Pressure Compensated Sensor Seal Volume Adjustment
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Solution Overview
Problem
Subsea sensors face challenges in maintaining performance due to the need for thick housings to withstand high pressures, which interfere with signal acquisition and require complex maintenance planning.
Innovation Solution
The use of pressure-compensated sensors with a housing, incompressible fluid, and a movable seal that adjusts volume to equalize internal and external pressures, allowing the sensor to match the surrounding pressure without thickening the housing, thereby facilitating accurate signal acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick walled housings are used to withstand subsea pressures, then the sensor can withstand high pressures, but the performance of the sensor decreases
Solution Approach 1:
The housing is divided into two separate housings: an inner housing that protects the transducer and an outer housing that provides pressure compensation. This segmentation allows each housing to have optimized wall thickness for its specific function, resolving the contradiction between strength and performance.
Solution Approach 2:
A fluid-filled inter-housing channel is introduced as an intermediary between the inner and outer housings. This fluid channel transmits external pressure to the transducer, allowing the transducer to experience compensated pressure rather than full external pressure, thus maintaining performance while withstanding subsea conditions.
2Strength
If thick walled housings are used to withstand subsea pressures, then the sensor can withstand high pressures, but the housing thickness interferes with signal acquisition
Solution Approach 1:
By segmenting the housing into inner and outer parts with a fluid channel between them, the design allows thin-walled inner housing for signal transmission while the outer housing provides pressure compensation, eliminating interference with signal acquisition.
Solution Approach 2:
The fluid-filled inter-housing channel acts as an intermediary that transmits pressure information to the transducer without requiring thick housing walls, thus maintaining both pressure withstanding capability and signal acquisition accuracy.
3Strength
If thick walled housings are used to withstand subsea pressures, then the sensor can withstand high pressures, but maintenance planning becomes complex
Solution Approach 1:
The segmented housing design with separate inner and outer housings allows for modular maintenance and repair, reducing planning complexity compared to a monolithic thick-walled housing that would require complete replacement or complex disassembly.
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 enables subsea sensors to maintain performance by sealing the sensing elements from the environment while matching external pressures, reducing the need for thick housings and simplifying maintenance, thus enhancing reliability and accuracy.
Implementation Method 1
The movable seal is configured to adjust the volume of the sealed cavity in response to a pressure difference between the external pressure of the fluid environment and an internal pressure of the incompressible fluid to equalize the internal pressure with the external pressure
Implementation Method 2
a sealed cavity containing at least one sensing element and an incompressible fluid
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A pressure compensated sensing system and methods for using the same are provided. The system can include a housing (202), a seal (224), an incompressible fluid, and sensing elements (112). The seal (224) can be positioned within a housing (202) cavity and divide the cavity into two portions. A first cavity (114,226) portion can be sealed from the fluid environment by the seal (224) and contain the sensing elements (112) and the incompressible fluid. A second cavity (116,230) portion can be in fluid communication with the fluid environment. The fluid environment can apply an external pressure to the seal (224) that is opposed by an internal pressure of the sealed cavity (114,226) applied to the seal (224) by the incompressible fluid. When the internal pressure and the external pressure are different, the seal (224) can move in a manner that changes the volume of the sealed cavity (114,226) by an amount sufficient to equalize the internal pressure with the external pressure.