Abstract: There is provided a fan assembly comprising a motor-driven impeller arranged to generate an airflow, an air outlet arranged to emit the airflow, a plurality of sensors arranged to measure a value for each of a plurality of air quality characteristics, a display and a processor. The processor is configured to receive measured values for each of the plurality of air quality characteristics, identify one of a corresponding set of intervals within which the measured value falls and select an air quality index value associated with the identified interval. The processor is then configured to identify the highest of the selected air quality index values as a current overall air quality index value and to cause the display to display a time series plot of the current air quality index value and a number of preceding air quality index values.

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 fan assembly comprising a motor-driven impeller arranged to generate an airflow, an air outlet arranged to emit the airflow, a plurality of sensors arranged to measure a value for each of a plurality of air quality characteristics, a display and a processor. The processor is configured to receive measured values for each of the plurality of air quality characteristics, identify one of a corresponding set of intervals within which the measured value falls and select an air quality index value associated with the identified interval. The processor is then configured to identify the highest of the selected air quality index values as a current overall air quality index value and to cause the display to display a time series plot of the current air quality index value and a number of preceding air quality index values.

Abstract: There is provided a fan assembly comprising a motor-driven impeller arranged to generate an airflow, an air outlet arranged to emit the airflow, at least one filter assembly that is arranged to purify the airflow, a plurality of sensors arranged to measure a value for each of a plurality of air quality characteristic, and a processor. The processor is configured to receive measured values for each of the plurality of air quality characteristics, identify one of a corresponding set of intervals within which the measured value falls, select an air quality index value associated with the identified interval, and generate a corresponding speed value using the selected air quality index value. The processor is then configured to set a speed of the motor-driven impeller in dependence upon the highest of the speed values.

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.