Inline TOC Measurement Loop in Water Purification Systems

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Solution Overview

Problem

Current water purification systems face challenges in accurately determining total organic carbon (TOC) content at the point of dispensing ultrapure water, often leading to false alarms due to TOC values measured downstream of the UV radiation source but upstream of the second purification step, and may not reflect the actual TOC levels in the dispensed water, especially when the first purification stage is not fully functional.

Innovation Solution

A water purification system with a measurement loop that includes a conductivity cell for measuring TOC content located downstream of the UV radiation treatment step and upstream of the polisher, allowing for continuous monitoring and accurate determination of TOC levels at the point of use, utilizing existing equipment within the system without requiring additional complex or expensive components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If TOC measurement is performed downstream of UV radiation source but upstream of second purification step, then measurement can be performed using existing equipment, but the measured TOC value may not reflect actual TOC content of dispensed water

Engineering Contradiction:

Improvesimplicity of measurement implementationVSAvoidaccuracy of TOC content determination

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The system performs UV radiation treatment and TOC measurement on a water sample before it is dispensed. This preliminary action allows the system to assess the TOC content of water that will be dispensed, enabling proactive quality control rather than reactive measurement after dispensing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A conductivity cell serves as an intermediary measurement device that indirectly determines TOC content by measuring conductivity changes. The cell is positioned to receive water from the purification system and provide measurement data without requiring direct intervention in the main water flow path.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If TOC measurement is performed continuously at the point of dispensing, then accurate TOC levels can be monitored, but additional complex or expensive equipment is required

Engineering Contradiction:

Improveaccuracy of TOC content determinationVSAvoidcomplexity of measurement system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The conductivity cell performs multiple functions: it measures conductivity for quality control and simultaneously determines TOC content through conductivity change analysis during UV irradiation. This multi-functionality eliminates the need for separate dedicated TOC measurement equipment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own existing UV radiation source and conductivity measurement capability to perform TOC determination. The water sample is irradiated by the system's UV source, and the conductivity cell measures the resulting conductivity changes, allowing the system to self-diagnose water quality without external measurement equipment.

Inventive Principle:

Principle #25Self-service

3Reliability

If water is continuously re-circulated through purification stages, then contaminant build-up is avoided, but energy consumption increases

Engineering Contradiction:

Improvemaintenance of water purityVSAvoidenergy consumption of re-circulation pump

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

Instead of continuous recirculation, the system implements periodic flushing where water is circulated through the purification stages at intervals. The TOC measurement triggers flushing operations only when needed, rather than maintaining constant circulation, thereby reducing energy consumption while maintaining water quality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses TOC measurement feedback to control recirculation operations. When TOC levels are within acceptable ranges, recirculation is minimized or stopped. When TOC levels exceed thresholds, the system triggers recirculation through purification stages to restore water quality, creating an energy-efficient feedback-controlled recirculation system.

Inventive Principle:

Principle #23Feedback

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 enables reliable and accurate measurement of TOC content in the dispensed water, preventing false alarms and allowing for timely replacement of purification stages, thereby maintaining water purity and reducing maintenance and operational costs.

Implementation Method 1

the UV radiation is generated by a low pressure mercury lamp. The water sample in the measurement cell is irradiated until conductivity no longer increases, meaning that all organic components originally present in the water have been oxidized.

Methodology Applied

Scientific EffectUV radiation: Light