Patent ID: 7237550

Claim:
A respirator containing a filter case, comprising at least one filter case of a substantially rectangular box-shape, having an inlet air panel, with a plurality of air holes, on a first major surface of said filter case, a breathing air panel, with a plurality of air holes, on a second major surface of said filter case, being substantially equal in size, and located opposite, to said first air panel, and a peripheral side wall connecting said inlet air panel to said breathing air panel, and a multi-layer filter element pressed between said inlet air panel and said breathing air panel, having an air-permeable positioning board adjacent to each of said air inlet panel and said breathing air panel with at least one refillable active filter layer sandwiched between said air-permeable positioning boards, thereby holding said refillable active filter layer in position; and a respirator body having an air-impermeable outer surface, a first opening adapted to fit over the mouth and nose of a user, at least one filter opening substantially opposite said first opening, each said filter opening being adapted to accommodate one said filter case, and a breathing space recess, between said first opening and said at least one filter opening, enclosed by said outer surface; wherein said respirator body further comprises an inner filter cup, having an opening adapted to fit over the mouth and nose of a user, and a protruded surface of air permeable material extending into said breathing space recess.