Pneumatic Isolation Valve for Aircraft Engine Oil Circuit

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Solution Overview

Problem

Existing shut-off and isolation valves in airplane engines require separate components for fire protection and anti-siphon functions, necessitating electrical power and complex control logic, which is not feasible in all turboprop engines, especially during flight stops where residual rotation is lost.

Innovation Solution

A pneumatically controlled isolation valve that uses compressed air from the engine compressor or pneumatic starter to perform both fire prevention and anti-siphon functions, eliminating the need for electronic control logic and separate components, utilizing a shuttle valve to select the higher pressure source and a flap valve with a bellows cylinder for efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single isolation valve is used to perform both fire prevention and anti-siphon functions, then device complexity is reduced, but reliability must be maintained through pneumatic control

Engineering Contradiction:

Improvevalve system complexityVSAvoidvalve operation reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent combines two separate valves (fire protection valve and anti-siphon valve) into a single isolation valve that performs both functions. This merging reduces device complexity and the number of components while maintaining the necessary reliability through integrated pneumatic control that responds to both fire detection signals and engine stop conditions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The isolation valve is designed with multi-functionality to serve dual purposes: fire protection by isolating the oil circuit during fire conditions, and anti-siphon by preventing oil leakage during engine stop. The pneumatic control system enables this universal valve to respond appropriately to different operational scenarios without requiring separate dedicated valves for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If electrical control valves are used for fire protection and anti-siphon functions, then control precision is improved, but use of energy increases and device complexity increases

Engineering Contradiction:

Improvecontrol signal accuracyVSAvoidelectrical power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces electrical control systems with a pneumatic control system for the isolation valve. Instead of using electric motors or solenoids that consume electrical energy, the system uses pneumatic actuators powered by compressed air from the engine's air compressor or pneumatic starter. This substitution eliminates electrical power requirements while maintaining reliable and precise control through pneumatic pressure regulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If separate valves are used for fire protection and anti-siphon functions, then reliability for each function is maximized, but device complexity and weight increase

Engineering Contradiction:

Improvefire protection reliabilityVSAvoidvalve system weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent merges two separate valve systems into one integrated isolation valve, thereby reducing the total weight of the valve system. By combining the fire protection valve and anti-siphon valve into a single unit with shared pneumatic control, the design eliminates redundant components while maintaining the reliability needed for both fire protection and oil leakage prevention functions.

Inventive Principle:

Principle #5Merging (Combining)

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 solution provides a single, weight- and cost-efficient valve that ensures fire protection and prevents oil leaks without electrical power, suitable for turboprop engines, by using pneumatic control for both power and signal, ensuring reliable operation during engine stops and starts.

Implementation Method 1

the isolation valve is pneumatically controlled and provided with a device allowing to automatically select as an operation the more highly compressed source of compressed air from two different sources

Methodology Applied

Scientific EffectCompressed air: Gas Compressor

Implementation Method 2

a shuttle valve whose two intakes are connected to said two sources of compressed air respectively and whose outlet is connected to the isolation valve

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

The isolation valve is preferably a flap valve provided with a bellows cylinder

Methodology Applied

Scientific EffectPneumatic actuation: Gas Compressor

Data Source

PatentUS8020664B2Isolation valve for the oil circuit of an airplane engine

Publication Date: 2011.09.20 TECHSPACE AERO

AI summary

The present invention relates to a turbomachine comprising an air compressor (3) and a lubrication circuit with an oil tank (1), said oil tank (1) being possibly isolated from the rest of the lubrication circuit (4,4A; 6,6A) by means of an isolation valve (7), wherein the isolation valve (7) is configured so as to:operate, i.e. to close and open respectively as the engine (2) stops and starts;remain open when the engine (2) is running;remain closed when the engine (2) is stopped.