Dishwasher Filter Flushing Control to Prevent Sump Clogging

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Solution Overview

Problem

Dishwashers face clogging issues due to foreign substances accumulating on the filter, reducing water flow and leading to decreased washing performance and potential odor issues from decaying substances.

Innovation Solution

A method involving controlled on/off operations of the washing water pump and discharging pump to adjust water levels in the filter, effectively removing foreign substances and preventing clogging, by driving the first pump for washing and rinsing processes and the second pump for discharging, with specific timing to manage water levels and flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the filter device continuously filters foreign substances from washing water, then filtering effectiveness is improved, but the filter becomes clogged and water flow rate decreases

Engineering Contradiction:
Improvefiltering effectivenessVSAvoidwater flow rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system alternates between filtration mode (first pump operating) and flushing mode (second pump operating) in periodic cycles. During flushing mode, the second pump reverses water flow to remove accumulated foreign substances from the filter, preventing clogging while maintaining continuous filtration capability. This periodic switching resolves the contradiction by temporarily suspending filtration to restore flow rate.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system discards accumulated foreign substances from the filter by reversing water flow through the second pump. The flushing process removes and discharges these substances, allowing the filter to recover its original flow characteristics. This discarding mechanism prevents permanent clogging and maintains long-term filtering effectiveness.

Inventive Principle:
Principle #34Discarding and recovering

2Reliability

If foreign substances are continuously stacked on the filter device, then filtering capacity is improved, but washing performance decreases and overload is applied to the pump unit

Engineering Contradiction:
Improvefiltering capacityVSAvoidwashing performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control unit switches between filtration operation and flushing operation at predetermined intervals. During flushing, the second pump operates to remove accumulated substances, preventing excessive buildup that would degrade washing performance and cause pump overload. This periodic maintenance ensures sustained high-performance operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system performs self-maintenance by automatically flushing the filter during operation without requiring external intervention. The second pump and control unit work together to periodically clean the filter, allowing the system to maintain its own filtering capacity and washing performance over extended operation periods.

Inventive Principle:
Principle #25Self-service

3Productivity

If foreign substances are removed from the filter, then water flow rate is improved, but filtering effectiveness temporarily decreases

Engineering Contradiction:
Improvewater flow rateVSAvoidfiltering effectiveness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system implements periodic flushing cycles where the second pump removes foreign substances to restore flow rate, followed by resumption of normal filtration. The control unit manages these cycles to ensure filtering effectiveness is maintained overall, balancing temporary reduction during flushing with long-term sustained performance.

Inventive Principle:
Principle #19Periodic action

4Reliability

If the second pump operates for extended time to remove foreign substances, then filter cleaning effectiveness is improved, but energy consumption increases

Engineering Contradiction:
Improvefilter cleaning effectivenessVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control unit operates the second pump in periodic flushing cycles rather than continuously, switching it off after predetermined time intervals. This periodic operation achieves sufficient filter cleaning effectiveness while minimizing energy consumption compared to continuous operation, resolving the contradiction between cleaning thoroughness and energy efficiency.

Inventive Principle:
Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach ensures efficient washing water flow, prevents filter clogging, and reduces odors by effectively removing foreign substances, thereby enhancing washing performance and reliability.

Implementation Method 1

a washing water pump disposed at a side of the filter part, and providing driving force to circulate the washing water within the washing chamber and the sump

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

a discharging pump disposed at another side of the filter part, and providing driving force to discharge the washing water out of the dishwasher

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

a filter part provided to the sump, and filtering a foreign substance from the washing water

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP2611351B1Control method for a dishwasher
Publication Date: 2016.06.29 LG ELECTRONICS INC
  • EP2611351B1 patent drawingFigure 1
  • EP2611351B1 patent drawingFigure 2~3
  • EP2611351B1 patent drawingFigure 4~5

AI summary

Provided is a method of controlling a dishwasher. The dishwasher includes a washing chamber accommodating a dish, a sump storing washing water, and supplying the washing water to the washing chamber, and a filter part provided to the sump, and filtering a foreign substance from the washing water. In the method, a first pump is driven to perform a washing or rinsing process, the first pump is stopped and a second pump is driven for a first set time to perform a discharging process, after the washing or rinsing process, the second pump is stopped and the first pump is driven for a second set time, and the first and second pumps are stopped.