Acoustic Pressure Sensor Diaphragm Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hydrophone sensors face challenges in sealing and head flexure due to gaps between the housing and the head mass, which affect their sensitivity and reliability, especially at low frequencies and adverse conditions.
Innovation Solution
The design incorporates a flexible diaphragm in direct contact with the housing and piezoelectric elements, eliminating the need for a gap and allowing controlled flexure, thereby enhancing sensitivity and sealing, and using a sealed housing with a moveable rod to eliminate the gap between the housing and the head mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gap is provided between the housing and the head mass, then the device allows for assembly and movement, but sealing problems occur and head flexure increases
Solution Approach 1:
The patent employs a flexible diaphragm made of elastomeric material that serves as both a seal and a structural component. The diaphragm is in direct contact with the housing outer edge and the piezoelectric element, eliminating the need for a gap while allowing controlled flexure during operation. This flexible film approach resolves the contradiction by providing both sealing and movement capability simultaneously.
2Reliability
If a gap is eliminated between the housing and the head mass, then sealing is improved, but the device becomes more complex to manufacture
Solution Approach 1:
The patent merges multiple functions into the diaphragm component: it serves as a seal between the housing and head mass, as a flexible membrane for acoustic sensing, and as a structural element that transmits acoustic pressure to the piezoelectric element. By combining these functions into a single integrated component, the design achieves improved sealing without significantly increasing manufacturing complexity.
3Measurement precision
If the diaphragm surface area is increased to enhance sensitivity, then the basic sensitivity of the sensing stack increases, but the device size increases
Solution Approach 1:
The patent optimizes the diaphragm parameters including its surface area, thickness, and material properties to achieve the desired sensitivity without excessive size increase. The diaphragm is designed with specific dimensional parameters that balance sensitivity enhancement with compact device size, allowing the outer edge to contact the housing while maintaining a reasonable overall footprint.
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 configuration increases the sensitivity of the sensor without the need for additional sealing materials, results in a more reliable and rugged device capable of operating effectively in harsh conditions, and allows for independent selection of housing and piezoelectric stack parameters, broadening the device's applications.
Implementation Method 1
The hydrophone typically converts acoustic energy into electrical energy. The acoustically responsive elements comprise one or more sectionalized vibratory elements such as a stack of piezoelectrically active ceramic elements or discs
Implementation Method 2
An external acoustic pressure to be sensed is transmitted to the one or more elements via a diaphragm which exists in an end cap closing a top portion of the housing
Data Source
AI summary
An acoustic pressure sensor includes a stack of one or more acoustically responsive elements which are contained within a housing. An external acoustic pressure to be sensed is transmitted to the stack via a diaphragm which exists in an end cap closing a top portion of the housing. The outer edge of the diaphragm is in direct contact with the outer edge of the housing. This area enhancement increases the basic sensitivity of the sensing stack without the need of a gap. The diaphragm allows flexure to occur in a controlled fashion. The housing is sealed at the top and bottom by end caps, the top end cap defining a diaphragm area, which diaphragm deflects to thereby apply pressure to the stack to convert acoustic signals into electrical signals.