...worn completely over the head of a person so that the person can breathe in the oxygen given off by the plants.

...in which impending fire and/or explosion is detected by monitoring gases from the drying chamber...

A portable hat... [includes] a filtration, purification and deionization system for removal of combustion products... and an exhaust system for expelling the filtered deodorized, deionized and optionally scented air from the hat.

...when inflated, the top and bottom ends expand to seal the hole and to retain the hollow tubular member as an easily removable plug