Portable Spirometer Thermal Flow Sensor Positional Accuracy

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Solution Overview

Problem

Existing portable spirometers face challenges in achieving accurate air flow measurements due to positional variations during use, leading to small deviations in airflow data, especially during rapid movements.

Innovation Solution

A portable spirometer design incorporating a sensor unit with at least one digital differential pressure sensor, a heating element, and temperature sensors arranged in series, which measures thermal flow and converts it to air flow values, along with two digital differential pressure sensors configured to measure differential pressures in overlapping intervals for enhanced accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a portable spirometer is used with varying positions during measurements, then the device becomes more versatile and easier to use, but measurement accuracy deteriorates due to positional deviations during rapid movements

Engineering Contradiction:

Improveease of useVSAvoidmeasurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical flow sensing with thermal flow sensing using a heating element and temperature sensors. The thermal flow sensor measures temperature differences caused by heated air flow, converting thermal energy measurements to air flow values. This substitution eliminates mechanical sensitivity to position while maintaining measurement accuracy across varying device orientations and movements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from mechanical flow detection to thermal parameter detection. By measuring temperature differences (thermal parameters) rather than mechanical flow directly, the system becomes insensitive to positional variations. The thermal flow sensor converts temperature measurements into air flow values through established thermal relationships, providing stable measurements regardless of device position or movement.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If thermal flow sensing with heating element and temperature sensors is implemented, then measurement accuracy improves by eliminating positional errors, but device complexity increases due to additional sensor components

Engineering Contradiction:

Improvemeasurement accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the heating element and temperature sensors into an integrated thermal flow sensor unit. This combined component performs multiple functions (heating and temperature measurement) within a single modular assembly that interfaces with the existing spirometer structure. The integration reduces overall system complexity compared to separate mechanical flow sensors and temperature measurement systems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The thermal flow sensor serves multiple functions: it acts as both a flow detection device and a temperature measurement device. The heating element provides thermal energy to the air flow while temperature sensors simultaneously measure the thermal characteristics. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall device complexity while maintaining high measurement accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 provides reliable and accurate air flow measurements by minimizing positional errors and ensuring high-resolution data across a wide range of differential pressures, improving the reliability of pulmonary function monitoring.

Implementation Method 1

a heating element, a temperature sensor arranged upstream of the heating element and a reference temperature sensor arranged downstream of the heating element

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the at least one digital differential pressure sensor may be configured to measure thermal flow of the air, and to convert the measured thermal flow to a value representing air flow

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

said sensor unit comprises at least one digital differential pressure sensor comprising a heating element, a temperature sensor arranged upstream of the heating element and a reference temperature sensor arranged downstream of the heating element

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS11684286B2Portable spirometer

Publication Date: 2023.06.27 UDVIRKE APS

AI summary

The present invention relates to a portable spirometer, comprising a housing and a mouthpiece being releasably connected to said housing, wherein the housing encloses a sensor unit being in fluid communication with a flow channel receiving part of a flow of exhaled or inhaled air from a main flow channel of the mouthpiece when connected to said housing, whereby the sensor unit is configured to measure one or more characteristics of part of the flow of exhaled or inhaled air passed to the sensor unit via the mouthpiece, characterised in that said sensor unit comprises at least one digital differential pressure sensor comprising a heating element and a temperature sensor arranged upstream of the heating element and a reference temperature sensor arranged downstream of the heating element.