Abstract: A powered air purifying respirator (PAPR) for delivering a forced flow of filtered air to a wearer is disclosed.

Abstract: A powered air purifying respirator (PAPR) for delivering a forced flow of filtered air to a wearer is disclosed.

Abstract: 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.

Abstract: A powered air purifying respirator (PAPR) for delivering a forced flow of filtered air to a wearer is disclosed.

Abstract: A method of controlling a powered air purifying respirator blower system to detect a low air pressure high airflow event is disclosed. The blower system comprises a fan powered by an electric motor, controlled by an electronic control unit for delivering a forced flow of filtered air to a user. The electronic control unit has a plurality of data points representing events defining an acceptable operating range in terms of different characteristics of the blower system stored therein. The method comprises sampling a characteristic that represents the operating condition of the blower to obtain a sampled data point; comparing the sampled data point and the stored data point representing a low air-pressure high airflow event, for the same characteristic; repeating the sampling during a fixed time period, and if the comparing step indicates the low air-pressure high airflow event has been reached for the majority of the time period; activating an alarm.

Abstract: A method of controlling a powered air purifying respirator blower system to deliver a substantially uniform volumetric airflow to a user (6) 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 (22) in response to said determination and said at least two calibration values. The powered air purifying respirator blower system may include a fan (21) powered by an electric motor (22), the motor being controlled by an electronic control unit (23) for delivering a forced flow of filtered air to a user (06). The electronic control unit (23) may include at least two calibration values for the electrical characteristics of the electric motor (22) stored therein. The system may include at least one sensor (26) adapted to be in communication with the electronic control unit and arranged to determine one of (a) ambient air density or (b) ambient air temperature and ambient air pressure.

Abstract: A method and configuration from maintaining a constant of air to a protective helmet (4) from a fan (3) in a battery powered fresh air unit. The fan (3) is a radial fan with a filter (5) positioned on the suction side of the fan and is operated by a brushless continuous current motor (2). With the aid of signals from position sensors (30) in the motor (2), a control unit (12) can determine the speed of the fan (3). The control unit also detects the motor's power consumption and compares this and the speed with a characteristic curve for the motor (2) for a given flow from the fan, which is stored in a memory (14). In the event of any deviation, the control unit (12) regulates a change of the voltage supply to the motor (2) so that the deviation is reduced.

Abstract: A method and configuration from maintaining a constant of air to a protective helmet (4) from a fan (3) in a battery powered fresh air unit. The fan (3) is a radial fan with a filter (5) positioned on the suction side of the fan and is operated by a brushless continuous current motor (2). With the aid of signals from position sensors (30) in the motor (2), a control unit (12) can determine the speed of the fan (3). The control unit also detects the motor's power consumption and compares this and the speed with a characteristic curve for the motor (2) for a given flow from the fan, which is stored in a memory (14). In the event of any deviation, the control unit (12) regulates a change of the voltage supply to the motor (2) so that the deviation is reduced.