Abstract: A vacuum cleaner has a removable bottom cannister that receives the refuse of the cleaning process. The bottom cannister is fitted with a plate forming an air channel along a portion of the interior side wall of the cannister. When air flows across the top of the air channel, as from cyclonic motion, suction occurs that is used to draw down a liner, or removable bag, against the inside of the cannister and thereby to prevent the liner from floating up and being drawn into the outlet, which would block the operation of the vacuum cleaner. The liner is positioned to receive the refuse and is desirable for reasons of convenience and hygiene during the process of emptying the cannister. In addition, the air channel can be fitted with a clip to aid in the insallation of the liner. The cannister can also be fitted with an interior hood or cone to optimize the flow of air across the top of the air channel.

Abstract: A wireless acoustic communicator is disclosed which permits a remotely-located operator to monitor and control a central vacuum cleaner. The acoustic communicator does not need problematic batteries, airflow blockers, or special wiring networks but uses only low-frequency acoustic signals that are transmitted through the pipe system of the vacuum cleaner. Command signals are effectively transmitted, even while air is flowing through the pipe system, by using a continuous multi-frequency signal, a resonant physical structure, and an adaptive signal detector. A preferred embodiment uses a powerful reed to generate a continuous acoustic signal. The reed is manually plucked by a slide switch to start vibration, which is then continued by the airflow through the pipe system caused by the running vacuum motor. The vacuum motor runs only if the signal is present. The acoustic communicator includes a resonant detection tube that filters the signal before it reaches a microphone.

Abstract: A wireless acoustic communicator is disclosed which permits a remotely-located operator to monitor and control a central vacuum cleaner. The acoustic communicator does not need problematic batteries, airflow blockers, or special wiring networks but uses only low-frequency acoustic signals that are transmitted through the pipe system of the vacuum cleaner. Command signals are effectively transmitted, even while air is flowing through the pipe system, by using a continuous multi-frequency signal, a resonant physical structure, and an adaptive signal detector. A preferred embodiment uses a powerful reed to generate a continuous acoustic signal. The reed is manually plucked by a slide switch to start vibration, which is then continued by the airflow through the pipe system caused by the running vacuum motor. The vacuum motor runs only if the signal is present. The acoustic communicator includes a resonant detection tube that filters the signal before it reaches a microphone.