Steam Generator Water Level Sensor Layout Against Bubble Errors

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Solution Overview

Problem

Conventional drum type steam generators for laundry machines are prone to malfunction of the water level sensor due to bubble formation and vibration, which causes incorrect water level measurements.

Innovation Solution

The steam generator incorporates a water level sensor with a common electrode part, a low water-level electrode part, and a high water-level electrode part, spaced apart and surrounded by an accommodating part with cutting portions, to prevent malfunctions caused by bubbles and vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional water level sensor is used in the steam generator, then the device complexity is reduced, but the reliability of water level measurement deteriorates due to bubble formation and vibration

Engineering Contradiction:
Improvewater level measurement reliabilityVSAvoidwater level sensor structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The water level sensor is divided into multiple electrode parts (first electrode part, second electrode part, third electrode part) positioned at different heights. Each electrode part independently detects water level at its specific position, allowing the system to identify the actual water level by determining which electrodes are in contact with water, thereby preventing malfunction caused by bubbles or vibration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces water as an intermediary medium to detect the presence of bubbles. When bubbles are present on the electrode parts, water cannot contact the electrodes, creating a detectable difference in electrical conductivity or contact state. This allows the system to distinguish between actual water level changes and false readings caused by bubbles.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the electrode parts are positioned close together to reduce sensor size, then the device complexity is reduced, but the measurement precision deteriorates due to difficulty in distinguishing adjacent water level levels

Engineering Contradiction:
Improvewater level detection precisionVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor uses multiple discrete electrode parts positioned at different heights along the water supply hose. Each electrode acts as an independent detection point, enabling precise determination of water level by identifying which specific electrodes are in contact with water. This segmented approach provides clear discrete measurement levels rather than continuous analog sensing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-point water level detection to a multi-point vertical array of electrodes. By adding the vertical dimension with multiple electrodes at different heights, the system can precisely determine water level by detecting which combination of electrodes are activated, effectively creating a dimensional resolution to water level measurement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a simple water level sensor is used, then the ease of manufacture is improved, but the reliability deteriorates due to malfunction from bubbles and vibration during operation

Engineering Contradiction:
Improveoperation reliability under vibration and bubblesVSAvoidsensor assembly complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The water level sensor comprises multiple electrode parts (first, second, and third electrode parts) positioned at different heights on the water supply hose. This segmented structure allows each electrode to independently detect water contact, making the system robust against bubbles and vibration since multiple contact points provide redundant detection capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of trying to protect a single electrode from bubbles and vibration, the patent inverts the approach by using multiple electrodes where the presence of bubbles or vibration can be detected as a discrepancy between expected and actual electrode contact patterns. The system detects abnormal conditions by comparing the water contact state across multiple electrodes rather than relying on a single electrode's accuracy.

Inventive Principle:
Principle #13The other way round (Inversion)

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 design effectively prevents water level sensor malfunctions by ensuring accurate water level measurement despite bubble formation and vibration, maintaining reliable operation of the steam generator.

Implementation Method 1

a water level sensor (60) which measures a water level. The water level sensor (60) includes a receptacle housing (61) which is mounted to an outer surface of the housing (80), and a plurality of electrode parts (62, 63 and 64) which are mounted downward at the receptacle housing (61)

Methodology Applied
Scientific EffectElectrical conductivity sensing: Conduction (electrical)

Data Source

PatentEP1892467B1Steam generator and laundry machine having the same
Publication Date: 2013.11.20 LG ELECTRONICS INC
  • EP1892467B1 patent drawingFigure 1
  • EP1892467B1 patent drawingFigure 2
  • EP1892467B1 patent drawingFigure 3

AI summary

Disclosed herein are a steam generator and a laundry machine having the same which can prevent malfunction of a water level sensor. The steam generator includes a common electrode part, a low water-level electrode part which senses a low water level, and a high water-level electrode part which senses a high water level, the high water-level electrode part having a lower end which is positioned above a lower end of the low water-level electrode part and an upper end which is positioned above the low water-level electrode part.