Two-Stage Pressure Compensation for Seawater-Safe Hydraulics
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Solution Overview
Problem
Existing pressure compensation devices for underwater hydraulic systems are prone to seawater penetration and have limited maintenance-free operating times due to diaphragm damage and compression spring degradation.
Innovation Solution
A two-stage pressure compensation device featuring a flexible wall accumulator and a piston accumulator in series, providing a redundant barrier against seawater penetration, with no direct compression spring loading on the flexible wall, ensuring high reliability and extended operating life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single diaphragm is used for pressure compensation, then the structure is simple, but seawater can penetrate into the hydraulic system upon diaphragm damage
Solution Approach 1:
The pressure compensation device is divided into two separate stages: a first stage with a diaphragm accumulator and a second stage with a piston accumulator. This segmentation creates multiple independent sealing barriers, so that if one barrier fails, the other continues to prevent seawater penetration while maintaining pressure compensation functionality.
Solution Approach 2:
The system incorporates a backup sealing mechanism (piston accumulator) that is预先 arranged to compensate for potential diaphragm failure. This prior cushioning ensures that even if the primary diaphragm fails, the secondary barrier is already in place to prevent seawater ingress and maintain system pressure.
2Power
If a diaphragm with compression spring is used, then pressure compensation is achieved, but the spring force diminishes over time limiting maintenance-free operating time
Solution Approach 1:
The compression spring is extracted from direct contact with the diaphragm and relocated to the second stage where it acts on the piston. This separation removes the deteriorating spring force from the primary sealing element, allowing the diaphragm to function without mechanical preload degradation while the spring provides pressure compensation in the isolated second stage.
Solution Approach 2:
The first stage diaphragm acts as an intermediary that transmits seawater pressure to the second stage without being directly loaded by the compression spring. This intermediary arrangement protects the diaphragm from spring force degradation while still achieving pressure compensation through the coupled two-stage system.
3Speed
If the flexible wall is directly loaded by seawater pressure, then pressure compensation is responsive, but the wall is susceptible to damage from high pressure
Solution Approach 1:
The pressure compensation device is divided into two separate stages: a first stage with a diaphragm accumulator and a second stage with a piston accumulator. This segmentation creates multiple independent sealing barriers, so that if one barrier fails, the other continues to prevent seawater penetration while maintaining pressure compensation functionality.
Solution Approach 2:
The system incorporates a backup sealing mechanism (piston accumulator) that is预先 arranged to compensate for potential diaphragm failure. This prior cushioning ensures that even if the primary diaphragm fails, the secondary barrier is already in place to prevent seawater ingress and maintain system pressure.
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 device effectively prevents seawater ingress with a double sealing mechanism, significantly increasing the maintenance-free operating period to 20 years or more by eliminating direct seawater contact and avoiding compression spring-related failures.
Implementation Method 1
The at least one accumulator (2) with the flexible wall region (4) can be loaded with the seawater, with the result that the flexible wall is movable in reaction to the seawater pressure. The movement of the flexible wall can then be transmitted (while being separated from the direct influence of the seawater) to a movement of the piston (5) in the downstream piston accumulator (3)
Implementation Method 2
The (resulting) movement of the piston can lead (directly) to a pressure adaptation in the fluid region, for which purpose the piston is preferably in direct contact with the fluid region
Data Source
AI summary
A system filled with a fluid, designed for underwater applications, in which the interior of a housing and/or tank forms a fluid region which is sealed with respect to the surrounding seawater region, includes at least one hydraulic pressure compensation device, which at least raises the pressure level of the fluid region to the ambient pressure prevailing in the seawater region. The pressure compensation device is constructed in two stages in such a way that at least one store having a flexible wall region and at least one piston store having a displaceable piston are arranged in series. The use of the pressure compensation device to pressurize at least one housing filled with fluid for a hydraulic actuating shaft is also proposed.