PAPR Blower Control via Ambient Air Density Adjustment
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Solution Overview
Problem
Current powered air purifying respirator (PAPR) systems deliver excessive airflow, leading to reduced battery life, premature filter clogging, and unnecessary filter replacements, due to inaccurate airflow control, which can result in increased operational costs and user downtime.
Innovation Solution
A method to control the PAPR blower system by adjusting electrical characteristics of the electric motor based on ambient air density, temperature, and pressure, using sensors to maintain a substantially uniform volumetric airflow, thereby optimizing airflow delivery and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a higher airflow is provided to ensure sufficient respiratory protection, then the level of respiratory protection is improved, but battery life is reduced and filter life is reduced
Solution Approach 1:
The system dynamically adjusts motor power parameters (voltage, current, speed) based on real-time airflow measurements and ambient conditions. The electronic control unit modifies electrical characteristics of the motor to maintain optimal airflow rates, preventing excessive power consumption while ensuring adequate respiratory protection. This parameter optimization allows the system to achieve reliable protection with reduced energy usage, extending battery life.
Solution Approach 2:
The system incorporates airflow sensors that continuously monitor actual airflow delivery and feed this information back to the electronic control unit. The control unit compares measured airflow with target values and automatically adjusts motor power accordingly. This closed-loop feedback mechanism ensures sufficient respiratory protection is maintained while minimizing power consumption, resolving the contradiction between protection level and battery life.
2Reliability
If a higher airflow is provided to ensure sufficient respiratory protection, then the level of respiratory protection is improved, but filter life is reduced due to premature clogging
Solution Approach 1:
The system optimizes motor power parameters to maintain airflow rates that are sufficient for respiratory protection but not excessively high. By dynamically adjusting electrical characteristics based on ambient conditions and actual demand, the system prevents premature filter clogging while ensuring adequate protection, thereby extending filter service life.
Solution Approach 2:
The system provides airflow at the minimum necessary level to ensure adequate respiratory protection rather than consistently operating at high airflow rates. This partial action approach maintains sufficient protection while significantly reducing the rate of filter contamination and clogging, extending filter replacement intervals.
3Device complexity
If inaccurate airflow control is used, then device complexity is reduced, but airflow regulation precision deteriorates leading to excessive airflow
Solution Approach 1:
The system uses airflow sensors to measure actual airflow delivery and provides this information back to the electronic control unit. This feedback mechanism enables precise airflow regulation by continuously comparing measured values with target values and adjusting motor power accordingly. The feedback approach achieves accurate airflow control without requiring overly complex control algorithms or additional sophisticated components.
Solution Approach 2:
The system replaces complex mechanical airflow control mechanisms with electronic control of the motor. By using electronic adjustment of electrical characteristics (voltage, current, speed) rather than mechanical throttling or dampers, the system achieves precise airflow regulation with simpler overall device architecture and fewer moving parts.
Data Source
AI summary
A method of controlling a powered air purifying respirator blower system to deliver a substantially uniform volumetric airflow to a user includes the steps of determining one of (a) ambient air density or (b) ambient air temperature and ambient air pressure, and adjusting an electrical characteristic of the electric motor in response to the determination and the at least two calibration values. The powered air purifying respirator blower system may include a fan powered by an electric motor, the motor being controlled by an electronic control unit for delivering a forced flow of filtered air to a user. In some embodiments, the electronic control unit may be operable to adjust an electrical characteristic of the motor in accordance with a predetermined correlation between the speed of the fan and the applied motor electrical characteristic for a selected substantially uniform volumetric airflow from the fan.