Abstract: A headgear is described that includes an air purifier, a microphone, and a control unit. The control unit analyses a signal output by the microphone to determine a magnitude of wind. The control unit then controls a flow rate of the air purifier in response to the determined magnitude.

Abstract: A headgear is described that includes a first air purifier, a second air purifier, a first microphone, a second microphone, and a control unit. The control unit analyses a first signal output by the first microphone and a second signal output by the second microphone to determine a direction of wind. The control unit then controls the relative flow rates of the first air purifier and the second air purifier in response to the determined direction of wind.

Abstract: There is provided an ear cup including a housing containing a filter assembly and a motor-driven impeller for creating an airflow through the filter assembly, the housing including an air outlet downstream from the filter assembly for emitting the filtered airflow from the housing. The ear cup further includes an acoustic driver carried by or mounted to, either directly or indirectly, the housing, a reference internal noise sensor disposed within the housing, and a reference ambient noise sensor carried by or mounted to, either directly or indirectly, the housing. The ear cup further includes active noise control circuitry that is configured, in a first operating state, to use a signal provided by the reference internal noise sensor to operate the acoustic driver and, in a second operating state, to use a signal provided by the reference ambient noise sensor to operate the acoustic driver.

Abstract: There is provided an ear cup including a housing containing a filter assembly and a motor-driven impeller for creating an airflow through the filter assembly, the housing including an air outlet downstream from the filter assembly for emitting the filtered airflow from the housing. The ear cup further includes an acoustic driver carried by the housing, a reference internal noise sensor carried by the housing, and active noise control circuitry that is configured to use a signal provided by the reference internal noise sensor to operate the acoustic driver.

Abstract: There is provided an ear cup including a housing containing a filter assembly and a motor-driven impeller for creating an airflow through the filter assembly, the housing including an air outlet downstream from the filter assembly for emitting the filtered airflow from the housing. The ear cup further includes an acoustic driver mounted to the housing, a reference internal noise disposed within the housing and a reference ambient noise mounted to the housing. The ear cup further includes active noise control circuitry that is configured to simultaneously use both a signal provided by the reference internal noise and the signal provided by the reference ambient noise to operate the acoustic driver.

Abstract: There is provided an ear cup comprising a housing, an ear pad attached to the housing and arranged such that the housing and the ear pad together define a cavity having an opening, and an acoustic driver disposed within the cavity. The ear cup further comprises a feedforward microphone, a feedback microphone, and active noise control (ANC) circuitry. The active noise control (ANC) circuitry is configured to use a feedforward signal provided by the feedforward microphone to operate the acoustic driver to attenuate noise having frequencies within a feedforward ANC range having a lower limit of no less than 300 Hz and an upper limit of more than 1.5 kHz and to use a feedback signal provided by the feedback microphone to operate the acoustic driver to attenuate noise having frequencies within a feedback ANC range having an upper limit of no more than 1.5 kHz.

Abstract: A pump assembly for a dental cleaning appliance includes a fluid chamber, a piston, and a drive. Magnets, connected respectively to the piston and the drive, enable the drive to couple to the piston and move it within the fluid chamber to draw fluid into the fluid chamber. A stop prevents the piston from being pulled beyond a stop position so that through continued actuation of the drive the magnets separate to allow a spring to push the piston away from the stop position to urge a burst of fluid from the fluid chamber.

Abstract: There is provided a head wearable air purifier comprising a first speaker assembly and a second speaker assembly, wherein the first speaker assembly comprises a filter assembly, a motor-driven impeller for creating an airflow through the filter assembly, and an air outlet downstream from the filter assembly for emitting a filtered airflow from the speaker assembly. The head wearable air purifier further comprises a nozzle arranged to receive the filtered airflow from the first speaker assembly, the nozzle comprising an air outlet arranged to emit the received filtered airflow from the head wearable air purifier, and a control circuit arranged to control a rotational speed of the motor-driven impeller of the first speaker assembly such that the maximum rotational speed of the motor-driven impeller is from 9000 to 18,000 RPM.

Abstract: A pump assembly for a dental cleaning appliance includes a fluid chamber, a piston, and a drive. Magnets, connected respectively to the piston and the drive, enable the drive to couple to the piston and move it within the fluid chamber to draw fluid into the fluid chamber. A stop prevents the piston from being pulled beyond a stop position so that through continued actuation of the drive the magnets separate to allow a spring to push the piston away from the stop position to urge a burst of fluid from the fluid chamber.