Filter Housing Pressure Sensor Immune to Ripple Effects

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Solution Overview

Problem

Fluid pressure sensors in aircraft fuel and oil distribution systems are notoriously unreliable due to long sense lines that can result in system dynamic response issues, signal distortion, and inaccurate pressure drop measurements, especially when located remotely from the filter assembly and exposed to turbulent flow and pressure ripples from pumps.

Innovation Solution

Locating the delta pressure sensor directly at the filter housing with sense lines extending into its interior volume, minimizing the length of sense lines and shielding them from turbulent flow, allows for direct and accurate measurement of the pressure drop across the filter element, reducing the impact of pressure ripples and signal distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the delta pressure sensor is located remotely from the filter assembly, then the sensor is more accessible for maintenance and replacement, but the sense lines become very long causing system dynamic response issues, signal distortion, and inaccurate pressure drop measurements

Engineering Contradiction:

Improvesensor accessibilityVSAvoidpressure drop measurement accuracy

Core Design Contradiction:

Ease of repairVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary chamber (the filter housing interior volume) that acts as a buffer between the turbulent pump outlet and the pressure sensor. This intermediary space allows the sensor to be positioned close to the filter element while shielding it from direct exposure to pressure ripples and turbulent flow, thus maintaining measurement accuracy without requiring long sense lines.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of repair

If the delta pressure sensor is located remotely from the filter assembly, then the sensor is more accessible for maintenance and replacement, but the sense lines are exposed to turbulent flow and pressure ripples from pumps causing signal distortion and sensor damage

Engineering Contradiction:

Improvesensor accessibilityVSAvoidsensor exposure to pressure ripples and turbulent flow

Core Design Contradiction:

Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The filter housing interior volume serves as a protective intermediary that buffers the sensor from harmful pressure ripples and turbulent flow. The sensor is positioned within this housing, using the housing structure itself as a shield, thereby eliminating exposure to damaging flow conditions while maintaining sensor accessibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the sensor from the turbulent flow environment by positioning it within the filter housing interior volume, separating it from the harmful external conditions (pressure ripples and turbulent flow) while keeping it functionally connected to the filter element through minimal-length sense lines.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of repair

If the sense lines are made very long to accommodate remote sensor placement, then the sensor is more accessible, but the system dynamic response deteriorates and measurement accuracy decreases

Engineering Contradiction:

Improvesensor accessibilityVSAvoidsystem dynamic response

Core Design Contradiction:

Ease of repairVSSpeed

Solution Approach 1:

The filter housing interior volume acts as an intermediary that allows the sensor to be positioned close to the filter element, minimizing sense line length and thereby maintaining fast system dynamic response while still providing sensor accessibility through the housing structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enhances the accuracy of pressure drop measurements, reduces the risk of sensor damage, and improves system dynamic response by attenuating unwanted pressure ripple effects, providing a clear and reliable signal of filter blockage for maintenance or replacement.

Implementation Method 1

A pressure sensor is positioned to measure a pressure drop across the filter element

Methodology Applied

Scientific EffectPressure differential measurement: Pressure Gradient

Implementation Method 2

Methodology Applied

Scientific EffectPressure ripple attenuation: Damping

Data Source

PatentEP3228375B1Pressure detection system immune to pressure ripple effects

Publication Date: 2021.08.04 HAMILTON SUNDSTRAND CORP

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Figure 3a~3b

AI summary

A filter assembly for a fluid flow system includes a filter housing (22), a housing inlet (24) to allow the fluid flow into the filter housing and a housing outlet (26) to allow the fluid flow to exit the filter housing. A filter element (34) is located in the filter housing to collect contaminants from the fluid flow. A pressure sensor (36) is located to measure a pressure drop across the filter element. The pressure sensor includes at least one sense line (44) extending into an interior volume (50) of the filter housing. A method of monitoring a filter assembly for a fluid flow system includes positioning a pressure sensor at a filter assembly, extending at least one sense line from the pressure sensor into an internal volume of a filter housing of the filter assembly, and measuring a pressure drop across a filter element of the filter assembly via the pressure sensor.