Micro Flow Meter Wheatstone Bridge Integration
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Solution Overview
Problem
Existing flow rate measurement devices using Wheatstone bridges are cumbersome and consume significant electrical energy due to the need for multiple amplifiers and complex electrical connections, which complicates the measurement chain and increases uncertainty.
Innovation Solution
A microflowmeter design that integrates a single Wheatstone bridge with gauges on two membranes, separated by a small channel, allowing for simplified electrical wiring and reduced energy consumption by performing differential measurements before analog conversion, using a single amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two separate Wheatstone bridges are used to measure pressure differential, then measurement capability is achieved, but device complexity and electrical consumption increase significantly
Solution Approach 1:
The patent combines two separate Wheatstone bridges into a single integrated bridge structure. The four resistors (R1, R2, R3, R4) form one unified bridge where R1 and R2 are connected to the first membrane and R3 and R4 are connected to the second membrane. This merging reduces the number of connection pads from 8 to 4 and eliminates the need for multiple amplifiers, directly resolving the contradiction between measurement capability and device complexity.
Solution Approach 2:
The single Wheatstone bridge serves multiple functions: it measures pressure differential across two membranes simultaneously, provides differential measurement capability, and reduces electrical connection requirements. This multi-functionality allows the same structure to achieve what previously required two separate bridges, thereby reducing complexity while maintaining measurement precision.
2Measurement precision
If two Wheatstone bridges with multiple amplifiers are used, then differential measurement is achieved, but electrical energy consumption increases
Solution Approach 1:
The patent merges the function of multiple amplifiers into a single amplifier that processes the output from the unified Wheatstone bridge. This single amplifier receives the differential signal from the bridge and performs the necessary amplification, eliminating the need for multiple amplifiers and their associated power consumption, while still achieving accurate differential measurement.
3Reliability
If multiple connection pads are used for electrical assemblies, then complete electrical connectivity is achieved, but manufacturing complexity and uncertainty increase
Solution Approach 1:
The patent reduces the number of connection pads from 8 to 4 by merging the electrical connections of two separate bridges into a single bridge structure. This reduction in connection pad数量 directly decreases manufacturing complexity and alignment uncertainty, while the bridge design ensures complete electrical connectivity is maintained through the integrated resistor network.
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 design reduces electrical connections, energy consumption, and measurement uncertainty, while maintaining sensitivity, making it suitable for medical and fast transient flow applications.
Implementation Method 1
a Wheatstone bridge comprising 2 gauges associated with, or on, the first membrane and 2 gauges associated with, or on, the second membrane
Implementation Method 2
Each gauge is able to supply a signal characteristic of a deformation of the corresponding membrane, deformation occurring under the action of the flow of a fluid
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~4C
AI summary
The invention relates to a flow meter comprising a first chamber (11) and a second chamber (13) that are interconnected by a channel (12), the first chamber being provided with a first deformable membrane (11') and a first and a second gauge (R1, R2), the second chamber (13) being provided with a second deformable membrane (13') and a third and a fourth gauge (R3, R4), the four gauges forming a Wheatstone bridge.