Hydraulic Circuit Filter with Electroactive Pore Control

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Solution Overview

Problem

Hydraulic circuits with temperature-dependent viscosity hydraulic fluids face challenges in maintaining optimal filter performance during startup and nominal operations, as the viscosity changes affect flow resistance and filter effectiveness, leading to potential damage from unfiltered fluid and contamination risks.

Innovation Solution

The integration of electroactive fibers in filter materials that adjust pore size based on electrical voltage, controlled by a viscosity-sensitive control device, allows for adaptive filter effectiveness and reduced flow resistance, ensuring sufficient filtration during both startup and nominal operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the filter element is designed for nominal operation with reduced viscosity, then filtering efficiency is optimized, but flow resistance becomes excessively high during start-up operation with higher viscosity

Engineering Contradiction:
Improvefiltering efficiencyVSAvoidflow resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The filter element incorporates a bypass channel with a pressure-dependent opening valve that dynamically adjusts the filtration path based on operating conditions. During start-up with high viscosity, the bypass opens to reduce flow resistance; during nominal operation with low viscosity, the bypass closes to maximize filtering efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the effective filtration parameters by introducing a bypass mechanism that alters the flow path based on viscosity conditions. The opening valve responds to pressure differential changes caused by viscosity variations, thereby adapting the filtration characteristics to match operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the bypass valve opens to relieve pressure during start-up operation, then flow resistance is reduced, but unfiltered hydraulic fluid is supplied to the machine

Engineering Contradiction:
Improvepressure reliefVSAvoidfiltration protection
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The filter element dynamically switches between filtration mode and bypass mode based on real-time pressure differential sensing. The opening valve responds to pressure changes that indicate high viscosity conditions, temporarily allowing unfiltered flow only when necessary to prevent damage, while restoring full filtration when conditions normalize.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bypass channel is designed as a pre-prepared emergency path that activates before damage can occur. The opening valve is positioned to relieve pressure buildup before it reaches damaging levels, cushioning the system against the harmful effects of high viscosity during start-up.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the filter device is designed with high filtering effect, then contamination protection is improved, but the risk of damage from excessive pressure differential increases

Engineering Contradiction:
Improvecontamination protectionVSAvoidpressure resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The filter element combines a high-efficiency filter medium with a dynamic bypass mechanism. The opening valve monitors pressure differential across the filter and automatically opens the bypass path when pressure exceeds safe thresholds, allowing the filter to maintain high filtering capability during normal operation while protecting itself from pressure-induced damage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the effective filtration parameters by introducing a pressure-dependent bypass. The opening valve responds to pressure differential changes, thereby adapting the filtration characteristics to match operating conditions and prevent structural damage.

Inventive Principle:
Principle #35Parameter changes

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 solution ensures effective filtration and reduced risk of damage by adapting pore size to viscosity changes, maintaining optimal filter performance across temperature variations, thus protecting machine components from contamination.

Implementation Method 1

the filter material (13) comprises electroactive fibers (14) made of an electroactive polymer, which change their geometric shape and/or size depending on an electrical voltage applied thereto

Methodology Applied
Scientific EffectElectroactive polymer: Electroactive Polymer

Implementation Method 2

The hydraulic fluids used in such hydraulic circuits can have a temperature-dependent viscosity, especially if they contain oil

Methodology Applied
Scientific EffectTemperature-dependent viscosity:

Data Source

PatentEP4368273A1Hydraulic circuit
Publication Date: 2024.05.15 FILTRATION GRP GMBH
  • EP4368273A1 patent drawingFigure 1
  • EP4368273A1 patent drawingFigure 2~5
  • EP4368273A1 patent drawing

AI summary

The invention relates to a hydraulic circuit (1) for circulating a hydraulic fluid (8) for a machine (3), with a filter device (6) for filtering the hydraulic fluid (8) and with a control device (7) for operating the hydraulic circuit (1), wherein the respective filter device (6) has at least one filter element (10) which has a filter body (12) with a filter material (13), wherein the respective filter element (10) is arranged in the associated filter device (6) such that, during operation of the hydraulic circuit (1), the filter material (13) is through which the hydraulic fluid (8) flows.Improved filtration during different operating phases of the hydraulic circuit (1) is achieved if the filter material (13) has electroactive fibers (14) made of an electroactive polymer which change their geometric shape and/or size depending on an applied electrical voltage, if the filter material (13) is configured such that changing the shape and/or size of the electroactive fibers (14) changes a pore size of the filter material (13), and if the control device (7) is electrically coupled to the respective filter device (6) and configured to control the filter material (13) of the respective filter element (10) to change the pore size depending on a viscosity of the hydraulic fluid (8).