Device for determining a liquid level in a steam generator of a steam cooker, steam cooker having such a device, and method for determining a liquid level

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Solution Overview

Problem

Existing steam cooking appliances face challenges in precisely and simply determining the liquid level in steam generating devices, leading to operational impairments and defects due to low filling levels or empty evaporator dishes.

Innovation Solution

A device with an electrode arrangement and an evaluation unit that detects the actual electrical resistance between electrodes to determine the liquid level, using stored reference resistance values to identify maximum and refill levels, allowing for precise and reliable liquid level detection and automatic refilling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional liquid level detection methods are used in steam cookers, then the device can detect liquid level, but the construction effort is high and the device is complex

Engineering Contradiction:
Improveliquid level detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or optical liquid level detection systems with a simple electrical resistance measurement system using electrodes. The evaluation unit determines liquid level by measuring electrical resistance between electrodes, which changes based on liquid contact, thereby achieving precise detection with minimal device complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes changes in electrical resistance parameter as liquid level changes. By monitoring the resistance value between electrodes (which varies when liquid contacts different electrode pairs), the system can precisely determine liquid level without complex mechanical structures

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If simple liquid level detection is used, then the device is compact and simple, but measurement precision is insufficient

Engineering Contradiction:
Improvedevice complexityVSAvoidliquid level detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the detection system into multiple electrode pairs positioned at different heights within the container. Each electrode pair detects a specific liquid level threshold, and by combining information from multiple segmented detection points, the system achieves high measurement precision while keeping each individual electrode simple

Inventive Principle:
Principle #1Segmentation

3Reliability

If precise liquid level detection is implemented, then operational reliability is improved, but the device becomes more complex

Engineering Contradiction:
Improveoperational reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a self-service detection system where the liquid itself serves as the electrical conductor. The liquid's natural electrical properties are utilized to detect its own level by completing or breaking the electrical circuit between electrodes, eliminating the need for external power sources or complex sensing mechanisms while ensuring high reliability

Inventive Principle:
Principle #25Self-service

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

Enables precise, space-saving, and durable liquid level determination, ensuring optimal operation and preventing defects by automatically refilling when necessary, regardless of the type of liquid used.

Implementation Method 1

an evaluation unit (11), which is designed to detect an actual electrical resistance value between the electrodes (9; 10), dependent on the current liquid level

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP2869736B1Device for determining a liquid level in a steam generator of a steam cooker, steam cooker having such a device, and method for determining a liquid level
Publication Date: 2023.05.24 BSH HAUSGERATE GMBH
  • EP2869736B1 patent drawingFigure 1~2

AI summary

The invention relates to a device (2) for determining a liquid level in a steam generator (3) of a steam cooker (1), having a container (4) for the liquid (6) and having an electrode arrangement (8), which has a first electrode (9) and a second electrode (10) spaced apart from the first, wherein the electrodes (9, 10) extend into the container (4), and having an evaluation unit (11), which is designed for sensing an actual electrical resistance value, dependent on an actual liquid level, between the electrodes (9, 10). The invention also relates to a steam cooker (1) and to a method for determining the liquid level.