CIP Electrolysis Control for pH-Stable Chlorine Measurement

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Solution Overview

Problem

Existing chlorine measurement systems for electrolytic cleaning solutions in CIP applications are inadequate due to pH variability, leading to inaccurate chlorine concentration readings, especially when dealing with high and variable chlorine concentrations produced by electrolysis, which can be corrosive to equipment and affect sensor sensitivity.

Innovation Solution

A control system that measures and adjusts the pH of electrolysis solutions within a specific range (5.5 to 7.5) using a pH probe and modifier, allowing for accurate chlorine oxyanion concentration measurement from 10 ppm to 1000 ppm through a feedback loop mechanism, ensuring consistent and reproducible chlorine levels without requiring continuous flow rate adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If commercially-available chlorine monitors are used for electrolytic CIP solutions, then chlorine measurement is attempted, but accurate measurement fails due to high and variable chlorine concentrations (10-1000 ppm) and pH variability

Engineering Contradiction:
Improvechlorine concentration measurement accuracyVSAvoidmeasurement reliability under variable pH and high chlorine conditions
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the measurement parameter from direct chlorine concentration measurement to pH measurement. By measuring pH and using the known relationship between pH and chlorine concentration in electrolytic solutions, the system achieves accurate chlorine monitoring without the limitations of conventional chlorine sensors. This parameter substitution resolves the measurement accuracy problem under variable conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces pH as an intermediary parameter to indirectly measure chlorine concentration. Instead of directly measuring chlorine with unreliable sensors, the system measures pH (which is stable and accurately measurable) and derives chlorine concentration from the established pH-chlorine relationship in electrolytic CIP solutions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If high chlorine concentrations are used for effective cleaning and sanitizing, then cleaning effectiveness is improved, but corrosion to CIP system equipment increases

Engineering Contradiction:
Improvecleaning and sanitizing effectivenessVSAvoidcorrosion to equipment
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback control system that continuously monitors pH and adjusts electrolysis parameters to maintain optimal chlorine concentration. The feedback mechanism prevents excessive chlorine buildup that would cause corrosion while ensuring sufficient chlorine levels for effective cleaning and sanitizing, thus resolving the contradiction between effectiveness and equipment protection.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

By monitoring and controlling pH as a proxy for chlorine concentration, the system can precisely regulate chlorine levels to remain within the optimal range for cleaning effectiveness while below the threshold for significant corrosion, thereby resolving the harmful effect of excessive chlorine.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If pH variability in water supply and dilution water is accommodated, then system adaptability is improved, but chlorine measurement accuracy deteriorates

Engineering Contradiction:
Improvesystem adaptability to water quality variationsVSAvoidchlorin concentration measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent measures pH instead of directly measuring chlorine concentration. Since pH measurement is not affected by the same limitations as chlorine sensors, the system can accurately measure pH across variable water quality conditions and then calculate chlorine concentration from the established pH-chlorine relationship, maintaining both adaptability and measurement accuracy.

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

This solution enables precise control of chlorine concentrations across a broad pH range, enhancing the effectiveness of electrolyzed water solutions for cleaning and sanitizing in CIP systems while preventing corrosion and improving sensor accuracy.

Implementation Method 1

Onsite chemistry production can be achieved through electrolysis of water and electrolytes to produce alkaline detergent solutions of sodium hydroxide (NaOH), hypochlorite solutions or chlorine for use as detergent, bleach, surface sanitizers and other disinfectant purposes.

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

measuring the pH of a portion of the electrolysis solution in a sensing cell with a pH probe connected in fluid communication with said portion of the electrolysis solution

Methodology Applied
Scientific EffectpH measurement:

Implementation Method 3

measuring the chlorine oxyanion concentration of said portion of the electrolysis solution from 10 ppm to 1000 ppm by using a chlorine sensor in said sensing cell

Methodology Applied
Scientific EffectChlorine detection:

Data Source

PatentEP2623465B1Method of cleaning or sanitizing or antimicrobial treatment of an equipment
Publication Date: 2018.04.25 ECOLAB USA INC
  • EP2623465B1 patent drawingFigure 1
  • EP2623465B1 patent drawingFigure 2
  • EP2623465B1 patent drawingFigure 3

AI summary

Control systems for use of electrolysis solutions for automated recirculating or single-pass cleaning systems, such as clean-in-place (CIP) applications are disclosed. Control systems and methods for using automated chlorine output solutions for various cleaning applications are measurable over broad pH ranges. The control systems generate consistent and predictable electrolytic solutions and include a measurement system that identifies chlorine oxyanion concentration across broad ranges of pH, overcoming the sensitivity of chlorine monitors to pH and permitting use of the control systems to control cleaning systems.