Abstract: A respirator filter assembly for use in a respirator apparatus wherein the assembly includes a respirator filter cartridge having a housing which contains filter material and has an inlet portion and an outlet portion, and a valve device that is selectively securable to an opening of the inlet portion, the outlet portion of the housing being preferably securable to respirator structure such as a face mask. The valve device preferably comprises a valve support member and a one-way valve element. The support member is provided with means for detachably securing the valve device over the inlet portion whereby the valve element is situated to regulate the inlet opening. The support member also desirably has a means for connecting the support member to the respirator apparatus, preferably the filter cartridge, such that the valve device may reside in a position so as not to obstruct the filter cartridge inlet opening when the valve device is not attached to the inlet portion.

Abstract: The present invention provides a cover assembly and pre-filter for use with a high-efficiency particulate filter of a respirator. The semi-rigid cover assembly fits easily and snugly over the high-efficiency particulate filter and remains in place due to friction between the edges of the ribs located on the inside of the cover housing and the sides of the high efficiency particulate filter. In this position, the ribs hold a removable pre-filter against the front face of the high-efficiency particulate filter while the cover housing protects both the pre-filter and high-efficiency particulate filter. This arrangement allows the inexpensive pre-filter which traps large diameter particulate matter, thereby extending the life of the more costly high-efficiency particulate filter, to be frequently and easily replaced.

Abstract: The present invention provides a filter cover assembly for use with the filter of a respirator. The semi-rigid filter cover assembly fits snugly over the face of the filter and, with the use of a one-way valve assembly mounted therein, allows the user to continue using the respirator while at the same time containing any contaminated particulate matter that may fall out of the filter. This permits the user to continue using the respirator while in a decontamination zone without danger of dispersing contaminated matter. It also permits easy handling and storage of the filter between uses without necessitating the cleaning of the filter.