Breath responsive powered air purifying respirator
Inventors
Hur, Ryan • Grudt, Dennis • Olson, Bob • Kim, Jeffrey • Palanisamy, Ramesh
Assignees
Publication Number
US-10888721-B2
Publication Date
2021-01-12
Expiration Date
2037-07-28
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Abstract
An air purifying respirator includes a dual stage fan that sucks outside air in through the filter canisters and then pushes the filtered air on to the user's mask or hood, where excess air escapes. A differential pressure sensor measures the pressure within the passages after the dual stage fan and in the ambient environment to estimate the user's rate of respiration. The microcontroller monitors the estimated rate of respiration, as well as the estimated altitude and its estimated amount of oxygen to calculate a user's filtered air flow need. The microcontroller adjusts the van via a fan controller to the appropriate air flow level. The microcontroller further monitors the battery level, filter life, and for low pressure within the user's mask and operates their respective indicators when problem levels arise. The battery supplies power to the microcontroller, power on/off button, and the dual stage fan.
Core Innovation
The invention is a breath-responsive Powered Air Purifying Respirator (PAPR) system designed to efficiently filter air in Chemical, Biological, Radiation, and Nuclear (CBRN) applications for individual user protection. The system comprises a dual stage fan blower assembly that draws contaminated air through rain-protected filter canisters and supplies purified air through a connected breathing tube to a NIOSH approved mask or hood. A differential pressure sensor measures pressures inside the air passages and the ambient environment to estimate the user's respiration rate.
The microcontroller monitors this estimated respiration rate, along with estimated altitude and oxygen levels to calculate the user's filtered air flow need, adjusting the fan speed via a fan controller accordingly. It also monitors battery life, filter life, and low pressure in the user's mask, triggering indicators to alert for any issues. This approach contrasts with prior PAPRs that supply a constant maximum air flow exceeding user demand, causing frequent filter and battery changes due to unnecessary air cycling.
Claims Coverage
The patent includes one independent claim, presenting inventive features related to the respirator's structure, operation, and adaptive control.
Dual elongated vertically oriented filter cartridge areas with valve mechanisms
The respirator housing includes separate first and second elongated vertical areas to receive corresponding filter cartridges. Each area has a top opening for insertion and a valve mechanism at the bottom that can be opened or closed to control air flow.
Air flow path integrating filter cartridges, valves, fan, and respirator output
Air is pulled through the upper inlets of both filter cartridges, passes through their bottoms into valves, then into a shared air passage connected to a fan and finally out through a respirator output connectable to a user breathing enclosure.
Fan speed adjustment based on user respiration sensed by a sensor
A sensor communicates with the air passage to measure user respiration characteristics, enabling the system to adjust fan speed responsively to the user's breathing demands.
Enabling cartridge replacement during operation
The design allows removal and replacement of one filter cartridge while continuing to deliver filtered air, maintaining respirator function without interruption.
Microprocessor integration with sensors to adjust fan speed
A microprocessor connected to respiration sensor and optionally an atmospheric pressure sensor estimates altitude and adjusts fan speed accordingly to meet oxygen demands based on environment and respiration.
Dual stage fan construction
The fan comprises dual rotating fan blade sets axially aligned, optionally including a disc with apertures connected to the fan axle, providing efficient air flow at slower motor speeds in a compact design.
Chemical sensor integration for user alerts
A chemical sensor in communication with the air passage detects harmful chemicals and triggers alerts to the user if contaminants bypass the filters.
Multi-layer cylindrical filter cartridge design
Each filter cartridge has a cylindrical shape with a central air passage featuring apertures for radial air flow, containing an inner HEPA filter and outer activated carbon bed for particulate and chemical filtration respectively.
Diaphragm valve mechanism for cartridge isolation
Valve mechanisms are diaphragm members positioned at bottoms of filter cartridge areas, moving vertically to open or close air flow passages, enabling isolation when changing cartridges.
Rain-protected filter cartridge top surfaces
Filter cartridges have closed tops with air inlets on upper sides, preventing rain intrusion and protecting filter media.
Overall, the claims cover a breath responsive PAPR respirator with dual vertical filter cartridges featuring valve isolation, a dual stage fan controlled by microprocessor based on respiration and environmental sensing, cartridge swap capability during operation, and multi-layered cylindrical filter cartridges with rain protection and chemical sensing integration.
Stated Advantages
Improved efficiency by adjusting filtered air flow exactly to user respiration needs, avoiding unnecessary air cycling.
Lower power consumption leading to extended battery life through variable fan speed control.
Enhanced safety features by monitoring filter life, battery status, and low pressure in the user’s mask with indicators for timely alerts.
Design flexibility and compatibility with standard commercial mask or hood tubing (e.g., 40 mm tube size).
Compact dual stage fan design allows achieving required air flow and pressure at slower speeds in a smaller form factor.
Cartridge valve mechanisms enable filter cartridge replacement without interrupting filtered air supply (hot swappable batteries).
Rain and dirt protection for filter cartridges increases reliability in adverse environmental conditions.
Documented Applications
Filtration of air for a single user to provide individual protection in Chemical, Biological, Radiation and Nuclear (CBRN) applications.
Protection against chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) in the form of dust, mist, and gas.
Use as a Powered Air Purifying Respirator with compatibility for NIOSH approved face masks or hoods.
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