Respirator Air Flow Sensor Acoustic Frequency Measurement
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Solution Overview
Problem
Conventional powered air purifying respirator systems face errors in air flow correction due to temperature and pressure changes, and lack accurate display of filter clogging rates, relying on separate air flow display devices and manual inspections.
Innovation Solution
An information display and control device with a precision air flow sensor, pulse width modulation drive unit, temperature sensor, oxygen sensor, voltage detection unit, differential pressure sensor, and a remote controller for electronic detection and display of air flow, battery power, and filter status, enabling real-time monitoring and control through a graphic screen and bi-directional wireless communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional air flow correction methods using current change or air flow sensors are used, then air flow correction is achieved, but measurement precision deteriorates due to temperature and pressure changes causing errors
Solution Approach 1:
The patent changes the measurement parameter from electrical current or pressure differential to acoustic frequency. The air flow sensor detects the frequency of air molecules passing through, which remains stable across different temperature and pressure conditions, thereby resolving the measurement precision issue while maintaining reliable air flow correction
Solution Approach 2:
The patent replaces the conventional mechanical/electrical measurement system (current sensors or pressure sensors) with an acoustic-based detection system. By measuring the frequency of air molecule movement through acoustic waves, the system achieves temperature and pressure compensation without requiring complex calibration mechanisms
2Loss of information
If separate air flow display devices are used to inspect air flow, then air flow inspection is possible, but device complexity increases and measurement precision deteriorates due to pressure difference between display device and respirator
Solution Approach 1:
The patent merges the air flow detection function directly into the respirator unit by mounting the air flow sensor on the respirator body. This integration eliminates the need for separate display devices and hoses, reducing system complexity while ensuring measurements are taken at the exact location where air flow is needed, thereby eliminating pressure difference errors
Solution Approach 2:
The respirator unit is designed to perform multiple functions: filtration, blowing, and air flow measurement. The control unit processes both operational control and measurement data, making the system universal and eliminating the need for dedicated separate display devices
3Ease of operation
If manual inspection methods are used to detect filter clogging, then simple operation is maintained, but measurement precision deteriorates as clogging rate cannot be displayed
Solution Approach 1:
The patent implements a feedback system where the air flow sensor continuously monitors air flow and the control unit calculates the clogging rate based on changes in air flow characteristics. The system provides real-time feedback to the user through displays or alarms, maintaining simple operation while delivering precise quantitative measurement of filter clogging rate
Solution Approach 2:
The system performs self-diagnosis by automatically monitoring its own air flow characteristics and calculating filter clogging rate without requiring external inspection tools or manual procedures. The respirator serves itself by using its built-in air flow sensor to assess its own operational status
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
Enables precise electronic detection and display of air flow and filter status, allowing workers to take corrective measures in real-time, reducing errors and improving operational safety by providing accurate system information and control without the need for separate air flow display devices.
Implementation Method 1
air flow sensor for detecting air flow
Implementation Method 2
differential pressure sensor for detecting a differential pressure value of the filter
Implementation Method 3
temperature sensor for detecting temperature
Implementation Method 4
oxygen sensor for detecting an amount of oxygen
Data Source
AI summary
An information display and control device of an air purifying respirator comprises: a blower motor; a pulse width modulation drive unit controlling rotation of the blower motor; a temperature sensor; an air flow sensor; an oxygen sensor; a voltage detection unit for a battery; a differential pressure sensor detecting a differential pressure value of a filter; a switch input unit for a user to input predetermined temperature, air flow, and oxygen amount and operation commands; a controller executing a diagnostic mode, calibrating the oxygen sensor, calculating a detected value of the voltage detection unit to determine whether the voltage is low, comparing the detected value of the differential pressure sensor with a reference to determine whether the filter is absent or clogged, and comparing the detected value of the oxygen sensor with a reference to determine whether oxygen is insufficient or excessive; and an alarm output unit outputting an alarm.