting the drying stage of the dishwashing cycle includes selecting a modified drying stage having a duration less than the standard duration if the rinse aid is present in fluid.

13. The method of claim 11, wherein selecting the drying stage of the dishwashing cycle includes selecting a modified drying stage having a temperature less than the standard temperature if the rinse aid is present in fluid.

14. The method of claim 8, further comprising:

supplying fluid alternately to an upper spray arm and a lower spray arm such that the upper spray arm and the lower spray arm alternately circulate fluid in a washing chamber,

suspending the supply of fluid to the lower spray arm before determining the first turbidity level such that fluid is circulated continuously from the upper spray arm, and

resuming the supply of fluid to the lower spray arm after determining the second turbidity level.

15. A method of operating a dishwashing machine, comprising:

heating fluid in the washing chamber to a first temperature during a rinsing stage of a dishwashing cycle,

opening a rinse aid dispenser of the dishwashing machine at a predetermined time during the rinsing stage,

determining if a rinse aid is present in the fluid in the dishwashing machine based on a first turbidity level and a second turbidity level subsequent to opening the rinse aid dispenser,

heating the fluid in the washing chamber to a second temperature subsequent to opening the rinse aid dispenser, and

completing the rinsing stage at the second temperature.

16. The method of claim 15, further comprising adjusting a drying stage of the dishwashing cycle if the rinse aid is present in fluid in the dishwashing machine.

17. The method of claim 15, further comprising:

determining the first turbidity level with an optical water indicator sensor prior to opening the rinse aid dispenser, and

determining the second turbidity level with the optical water indicator sensor subsequent to opening the rinse aid dispenser.

18. The method of claim 17, wherein determining if a rinse aid is present in fluid includes:

comparing a first turbidity level to a second turbidity level, and

concluding the rinse aid is present when the second turbidity level exceeds the first turbidity level by a predetermined threshold value.