Apparatus for cleaning particles from a web

Apparatus for directing an air flow against the surface of a moving web, with sufficient velocity to penetrate a boundary layer adjacent the surface of the web and for creating sufficient turbulence in the air flow to produce microvibrations in the web for cleaning particles therefrom, comprising:

• a box positioned adjacent the surface of a web to be cleaned, said box including at least first and second chambers extending across the width of the web to be cleaned and transversely to the direction of motion of the web to be cleaned, said first and second chambers including first and second walls, respectively, each wall facing and being generally parallel to the surface of the web to be cleaned;
• first and second elongated slits extending along said first and second walls, respectively, said first and second slits each extending generally across the width of the web to be cleaned and being spaced apart in the direction of the motion of the web to be cleaned, said first and second slits having respective axes perpendicular to said first and second walls, respectively, and thus perpendicular to the surface of the web to be cleaned;
• means to provide an elevated air pressure in said first chamber;
• means to provide a negative air pressure in said second chamber;
• first and second blades positioned on said first wall adjacent and on opposite sides of said first elongated slit and extending from said first wall toward the surface of the web to be cleaned, said first and second blades each being generally triangular in cross-section, each having a first surface inclined away from said axis of said first slit, and each having a second surface, said first and second surfaces of each of said first and second blades intersecting at corresponding first and second edges on opposite sides of said first slit and adjacent the web to be cleaned, said first and second blades cooperating to form a diverging nozzle for elevated pressure air in said first chamber, said first and second edges being located sufficiently close to the surface of the web to be cleaned that elevated pressure air passing through said diverging nozzle penetrates the boundary layer at the surface of the web and is deflected by the web to pass beyond said first and second blades to create turbulent air flow to produce micro-vibration of the web to be cleaned and to loosen particles at the surface of the web;
• third and fourth blades positioned on said second wall adjacent and on opposite sides of said second elongated slit and extending from said second wall toward the surface of the web to be cleaned, said third and fourth blades each being generally triangular in cross-section, and each having a first surface generally parallel to said axis of said second slit and having a second surface inclined toward said axis of said second slit, said first and second surfaces of each of said third and fourth blades intersecting at corresponding third and fourth edges on opposite sides of said second slit and adjacent to the web to be cleaned, said third and fourth edges being located sufficiently close to the surface of said web to create turbulent air flow to further loosen particles at the surface of the web as the air from said first slit flows along the web to be cleaned and into said second slit.