Centrifugal Separator Discs with Sol-Gel Coating for Fouling

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Solution Overview

Problem

Centrifugal separators face fouling issues due to deposits and microbial growth, leading to reduced throughput and frequent downtime, with existing anti-fouling coatings exhibiting poor wear resistance and susceptibility to cracking in abrasive environments.

Innovation Solution

A centrifugal separator with separation discs coated using sol-gel processing, featuring a silicon oxide layer with an atomic ratio of O/Si > 1 and ≥ 10 atomic% carbon, providing a thin, durable, and flexible coating that reduces fouling and enhances wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a fluorinated polyalkene coating (e.g., PTFE) is applied to separator discs, then anti-fouling properties are improved, but wear resistance deteriorates in abrasive media

Engineering Contradiction:
ImprovefoulingVSAvoidwear resistance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies a composite coating comprising PTFE and alumina particles. The PTFE provides anti-fouling properties while the alumina particles enhance wear resistance. This composite structure allows the coating to withstand abrasive media containing sand or particulate material while maintaining its anti-fouling capability, resolving the contradiction between anti-fouling performance and wear resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the coating composition by adding inorganic particles (alumina) to the PTFE matrix, changing the physical and mechanical parameters of the coating. This parameter change enables the coating to maintain flexibility and adhere to the separator disc under centrifugal forces while providing enhanced abrasion resistance, thus resolving the wear resistance issue without sacrificing anti-fouling properties.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a thick coating is applied to separator discs, then anti-fouling properties are improved, but the coating thickness becomes significant relative to disc thickness

Engineering Contradiction:
ImprovefoulingVSAvoidcoating thickness ratio
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The coating is applied as a thin layer (5-50 μm) rather than a thick coating, and the alumina particles create a microstructured surface that enhances anti-fouling properties through reduced surface area for deposit accumulation. This thin coating approach maintains anti-fouling effectiveness while being insignificant relative to the disc thickness, resolving the contradiction between anti-fouling performance and device complexity.

Inventive Principle:
Principle #31Porous materials

3Object-affected harmful factors

If separator discs are polished to prevent deposit accumulation, then anti-fouling properties are improved, but deposits still form requiring periodic cleaning

Engineering Contradiction:
Improvedeposit accumulationVSAvoiddowntime for cleaning
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The PTFE-based coating provides continuous anti-fouling protection that significantly reduces deposit accumulation on separator discs. The coating's low surface energy prevents adhesives and organic materials from bonding strongly to the disc surface, enabling easier cleaning and extending the time between cleaning operations. This reduces downtime and maintains separation capability for longer periods, resolving the contradiction between anti-fouling performance and cleaning frequency.

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

The coating significantly reduces fouling, facilitates easier cleaning, and provides excellent wear resistance, minimizing downtime and maintaining separation performance while withstanding abrasive conditions.

Implementation Method 1

The separation discs are at least partly provided with a coating that has a layer thickness of about 5-60 μm, is prepared by sol-gel processing, comprises silicon oxide, SiOx, having an atomic ratio of O/Si > 1, and comprises ≥ 10 atomic% of carbon

Methodology Applied
Scientific EffectSol-gel processing: Sol

Data Source

PatentEP2785465B1Centrifugal separator with Anti-fouling properties
Publication Date: 2016.01.13 ALFA LAVAL CORP AB
  • EP2785465B1 patent drawingFigure 1~2a
  • EP2785465B1 patent drawingFigure 2b~2c
  • EP2785465B1 patent drawingFigure 3

AI summary

A centrifugal separator for continuous separation of a fluid mixture into components. The separator comprises a rotor (3), which forms within itself a separation chamber (4), comprising in said separation chamber (4) a set of separation discs (6) defining separation passages (7) between adjacent separation discs. The separator further comprises an inlet (8) operatively connected to said rotor (3) for continuous supply of a fluid mixture to be separated in the separation chamber (4), a first outlet (9) for a separated lighter first component of the fluid mixture extending from a radially inner portion of the separation space, and a second outlet (11) for a separated denser second component of the fluid mixture extending from the radially outer portion of the separation space. The separation discs are provided with a coating comprising silicon oxide, SiOx, prepared through sol-gel processing.