Method of controlling a powered air purifying respirator
There is provided a method of controlling a powered air purifying respirator blower system to deliver a substantially uniform volumetric airflow to a user, the system comprising a fan powered by a battery in communication with a variable speed electric motor, the variable speed electric motor is controlled by an electronic control unit for delivering a forced flow of air through at least one filter to a user, comprising the steps of: (a) determining an estimated system run time by summing a battery run time remaining and a system run time; and (b) altering a speed of the variable speed electric motor when the estimated system run time is equal to or less than a desired system run time.
1. A method of controlling a powered air purifying respirator blower system, the system comprising a fan powered by a battery in communication with a variable speed electric motor, the variable speed electric motor is controlled by an electronic control unit for delivering a forced flow of air through at least one filter to a user, comprising the steps of:
(a) determining an estimated system run time by summing a battery run time remaining and a system run time; and
(b) altering a speed of the variable speed electric motor when the estimated system run time is equal to or less than a desired system run time.
2. The method of claim 1 , wherein altering the speed of the variable speed electric motor is decreasing the speed of the variable speed electric motor.
3. The method of claim 2 , wherein the decreasing of the speed of the variable speed electric motor increases the battery run time remaining.
4. The method of claim 1 , further comprising, before step (a), determining a speed of the variable speed electric motor and establishing an electrical characteristic applied by the electronic control unit to the variable speed electric motor.
5. The method of claim 1 , further comprising step (c) altering the speed of the variable speed electric motor to a speed lower than the speed established in step (b) by establishing and applying a new electrical characteristic to the variable speed electric motor.
6. The method of claim 5 , wherein a substantially uniform volumetric airflow from the fan is varied based on the speed of the electric motor.
7. The method of claim 5 , wherein a substantially uniform volumetric airflow from the fan is variable and chosen from any one of a number of pre-selected airflow values.