Ultrasonic Spirometer Calibration Verification

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Solution Overview

Problem

The calibration of ultrasonic spirometers is laborious and prone to inaccuracies due to factors like incorrect connections, fluid tightness defects, and user errors, requiring frequent use of calibration pumps.

Innovation Solution

A method that verifies the calibration of ultrasonic spirometers by determining the distance between transducers and comparing it to a nominal value, using threshold values to assess calibration validity, eliminating the need for calibration pumps and allowing for fully automated, reliable verification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If calibration pump is used for spirometer calibration, then calibration can be performed, but calibration accuracy deteriorates due to connection errors, fluid tightness defects, and user errors

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the calibration verification function from the complex manual calibration pump operation. By measuring the actual distance between ultrasonic transducers and comparing it to the nominal distance, the system verifies calibration without requiring a calibration pump, thereby eliminating connection errors, fluid tightness defects, and user execution errors while maintaining calibration reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical calibration pump system with an automated measurement system. Instead of using a mechanical pump to deliver a known volume of gas, the system uses ultrasonic transducers to measure the actual distance between them and compares this to the nominal distance stored in memory, substituting a mechanical calibration process with an automated electronic verification process that eliminates manual operation errors

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

2Productivity

If manual calibration with calibration pump is used, then calibration can be performed, but time consumption increases due to laborious process

Engineering Contradiction:
Improvecalibration efficiencyVSAvoidcalibration time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent implements self-service calibration verification where the spirometer automatically measures the actual distance between its ultrasonic transducers and compares it to the nominal distance stored in its memory. The control unit automatically determines whether the actual calibration is still valid based on the comparison, eliminating the need for manual operation of calibration pumps and significantly reducing calibration time while improving productivity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies preliminary action by storing the nominal distance between ultrasonic transducers in the memory during manufacturing or initial setup. This pre-stored reference value enables rapid automated verification without requiring manual calibration pumps or complex procedures during routine checks, thereby reducing calibration time and improving efficiency

Inventive Principle:
Principle #10Preliminary action

3Reliability

If frequent calibration verification is performed, then calibration accuracy is maintained, but device complexity increases

Engineering Contradiction:
Improvecalibration validityVSAvoidverification system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by using the existing ultrasonic transducers, which are already part of the spirometer's measurement system, for dual purposes: both for measuring patient breathing parameters and for verifying calibration by measuring the actual distance between them. The control unit also serves dual functions by managing both patient data acquisition and calibration verification. This multi-functionality maintains calibration reliability without adding separate verification hardware, thereby avoiding increased device complexity

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

This method significantly reduces the probability of incorrect calibration, ensuring accurate measurements and reducing the need for manual intervention and calibration pump inaccuracies, while maintaining high accuracy and reliability.

Implementation Method 1

Ultrasonic spirometers are devices for measuring the mean velocity of a flowing gas along an ultrasonic transmission path

Methodology Applied
Scientific EffectSpeed of sound: Speed of Sound

Data Source

PatentUS11162833B2Method for verifying a calibration of a spirometer
Publication Date: 2021.11.02 NDD MEDIZINTECHN

AI summary

The invention relates to a method for verifying a calibration of an ultrasonic spirometer, the method comprising determining an actual value of a distance between a first ultrasonic transducer and a second ultrasonic transducer of a spirometer, determining a difference between the actual value of the distance and a nominal value of the distance that is assigned to the spirometer, and accepting an actual calibration of the spirometer if an absolute value of the difference is smaller than or equal to a first threshold value, or refusing the actual calibration of the spirometer if the absolute value of the difference is bigger than the first threshold value, wherein the first threshold value is 5% of the nominal value of the distance. The invention further relates to a spirometer that is adapted to carry out this method as well as to a method for calibrating a spirometer.