Ground pH Sensor with Conductive Polymer for Cathodic Protection

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Solution Overview

Problem

Existing methods for determining the pH of soil surrounding buried pipelines are imprecise, costly, or pose safety risks, and do not allow for continuous monitoring, which is crucial for effective cathodic protection.

Innovation Solution

A pH sensor using conductive polymers, such as polypyrrole, combined with a metallic element, is inserted near the pipeline to measure pH at a shallow depth, mimicking the environment of the buried pipe and receiving the same electrical potential, allowing for precise and continuous pH monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pH test strips are placed in the soil near pipes, then a pH reading can be obtained, but the reading is imprecise and only approximate

Engineering Contradiction:
ImprovepH measurement precisionVSAvoidoperational simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces chemical pH test strips with an electrical measurement system using a pH sensor that measures electrical potential difference. This substitution enables precise continuous measurements while maintaining ease of operation through automated electrical readings rather than subjective color interpretation.

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

Solution Approach 2:

The patent creates a simplified model system by placing a metallic element and pH sensor at shallow depth in the soil, which copies the electrochemical environment experienced by buried pipelines. This model allows accurate pH measurement without requiring excavation to access the actual pipeline environment.

Inventive Principle:
Principle #26Copying

2Measurement precision

If the leachate method is used to measure pH, then a pH value can be obtained, but the measurement is not precise due to dilution

Engineering Contradiction:
ImprovepH measurement precisionVSAvoidmeasurement procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the chemical extraction and dilution process of the leachate method with a direct electrical potential measurement using a pH sensor. This eliminates the need for soil sampling, laboratory processing, and dilution steps, providing precise measurements in situ without altering the soil chemistry.

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

3Measurement precision

If an antimony-based electrode is used, then pH measurement is possible, but the sensor is toxic and carcinogenic

Engineering Contradiction:
ImprovepH measurement precisionVSAvoidtoxicity and carcinogenicity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter of the pH sensor from antimony-based electrode to a metallic element with polymer coating. This material substitution eliminates toxicity and carcinogenicity while maintaining the sensor's ability to measure pH through electrical potential difference in the soil environment.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If excavation is performed to measure pH near buried pipes, then accurate pH measurement is possible, but the cost is high

Engineering Contradiction:
ImprovepH measurement precisionVSAvoidmeasurement cost
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent creates a simplified model system at shallow depth that replicates the electrochemical conditions around buried pipelines. By measuring pH in this model system using a metallic element and polymer-coated sensor, accurate pipeline environment data is obtained without the high costs of excavation and direct pipeline access.

Inventive Principle:
Principle #26Copying

5Productivity

If pH paper is used for measurement, then a single reading is obtained, but continuous monitoring is not possible

Engineering Contradiction:
Improvecontinuous monitoring capabilityVSAvoidmeasurement system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces single-use chemical pH paper with an electrical sensor system that can continuously measure pH through electrical potential difference. This enables ongoing monitoring of soil pH conditions around pipelines while maintaining simplicity through automated electrical measurements that can be taken repeatedly without consuming additional materials.

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

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 solution provides a robust, safe, and accurate pH measurement at the soil surface, enabling effective cathodic protection of pipelines without direct excavation, and allows for automatic adjustment of electrical potential based on pH readings.

Implementation Method 1

a surface comprising a polymer material capable of attracting protons

Methodology Applied
Scientific EffectProton attraction: Ion Repulsion/Attraction

Implementation Method 2

an electrical potential, in particular a cathodic protection electrical potential, is applied to the metallic element

Methodology Applied
Scientific EffectCathodic protection: Electrochemiluminescence

Data Source

PatentEP4085160B1Ph sensor device for insertion into the ground, method for measuring the ph, in particular for cathodic protection
Publication Date: 2026.02.25 GRTGAZ
  • EP4085160B1 patent drawingFigure 1
  • EP4085160B1 patent drawingFigure 2
  • EP4085160B1 patent drawingFigure 3~4

AI summary

A pH sensor device, intended to be inserted into the ground in order to be in contact with a region containing a fluid from the ground of which one would like to know the pH, comprises: • - a pH sensor (101) comprising a surface (102) covered in a polymer material configured to be in contact with the region containing a fluid when the device is inserted into the ground • - a metal element (104) provided with a surface (105) configured to be in contact with the region containing the fluid when the device is inserted into the ground, • - electrical connection means (108, 109, 110) connected at least to the metal element and configured to receive a cathodic protection electrical potential for the metal element. The invention also relates to a method for measuring pH that can be used for cathodic protection.