Pressure Sensor Circuit for Excessive Flexure Detection

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Solution Overview

Problem

Pressure sensors with monolithic bodies and sealingly applied membrane elements can experience excessive flexure due to fluid pressure, leading to imprecise pressure detection without sensor failure, as the membrane may contact the lower face, causing errors in pressure measurement.

Innovation Solution

A pressure sensor design featuring a sensor body with two parts joined by a fixing material, where one part defines the membrane portion and the other supports a deformation-detection circuit, with a circuit element that interacts with the detection circuit upon excessive flexure to distinguish excessive pressure conditions, modifying the output signal to prevent measurement errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the membrane portion is made thin and flexible to improve pressure detection sensitivity, then measurement precision is improved, but the membrane may contact the lower face under excessive pressure causing measurement errors

Engineering Contradiction:
Improvepressure detection sensitivityVSAvoidmeasurement accuracy under excessive pressure
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A circuit element is introduced as an intermediary between the membrane portion and the lower face. This circuit element interacts with the deformation-detection circuit to modify the output signal when the membrane contacts the lower face, preventing measurement errors while maintaining the thin, flexible membrane design for high sensitivity pressure detection

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The deformation-detection circuit continuously monitors the membrane's deformation state and provides feedback through the circuit element. When excessive pressure causes the membrane to contact the lower face, the feedback mechanism modifies the output signal to indicate the excessive pressure condition, preventing inaccurate measurements

Inventive Principle:
Principle #23Feedback

2Reliability

If mechanical compensation elements are added to prevent excessive bending of the membrane, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvemembrane protection against excessive bendingVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical compensation elements with an electrical/circuit-based solution. The circuit element and deformation-detection circuit provide protection against measurement errors through electrical signal modification rather than mechanical constraints, significantly reducing structural complexity while maintaining reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution enables precise discrimination of excessive fluid pressure, preventing measurement errors by modifying the output signal when the membrane contacts the sensor body, thus ensuring accurate pressure detection within the nominal working range.

Implementation Method 1

detection of the pressure is obtained by exploiting the elastic flexure or deformability of the membrane portion, caused by the action of the fluid to be detected

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The degree of the flexure or deformation, which is representative of the pressure of the fluid, is measured electrically via suitable circuit means provided directly on the membrane portion, these means usually being of a piezoelectric type, or else of a piezoresistive type

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP4045884B1Pressure sensor
Publication Date: 2024.12.25 METALLUX SA
  • EP4045884B1 patent drawingFigure 1~2
  • EP4045884B1 patent drawingFigure 3~4
  • EP4045884B1 patent drawingFigure 5~6

AI summary

A sensor (1) for detecting the pressure of a fluid has a sensor body (2) that comprises at least one first body part (3) and one second body part (4), each having a first face and a second face opposite to one another. The first body part (3) and the second body part (4) are joined together in such a way that the first face of the first body part (3) faces the first face of the second body part (4), at a distance therefrom. At least one of the first body part (3) and the second body part (4) includes a membrane portion (7), subject to elastic flexure or deformation towards the other one of the first part body (3) and the second body part (4) as a result of the pressure of the fluid, the membrane portion (7) defining the first face of the first body part (3) or of the second body part (4). The pressure sensor (1) has a circuit arrangement (8, 10) supported by the sensor body (2), which comprises at least one first electrical circuit (10) that extends at least in part in an area corresponding to the membrane portion (7) and is configured for detecting an elastic flexure or deformation thereof through at least one respective detection component (R1, R2, R4). The first electrical circuit (10) is associated to the first face of one of the first body part (3) and the second body part (4), and the first face of the other one of the first body part (3) and the second body part (4) forms or has associated thereto at least one circuit element (20), prearranged for interacting with the first electrical circuit (10) when an elastic flexure or deformation of the membrane portion (7) is of a degree at least equal to a substantially predetermined limit, to generate thereby information or a warning representative of at least one from among an excessive pressure of the fluid, an incorrect pressure measurement, and an anomalous state of the device.