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High efficiency respirator

  • US 4,827,924 A
  • Filed: 03/02/1987
  • Issued: 05/09/1989
  • Est. Priority Date: 03/02/1987
  • Status: Expired due to Term
First Claim
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1. An expanded area filtration face mask adapted to cover the mouth and nose of a wearer of the mask comprising:

  • a filter member including at least one layer of filter material, said filter member having,a shape-retaining annular base adapted to fit confomingly against the face of a wearer of the mask and tending to hold said filter member in the opened position;

    at least two sidewall portions generally extending away from said annular base;

    a frontal portion bridging said sidewall portions; and

    at least two supporting arch structures disposed at the junction of said sidewall and frontal portions, and intersecting said annular base;

    the interior surface area of said filter member defined by said sidewall and frontal portions being greater than that of the segment of a sphere defined by a plane having the same area as enclosed by said annular base and a height equal to that of the interior of the filter member, whereby the pressure drop through said filter member is no more than 40 mm H2 O at a flow rate of 85 liters/minute;

    said filter member being constituted such that upon removal of said annular base, said sidewall portion can be folded along with supporting arch, in face-to-face contact with said frontal portion to form a flat structure having an at least partially curved perimeter.

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