Optical Measurement Cell Thermal Stress Reduction

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Solution Overview

Problem

Conventional optical measurement cells experience thermal stress and potential fracturing due to differences in thermal expansion coefficients between materials, leading to airtight seal failures and degradation, especially when using O-rings or flange joints.

Innovation Solution

Incorporating a low thermal expansion component on the outer circumferential surface of the join supporting portion, with a coefficient of thermal expansion lower than the join supporting portion, to suppress deformation and reduce thermal stress, and using an annular groove with a thermal deformation absorbing portion to further mitigate stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flange component is joined directly to the window material to achieve an airtight seal, then sealing performance is improved, but thermal stress causes fracturing of the join portion or window material

Engineering Contradiction:

Improvesealing performanceVSAvoidjoin portion strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

A low thermal expansion component is introduced as an intermediary between the flange component and the window material. This intermediary component has a coefficient of thermal expansion that is lower than the flange component, allowing it to better match the window material's thermal properties and reduce thermal stress at the join portion while maintaining the airtight seal.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The join structure employs a composite arrangement combining the flange component, low thermal expansion component, and window material. Each material is selected for its specific properties: the flange component provides structural support, the low thermal expansion component mitigates thermal stress, and the window material provides optical functionality. This composite structure resolves the contradiction between sealing performance and join strength.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If an O-ring is used to fix the window material for a simple structure, then ease of manufacture is improved, but gas permeation prevents extreme airtight sealing

Engineering Contradiction:

Improveassembly simplicityVSAvoidsealing performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The O-ring sealing element is extracted from the direct join between the flange and window material. Instead, the low thermal expansion component provides the primary sealing interface with the window material, while the O-ring can be retained in a modified configuration or replaced with a more robust sealing mechanism that does not compromise the thermal stress issue.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of manufacture

If the join supporting portion is made from a material with high thermal expansion for ease of manufacture, then manufacturing flexibility is improved, but thermal deformation increases causing stress concentration

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoiddimensional stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The low thermal expansion component is applied locally at the critical interface between the flange component and window material, rather than requiring the entire join supporting portion to be made from low thermal expansion material. This allows the majority of the structure to use easily manufactured materials while the critical sealing area uses materials optimized for thermal stability.

Inventive Principle:

Principle #3Local quality

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 effectively reduces thermal stress and prevents fracturing of the join portion and window material, maintaining an airtight seal and extending the lifespan of the optical measurement cell.

Implementation Method 1

due to differences between a coefficient of thermal expansion of the material (for example, stainless steel) forming the flange component and a coefficient of thermal expansion of the material (for example, zinc selenide) forming the window material, thermal stress may be generated in the join portion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS11892395B2Optical measurement cell and optical analysis device

Publication Date: 2024.02.06 HORIBA STEC CO LTD

AI summary

The present invention reduces thermal stress that is generated in a join portion of a window material in an optical measurement cell, and is an optical measurement cell having translucent windows through which light is transmitted and into an interior of which is introduced a test sample. This optical measurement cell has a planar window material that forms the translucent windows, a join supporting portion that is joined to an outer edge portion of a main surface of the window material and supports the window material, and a low thermal expansion component that is provided on an outer-side circumferential surface of the join supporting portion and whose coefficient of thermal expansion is lower than a coefficient of thermal expansion of the join supporting portion.