Liquid Pump Gas Extraction System for Transformer Oil Analysis

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Solution Overview

Problem

Current methods for on-line measurement of gases or gas mixtures dissolved in oil, such as in power transformers, are inaccurate due to solubility variations and contamination issues, and high-end devices rely on expensive vacuum technology.

Innovation Solution

A system that extracts gases or gas mixtures using mechanical agitation and reduced pressure, circulating liquid to vary gas pressure, and includes a gas analyzer for precise concentration measurement without semipermeable membranes or vacuum pumps, allowing for accurate gas measurement at different pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If vacuum extraction sampling is used to achieve high measurement precision, then device complexity and cost increase due to vacuum pumps and complicated technology

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of vacuum extraction (gas removal from liquid) but eliminates the vacuum pump component. Instead, it uses a liquid pump to create pressure differential by removing liquid from the extraction chamber, thereby extracting gas without complex vacuum technology. This resolves the contradiction by maintaining measurement precision while reducing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the vacuum pump mechanical system with a liquid pump-based pressure control system. By using liquid removal to create negative pressure in the extraction chamber, the system achieves gas extraction functionality without relying on vacuum pump mechanics, thus reducing device complexity while maintaining precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If vacuum pumps are used to achieve high measurement precision, then cost increases due to expensive vacuum technology

Engineering Contradiction:
Improvemeasurement precisionVSAvoidcost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the core functionality of vacuum extraction while removing the expensive vacuum pump component. By using a standard liquid pump to achieve pressure differential, the system maintains measurement precision while significantly reducing manufacturing cost and eliminating dependence on expensive vacuum technology.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, maintenance-intensive vacuum pumps with simpler, more affordable liquid pumps and disposable-like extraction chambers. This substitution reduces both initial manufacturing cost and long-term operational costs while maintaining the necessary measurement precision.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If semipermeable membranes are used for gas extraction, then device complexity is reduced, but measurement precision deteriorates due to contamination problems

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent removes semipermeable membranes from the system entirely, replacing them with a direct liquid-pump-based extraction mechanism. This eliminates contamination risks associated with membranes while maintaining simple device architecture, thereby improving measurement precision without increasing complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

4Device complexity

If headspace sampling method is used to reduce device complexity, then measurement precision deteriorates due to solubility coefficient variations

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent eliminates the headspace sampling approach and implements direct liquid phase extraction using a pump system. This allows for controlled pressure differential extraction that compensates for solubility variations, maintaining measurement precision while keeping the device structure relatively simple.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces dynamic pressure control through the liquid pump system, allowing real-time adjustment of extraction conditions. This dynamic control enables compensation for solubility coefficient variations across different samples, maintaining measurement precision without requiring complex static calibration systems.

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 system provides high-degree extraction comparable to vacuum methods, is cost-effective, and maintains measurement accuracy and stability with extended calibration intervals, reducing contamination risks and device complexity.

Implementation Method 1

extracting the gas or gas mixture from the liquid utilizing mechanical agitation and pressure substantially reduced from ambient pressure

Methodology Applied
Scientific EffectMechanical agitation: Stirring

Implementation Method 2

extracting the gas or gas mixture from the liquid utilizing mechanical agitation and pressure substantially reduced from ambient pressure

Methodology Applied
Scientific EffectPressure reduction: Depressurisation

Implementation Method 3

varying a gas pressure or gas mixture pressure between successive measurements by the gas analyzer by elevating or lowering a liquid level

Methodology Applied
Scientific EffectHydrostatic pressure variation: Pressure Increase

Implementation Method 4

dissolving the gas or gas mixture back into the liquid

Methodology Applied
Scientific EffectDissolution: Solvation

Data Source

PatentEP3183572B1Method and system for extracting gas or gas mixtures from a liquid for performing dissolved gas or gas mixture analysis
Publication Date: 2021.04.07 VAISALA
  • EP3183572B1 patent drawingFigure 1
  • EP3183572B1 patent drawingFigure 2
  • EP3183572B1 patent drawingFigure 3

AI summary

The present invention concerns asystem (1) for extracting gas or gas mixtures from a liquid for performing dissolved gas or gas mixture analysis, the system (1) comprising a container (2) for storing a liquid and/or a gas or gas mixture, a liquid pump (3) which is connected to the container (2), a means for feeding the system (1) with a liquid and emptying the system (1) of the liquid, a gas analyzer which is connected to the container (2), and a piping (14) which is connected to the container (2), and wherein the piping (14), the liquid pump (3) and the container (2) are configured to circulate the liquid. The invention also concerns a method for extracting gas or gas mixtures from a liquid for performing dissolved gas or gas mixture analysis.