Three-Wafer Channel Structure for Fluid Analyzer Sensitivity

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Solution Overview

Problem

Micro fluid analyzers face challenges in enhancing the sensitivity of thermal conductivity detectors due to limitations in fluid carrying channel structures, which affect the detection efficiency and accuracy in chromatography applications.

Innovation Solution

A channel structure with gaps or openings on the membrane of the channel, integrated with a phased heater array and interactive elements, allows for improved thermal conductivity detection by optimizing sample flow and interaction with heaters, enhancing sensitivity and separation capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional fluid carrying channel structure is used, then the device complexity is low, but the detector sensitivity is insufficient

Engineering Contradiction:
Improvedetector sensitivityVSAvoidchannel structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The channel structure is segmented into multiple sections: a first channel section with a first cross-sectional area and a second channel section with a second cross-sectional area. This segmentation allows optimization of detector sensitivity in the first section while maintaining appropriate flow characteristics in the second section, resolving the contradiction between sensitivity and complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a dimensional change by varying the cross-sectional area along the channel length. The transition from a larger first cross-sectional area to a smaller second cross-sectional area creates a gradient structure that enhances detector sensitivity without requiring complex additional components, thus addressing the contradiction between sensitivity improvement and device complexity.

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

2Measurement precision

If the channel cross-sectional area is reduced to improve sensitivity, then the detector sensitivity increases, but the fluid flow rate decreases

Engineering Contradiction:
Improvedetector sensitivityVSAvoidfluid flow rate
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The channel is divided into segments with different cross-sectional areas. The first section has a larger area to maintain flow rate, while the second section has a smaller area to enhance sensitivity. This segmentation allows both flow rate and sensitivity requirements to be satisfied simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The channel structure transitions dynamically from a larger cross-sectional area to a smaller cross-sectional area along the flow path. This dynamic variation in geometry allows the system to maintain high flow rates in the initial section while achieving enhanced sensitivity in the detection section, resolving the contradiction between productivity and measurement precision.

Inventive Principle:
Principle #15Dynamics

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

The proposed channel structure increases detector sensitivity by two times, enabling effective sample analysis under high pressures with reduced thermal conduction losses and maintaining low fabrication costs, suitable for various applications including medical and industrial uses.

Implementation Method 1

a phased heater array structure for enhanced detection (PHASED) micro gas analyzer (MGA)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a differential thermal-conductivity detector (TCD)

Methodology Applied
Scientific EffectThermal conductivity detection: Conduction (thermal)

Data Source

PatentEP1994405B1A three-wafer channel structure for a fluid analyzer
Publication Date: 2018.01.10 HONEYWELL INTERNATIONAL INC
  • EP1994405B1 patent drawingFigure 1
  • EP1994405B1 patent drawingFigure 2
  • EP1994405B1 patent drawingFigure 3

AI summary

A three-wafer channel or column structure for a fluid analyzer. The structure may have a support member, membrane, or support wafer (42) containing heaters and interactive elements. The membrane may have a channel (32) of one wafer (30) facing the interactive element side and a space (46) of another wafer (44) facing the other side. The membrane (42) may have perforations (45) to equalize the pressures on both sides of the membrane. A detector in the membrane may have exposure to both the channel (32) and space (46) for good sensitivity, as the sample may be on both sides of the membrane. The wafers may be bonded with a thin film of non-flowing viscous material. Capillaries may be attached to an inlet and outlet of the channel and be parallel to an elongated dimension of the channel.