| 摘要 |
<p>A vacuum cleaner having an inlet nozzle for conveying air and dust to a dirt separator chamber via a dirty air inlet passage is provided. The dirt separator chamber has a chamber opening, an emitter window, and a receiver window. The emitter window and the receiver window may be substantially transparent. An emitter is positioned so that it emits light or another electromagnetic energy into the separator chamber via the emitter window. A receiver is positioned so that it receives light or another electromagnetic energy from the separator chamber via the receiver window. The emitter window and the receiver window each form a projection into the separator chamber during operation of the vacuum cleaner. Airflow creates a cyclone in the dirt separator chamber, and the projections increase the air velocity over the projections, cleaning the emitter window and the receiver window of dust.</p> |
