APPARATUS AND ASSOCIATED METHOD FOR CONTROLLING A WASHING FLUID LEVEL IN A DISHWASHER

• US 20100175718A1
• Filed: 01/09/2009
• Published: 07/15/2010
• Est. Priority Date: 01/09/2009
• Status: Abandoned Application

• Current Assignee: Electrolux Home Products Incorporated (AB Electrolux)
• Original Assignee: Electrolux Home Products Incorporated (AB Electrolux)
• Inventors: Kedjierski, Fred Dennis, Montgomery, Mark D., Dalsing, Troy, Poyner, Dennis A.
• Application Number:
  US12/351,325
• Publication Number:
  US 20100175718A1
• Time in Patent Office: Days
• US Class Current: 134/18
• CPC Class Codes: A47L 15/4244 Water-level measuring or regulating arrangements
• CPC Class Codes: G01F 23/243 Schematic arrangements of probes combined with measuring circuits
• CPC Class Codes: G01F 23/247 for discrete levels
• CPC Class Codes: G01F 23/248 Constructional details; Mounting of probes
• CPC Class Codes: G01F 23/366 using optoelectrically actuated indicating means
• CPC Class Codes: G01F 23/38 using magnetically actuated indicating means
• CPC Class Codes: G01F 23/72 using magnetically actuated indicating means
• CPC Class Codes: G01F 23/74 for sensing changes in level only at discrete points

Abstract

A method and associated device and appliance for controlling a washing fluid level in a dishwashing appliance are provided. A sump assembly of a dishwashing appliance is filled with washing fluid to a predetermined fluid level determined by a fluid level sensing device directly engaged with the sump assembly. The sump assembly is operably engaged with a tub portion at a lower end thereof. Washing fluid is circulated between the sump assembly and the tub portion. After circulating the washing fluid, an operational fluid level within the sump assembly is determined by the fluid level sensing device. When the operational fluid level differs from the predetermined fluid level by more than a threshold level, one of a washing fluid drain valve and a washing fluid fill valve is actuated to substantially restore the washing fluid to the predetermined fluid level.

Claims

1. A method of controlling a washing fluid level in a dishwashing appliance, comprising:

filling a sump assembly of a dishwashing appliance with washing fluid to a predetermined fluid level, the predetermined fluid level being determined by a fluid level sensing device directly engaged with the sump assembly, the sump assembly being operably engaged with a tub portion at a lower end thereof;

circulating washing fluid between the sump assembly and the tub portion;

after circulating the washing fluid, determining an operational fluid level within the sump assembly by the fluid level sensing device; and

when the operational fluid level differs from the predetermined fluid level by more than a threshold level, actuating one of a washing fluid drain valve and a washing fluid fill valve to substantially restore the washing fluid to the predetermined fluid level.

2. A method according to claim 1 further comprising generating a signal associated with the determined operational fluid level, with the fluid level sensing device, the signal being directed by the fluid level sensing device to a controller device in communication therewith and capable of directing actuation of the one of the washing fluid drain valve and the washing fluid fill valve in response to the determined operational fluid level.

3. A method according to claim 1 wherein determining an operational fluid level further comprises determining an operational fluid level with the fluid level sensing device comprising an optical sensor device having a light-sensitive detector operably engaged with and capable of sensing light emitted from an associated light source and a change in the sensed light in response to the washing fluid associated with the fluid level.

4. A method according to claim 1 wherein determining an operational fluid level further comprises determining an operational fluid level with the fluid level sensing device comprising a resistive sensor device having a plurality of resistor members configured to interact with the washing fluid and a monitoring device in communication therewith, the monitoring device being configured to monitor at least one of a voltage change and a resistance change associated with the resistor members in response to the washing fluid associated with the fluid level.

5. A method according to claim 1 wherein determining an operational fluid level further comprises determining an operational fluid level with the fluid level sensing device comprising a magnetic sensor device having at least one magnetic member capable of moving with the washing fluid as the fluid level changes, and a magnetic detector configured to detect movement of the at least one magnetic member in response to the washing fluid associated with the fluid level.

6. A method according to claim 1 wherein determining an operational fluid level further comprises determining an operational fluid level with the fluid level sensing device comprising a conductive sensor device having a plurality of conductive contact portions vertically spaced-apart and disposed within the sump assembly so as to be capable of interacting with the washing fluid therein, and a conduction detector in communication therewith and configured to detect completion of a circuit associated with the conductive contact portions in response to the washing fluid associated with the fluid level.

7. A fluid level control device for a dishwashing appliance having a tub portion adapted to contain washing fluid for circulation about dishware received therein, the dishwashing appliance further including a sump assembly disposed at a lower end of the tub portion for receiving the washing fluid therefrom, a washing fluid drain valve for removing washing fluid from the dishwashing appliance, and a washing fluid fill valve for directing washing fluid to the dishwashing appliance, the fluid level control device comprising:

a fluid level sensing device adapted to be directly engaged with the sump assembly of the dishwashing appliance, the fluid level sensing device being configured to determine a washing fluid level, including a predetermined fluid level and an operational fluid level, associated with the washing fluid within the dishwashing appliance, and to generate a first signal and a second signal corresponding to the predetermined fluid level and the operational fluid level, respectively; and

a controller device in communication with the fluid level sensing device and configured to receive the first signal therefrom and respond to the first signal to originate a washing fluid circulation event such that washing fluid is circulated between the sump assembly and the tub portion, the controller device being further configured to receive the second signal after at least a portion of the washing fluid circulation event has elapsed, and respond to the second signal to direct actuation of one of the washing fluid drain valve and the washing fluid fill valve when the operational fluid level differs from the predetermined fluid level by more than a threshold level, to substantially restore the washing fluid to the predetermined fluid level.

8. A device according to claim 7 wherein the fluid level sensing device further comprises an optical sensor device having a light-sensitive detector operably engaged with and capable of sensing light emitted from an associated light source and a change in the sensed light in response to the washing fluid associated with the fluid level.

9. A device according to claim 8 wherein the optical sensor device is configured to be operable with infrared light.

10. A device according to claim 8 further comprising an arm member adapted to be pivotably engaged with the sump assembly at one end, and having a float member engaged therewith about an opposing end, the arm member having a plurality of uniquely-configured reflective portions engaged therewith, the reflective portions being movable in conjunction with the pivotably engaged arm member and the float member, in response to the washing fluid associated with the fluid level and with respect to one of the light source and the light-sensitive detector, such that at least a portion of the light emitted from the light source is reflected from one of the reflective portions and detected by the light-sensitive detector.

11. A device according to claim 7 wherein the fluid level sensing device further comprises a resistive sensor device having a plurality of resistor members configured to interact with the washing fluid and a monitoring device in communication therewith, the monitoring device being configured to monitor at least one of a voltage change and a resistance change associated with the resistor members in response to the washing fluid associated with the fluid level.

12. A device according to claim 7 wherein the fluid level sensing device further comprises a magnetic sensor device having at least one magnetic member capable of moving with the washing fluid as the fluid level changes, and a magnetic detector configured to detect movement of the at least one magnetic member in response to the washing fluid associated with the fluid level.

13. A device according to claim 12 wherein the at least one magnetic member is operably engaged with a float member and is movable with the float member in response to the washing fluid associated with the fluid level, and wherein the magnetic detector comprises at least two vertically spaced-apart reed sensor elements configured to cooperate to sense one of a disposition and a movement of the at least one magnetic member with respect thereto.

14. A device according to claim 12 further comprising an arm member adapted to be pivotably engaged with the sump assembly at one end, and having a float member engaged therewith about an opposing end, the arm member having at least two magnetic members operably engaged therewith, the magnetic members being movable in conjunction with the pivotably engaged arm member and the float member, in response to the washing fluid associated with the fluid level and with respect to the magnetic detector.

15. A device according to claim 7 wherein the fluid level sensing device further comprises a conductive sensor device having a plurality of conductive contact portions vertically spaced-apart and disposed within the sump assembly so as to be capable of interacting with the washing fluid therein, and a conduction detector in communication therewith and configured to detect completion of a circuit associated with the conductive contact portions in response to the washing fluid associated with the fluid level.

16. A device according to claim 15 wherein the conductive contact portions are one of received in a mounting body adapted to operably engage the sump assembly and adapted to operably engage a wall of the sump assembly.

17. A dishwashing appliance comprising:

a tub portion configured to contain washing fluid for circulation about dishware received therein;

a sump assembly disposed at a lower end of the tub portion for receiving the washing fluid therefrom;

a washing fluid drain valve in communication with the sump assembly for removing washing fluid therefrom;

a washing fluid fill valve in communication with the sump assembly for directing washing fluid thereto;

a fluid level sensing device directly engaged with the sump assembly of the dishwashing appliance, the fluid level sensing device being configured to determine a washing fluid level, including a predetermined fluid level and an operational fluid level, associated with the washing fluid within the dishwashing appliance, and to generate a first signal and a second signal corresponding to the predetermined fluid level and the operational fluid level, respectively; and

a controller device in communication with the fluid level sensing device and configured to receive the first signal therefrom and respond to the first signal to originate a washing fluid circulation event such that washing fluid is circulated between the sump assembly and the tub portion, the controller device being further configured to receive the second signal after at least a portion of the washing fluid circulation event has elapsed, and respond to the second signal to direct actuation of one of the washing fluid drain valve and the washing fluid fill valve when the operational fluid level differs from the predetermined fluid level by more than a threshold level, to substantially restore the washing fluid to the predetermined fluid level.

18. An appliance according to claim 17 wherein the fluid level sensing device further comprises an optical sensor device having a light-sensitive detector operably engaged with and capable of sensing light emitted from an associated light source and a change in the sensed light in response to the washing fluid associated with the fluid level.

19. An appliance according to claim 18 wherein the optical sensor device is configured to be operable with infrared light.

20. An appliance according to claim 18 further comprising an arm member pivotably engaged with the sump assembly at one end, and having a float member engaged therewith about an opposing end, the arm member having a plurality of uniquely-configured reflective portions engaged therewith, the reflective portions being movable in conjunction with the pivotably engaged arm member and the float member, in response to the washing fluid associated with the fluid level and with respect to one of the light source and the light-sensitive detector, such that at least a portion of the light emitted from the light source is reflected from one of the reflective portions and detected by the light-sensitive detector.

21. An appliance according to claim 17 wherein the fluid level sensing device further comprises a resistive sensor device having a plurality of resistor members configured to interact with the washing fluid and a monitoring device in communication therewith, the monitoring device being configured to monitor at least one of a voltage change and a resistance change associated with the resistor members in response to the washing fluid associated with the fluid level.

22. An appliance according to claim 17 wherein the fluid level sensing device further comprises a magnetic sensor device having at least one magnetic member capable of moving with the washing fluid as the fluid level changes, and a magnetic detector configured to detect movement of the at least one magnetic member in response to the washing fluid associated with the fluid level.

23. An appliance according to claim 22 wherein the at least one magnetic member is operably engaged with a float member and is movable with the float member in response to the washing fluid associated with the fluid level, and wherein the magnetic detector comprises at least two vertically spaced-apart reed sensor elements configured to cooperate to sense one of a disposition and a movement of the at least one magnetic member with respect thereto.

24. An appliance according to claim 22 further comprising an arm member pivotably engaged with the sump assembly at one end, and having a float member engaged therewith about an opposing end, the arm member having at least two magnetic members operably engaged therewith, the magnetic members being movable in conjunction with the pivotably engaged arm member and the float member, in response to the washing fluid associated with the fluid level and with respect to the magnetic detector.

25. An appliance according to claim 17 wherein the fluid level sensing device further comprises a conductive sensor device having a plurality of conductive contact portions vertically spaced-apart and disposed within the sump assembly so as to be capable of interacting with the washing fluid therein, and a conduction detector in communication therewith and configured to detect completion of a circuit associated with the conductive contact portions in response to the washing fluid associated with the fluid level.

26. An appliance according to claim 25 wherein the conductive contact portions are one of received in a mounting body operably engaged with the sump assembly and operably engaged with a wall of the sump assembly.