Bellows Accumulator Seal Holder for Fire Pressure Release

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Solution Overview

Problem

The existing accumulator designs face a challenge in maintaining longevity due to non-uniform bonding of the elastic member to the substrate, leading to premature detachment under repeated gas pressure, and are prone to breakage during high-temperature events like fires.

Innovation Solution

The accumulator incorporates a design with multiple through holes and communication passages aligned in the circumferential or radial direction, forming a pressure releasing flow passage that allows fluid to flow from the liquid chamber to the fluid inlet/outlet passage, even when the elastic member melts and burns out, without specific processing of the sealing member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If recesses and projections are provided on the substrate surface to form pressure releasing flow passage, then fire safety is improved, but the elastic member bonds non-uniformly and detaches prematurely

Engineering Contradiction:
Improvefire safetyVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The pressure releasing flow passage is segmented into multiple passages distributed around the sealing member, rather than relying on a single passage. This segmentation allows the system to maintain fire safety functionality while distributing stress more evenly, preventing premature detachment of the elastic member.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the pressure releasing function from the sealing member's substrate surface (by removing recesses and projections) and relocates it to the seal holder structure. This is achieved by providing through holes in the seal holder that form pressure releasing passages when the elastic member melts, separating the sealing function from the pressure releasing function.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the elastic member melts and burns out during fire, then pressure releasing should occur, but the through holes close and housing breaks

Engineering Contradiction:
Improvepressure release capabilityVSAvoidhousing integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The seal holder is pre-designed with through holes positioned and sized to automatically form functional pressure releasing passages when the elastic member melts during fire. This preliminary design ensures that the pressure release path is already prepared in the structure, eliminating the need for complex active mechanisms and ensuring reliable pressure release while maintaining housing integrity.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the sealing member is closely attached to seal the through holes, then pressure balance is achieved, but the elastic member detaches due to local stress

Engineering Contradiction:
Improvesealing performanceVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The invention extracts the pressure releasing function from the sealing member's substrate surface and relocates it to the seal holder structure. The seal holder includes through holes that form pressure releasing passages when the elastic member melts, separating the sealing function from the pressure releasing function and eliminating stress concentration on the substrate.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The seal holder is designed with specific local features (through holes positioned at predetermined intervals) that create pressure releasing passages only when needed (when the elastic member melts). This local quality change allows the system to maintain strong sealing during normal operation while providing automatic pressure release during fire conditions.

Inventive Principle:
Principle #3Local quality

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 design extends the accumulator's lifespan by efficiently releasing pressure and preventing housing breakage during high-temperature events, ensuring reliable operation and reducing the risk of premature failure.

Implementation Method 1

a sealing member formed by a substrate which is made by a metal disc plate and an elastic member that covers a surface of the substrate

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the bellows main body is expandable and contracted so as to balance gas pressure in the gas chamber and liquid pressure in the liquid chamber

Methodology Applied
Scientific EffectPressure balance: Pascal's Law

Implementation Method 3

in accordance with discharge of the liquid stored in the liquid chamber, the bellows is expandable by the gas pressure in the bellows

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Implementation Method 4

a pressure releasing flow passage communicating with the fluid inlet/outlet passage is formed by a gap formed between the recesses and the projections on the surface of the substrate and the sealing face of the partition wall

Methodology Applied
Scientific EffectGap flow: Flow Separation

Implementation Method 5

the liquid in the liquid chamber is expanded due to a high temperature

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3578828B1accumulator
Publication Date: 2022.09.28 EAGLE INDS
  • EP3578828B1 patent drawingFigure 1
  • EP3578828B1 patent drawingFigure 2
  • EP3578828B1 patent drawingFigure 3

AI summary

The present invention is to provide an accumulator whose life is long without specifically processing a sealing member. An accumulator 1 comprising a housing 2 having a sealing face 25 and a fluid inlet/outlet passage 24, a bellows 3 fixed at least one end to the housing 2 such that an inner space of the housing 2 such that an inner space of the housing 2 is hermetically partitioned by the bellows 3 into an interior and an exterior of the bellows 3, the bellows 3 including a bellows main body 31 capable of expanding and contracting and a bellows cap including an annular seal holder, and a sealing member 35 formed by covering a disc-shaped substrate 36 with an elastic body 37 that is opposed to and capable of being closely attached to the sealing face 25 of the housing 2, the sealing member is 35 held by a holding portion 34c of the annular seal holder 34 on an inner diameter side of the annular seal holder 34, the fluid inlet/outlet passage 24 of the housing 2 being closed upon a close attachment of the elastic body 37 to the sealing face25. Through holes 38, 38,... passing through in a radial direction are provided in the seal holder 34, and communication passages 39, 39,... extending in the radial direction so as to partially form a space A1 providing communication between the through holes 38, 38,... and the fluid inlet/outlet passage 24 are provided in the seal holder 34 or the sealing face 25.