Washing Machine Circulation Fault Detection via Liquid Level Drop

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Solution Overview

Problem

Existing washing machine operation methods fail to reliably monitor and manage the flooding device, leading to unnecessary activation of the circulation pump due to defects such as a blocked bypass nozzle or line, resulting in inefficient water utilization and potential damage.

Innovation Solution

Utilizing the existing liquid level sensor to monitor the liquid level drop after activating the circulation device, switching off the pump if the level doesn't drop within a predetermined time, and sending a status report to the user, allowing for continued or terminated washing programs, and adjusting parameters for effective washing without the circulation device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the circulation device is activated continuously to ensure washing liquid circulation, then washing effectiveness is improved, but the circulation pump may be unnecessarily loaded or damaged if defective (blocked bypass nozzle or line)

Engineering Contradiction:
Improvewashing effectivenessVSAvoidunnecessary pump load or damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by monitoring the liquid level in the tub before and during circulation device activation. The control device detects whether the liquid level drops by a predefined value after a fixed predetermined time following pump activation. If the expected level drop does not occur, the system identifies a defect (such as blocked bypass nozzle or line) and switches off the circulation pump before unnecessary damage can occur, while still maintaining washing effectiveness through proper liquid level management.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If the circulation pump is switched off immediately upon detecting a fault, then pump damage is prevented, but washing program completion may be affected

Engineering Contradiction:
Improvepump damage preventionVSAvoidwashing program completion
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies dynamics by providing flexible program continuation options after fault detection. When a circulation device defect is detected, the control device can either continue the washing program without the circulation device or end it prematurely, depending on the specific situation. This dynamic approach allows the system to prevent pump damage while adapting the washing program completion based on the severity and type of fault, balancing pump protection with washing program productivity.

Inventive Principle:
Principle #15Dynamics

3Reliability

If additional sensor devices are added to monitor circulation device function, then fault detection reliability is improved, but device complexity increases

Engineering Contradiction:
Improvefault detection reliabilityVSAvoidsensor device quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by using the existing liquid level sensor in the tub for multiple purposes: its original function of monitoring liquid level for washing operations, and an additional function of detecting circulation device faults by measuring liquid level changes during pump operation. This multi-functional use of the existing sensor achieves reliable fault detection without adding additional sensor devices, thereby maintaining simplicity while improving circulation device monitoring reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Ensures reliable operation of the flooding device, detects potential faults like a blocked pump or clogged line, and maintains washing effectiveness by adjusting parameters like water inlet and drum rotation, thus preventing unnecessary pump activation and ensuring user notification for maintenance.

Implementation Method 1

the circulation device being activated at least during one of these phases, in which washing liquid is pumped from the lower area of ​​the tub to the upper area

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

The essential advantage of the method according to the invention is that the flooding device is monitored for its proper function in a simple manner. In the method according to the invention, the already existing sensor for detecting the liquid level in the tub is used for monitoring.

Methodology Applied
Scientific EffectLiquid level detection:

Data Source

PatentEP2426246B1Method for operating a washing machine with flow device and washing machine
Publication Date: 2013.11.06 MIELE & CO KG
  • EP2426246B1 patent drawingFigure 1
  • EP2426246B1 patent drawingFigure 2
  • EP2426246B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a method for operating a washing machine (1) with a tub (2) for holding washing liquid (19) for treating laundry (8) and a circulation device (17), the method involving the implementation of a washing program (WP). washing phase (Wa) and at least one rinsing phase (Sp), with the circulation device (17) being activated at least during one of these phases (WA, Sp), in which the washing liquid (19) flows from the lower region of the tub (2) into the upper Area, based on the operational installation position of the washing machine (1), is funded. In order to ensure reliable operation and to avoid damage to the components of the bypass device, the time (TA) of the drop in level after activation of the bypass device (17), starting from an upper limit value (limit) until a lower limit value (low) is reached , recorded and evaluated in order to determine the predetermined error-free function of the flooding device (17). The invention also relates to a corresponding washing machine (1).