Electroactive Polymer Actuator for High-Pressure Valve Sealing

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Solution Overview

Problem

Existing shut-off devices using electroactive materials fail to achieve a tight seal under high pressure due to insufficient force exerted by the closing element and are not compact due to the arrangement of additional components, such as shafts and sealing requirements.

Innovation Solution

The arrangement features multiple shut-off elements with actuators made of electroactive material and electrodes, where the closing elements firmly contact the passage elements, and the use of multiple foils between electrodes increases actuator stroke and contact pressure, allowing for a tighter seal and compact design with a frusto-conical closure for enhanced tightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single piece of electroactive material is used as the actuator, then the actuator can be simple in structure, but the relative length extension is small and the actuator must be made relatively long to achieve sufficient stroke

Engineering Contradiction:
Improveactuator structureVSAvoidactuator length
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The actuator is segmented into multiple electroactive material pieces (first, second, and third pieces) arranged in sequence. Each piece contributes to the overall length extension, allowing the actuator to achieve sufficient stroke while keeping individual pieces short and the structure compact.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electroactive material pieces are arranged not only in series but also with overlapping regions in the longitudinal direction, utilizing three-dimensional space efficiently. This dimensional arrangement maximizes the length extension within a compact volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If the closing element is not pressed against the passage element, then the actuator structure remains simple, but no tight seal is created that can withstand high pressure loads

Engineering Contradiction:
Improveactuator structureVSAvoidseal tightness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The actuator uses electroactive material pieces that dynamically change length in response to voltage application. When voltage is applied, the pieces extend and press the closing element firmly against the passage element, creating a tight seal. When voltage is removed, the pieces contract, allowing the closing element to open. This dynamic mechanism provides both simple structure and reliable sealing.

Inventive Principle:
Principle #15Dynamics

3Force

If the actuator stroke is increased by making the electroactive material longer, then sufficient contact pressure can be achieved, but the overall device size increases and compact design is compromised

Engineering Contradiction:
Improvecontact pressureVSAvoiddevice size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The electroactive material pieces are arranged with overlapping regions, where the second piece overlaps with both the first and third pieces in the longitudinal direction. This nested arrangement allows the pieces to work together synergistically, multiplying the effective stroke and contact pressure while minimizing the overall device volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Force

If multiple electroactive material pieces are arranged with overlapping regions, then the actuator stroke and contact pressure are increased, but the manufacturing complexity increases

Engineering Contradiction:
Improvecontact pressureVSAvoidactuator assembly
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

Multiple electroactive material pieces and electrodes are merged into a single integrated component through co-molding. This combining of multiple elements into one manufacturing step simplifies production despite the complex three-dimensional overlapping arrangement, reducing assembly steps and ensuring precise positioning of all components.

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

This solution achieves a high level of tightness in the closed position and efficient flow in the open position, enabling the shut-off devices to withstand high pressure loads while maintaining a compact form factor.

Implementation Method 1

the actuators comprise a common element made of an electroactive material and two electrodes each. When opposite voltages are applied to the electrodes, the piece of electroactive material stretches longitudinally

Methodology Applied
Scientific EffectElectroactive material deformation: Electroactive Polymer

Implementation Method 2

the closing elements in the closed position each lie firmly against an area of the respective passage elements that surrounds the respective passage opening

Methodology Applied
Scientific EffectContact pressure: Mechanical Force

Data Source

PatentEP2110590B1Blocking device
Publication Date: 2012.04.04 ROBERT BOSCH GMBH
  • EP2110590B1 patent drawingFigure 1A~1B
  • EP2110590B1 patent drawingFigure 2A~2B
  • EP2110590B1 patent drawingFigure 2C

AI summary

The device has a through-opening (2) formed in a discharge element (1). An actuator (4) is provided for moving a closure element (3) between a close position and open position. The actuator is accommodated in a through-flow region (7), and includes a foil (10) made of electroactive material e.g. silicone, formed between two flat electrodes (11, 12). The closure element fixedly lies at a region of the discharge element in the close position, where the region surrounds the through-opening. The foil includes thickness between 4 micrometers and 100 micrometers.