Abstract: A method of controlling a blower system of a powered air purifying respirator to deliver a substantially uniform volumetric airflow to a user, the system including a fan powered by a variable speed electric motor, the motor controlled by an electronic control unit for delivering a forced flow of air through at least one filter to a user. There is also provided an air purifying respirator blower system using such a method.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 variable speed electric motor, the 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) monitoring system loading; and (b) decreasing a speed of the electric motor when system loading reaches a predetermined value. There is also provided an air purifying respirator blower system using such a method.

Abstract: Methods and systems for controlling a powered air purifying respirator blower system where volumetric airflow is stepped down into predetermined discrete ranges based on system loading and desired runtime.

Abstract: 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.

Abstract: 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.

Abstract: 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 variable speed electric motor, the 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) monitoring system loading; and (b) decreasing a speed of the electric motor when system loading reaches a predetermined value. There is also provided an air purifying respirator blower system using such a method.

Abstract: 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.

Abstract: An article of headgear that has a head-covering article, a lens moveably attached to the head-covering article, and a seal attached to the lens, the seal comprising a first polymeric material and a second polymeric material, the first polymeric material having a greater tensile modulus than the second material. In an exemplary embodiment, the lens is moveable from a first, lowered position to a second, raised position, and when in the first, lowered position, the seal sealingly engages the head-covering article. In some embodiments, the tensile modulus of the first polymeric material is at least about 5× greater or even about 10× greater than the tensile modulus of the second material.

Abstract: An article of headgear that has a head-covering article, a lens moveably attached to the head-covering article, and a seal attached to the lens, the seal comprising a first polymeric material and a second polymeric material, the first polymeric material having a greater tensile modulus than the second material. In an exemplary embodiment, the lens is moveable from a first, lowered position to a second, raised position, and when in the first, lowered position, the seal sealingly engages the head-covering article. In some embodiments, the tensile modulus of the first polymeric material is at least about 5× greater or even about 10× greater than the tensile modulus of the second material.