3m Innovative Properties Company

Bengt Garbergs

Marcus Wiederkehr

Desmond T Curran

Andrew Murphy

Bengt Kallman

Alan W Lee

Vladimir Dubrovskii

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.

Method of controlling a powered air purifying respirator

A protective automatic darkening filter (ADF) and an associated tool, such as a welding torch, are controlled by a corresponding communication unit. The invention helps to ensure that the tool is not activated before the ADF has reached its dark state. A communication channel between the communication unit and the ADF may be established using a wired or wireless medium.

Control of an automatic darkening filter

Growing community of inventors

Falun, Sweden

Bengt Garbergs