Ultra micron filter for a dishwasher

Patent metadata

Field	Value
Publication number	US-10813525-B2
Application number	US-201715479590-A
Country	US
Kind code	B2
Filing date	Apr 5, 2017
Priority date	Jun 20, 2011
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

A dishwasher having a tub at least partially defining a treating chamber, a liquid spray system, a liquid recirculation system fluidly coupling the treating chamber to the spray system to recirculate wash liquid from the treating chamber to the spray system, and filters capable of removing particles from the wash liquid. The filters include a microfilter fluidly coupled to at least one of the recirculation system and the spray system and an ultrafilter fluidly coupled to an outlet side of the microfilter.

First claim

What is claimed is:

1. An automatic dishwasher for treating utensils according to a cycle of operation, the automatic dishwasher comprising:
a tub at least partially defining a treating chamber for receiving utensils for treatment;
a spray system comprising at least one sprayer for spraying wash liquid in the treating chamber;
a recirculation system having a recirculation circuit and a recirculation pump, the recirculation circuit fluidly coupling the treating chamber to the spray system and the recirculation pump adapted to recirculate wash liquid from the treating chamber to the spray system;
a microfilter fluidly coupled to the recirculation circuit, the microfilter including a hollow rotary filter coupled at a first end to an impeller of the recirculation pump and wherein the wash liquid is drawn through the hollow rotary filter, into the recirculation pump and expelled through an outlet of the recirculation pump and where the microfilter is configured to let pass only particles smaller than 150 microns from the wash liquid recirculated from the treating chamber to the spray system;
an ultrafilter fluidly coupled to an outlet side of the microfilter and where the ultrafilter is configured to let pass only particles 5 microns and smaller from the wash liquid after it is filtered by the microfilter and adapted to remove grit particles therefrom; and
a return circuit fluidly coupling an output side of the ultrafilter to the recirculation circuit downstream of the treating chamber.

2. The automatic dishwasher of claim 1 , further comprising a sump forming a portion of the recirculation system and fluidly coupled to receive the wash liquid from the treating chamber and wherein the return circuit fluidly couples to the sump.

3. The automatic dishwasher of claim 2 wherein the sump is located in a housing physically separate from the treating chamber.

4. The automatic dishwasher of claim 3 wherein the hollow rotary filter is located within the housing and encloses a hollow interior and fluidly divides the housing into a first part that contains filtered soil particles and a second part that excludes filtered soil particles.

5. The automatic dishwasher of claim 4 wherein the ultrafilter is located within the hollow interior such that wash liquid passing through the hollow rotary filter into the hollow interior, then passes through the ultrafilter, before entering the recirculation pump.

6. The automatic dishwasher of claim 1 wherein the return circuit fluidly couples to the recirculation circuit fluidly downstream of the treating chamber.

7. The automatic dishwasher of claim 1 wherein a lower flow rate of wash liquid is provided to the ultrafilter than to the microfilter.

8. The automatic dishwasher of claim 7 , further comprising an auxiliary pump fluidly coupled to an output side of the ultrafilter and configured to expel the ultrafiltered wash liquid from the spray system.

9. An automatic dishwasher for treating utensils according to a cycle of operation, the automatic dishwasher comprising:
a tub at least partially defining a treating chamber for receiving utensils for treatment;
a spray system comprising at least one sprayer for spraying wash liquid in the treating chamber;
a recirculation system having a recirculation pump and a recirculation circuit fluidly coupling the treating chamber to the spray system to recirculate wash liquid from the treating chamber to the spray system;
a microfilter fluidly coupled to the recirculation circuit, the microfilter including a hollow rotary filter coupled at a first end to an impeller of the recirculation pump and wherein the wash liquid is drawn through the hollow rotary filter, into the recirculation pump and expelled through an outlet of the recirculation pump and where the microfilter is configured to let pass only particles smaller than 150 microns from wash liquid recirculated from the treating chamber to the spray system;
an ultrafilter fluidly coupled to an outlet side of the microfilter and where the ultrafilter is configured to let pass only particles 5 microns and smaller from the wash liquid after it is filtered by the microfilter;
a variable diverter valve fluidly coupled between the outlet side of the microfilter and an inlet of the ultrafilter; and
a controller operably coupled to the variable diverter valve and configured to control positioning of the variable diverter valve to actively control a volume of microfiltered liquid supplied to the ultrafilter to include 10-20% of a flow from the outlet side of the microfilter during ultrafiltration.

10. The automatic dishwasher of claim 9 wherein the controller is configured to control the positioning of the variable diverter valve based on a phase of the cycle of operation and a sensed soil level.

11. An automatic dishwasher for treating utensils according to a cycle of operation, the automatic dishwasher comprising:
a tub at least partially defining a treating chamber for receiving utensils for treatment;
a spray system comprising at least one sprayer for spraying wash liquid in the treating chamber;
a recirculation system having a recirculation circuit fluidly coupling the treating chamber to the spray system and a recirculation pump adapted to recirculate wash liquid from the treating chamber to the spray system;
a microfilter including a hollow rotary filter coupled at a first end to an impeller of the recirculation pump and wherein the wash liquid is drawn through the hollow rotary filter, into the recirculation pump and expelled through an outlet of the recirculation pump, wherein the microfilter removes particles larger than 150 microns from wash liquid recirculated from the treating chamber to the spray system and to let pass particles smaller than 150 microns;
an ultrafilter fluidly coupled to an outlet side of the microfilter to remove particles larger than 5 microns from the wash liquid after it is filtered by the microfilter and to let pass only particles 5 microns and smaller;
a diverter valve fluidly coupled between the outlet side of the microfilter and an inlet of the ultrafilter and configured to control a volume of microfiltered liquid supplied to the ultrafilter; and
a return circuit fluidly coupling an output side of the ultrafilter to the recirculation circuit downstream of the treating chamber and upstream of the recirculation pump.

12. The automatic dishwasher of claim 11 wherein the ultrafilter is fluidly coupled to the outlet of the recirculation pump such that at least part of the wash liquid filtered by the microfilter passes through the ultrafilter.

13. The automatic dishwasher of claim 12 wherein 10-20% of the microfiltered liquid is provided by the diverter valve to the ultrafilter.

14. The automatic dishwasher of claim 11 wherein the hollow rotary filter encloses a hollow interior and is positioned within a sump housing and fluidly divides the sump housing into a first part that contains filtered soil particles and a second part that excludes filtered soil particles.

15. The automatic dishwasher of claim 11 wherein the ultrafilter is replaceable by a user.

16. The automatic dishwasher of claim 15 wherein the ultrafilter is accessible by a user when a door to the treating chamber is opened or wherein the ultrafilter is located in a toe-kick area of the automatic dishwasher.

17. The automatic dishwasher of claim 15 , further comprising a sensor configured to sense a presence of the ultrafilter and provide an output to a controller, the controller configured to operate the diverter valve based on the output.

Assignees

• Whirlpool Co

Inventors

• Fountain Jordan R
• Rappette Antony M
• Tuller Barry E
• Welch Rodney M

Classifications

• A47L15/4285

  Water-heater arrangements (steam generating arrangements A47L15/4234) · CPC title

• A47L15/46

  Devices for the automatic control of the different phases of cleaning {; Controlling devices (A47L15/449 takes precedence)} · CPC title

• A47L15/4202 Primary

  Water filter means or strainers · CPC title

• A47L15/4219

  Water recirculation (A47L15/0078 takes precedence) · CPC title

• A47L15/22

  Rotary spraying devices · CPC title