Media-Isolated Gauge Pressure Sensor With Sealed Reference Venting
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Solution Overview
Problem
Existing pressure sensors face challenges such as inaccurate readings due to lack of consideration for reference pressures and vulnerability to moisture and contaminants, which can damage components.
Innovation Solution
A media-isolated relative gauge pressure sensor design that includes a tubular connector with an O-ring to prevent contaminants, a diaphragm to isolate the medium, and a system to measure both medium and reference pressures using an incompressible fluid and a piezoresistive sensing element to calculate net pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensing element is exposed to the medium being measured, then the pressure measurement is direct and simple, but the sensing element becomes vulnerable to moisture and contaminants that can damage it
Solution Approach 1:
A diaphragm is introduced as an intermediary component between the sensing element and the medium being measured. The diaphragm transmits pressure from the medium to the sensing element while preventing direct contact, thus protecting the sensing element from moisture and contaminants while maintaining pressure measurement capability
Solution Approach 2:
The pressure sensor is divided into separate functional zones: a first region containing the sensing element isolated from the medium, and a second region where the medium can access. The diaphragm forms the boundary between these regions, allowing pressure transmission while maintaining physical separation and protection
2Reliability
If a diaphragm is used to isolate the sensing element from the medium, then the sensing element is protected from contaminants, but the device complexity increases
Solution Approach 1:
The diaphragm is integrated with the housing structure, forming a unified component that combines the isolation function with the structural framework. This merging reduces the number of separate parts and simplifies assembly while maintaining effective contaminant isolation
Solution Approach 2:
The diaphragm is implemented as a thin, flexible membrane that can transmit pressure while providing effective isolation. This thin-film approach minimizes the space required for the isolation structure and reduces overall device complexity while maintaining reliable contaminant protection
3Measurement precision
If the sensor measures relative gauge pressure, then it provides accurate readings with respect to reference pressure, but it requires additional structures to manage reference pressure access
Solution Approach 1:
The reference pressure access is achieved through a lateral opening in the housing that allows reference pressure to enter a first cavity, rather than requiring a separate access path. This dimensional approach to pressure access simplifies the overall structure while enabling accurate relative gauge pressure measurement
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 design provides accurate pressure readings by isolating the sensing element from the medium, protecting it from contaminants and ensuring reliable operation in harsh environments.
Implementation Method 1
Some pressure sensors, in some examples, comprise a piezoresistive sensing element which is configured to convert a pressure exerted by a medium to be measured into a change in resistance
Implementation Method 2
the incompressible fluid is configured to impart the pressure to a sensing side of the sensing element
Implementation Method 3
The tubular connector may comprise an O-ring, wherein the O-ring is configured to prevent moisture and/or other contaminants from reaching a sensing element
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Apparatuses, systems, and methods are provided for media-isolated relative gauge pressure sensors. In some embodiments, an apparatus comprises a base port, an assembly, and a tubular connector. The tubular connector may comprise a cavity for allowing air at a reference pressure to enter internal portions of the tubular connector and the assembly such that the cavity is configured to facilitate flow of the air at the reference pressure to a back side of a sensing element, wherein the back side of the sensing element is opposite to a sensing side of the sensing element that is configured to receive pressure, via an incompressible fluid, from a medium being measured. The tubular connector may be mechanically coupled to a metal tube inserted in at least a portion of the cavity. The tubular connector may comprise an O-ring surrounding an outer circumference of the metal tube.