Air purifier

摘要

An air purifier includes a cabinet, an electrically driven fan, a replaceable filter element, and an air quality sensor. A display provides a visual indication of the air quality condition. A microprocessor is programmed to control the speed of the fan automatically according to the air quality condition. The microprocessor also computes when the filter element must be changed by totalling the time of operation and its speed (which equals air quality) so that for example the filter element will be changed more often (used for less aggregate time) when the air purifier is operated in a poor quality environment.