Molybdate Testing Dip Pad with Iron Compensation

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Solution Overview

Problem

Existing color-change dip tests are unreliable for accurately measuring molybdate concentration in central heating system water due to interactions with various chemicals and iron contamination, which affects the accuracy of corrosion inhibitor quantity determination.

Innovation Solution

A method using two color-change dip tests, one for iron and one for molybdate, with image processing software to assess concentrations based on multiple color reference scales selected according to the iron concentration, ensuring accurate molybdate measurement by accounting for varying iron levels, and using a carrier with absorbent buffer pads to prevent reagent bleeding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single colour-change dip test is used to test for molybdate concentration, then the testing process is simple and quick, but the measurement accuracy deteriorates due to interference from iron and other chemicals in the water

Engineering Contradiction:
Improvetesting speedVSAvoidmolybdate concentration accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The testing process is segmented into multiple independent dip tests, each targeting a specific chemical parameter (molybdate, iron, copper, pH). Each test pad on the carrier is impregnated with a specific reagent that reacts selectively with its target chemical, allowing simultaneous measurement of multiple parameters without mutual interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary computational layer that processes the colour data from multiple dip tests. The image processing software analyzes the colour changes of each pad and uses algorithms to compensate for chemical interactions, effectively using the intermediary computation to resolve the accuracy problem while maintaining the simplicity of the dip test method.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple colour reference scales are used to account for varying iron concentrations, then the measurement accuracy improves, but the device complexity increases due to multiple references and selection criteria

Engineering Contradiction:
Improvemolybdate concentration accuracyVSAvoidreference scale system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system dynamically selects the appropriate colour reference scale based on the measured iron concentration. The image processing software automatically determines which reference scale to use by analyzing the iron pad's colour change, making the system adaptive to varying water conditions without requiring manual intervention or complex user decisions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs self-calibration by automatically selecting the appropriate reference scale based on the iron concentration measurement. The image processing software autonomously handles the complexity of multiple reference scales, freeing the user from manual selection and making the complex system as easy to use as a single-reference system.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If digital image processing is used to assess dip test colours, then measurement precision improves, but the ease of operation deteriorates due to the need for photographing and software processing

Engineering Contradiction:
Improveconcentration assessment accuracyVSAvoidtesting procedure simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent merges the dip test carrier with an integrated colour reference scale printed directly on the carrier itself. This integration eliminates the need for separate reference cards or complex setup procedures, allowing users to simply photograph the entire carrier with their mobile device while the software automatically processes the image and provides results.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses the mobile device's existing camera and processing capabilities to perform the analysis, leveraging technology that users already possess. The software automatically handles image processing, colour analysis, and result calculation without requiring manual intervention, making the sophisticated digital assessment as easy to operate as traditional visual comparison.

Inventive Principle:
Principle #25Self-service

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

Enables reliable and accurate determination of molybdate concentration in central heating system water, ensuring correct corrosion inhibitor levels despite iron contamination, improving the precision of corrosion inhibitor assessment in central heating systems.

Implementation Method 1

a pad impregnated with a reagent, which in turn is mounted on a stick to act as a carrier. The pad is dipped in a sample of the liquid to be tested, and the impregnated pad then changes colour.

Methodology Applied
Scientific EffectColour change reaction:

Implementation Method 2

The carrier may for example be an elongate stick, which may be made from plastics or another water-resistant material. Preferably, one or more absorbent buffer pads may be provided between the first and second pads.

Methodology Applied
Scientific EffectCapillary absorption: Capillary Action

Data Source

PatentEP4196772B1Testing of central heating system water
Publication Date: 2024.10.16 ADEY HLDG
  • EP4196772B1 patent drawingFigure 1

AI summary

A method of testing central heating system water for concentration of molybdate corrosion inhibitor is disclosed. The method comprises use of a dip test pad to test for iron concentration, and use of a dip test pad to test for molybdate concentration. In assessment of the dip test pad to test for molybdate concentration, the assessed iron level is taken into account. This leads to a more accurate and reliable result than is realised with known dip test.