Differential Thermal Flow Meter Circuit for Noise-Resistant Sensing
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Solution Overview
Problem
Existing fluidic devices often lack flow meters to detect fluid flow, which can lead to reliability issues due to noise, sensor variations, and environmental changes, and are also costly and space-intensive.
Innovation Solution
A differential fluid flow meter is implemented using simple and space-efficient circuitry, comprising a heater and multiple resistive sensors connected in series, which detects fluid flow by measuring differential resistance and voltage shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional flow meters are used to detect fluid flow, then measurement capability is provided, but device complexity, cost, and space requirements increase
Solution Approach 1:
The patent replaces traditional mechanical flow meters with a thermal-based detection system using a heater and resistive sensors. The heater generates thermal energy that is carried by fluid flow to the sensors, converting mechanical flow measurement into a thermal field measurement. This substitution eliminates complex mechanical moving parts while maintaining flow detection capability.
Solution Approach 2:
The patent introduces thermal energy as an intermediary between the fluid flow and the measurement system. The heater converts electrical energy to thermal energy, which then serves as the medium that interacts with the flowing fluid and transfers information to the resistive sensors. This intermediary approach simplifies the direct measurement interface while enabling flow detection through thermal transport.
2Measurement precision
If traditional flow meters are used to detect fluid flow, then measurement capability is provided, but device cost and space requirements increase
Solution Approach 1:
The patent embeds the flow detection functionality within the existing fluid conduit structure. The heater and resistive sensors are positioned to utilize the same fluid pathway, nesting the measurement components within the flow channel rather than adding separate external measurement devices. This integration reduces overall device footprint while maintaining detection capability.
3Measurement precision
If absolute sensor measurements are used, then flow detection is achieved, but noise sensitivity and environmental impact increase
Solution Approach 1:
The patent employs asymmetric positioning of the heater and resistive sensors relative to the fluid flow direction. The heater is positioned upstream and the sensors downstream, creating a directional thermal gradient that aligns with the flow direction. This asymmetric arrangement enables the system to detect flow direction and magnitude while being less sensitive to symmetric environmental disturbances and noise.
Solution Approach 2:
The patent implements a feedback mechanism where the voltage output from the resistive sensors is processed to determine fluid flow characteristics. The system continuously monitors the voltage signal and uses this feedback to adjust or confirm flow detection, enabling the system to compensate for environmental variations and reduce the impact of noise on measurement accuracy.
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 differential fluid flow meter effectively detects fluid flow without relying on absolute sensor measurements, reducing noise sensitivity and environmental impact, while being cost-effective and compact.
Implementation Method 1
a heater to generate heat
Implementation Method 2
the generated heat to be carried by the fluid to one of the resistive sensors
Implementation Method 3
multiple resistive sensors including a first resistive sensor on a first side of the heater and a second resistive sensor on an opposite second side of the heater
Data Source
AI summary
In some examples, a fluid flow meter for a conduit to carry a fluid, includes a first voltage connection point, a second voltage connection point, and a heater. The fluid flow meter includes a plurality of resistive sensors comprising a first resistive sensor on a first side of the heater and a second resistive sensor on a second side of the heater, wherein the first resistive sensor and the second resistive sensor are connected in series between the first voltage connection point and the second voltage connection point, wherein a sense connection point between the first resistive sensor and the second resistive sensor is to output a sense voltage that provides an indication of a fluid flow in the conduit.