Portable Spirometer With MEMS Flow Sensing for Full Lung Function Tests
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Solution Overview
Problem
Existing portable spirometers lack the capability to perform full spirometry, including measurements of key parameters like FEV1, FVC, PEF, FEV6, FRC, SVC, MVV, and ERV, and often require frequent calibration due to the use of movable parts, while also being limited by the need for specific smartphone compatibility and environmental conditions.
Innovation Solution
A portable spirometer utilizing MEMS-based thermal fluid flow sensors with a flow restrictor and bypass channel, combined with a microcontroller, to accurately measure lung function parameters without movable parts, and optionally includes sensors for environmental data, enabling full spirometry and connectivity to smartphones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional spirometers use movable parts (turbines, rotors) to measure fluid flow, then measurement capability is achieved, but frequent calibration is required and device reliability decreases
Solution Approach 1:
The patent replaces mechanical flow measurement systems (turbines, rotors) with a MEMS-based thermal fluid flow sensor that uses thermal principles to measure fluid flow. This eliminates movable parts that require calibration, providing both measurement precision and reliability without frequent calibration needs
2Ease of operation
If portable spirometers are designed with simplified measurement capabilities, then device portability and ease of use improve, but full spirometry functionality is lost
Solution Approach 1:
The patent segments the fluid flow measurement into two paths: a main fluid channel for bulk flow and a bypass fluid channel connected to the MEMS sensor for precise measurement. This segmentation enables the portable device to perform full spirometry functionality while maintaining ease of operation
Solution Approach 2:
The patent introduces a bypass channel as an intermediary path that diverts a portion of the fluid flow to the MEMS sensor. This intermediary structure enables accurate spirometry measurements without requiring complex mechanical systems, maintaining portability while achieving full functionality
3Reliability
If portable spirometers use thermal fluid flow sensors, then calibration frequency decreases, but sensor susceptibility to vibration increases
Solution Approach 1:
The patent segments the fluid flow path, directing flow through separate channels that isolate the MEMS sensor from direct exposure to high-velocity flow and vibrations. This segmentation protects the vibration-sensitive sensor while maintaining measurement capability
Solution Approach 2:
The bypass channel acts as an intermediary that diverts fluid flow away from the MEMS sensor location. This intermediary structure reduces the sensor's exposure to vibration-inducing flow conditions while still enabling accurate flow measurement through thermal principles
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 device provides accurate, reproducible spirometric measurements of key lung function parameters, is energy-efficient, and can be used without medical staff, offering full spirometry capabilities and environmental data integration, while eliminating the need for frequent calibration.
Implementation Method 1
a MEMS-based thermal fluid flow sensor (13) which is positioned at the bypass fluid channel (12) for generating a signal in response to the fluid flow in the bypass fluid channel (12)
Implementation Method 2
a flow restrictor (8) positioned in the main fluid channel (5) between the first and the second lateral opening (6 and 7)
Data Source
AI summary
The disclosure relates to a spirometer comprising a MEMS-based thermal fluid flow sensor for generating a signal in response to a fluid flow generated during inhalation or exhalation; and a microcontroller for calculating the fluid flow from the signal generated by the flow sensor. The spirometer may be connected to other devices, such as a smartphone or a personal computer or any other computing unit which is adapted to collect, store, analyse, exchange and/or display data. The disclosure further describes the use of the spirometer in measuring a user's lung performance and/or monitoring it over time. Furthermore, the spirometer may be provided in a system together with an air quality measurement device for determining the air quality at a location of interest; and a computing unit for collecting, analysing and correlating the user's lung performance data obtained from the spirometer with the air quality data.