Two-Stage Pressure Compensation Device for Underwater Seawater Intrusion

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Solution Overview

Problem

Existing pressure compensation devices for underwater hydraulic systems are prone to seawater intrusion due to diaphragm damage, leading to reduced service life and potential mechanical damage, and require complex configurations to maintain pressure equality.

Innovation Solution

A two-stage pressure compensation device with two flexible-walled reservoirs arranged in series, where each reservoir acts as a redundant barrier against seawater intrusion, using a piston accumulator with a compression spring to maintain pressure and a travel sensor for leakage detection, ensuring seawater cannot enter the system without simultaneous failure of both reservoirs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single diaphragm is used for pressure compensation, then the structure is simple, but seawater can enter the hydraulic system if the diaphragm is damaged

Engineering Contradiction:
ImprovestructureVSAvoidseawater intrusion prevention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The pressure compensation device is divided into multiple independent chambers (first pressure compensation chamber and second pressure compensation chamber) separated by bulkheads with bellows portions. Each chamber has its own diaphragm, creating redundant barriers against seawater intrusion while maintaining pressure compensation functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preventive protection by creating multiple barrier layers (first diaphragm and second diaphragm) before seawater can reach the hydraulic system. This redundant design ensures that even if one diaphragm fails, the other continues to protect the system.

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

2Reliability

If multiple pressure compensation chambers are arranged in series, then reliability against seawater intrusion is improved, but device complexity increases

Engineering Contradiction:
Improveseawater intrusion preventionVSAvoidstructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a nested configuration where the first and second pressure compensation chambers are arranged in series within the housing, with bulkheads containing bellows portions integrated into the chamber walls. This nested arrangement achieves redundant protection while minimizing the overall device footprint and structural complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Stress or pressure

If pressure compensation devices are used for underwater applications, then pressure equalization is achieved, but service life is reduced due to diaphragm damage and corrosion

Engineering Contradiction:
Improvepressure equalizationVSAvoidservice life
Core Design Contradiction:
Stress or pressureVSDuration of action of stationary object

Solution Approach 1:

The patent implements preventive protection by creating multiple barrier layers (first diaphragm and second diaphragm) before seawater can reach the hydraulic system. This redundant design ensures that even if one diaphragm fails, the other continues to protect the system, significantly extending service life.

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

Solution Approach 2:

By dividing the pressure compensation function into multiple independent chambers with separate diaphragms, the patent reduces the risk of total system failure from a single point of damage. Each chamber acts as an independent protective barrier.

Inventive Principle:
Principle #1Segmentation

4Volume of stationary object

If a compact pressure compensation device is designed, then space efficiency is improved, but mechanical protection of internal components is reduced

Engineering Contradiction:
Improvedevice volumeVSAvoidmechanical protection
Core Design Contradiction:
Volume of stationary objectVSStrength

Solution Approach 1:

The patent employs a nested configuration where pressure compensation chambers are integrated within the housing structure, with bellows portions formed as integral parts of the bulkheads. This nested arrangement achieves compact dimensions while the outer housing provides mechanical protection to internal components.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

The solution provides a reliable, space-efficient, and long-lasting pressure compensation system that maintains internal fluid pressure equal to or higher than seawater pressure, significantly reducing maintenance needs and ensuring operation for 20 years or more without seawater ingress.

Implementation Method 1

A piston accumulator with a compression spring to maintain pressure

Methodology Applied
Scientific EffectCompression spring: Spring

Implementation Method 2

The pressure compensation device is constructed in at least two stages in such a way that at least two reservoirs with a flexible wall area are arranged in series

Methodology Applied
Scientific EffectHydraulic pressure transmission: Hydraulic Press

Data Source

PatentEP3864302B1Pressure compensating device, adapted to be used under water
Publication Date: 2023.08.16 ROBERT BOSCH GMBH
  • EP3864302B1 patent drawingFigure 1
  • EP3864302B1 patent drawingFigure 2~3
  • EP3864302B1 patent drawingFigure 4

AI summary

The invention relates to a pressure compensation device (1) designed for underwater applications and by means of which an interior of a container (39), which forms a fluid region (8), can be sealed with respect to the surrounding seawater region (7), wherein a pressure level of the fluid region (8) can be raised at least to the surrounding pressure prevailing in the seawater region (7) by the pressure compensation device (1), wherein the pressure compensation device (1) is constructed in such a way that at least two accumulators (2; 2a, 2b) having a flexible wall region (4) are arranged in series, wherein the at least two accumulators (2; 2a, 2b) are arranged in an annular pressure space of a housing (27). Also proposed is the use of the pressure compensation device (1) for pressurizing at least one fluid-filled container (39) for a hydraulic actuating shaft (37).