Filtered air moving apparatus

Claim 1

Filtered air moving apparatus comprising: housing means defining an air inlet, an air outlet, and an air flow path therebetween; a blower means disposed in said housing means and arranged to move air in said flow path from said inlet to said outlet; drive means rotatably coupled to said blower; air filter means disposed within said housing means in said air flow path; tubulation means providing fluid communication between a particular location in said air flow path and a position separate from said particular location, said tubulation means including a hollow at least partially transparent viewing section defining a curved inner surface and a curved outer surface juxtaposed thereto; and float means retained in said viewing section and movable therein between a first position in response to a given rate of air flow through said tubulation means and a visible second position in response to another rate of air flow through said tubulation means different than said given rate, said inner and outer surfaces forming a lens means that magnifies said float means in said second position so as to provide thereof a virtual image larger than its actual size and at least as large as it appears in said first position, and wherein said location and said position establish through said tubulation means a differential pressure that produces said second position of said float means in response to a clogged condition of said air filter means.