Washer Heating Element Thermal Bridge for Overheat and Scale Control

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Solution Overview

Problem

Existing washing machines and dishwashers face challenges in accurately detecting the temperature of electric resistances used for heating, leading to overheating risks and calcareous deposit buildup, which affects efficiency and requires frequent maintenance or replacement.

Innovation Solution

A device that uses a thermal bridge between the temperature sensor and electric resistance to detect the resistance's temperature, allowing for controlled heating and cooling cycles to prevent overheating and remove calcareous deposits, thereby reducing component count and maintenance costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a temperature sensor is placed inside the tub to detect wash liquid temperature, then washing performance is improved through accurate temperature control, but the resistance temperature detection becomes inaccurate leading to overheating risks

Engineering Contradiction:

Improvewash liquid temperature detection accuracyVSAvoidresistance temperature detection accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a thermal bridge as an intermediary element that couples the temperature sensor to the heating resistance. This thermal bridge conducts heat from the resistance to the sensor, allowing the sensor to indirectly detect resistance temperature while remaining positioned in the wash liquid for accurate washing temperature control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the need for a separate resistance temperature sensor with a wash liquid temperature sensor that uses thermal conduction through a rigid support structure. This substitution eliminates additional sensors and simplifies the temperature detection system while maintaining reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If additional temperature sensors and complex circuits are added to accurately detect resistance temperature, then overheating prevention is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:

Improveoverheating prevention capabilityVSAvoidtemperature detection system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the wash liquid temperature sensor serve a dual function: detecting both wash liquid temperature for washing control and resistance temperature for overheating prevention. The thermal bridge enables this multi-functionality by conducting heat from the resistance to the sensor.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the temperature detection functions for wash liquid control and resistance monitoring into a single sensor system. By positioning the sensor on the tub wall and using the rigid support structure as a thermal bridge, the system merges two detection functions into one integrated solution.

Inventive Principle:

Principle #5Merging (Combining)

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 solution allows for accurate temperature detection and prevention of overheating, while also effectively removing calcareous deposits, enhancing the efficiency and longevity of the electric resistance without the need for additional sensors or complex circuits.

Implementation Method 1

a device which uses a thermal bridge between the temperature sensor and electric resistance to detect the resistance's temperature

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

electric resistances comprise a metal filament (which becomes hot by Joule effect when current is flowing through it)

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 3

microswitches controlled by a metal rod which expands when heated, thus opening the power supply circuit as soon as the resistance temperature reaches a threshold value

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS8882346B2Washing machine, in particular a laundry machine or washing/drying machine or a dishwasher, equipped with a device for detecting the temperature of the electric resistance used for warming up the wash liquid

Publication Date: 2014.11.11 WHIRLPOOL EMEA SPA

AI summary

The present invention relates to a washing machine (2), in particular a laundry washing or washing/drying machine or a dishwasher, comprising: a tub (3) adapted to contain a wash liquid (4), an electric resistance (1) for heating the wash liquid (4), a temperature sensor (5) for detecting the temperature of the wash liquid (4), wherein the resistance (1) and the temperature sensor (5) are put in a condition of thermal exchange by conduction. The invention also relates to a method for evaluating whether the resistance is emerged from or submerged in the wash liquid and to a method for removing calcareous deposits (17) from an electric resistance (1) adapted to heat a wash liquid (4) in a washing machine (2), in particular a laundry washing or washing/drying machine or a dishwasher, characterized in that the resistance (1) is subjected to at least one heating and cooling cycle while the resistance (1) is kept above the wash liquid (4).