Phosphate Ester Hydraulic Fluid Thermal Stability

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Solution Overview

Problem

Aircraft hydraulic fluids require enhanced thermal stability, low temperature viscosity, and extended fluid life while maintaining acceptable fire/flash points and material compatibility to meet the increasing demands of high-performance aircraft operations.

Innovation Solution

Aircraft hydraulic fluid compositions comprising 55-65% tri(n-butyl)phosphate, 8-12% tri(iso-propylphenyl) phosphate, and 8-12% tri(isobutyl) phosphate, along with additives such as polymeric viscosity index improvers, anti-erosion agents, corrosion inhibitors, and antioxidants, to achieve improved performance standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If traditional phosphate ester formulations are used, then thermal and oxidative stability is provided, but fluid life and fire resistance are insufficient

Engineering Contradiction:
Improvethermal stabilityVSAvoidfluid life
Core Design Contradiction:
Stability of the object's compositionVSDuration of action of moving object

Solution Approach 1:

The patent changes the chemical composition parameters by specifying precise ratios of trialkyl phosphates (30-45% triisobutyl phosphate, 30-45% tri-n-butyl phosphate) and triaryl phosphates (10-15%), along with controlled additive levels, to simultaneously achieve extended fluid life exceeding 1000 hours at 125°C and 10,000 hours at 60°C while maintaining thermal stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite hydraulic fluid formulation combining multiple phosphate ester components (trialkyl phosphates and triaryl phosphates) with specific additives including viscosity index improvers, corrosion inhibitors, antierosion agents, and antioxidants in optimized proportions to achieve superior overall performance

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If phosphate ester base stocks are formulated for high performance, then thermal stability is improved, but fire/flash point requirements are compromised

Engineering Contradiction:
Improvethermal stabilityVSAvoidfire/flash point
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the chemical composition parameters by controlling the ratios of different phosphate ester components and additive concentrations to achieve a balance where thermal stability is enhanced while fire/flash point requirements are maintained at acceptable levels

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If fluid composition is optimized for extended fluid life, then thermal stability is improved, but low temperature viscosity performance deteriorates

Engineering Contradiction:
Improvefluid lifeVSAvoidlow temperature viscosity
Core Design Contradiction:
Duration of action of moving objectVSTemperature

Solution Approach 1:

The patent modifies the fluid composition parameters by selecting specific phosphate ester components and controlling additive levels, including viscosity index improvers, to simultaneously achieve extended fluid life and acceptable low temperature viscosity performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent formulates a composite fluid composition combining phosphate ester base stocks with specific additives including viscosity index improvers, corrosion inhibitors, and antioxidants in optimized proportions to achieve both extended fluid life and satisfactory low temperature viscosity

Inventive Principle:
Principle #40Composite materials

4Stability of the object's composition

If hydraulic fluid performance requirements are increased for high-performance aircraft, then thermal stability is improved, but material compatibility is compromised

Engineering Contradiction:
Improvethermal stabilityVSAvoidmaterial compatibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent adjusts the chemical composition parameters by controlling the ratios of phosphate ester components and additive concentrations to maintain compatibility with elastomer seals and other hydraulic system materials while achieving improved thermal stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite fluid formulation combining phosphate ester base stocks with specific additives including corrosion inhibitors and antioxidants in optimized proportions to maintain material compatibility while achieving high-performance thermal stability

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP1904599B1Phosphate ester hydraulic fluid
Publication Date: 2013.12.25 SOLUTIA INC

AI summary

This application discloses a high performance hydraulic fluid suitable for use as an aircraft hydraulic fluid comprising a major amount of tri(n-butyl)phosphate, a minor amount of a triaryl phosphate and optionally a minor amount of tri(isobutyl)phosphate. The compositions of this invention provide superior performance with respect to flash and fire points as well as extended useful fluid life in service. Such properties are highly valuable as hydraulic fluids modern jet aircrafts.