GB297854A - Improvements in or relating to respirators, gas-masks and other like apparatus - Google Patents

Abstract

297,854. Sadd, J. A. June 1, 1921. Respirators. - A fitting for a respirator mask a, Fig. 2, comprises a tube b secured to the mask and enclosing the exhaling valve d; a branch tube c, connected with the filter canister or the like, communicates with an annular space c<1> opening into the mask. The exhaling valve is secured by a corrugated nipple e or otherwise to a tube e<1> opposite the mouth. A sound concentrating cone f is secured to the tube e<1>. The member b also may be flared or trumpet shaped to facilitate the transmission of sound from the mask. In the fitting shown in Fig. 6 for use with a mask in which the inhaled air is drawn over the eyepieces to prevent condensation thereon, such air is drawn through a tube h which may be closed, when direct breathing is desired, by a spring pressed valve g operated by a lever i engaged by the teeth. The exhaling valve comprises a diaphragm d<1> having a central aperture d' closed during inhalation by contact with an occlusion member d<4> carried by a spider d<2>. The valve is protected by an apertured plate k. Leakage of noxious gases into the mask during use may be obviated by forming a channel such as l, Fig. 9, around those parts liable to leakage. The channel is supplied with exhaled air by a pipe communicating with the member b, or may be otherwise supplied with purified air. Alternatively several parallel channels such as l not supplied with air may be provided.