Aircraft Fuel System Deflector Prevents Siphoning

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Solution Overview

Problem

Aircraft fuel transfer systems face issues with unwanted fuel transfer between tanks due to siphoning, particularly when ejector pumps are deactivated, leading to uncommanded fuel flow from higher to lower elevation tanks.

Innovation Solution

The implementation of a fuel system with a conduit and a deflector to prevent unwanted fuel transfer, featuring a non-return valve and an ejector pump, where the deflector directs fuel discharged from an orifice back into the tank, and the orifice provides venting to prevent continued fuel flow after pump deactivation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conduit is used to transfer fuel between tanks, then fuel transfer capability is improved, but unwanted fuel transfer due to siphoning occurs

Engineering Contradiction:

Improvefuel transfer capabilityVSAvoidunwanted fuel transfer prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A deflector is introduced as an intermediary component between the conduit and the fuel tank. The deflector intercepts the fuel stream discharged from the conduit and redirects it back into the tank, preventing unwanted fuel transfer while maintaining the conduit's fuel transfer capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful siphoning effect is extracted and isolated from the main fuel transfer system by using the deflector to separate the discharged fuel stream from the tank interior, redirecting it back through a controlled path that prevents uncommanded fuel flow.

Inventive Principle:

Principle #2Taking out (Extraction)

2Productivity

If fuel is discharged from the conduit during transfer, then fuel transfer efficiency is improved, but fuel misting and vaporization risks increase

Engineering Contradiction:

Improvefuel transfer efficiencyVSAvoidfuel misting and vaporization

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The potentially harmful discharged fuel stream that could cause misting and vaporization is converted into a beneficial flow by using the deflector to redirect it back into the tank in a controlled manner, transforming a hazard into part of the normal fuel transfer process.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The deflector serves as a mediator between the high-velocity fuel discharge and the tank interior, intercepting the fuel stream and redirecting it in a way that prevents atomization and vaporization while maintaining transfer efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the conduit is vented to the tank interior, then pressure equalization is improved, but continued fuel flow after pump deactivation occurs

Engineering Contradiction:

Improvepressure equalizationVSAvoidfuel flow control

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The deflector acts as an intermediary that allows pressure equalization through the vent while simultaneously intercepting and redirecting any fuel that flows through the vent, preventing uncommanded fuel transfer while maintaining pressure stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The venting function is separated from the main fuel transfer path by using the deflector to isolate and redirect any fuel that escapes through the vent, allowing pressure equalization without compromising flow control.

Inventive Principle:

Principle #2Taking out (Extraction)

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 configuration effectively prevents unwanted fuel transfer and reduces the risk of fuel misting and vaporization, minimizing flammability and electrostatic charging risks, while ensuring safe and controlled fuel distribution between tanks.

Implementation Method 1

the orifice permitting venting of an interior of the conduit to an interior of the fuel tank

Methodology Applied

Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 2

a deflector disposed outside of the conduit and adjacent the orifice to deflect a stream of fuel discharged from the conduit via the orifice during fuel transfer

Methodology Applied

Scientific EffectFluid deflection: Fluid Spray

Implementation Method 3

The pump may be an ejector pump disposed inside the first fuel tank

Methodology Applied

Scientific EffectEjector pump operation: Injector

Data Source

PatentUS11332257B2Aircraft fuel system and associated method

Publication Date: 2022.05.17 BOMBARDIER INC

AI summary

Fuel systems, apparatus and associated methods for preventing or hindering unwanted fuel transfer between fuel tanks of aircraft are described. An exemplary apparatus comprises a conduit portion disposed inside a fuel tank for receiving fuel in the first fuel tank. The conduit portion includes an orifice through a wall of the conduit. The orifice permits venting an interior of the conduit portion to an interior of the fuel tank to prevent unwanted fuel transfer due to siphoning. A deflector is disposed and configured to deflect a stream of fuel discharged from the orifice during fuel transfer.