Balanced Pressure Sensor Package with Counterweight Diaphragms
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Solution Overview
Problem
Differential pressure sensors face measurement errors due to the weight of the transmission fluid and diaphragm, which can introduce inaccuracies and vary with the orientation of the sensor, especially in environments where the sensor is subjected to acceleration or vibration.
Innovation Solution
A balanced pressure sensor package is designed with a primary and secondary diaphragm configuration, where the first transmission fluid pressure and the second transmission fluid pressure are equal in magnitude and opposite in direction, ensuring that the weight of the transmission fluids is balanced regardless of the sensor's orientation, thus maintaining accurate differential pressure measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single-sided oil-filled enclosure is used to protect the pressure sensor, then the sensor is isolated from damaging fluid environments, but measurement precision deteriorates due to hydrostatic pressure errors from the oil weight
Solution Approach 1:
The patent applies the counterweight principle by introducing a second oil-filled enclosure on the reference side that mirrors the first enclosure. The oil column in the second enclosure exerts hydrostatic pressure that counterbalances the hydrostatic pressure from the first enclosure, effectively canceling out the measurement errors caused by oil weight while maintaining protection from damaging fluids on both sides
2Measurement precision
If the sensor orientation is fixed to ensure accurate measurements, then measurement precision is maintained, but adaptability deteriorates because the sensor cannot be installed in various orientations
Solution Approach 1:
By symmetrizing the dual oil-filled enclosure configuration, the patent creates a balance where the hydrostatic pressure effects from both sides cancel each other out regardless of orientation. This allows the sensor to maintain measurement accuracy in any installation orientation without requiring post-installation correction
3Object-affected harmful factors
If the oil head height is increased to improve protection, then protection from damaging fluids is enhanced, but measurement precision worsens due to increased hydrostatic pressure errors
Solution Approach 1:
The patent resolves this contradiction by creating a balanced system where the oil columns in both enclosures are of equal height. The hydrostatic pressure from the taller oil column on one side is exactly counterbalanced by the oil column on the reference side, allowing sufficient oil head for protection while minimizing hydrostatic pressure errors in the differential 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
This configuration allows for high-accuracy differential pressure measurements at any orientation, eliminating the need for post-installation correction and ensuring consistent measurement accuracy across various environmental conditions.
Implementation Method 1
Pressure exerted by the damaging fluid environment can be applied to the diaphragm and transmitted to the pressure sensing element via the oil
Implementation Method 2
A height of the oil protecting a differential pressure sensor, also referred to as a head, can exert a pressure on the differential pressure sensor due to the weight of the oil
Data Source
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AI summary
A pressure sensing package includes a sensor chamber and an annular chamber extending about the sensor chamber. A primary diaphragm divides the sensor chamber into a first part receiving a first pressure and a second part including a differential pressure sensor approximately centered with respect to a sensor axis and a first transmission fluid. The first transmission fluid transmits the first pressure to a first differential pressure sensor face. A secondary diaphragm divides the annular chamber into a first part receiving a second pressure and a second part including a second transmission fluid. The second pressure is transmitted to a second pressure sensor face via the secondary diaphragm and the second transmission fluid. The primary and secondary diaphragms are positioned with respect to one another along the sensor axis direction such that pressures other than the first and second pressures acting on the pressure sensor sum to approximately zero.