Abstract: Breathing equipment, e.g., a half mask-type respirator, is disclosed. A mask is provided with three ports of common dimension in any one of which inhalation or exhalation fittings housing inhalation or exhalation valves may be mounted. Disclosed are chemical and mechanical filtration cartridges usable alternatively or in combination. Disposable chemical filtration cartridges having novel lock and seal structure are disclosed. Bayonet-type couplings for coupling the filter housings to the inhalation respiratory fittings and an audible device to indicate that the filter housings are properly coupled are disclosed. The respirator valve is a thin umbrella-shaped disk valve having a multiplicity of radiating ribs which biases the valve to the closed position. A novel crown strap suspension is also provided.

Abstract: Breathing equipment, e.g., a half mask-type respirator, is disclosed. A mask is provided with three ports of common dimension in any one of which inhalation or exhalation fittings housing inhalation or exhilation valves may be mounted. Disclosed are chemical and mechanical filtration cartridges usable alternatively or in combination. Disposable chemical filtration cartridges having novel lock and seal structure are disclosed. Bayonet-type couplings for coupling the filter housings to the inhalation respiratory fittings and an audible device to indicate that the filter housings are properly coupled are disclosed. The respirator valve is a thin umbrella-shaped disk valve having a multiplicity of radiating ribs which biases the valve to the closed position. A novel crown strap suspension is also provided.