Fluorinated Plastic Connection for Chlorine-Resistant Sensor Assembly

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Solution Overview

Problem

Soldered connections between carrier elements and micromechanical sensors are not resistant to certain fluids, particularly those containing chlorine, which can cause metal complexation and damage.

Innovation Solution

A measuring arrangement using a carrier element with a fluid channel and a sensor, where a connection layer made of a fluorinated plastic compound, such as a thermoplastic or thermoelastic copolymer like Halar ECTFE, forms a mechanical and fluid-conducting connection between the carrier element and the sensor, providing enhanced chemical resistance and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If soldered connections are used to connect the carrier element and sensor, then mechanical strength and ease of manufacture are improved, but chemical resistance to chlorine-containing fluids deteriorates

Engineering Contradiction:
Improvemechanical strength of connectionVSAvoidchemical resistance to fluids
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by combining metal components (carrier element, sensor) with a fluorinated plastic compound (connection layer). This composite structure allows the metal parts to provide mechanical strength while the fluorinated plastic layer provides chemical resistance to chlorine-containing fluids, resolving the contradiction between mechanical strength and chemical resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The fluorinated plastic compound serves as an intermediary material between the metal carrier element and sensor. Instead of directly soldering metal-to-metal, the plastic compound mediates the connection, providing a barrier that prevents chlorine-containing fluids from attacking the metallic solder connection through metal complexation, while still enabling mechanical and fluid-conducting connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If fluorinated plastic compound is used as connection layer, then chemical resistance to fluids is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvechemical resistance to fluidsVSAvoidease of manufacturing connection
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent utilizes parameter changes by exploiting the thermal properties of the fluorinated plastic compound. The connection layer is applied in a softened state (above its glass transition temperature) to enable conformal coating and good adhesion, then cooled to below its glass transition temperature to achieve dimensional stability and mechanical strength. This parameter change approach simplifies manufacturing while maintaining chemical resistance.

Inventive Principle:
Principle #35Parameter changes

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 fluorinated plastic connection layer creates a stable, fluid-conducting link with improved chemical resistance to various fluids, reducing the risk of damage from corrosive substances and maintaining mechanical integrity, especially when used with sensors measuring chlorine-containing compounds.

Implementation Method 1

the connection layer has at least one fluorinated plastic compound

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

It is characterized, among other things, by its high chemical resistance to a large number of fluids. This applies in particular to fluids containing chlorine, which can attack the metallic solder connection through metal complexation.

Methodology Applied
Scientific EffectChemical resistance:

Implementation Method 3

The connection layer preferably forms a fluid-conducting connection between the carrier element and the sensor, so that the fluid can be transferred from the fluid channel of the carrier element to the fluid channel of the sensor.

Methodology Applied
Scientific EffectFluid conduction:

Data Source

PatentEP3057707B1Measurement arrangement having a carrier element and having a sensor
Publication Date: 2018.11.07 ENDRESS HAUSER FLOWTEC AG
  • EP3057707B1 patent drawingFigure 1~2
  • EP3057707B1 patent drawingFigure 3~4
  • EP3057707B1 patent drawingFigure 5

AI summary

A measurement arrangement comprising: a) a carrier element (14, 21, 32, 41) with a longitudinal axis (A), on which carrier element there is arranged a sensor (22, 33) for determining a process variable of a gaseous or liquid fluid, and b) the sensor (22, 33), wherein the sensor (22, 33) has a fluid duct (34) which extends within the sensor (22, 33), and wherein the carrier element has a fluid duct, characterized in that the carrier element (14, 21, 32, 41) has, for the mechanical connection of the fluid duct (15, 24, 36) of the carrier element (14, 21, 32, 41) to the fluid duct (34) of the sensor (22, 33), a connection layer (38, 39) which extends over a subregion of a surface of the carrier element (14, 21, 32, 41) and over a subregion of a surface of the sensor (22, 33), wherein the connection layer (38, 39) has at least one fluorinated plastics connection, or wherein, for the connection of the fluid duct (15, 24, 36) of the carrier element (14, 21, 32, 41) to the fluid duct (34) of the sensor (1, 22, 33), the carrier element (14, 21, 32, 41) has in each case at least one connection element (23, 35, 42) which protrudes from the carrier element (14, 21, 32, 41) perpendicularly with respect to the longitudinal axis (A) and which projects into the fluid duct (34) of the sensor (1, 22, 33), and wherein the connection element (23, 35, 42) is fixed by means of a connection layer (38, 39) at least to the sensor (22, 33), and wherein said mechanical connection layer (23, 35, 42) has a fluorinated plastics connection.