Controlling chemical dispense operations based on conductivity offset considerations

• US 6,990,411 B2
• Filed: 12/03/2004
• Issued: 01/24/2006
• Est. Priority Date: 05/22/2003
• Status: Active Grant

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: Ecolab, Inc.
• Inventors: May, Robert Eugene, Peterson, Jeff W., Howes, Ronald Bruce Jr.
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US11/004,478
• Publication Number:
  US 20050149273A1
• Time in Patent Office: 417 Days
• Field of Search: 702/31, 702/25, 702/30, 702 22- 23, 700/9, 700/80, 700/239, 700/265, 700/283, 340/853.3, 340/853.2, 340/870.07, 705/1
• US Class Current: 702/31
• 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 15/0063 using remote monitoring or controlling of the dishwasher operation, e.g. networking systems
• CPC Class Codes: A47L 15/241 the dishes moving in a horizontal plane
• CPC Class Codes: A47L 15/4418 in the form of liquids A47L15/4409, A47L15/4436, A47L15/4445 take precedence
• CPC Class Codes: A47L 15/4436 in the form of a detergent solution made by gradually dissolving a powder detergent cake or a solid detergent block
• CPC Class Codes: A47L 15/46 Devices for the automatic control of the different phases of cleaning ; Controlling devices A47L15/449 takes precedence
• CPC Class Codes: A47L 2401/023 Quantity or concentration of the consumable product
• CPC Class Codes: A47L 2401/30 Variation of electrical, magnetical or optical quantities
• CPC Class Codes: A47L 2501/07 Consumable products, e.g. detergent, rinse aids or salt
• CPC Class Codes: A47L 2501/26 Indication or alarm to the controlling device or to the user
• CPC Class Codes: D06F 2101/12 Washing temperature
• CPC Class Codes: D06F 2101/14 Time settings
• CPC Class Codes: D06F 2105/58 Indications or alarms to the control system or to the user
• CPC Class Codes: D06F 34/22 Condition of the washing liquid, e.g. turbidity
• CPC Class Codes: G01N 27/06 of a liquid involving electrolysis G01N27/26
• CPC Class Codes: G05D 11/138 by sensing the concentration of the mixture, e.g. measuring pH value

Abstract

A system and method is disclosed for controlling concentration of a component chemical product in a chemical solution. The chemical solution is formed in a solution tank by combining the component chemical product with water. The component chemical product is dispensed to the solution tank by a chemical dispenser that is controlled by measured conductivity readings of the chemical solution taken in the solution tank. The conductivity readings are analyzed against a conductivity setpoint to determine whether the component chemical product should be added to the chemical solution. A conductivity offset is determined and applied to the analysis thereby taking into consideration any conductivity that may be attributable to constituents of the chemical solution other than the component chemical product. Such constituents include soil washed from the articles and the water used to form the chemical solution.

Claims

1. In a computer system, a method for controlling concentration of a component chemical product in a chemical solution, the method comprising:

determining a conductivity measurement for the chemical solution, wherein the conductivity measurement indicates a percent concentration of the component chemical product in the chemical solution;

determining a conductivity offset value that represents a portion of the conductivity measurement that is attributable to one or more constituents of the chemical solution other than the component chemical product; and

analyzing the conductivity offset value, the conductivity measurement and a conductivity setpoint indicating a desired percent concentration of the component chemical product in the chemical solution to determine whether the component chemical product should be added to the chemical solution.

2. A method as defined in claim 1, wherein the chemical solution is formed by combining the component chemical product with water in a solution tank and used by a utility device to clean and sanitize articles having soil deposited thereon, wherein the utility device applies the chemical solution to the articles thereby washing the soil and applied chemical solution into the solution tank, the determining act comprising:

determining a soil conductivity offset value that represents a portion of the conductivity measurement that is attributable to soil mixed into the chemical solution;

determining a water conductivity offset value that represents a portion of the conductivity measurement that is attributable to water used to form the chemical solution; and

adding the soil conductivity offset value and the water conductivity offset value to render the conductivity offset value.

3. A method as defined in claim 2, wherein the analyzing act comprises:

subtracting the conductivity offset value from the conductivity measurement to render a normalized conductivity reading for the chemical solution; and

comparing the normalized conductivity reading of the chemical solution to the conductivity setpoint.

4. A method as defined in claim 3, wherein the analyzing act comprises:

adding the conductivity offset value to the conductivity setpoint to render an normalized conductivity setpoint for the chemical solution; and

comparing the conductivity measurement of the chemical solution to the normalized conductivity setpoint.

5. A method as defined in claim 4, further comprising:

prior to supplying the component chemical product to the solution storage tank, filling the solution storage tank with water and analyzing one or more samples of the water to generate the water conductivity offset value.

6. A method as defined in claim 5, further comprising:

after the water conductivity offset value has been determined by the analyzing act, supplying the component chemical product to the solution storage tank to begin formation of the chemical solution therein, wherein the act of determining a conductivity measurement for the chemical comprises analyzing one or more samples of the chemical solution to generate the conductivity measurement.

7. A method as defined in claim 6, wherein the chemical solution is flushed from the solution tank after a predetermined period in time, the method further comprising:

defining an interval for adjusting the soil conductivity offset value, wherein the interval represents periods in time that the soil conductivity offset value is to be maintained at a constant value;

setting the soil conductivity offset value to an initial value during an initial period in time conforming to the interval, wherein the initial period in time begins concurrently with the predetermined period in time; and

increasing the soil conductivity offset value by a specified magnitude at each of a subsequent periods in time conforming to the interval.

8. A method as defined in claim 7, further comprising:

storing the increased soil conductivity offset value to a location in a memory such that any previous soil conductivity offset value in the location is overwritten by the increased soil conductivity offset value, wherein act of determining the soil conductivity offset value comprises retrieving the soil conductivity offset value from the memory location for use by the analyzing act.

9. In a computer system, a method for controlling conductivity of a chemical solution contained in a solution tank and used by a utility device to clean and sanitize articles having soil deposited thereon, wherein the utility device applies the chemical solution to the articles thereby washing the soil and applied chemical solution into the solution tank, the method comprising:

determining a conductivity measurement for the chemical solution, wherein the conductivity measurement indicates a percent concentration of a component chemical product in the chemical solution;

determining a soil conductivity offset value that represents a portion of the conductivity measurement that is attributable to soil mixed into the chemical solution; and

analyzing the soil conductivity offset value, the conductivity measurement and a conductivity setpoint indicating a desired percent concentration of the component chemical product in the chemical solution to determine whether the component chemical product should be added to the chemical solution.

10. A method as defined in claim 9, wherein the analyzing act comprises:

subtracting the soil conductivity offset value from the conductivity measurement to render a normalized conductivity reading for the chemical solution; and

comparing the normalized conductivity reading of the chemical solution to the conductivity setpoint.

11. A method as defined in claim 10, further comprising:

if the normalized conductivity reading for the chemical solution is less than the conductivity setpoint, requesting that a specified volume of component chemical product be supplied to the solution tank.

12. A method as defined in claim 11, wherein the specified volume is defined based on a relative discrepancy between the normalized conductivity reading and the conductivity setpoint.

13. A method as defined in claim 11, wherein the specified volume is a predetermined volume that is to be supplied to the solution storage tank each time the normalized conductivity reading of the chemical solution is less than the conductivity setpoint.

14. A method as defined in claim 11, further comprising:

if the normalized conductivity reading for the chemical solution is greater than the conductivity setpoint, requesting that a specified volume of water be supplied to the solution tank.

15. A method as defined in claim 14, wherein the specified volume of water is defined based on a relative discrepancy between the conductivity measurement and the normalized conductivity reading.

16. A method as defined in claim 9, wherein the analyzing act comprises:

adding the soil conductivity offset value to the conductivity setpoint to render an normalized conductivity setpoint for the chemical solution; and

comparing the conductivity measurement of the chemical solution to the normalized conductivity setpoint.

17. A method as defined in claim 16, further comprising:

if the conductivity measurement of the chemical solution is less than the normalized conductivity setpoint, requesting that a specified volume of component chemical product be supplied to the solution tank.

18. A method as defined in claim 17, wherein the specified volume is defined based on a relative discrepancy between the conductivity measurement and the normalized conductivity setpoint.

19. A method as defined in claim 17, wherein the specified volume is a predetermined volume that is to be supplied to the solution tank each time the conductivity measurement of the chemical solution is less than the normalized conductivity setpoint.

20. A method as defined in claim 17, further comprising:

if the conductivity measurement of the chemical solution is greater than the normalized conductivity setpoint, requesting that a specified volume of water be supplied to the solution tank.

21. A method as defined in claim 20, wherein the specified volume of water is defined based on a relative discrepancy between the conductivity measurement and the normalized conductivity setpoint.

22. A method as defined in claim 9, further comprising:

transmitting at least one of the conductivity measurement for the chemical solution and the soil conductivity offset value to a remote computer over a network connection.

23. A method as defined in claim 9, further comprising:

transmitting results rendered by the analyzing act to a remote computer over a network connection.

24. A method as defined in claim 9, wherein the chemical solution is flushed from the solution tank after a predetermined period in time, the method further comprising:

defining an interval for adjusting the soil conductivity offset value, wherein the interval represents periods in time that the soil conductivity offset value is to be maintained at a constant value;

setting the soil conductivity offset value to an initial value during an initial period in time conforming to the interval, wherein the initial period in time begins concurrently with the predetermined period in time; and

increasing the soil conductivity offset value by a specified magnitude at each of a subsequent periods in time conforming to the interval.

25. A method as defined in claim 24, further comprising:

storing the increased soil conductivity offset value to a location in a memory such that any previous soil conductivity offset value in the location is overwritten by the increased soil conductivity offset value, wherein act of determining the soil conductivity offset value comprises retrieving the soil conductivity offset value from the memory location for use by the analyzing act.

26. A method as defined in claim 24, wherein the interval represents a period in time between detection of a first article rack carrying articles for washing by the utility device and a second article rack carrying articles for washing by the utility device.

27. A method as defined in claim 24, wherein the interval represents a period in time derived from a clock count.

28. A method as defined in claim 24, further comprising:

repeating the setting act at the conclusion of the predetermined period in time such that the soil conductivity offset value is returned to the initial value after the solution tank has been flushed.

29. A computer program storage device accessible to a computing system and encoding a computer program for executing a computer process for controlling conductivity of a chemical solution contained in a solution tank and used by a utility device to clean and sanitize articles having soil deposited thereon, wherein the utility device applies the chemical solution to the articles thereby washing the soil and applied chemical solution into the solution tank, the method comprising:

determining a conductivity measurement for the chemical solution, wherein the conductivity measurement indicates a percent concentration of a component chemical product in the chemical solution;

determining a soil conductivity offset value that represents a portion of the conductivity measurement that is attributable to soil mixed into the chemical solution; and

analyzing the soil conductivity offset value, the conductivity measurement and a conductivity setpoint indicating a desired percent concentration of the component chemical product in the chemical solution to determine whether the component chemical product should be added to the chemical solution.

30. A computer program storage device as defined in claim 29, wherein the analyzing act comprises:

subtracting the soil conductivity offset value from the conductivity measurement to render a normalized conductivity reading for the chemical solution; and

comparing the normalized conductivity reading of the chemical solution to the conductivity setpoint.

31. A computer program storage device as defined in claim 29, wherein the analyzing act comprises:

adding the soil conductivity offset value to the conductivity setpoint to render an normalized conductivity setpoint for the chemical solution; and

comparing the conductivity measurement of the chemical solution to the normalized conductivity setpoint.

32. A computer program storage device as defined in claim 29, further comprising:

transmitting at least one of the conductivity measurement for the chemical solution and the soil conductivity offset value to a remote computer over a network connection.

33. A computer program storage device as defined in claim 29, further comprising:

transmitting results rendered by the analyzing act to a remote computer over a network connection.

34. A computer program storage device as defined in claim 29, wherein the chemical solution is flushed from the solution tank after a predetermined period in time, the method further comprising:

defining an interval for adjusting the soil conductivity offset value, wherein the interval represents periods in time that the soil conductivity offset value is to be maintained at a constant value;

setting the soil conductivity offset value to an initial value during an initial period in time conforming to the interval, wherein the initial period in time begins concurrently with the predetermined period in time; and

increasing the soil conductivity offset value by a specified magnitude at each of a subsequent periods in time conforming to the interval.

35. A computer program storage device as defined in claim 34, further comprising:

storing the increased soil conductivity offset value to a location in a memory such that any previous soil conductivity offset value in the location is overwritten by the increased soil conductivity offset value, wherein act of determining the soil conductivity offset value comprises retrieving the soil conductivity offset value from the memory location for use by the analyzing act.

36. A computer program storage device as defined in claim 35, wherein the interval represents a period in time between detection of a first article rack carrying articles for washing by the utility device and a second article rack carrying articles for washing by the utility device.

37. A computer program storage device as defined in claim 35, wherein the interval represents a period in time derived from a clock count.

38. A computer program storage device as defined in claim 35, further comprising:

repeating the setting act at the conclusion of the predetermined period in time such that the soil conductivity offset value is returned to the initial value after the solution tank has been flushed.

39. A computer program storage device accessible to a computing system and encoding a computer program for executing a computer process for controlling conductivity of a chemical solution, the method comprising:

determining a conductivity measurement for the chemical solution, wherein the conductivity measurement indicates a percent concentration of a component chemical product in the chemical solution;

determining a conductivity offset value that represents a portion of the conductivity measurement that is attributable to a component of the chemical solution other than the component chemical product; and

analyzing the conductivity offset value, the conductivity measurement and a conductivity setpoint indicating a desired percent concentration of the component chemical product in the chemical solution to determine whether the component chemical product should be added to the chemical solution.

40. A computer program storage device as defined in claim 39 wherein the chemical solution is formed by combining the component chemical product with water in a solution tank and used by a utility device to clean and sanitize articles having soil deposited thereon, wherein the utility device applies the chemical solution to the articles thereby washing the soil and applied chemical solution into the solution tank, the determining act comprising:

determining a soil conductivity offset value that represents a portion of the conductivity measurement that is attributable to soil mixed into the chemical solution;

determining a water conductivity offset value that represents a portion of the conductivity measurement that is attributable to water used to form the chemical solution; and

adding the soil conductivity offset value and the water conductivity offset value to render the conductivity offset value.