Water Level Sensor Insulation for Steam Generator Electrical Stability

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Solution Overview

Problem

Moisture absorption in the resin lid portion of a steam generation device leads to fluctuations in electrical resistance between the terminals of the water level sensor due to gaps generated by thermal expansion differences, causing erroneous water level detection.

Innovation Solution

The steam generation device incorporates a water level sensor with a first electrode rod fixed to the lid portion and a second electrode rod held by a bracket and interposition component, which is electrically insulated from the lid portion using a silicone rubber interposition, increasing the distance between the electrodes and stabilizing electrical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the second electrode rod is inserted directly into the lid portion, then the device complexity is reduced, but moisture absorption and thermal expansion gaps cause electrical resistance fluctuations

Engineering Contradiction:

Improvestructure complexityVSAvoidelectrical resistance stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces an interposition component as a mediator between the bracket and the lid portion. This component electrically insulates the second electrode rod from the lid portion, preventing moisture absorption and thermal expansion gaps from affecting electrical resistance. The interposition component serves as an intermediary that blocks the harmful transmission path while maintaining the simple insertion structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the electrode rod is held through an interposition component, then electrical resistance stability is improved, but the device complexity increases

Engineering Contradiction:

Improveelectrical resistance stabilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The interposition component is designed as a simple ring-shaped element that fits between the bracket and lid portion. It provides electrical insulation without requiring complex assembly or additional components, thus improving reliability while minimizing increases in device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The interposition component functions as a thin insulating barrier that electrically isolates the electrode rod from the lid portion. This thin film approach provides effective insulation without adding significant structural complexity or volume to the device.

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If the bracket is inserted into the lid portion without an interposition component, then ease of manufacture is improved, but gaps from thermal expansion cause water ingress and electrical resistance fluctuations

Engineering Contradiction:

Improveassembly easeVSAvoidwater ingress from gaps

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The interposition component acts as a sealant intermediary between the bracket and lid portion. It fills and seals the gaps that would otherwise form due to thermal expansion differences, preventing water ingress while maintaining the simple insertion assembly process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent acknowledges the thermal expansion difference between metal and resin materials. The interposition component compensates for this thermal expansion effect by providing a flexible seal that accommodates dimensional changes without creating gaps that would allow water ingress.

Inventive Principle:

Principle #37Thermal expansion

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 configuration suppresses fluctuations in electrical resistance between the terminals of the water level sensor, ensuring accurate water level detection by maintaining stable electrical resistance.

Implementation Method 1

The interposition component is interposed between the bracket and the lid portion... the second electrode rod out of a first electrode rod and the second electrode rod of a water level sensor is held through an interposition component to be electrically insulated from a lid portion

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

a gap may be generated in an insert portion (a portion where a first electrode rod and a second electrode rod are inserted into a lid portion of the steam generation device) due to a difference in thermal expansion coefficient between a metal and a resin

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12478207B2Steam generation device and heating cooking apparatus

Publication Date: 2025.11.25 SHARP KK

AI summary

The steam generation device includes a steam generation container, a lid portion, and a water level sensor. The steam generation container heats water. The lid portion covers an upper opening portion of the steam generation container. The water level sensor detects a water level in the steam generation container. The water level sensor includes a first electrode rod, a second electrode rod, a bracket, and silicone rubber. The first electrode rod is fixed to the lid portion in a state where the first electrode rod penetrates the lid portion. The bracket is configured integrally with the second electrode rod, inserted into an opening portion provided in the lid portion, and fixed to a peripheral edge portion of the opening portion. The silicone rubber is interposed between the bracket and the lid portion.