Cooling Mixture Below -10°C for Precise SF6 Alternative Distribution

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Solution Overview

Problem

The distribution of new organic electrical cut-off chemicals for high or medium voltage electrical devices is inefficient due to non-homogeneous mixing with dilution gases, leading to variable concentration and reduced effectiveness in electrical insulation, and the existing methods are complex and costly, especially when compared to sulfur hexafluoride (SF6) distribution.

Innovation Solution

A method involving cooling the mixture of organic electrical cut-off chemicals and diluents to a temperature below -10°C, followed by evaporation and distribution, ensuring precise metering and high efficiency, with the diluent having a significantly higher saturation vapor pressure than the cut-off chemical, allowing for a stable and optimal gas distribution in the electrical device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the mixture is stored and distributed at ambient temperature, then the distribution process is simple, but the concentration of electrical cut-off product in the gaseous phase is insufficient and variable (at least 8% variation)

Engineering Contradiction:
Improvedistribution process simplicityVSAvoidconcentration precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent changes the temperature parameter from ambient to below -10°C during storage and distribution. This temperature change transforms the mixture into a liquid state with homogeneous composition, eliminating the concentration variation problem that occurs at ambient temperature when distributing from gaseous phase.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transition by cooling the mixture below -10°C to maintain it in liquid state during storage and distribution. The evaporation step then transitions the liquid back to gaseous phase for filling the electrical device, ensuring precise concentration control during the liquid storage and distribution phase.

Inventive Principle:
Principle #36Phase transitions

2Manufacturing precision

If a gas mixing circuit with mass flowmeters is used to control the ratio, then the concentration precision is improved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improveconcentration precisionVSAvoidmixing circuit complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of using complex flow measurement and control devices, the patent changes the temperature parameter to below -10°C, which fundamentally alters the physical state of the mixture to liquid. This simple parameter change achieves precise concentration control without requiring any complex mixing circuits or mass flowmeters.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent exploits the phase transition property of the mixture at low temperatures. By maintaining the mixture in liquid state below -10°C during storage and distribution, homogeneous mixing is achieved naturally without any mechanical mixing devices, greatly simplifying the system while ensuring concentration precision.

Inventive Principle:
Principle #36Phase transitions

3Productivity

If the gaseous phase is withdrawn from the container at ambient temperature, then the distribution process is fast, but the exploitable mass is limited to only 20-30% by weight

Engineering Contradiction:
Improvedistribution speedVSAvoidexploitable mass
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent changes the temperature parameter to below -10°C, transforming the mixture into liquid state. This allows much greater mass to be stored in the same container volume and distributed efficiently. The liquid phase enables complete utilization of the mixture mass, not limited to the small fraction available in gaseous phase at ambient temperature.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By cooling the mixture below -10°C to liquid state for storage and distribution, then evaporating it to gaseous phase for filling the electrical device, the patent maximizes the exploitable mass. The liquid phase allows dense storage and complete distribution of the mixture, overcoming the 20-30% limitation of gaseous phase withdrawal at ambient temperature.

Inventive Principle:
Principle #36Phase transitions

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 ensures a precise concentration variation of less than 2% by weight, improves distribution efficiency, and allows for a higher quantity of the mixture to be used, overcoming the limitations of prior art by enabling quick and effective filling of electrical enclosures with environmentally friendly alternatives to SF6.

Implementation Method 1

a step of cooling said mixture to a temperature below -10°C

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 2

the method comprises a step of evaporating said mixture (M) then a step of distributing the mixture in the enclosure

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3286776B1Method and system for distributing a mixture
Publication Date: 2022.08.10 DEHON SA
  • EP3286776B1 patent drawingFigure 1~2

AI summary

A method for distributing a mixture (M) capable of providing electrical insulation and/or stopping an electric arc in a chamber (10) of a high or medium voltage electrical apparatus (1), the mixture (M) comprising at least one organic, electrically-isolating, chemical product (Gl) and at least one diluting product (G2), the mixture (M) being stored in a container (2), the method comprising a step of cooling said mixture (M) to a temperature less than -10 °C, a step of draining the container (2) containing the cooled mixture (M) and a step of distributing the mixture (M) in the chamber (10) of the high or medium voltage electrical apparatus (1).