Resistance-Heated Capillary with Convective Cooling for GC

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Solution Overview

Problem

Existing gas chromatography methods face challenges in achieving efficient separation with temperature gradients along long capillary columns, as they require complex and costly setups for uniform temperature control, leading to inefficient separation and measurement issues.

Innovation Solution

A method utilizing resistance-heated separation capillaries or sheath capillaries with controlled temperature gradients achieved through a forced convective flow field, eliminating the need for complex temperature control fluids and allowing dynamic temperature control with minimal energy usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If temperature-programmed GC is used to achieve transport of all substances through the column, then substances are exposed to higher temperatures than required for separation, but this reduces separation efficiency

Engineering Contradiction:

Improvetransport speedVSAvoidseparation efficiency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The chromatography column is divided into multiple independently controllable heating zones along its length. Each zone can be heated to different temperatures, allowing the creation of a temperature gradient that maintains optimal separation conditions in different sections of the column simultaneously, preventing substances from being exposed to excessively high temperatures while ensuring complete transport.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the column are assigned different temperature characteristics - the inlet region maintains lower temperatures for effective separation, while downstream regions are heated to higher temperatures to ensure transport of less volatile substances. This local temperature optimization resolves the contradiction between separation efficiency and transport speed.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If a temperature gradient is implemented along the separation column to improve separation efficiency, then complex and costly temperature control setups are required

Engineering Contradiction:

Improveseparation efficiencyVSAvoidtemperature control setup

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The complex mechanical temperature control system with multiple external heating elements and control mechanisms is replaced by integrating resistive heating elements directly into the column structure. The column itself becomes the heating element, eliminating the need for separate external temperature control apparatus and simplifying the overall system while maintaining precise temperature gradient control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The temperature control function is merged with the column structure by integrating heating elements directly into the column wall. This consolidation eliminates separate temperature control devices and reduces system complexity while enabling precise spatial temperature control along the column length.

Inventive Principle:

Principle #5Merging (Combining)

3Speed

If rapid heating rates are employed in GC separation processes, then substances are exposed to higher temperatures for longer periods, but this reduces separation efficiency

Engineering Contradiction:

Improveheating rateVSAvoidseparation efficiency

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The temperature profile along the column is made dynamically controllable, allowing different heating rates in different zones. The inlet region can be heated rapidly to reach separation temperatures quickly, while downstream regions maintain lower temperatures for extended periods to ensure complete substance transport, optimizing both speed and separation efficiency through spatially differentiated dynamic control.

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

This approach enables precise and efficient gas chromatography with improved separation efficiency and measurement sensitivity by maintaining optimal temperatures for substance analysis, reducing energy consumption and simplifying the setup.

Implementation Method 1

the separation capillary and/or a sheath capillary surrounding the separation capillary is/are electrically conductive and is/are heated with current in the form of resistance heating

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

is/are cooled by a forced convective flow by means of a fluid

Methodology Applied

Scientific EffectForced convection: Forced Convection

Data Source

PatentUS10641748B2Flow-field-induced temperature gradient gas chromatography

Publication Date: 2020.05.05 BOEKER PETER

AI summary

The invention relates to a method, to a device, and to the use of a method for the gas-chromatic separation and determination of volatile substances in a carrier gas by means of a chromatographic separating capillary (1), wherein the separating capillary and/or an enveloping capillary (2) surrounding the separating capillary (1) is electrically conductive and is heated with current in the form of a resistance heater and is cooled by a forced convective flow by means of a fluid in the form of a gradient flow field in such a way that a continuous temperature gradient arises over the length of the separating capillary.