Rotating element fume collection apparatus

Air filter comprising:

• A. Fan support structure having an upstream forward end and a downstream rearward end;
• B. Fan motor and air impeller means affixed to each other having an axis of rotation and mounted in said fan support structure for driving air from said forward end to said rearward end substantially parallel to said axis;
• C. Filter element retaining hub carried by said impeller means and extending forwardly therefrom and having an outer, cylindrical surface of a first diameter and having a predetermined axial length;
• D. Filter element having the form of a thick, annular disc having an outer, second diameter and an inner diameter approximately equal to said first diameter, the thickness of said disc being approximately equal to said axial length of said retaining hub, said filter element being mounted thereon and rotationally carried thereby;
• E. Cylindrical thin walled shroud member carried by said fan support structure and extending forwardly therefrom concentrically with said axis, the inner diameter of said shroud member being slightly greater than said outer, second diameter of said filter element and having an axial length at least approximately equal to that of said hub;
• F. A circular base plate affixed coaxially to the forward, upstream end of said impeller means;
• G. A hollow cylindrical portion extending coaxially forwardly therefrom and having an outer diameter equal to said first diameter and having an inner hub diameter;
• and
• H. A set of filter element supporting vanes mounted on the forward surface of said circular base plate and extending radially outwardly from said cylindrical portion, said vanes having a predetermined axial length substantially equal to or less than the thickness of said filter element and being of the character to impress the rear surface thereof and provide an axial space between said filter element and said circular base plate, said hollow cylindrical portion extending axially forwardly from said vanes by a length at least approximately equal to the thickness of said filter element.