ACCURATE DETERMINATION OF REMAINING TIME TO BATTERY EMPTY IN A POWERED AIR PURIFYING RESPIRATOR

摘要

A powered air purifying respirator (PAPR) that alerts when remaining battery time is below a predefined threshold. The powered air purifying respirator comprises an electric motor mechanically coupled to a blower, a battery coupled to the electric motor, an alarm device, and an electronic controller. The electronic controller determines a second battery time remaining value and actuates the alarm device when the second battery time remaining value is less than a predefined threshold, wherein the controller determines the second battery time remaining value based on indexing into a look-up table of values with a first battery time remaining value and a battery voltage.