Neutral Aqueous Cleaning Solution for Rouging Removal

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Solution Overview

Problem

Current methods for removing rouging deposits on stainless steel surfaces in pharmaceutical and food processing industries are laborious, often require strong acids, and pose safety risks, while existing solutions do not effectively address the contamination risk from oxidic iron compounds.

Innovation Solution

Aqueous cleaning solutions containing a reducing agent and complexing agents, such as dithionite and phosphonic acids, are used to remove rouging deposits in a neutral pH range, effectively dissolving and removing oxidic iron compounds without damaging the stainless steel surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If strong acids are used to remove rouging deposits, then cleaning effectiveness is improved, but safety risks and surface damage increase

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidsurface damage and safety risks
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the cleaning solution by using neutral pH cleaners with reducing agents (sodium dithionite, sodium disulfite) and complexing agents (EDTA, DTPA, HEDP) instead of strong acids. This parameter change maintains cleaning effectiveness while eliminating the harmful effects of acid corrosion and safety risks associated with handling concentrated acids.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/chemical aggressive system of strong acids with a gentler chemical system based on redox reactions and complexation. The reducing agents chemically reduce iron oxide deposits to soluble forms, while complexing agents bind the metal ions, achieving removal without the harsh mechanical action or corrosive effects of acid-based methods.

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

2Ease of operation

If mechanical removal methods are used, then ease of operation is improved, but contamination risk from heavy metal particles increases

Engineering Contradiction:
Improveease of removalVSAvoidheavy metal particle contamination
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent replaces mechanical removal methods with a chemical solution-based approach. The reducing agents and complexing agents work together to chemically dissolve and bind iron oxide deposits, transforming them from loose particles that can be mechanically removed to soluble complexes that are rinsed away, thereby eliminating the contamination risk of heavy metal particles.

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

Solution Approach 2:

The patent introduces complexing agents (EDTA, DTPA, HEDP) as intermediary substances that bind to iron ions released during the reduction process. These intermediaries form stable soluble complexes with the metal ions, preventing them from precipitating as contaminating particles and enabling complete removal through rinsing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If conventional cleaning solutions are used, then manufacturing precision is maintained, but contamination of products occurs

Engineering Contradiction:
Improvesurface quality maintenanceVSAvoidproduct contamination
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of cleaning solutions to be neutral pH with specific reducing and complexing agents. This parameter change allows complete dissolution of iron oxide deposits without leaving residual contaminants, maintaining surface quality and preventing product contamination through thorough chemical removal and rinsing.

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 method provides a safe, efficient, and gentle process for removing rouging deposits, reducing contamination risks and extending the service life of stainless steel surfaces, while avoiding the hazards associated with strong acids.

Implementation Method 1

The cleaning solution contains a reducing agent which converts the oxidically bound Fe(III) in the surface changes into soluble Fe(II)

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 2

The complexing agents significantly improve the detachment process of the oxidic iron components from the rust-free metal surface

Methodology Applied
Scientific EffectComplexation: Chemical Bonding

Data Source

PatentEP2122011B1Use of an aqueous neutral cleaning solution and method for removing rouging from stainless steel surfaces
Publication Date: 2011.08.24 ATECO SERVICES

AI summary

The invention relates to a method for removing films and deposits from stainless surfaces, especially from stainless metal surfaces such as they are used in process stations and production units in the pharmaceutical, food and biotechnological industries, and to aqueous cleaning solutions which contain a reducing agent and at least one complexing agent for use in said method.