GB464458A - Improvements in or relating to gas masks - Google Patents

Abstract

464,458. Gas-masks. PINELLI, V. Feb. 7, 1936, No. 3814. [Class 81 (ii)] A gas-mask 1 is provided with an exhaling valve 8 set immediately opposite the mouth in a fitting through which speech is readily transmitted and comprising a sound-collecting mouthpiece 13 fitting approximately air-tightly around the mouth, and a sound-delivery duct 9 provided internally with concentric sounddirecting rings 11. The mask has a flanged portion 2 into which is fitted a sleeve 3 screwthreadedly holding a valve casing 4. The valve 8 is of the kind described in Specification 353,380, [Group XXIX], and is held by its flanged base between an internal flange 7 on the casing 4 and the sleeve 9 screwed into the casing at 10. The casing 4 has an external flange 5 bearing on the sleeve 3 with interposed packing 6. The mouthpiece 13 is of rubber and the rings 11 are secured in the duct 9 by rods 12. The valve 8 may constitute or be additional to the normal exhaling valve. An inlet valve 14 is secured in a separate tubular fitting 15. In a modification, the sleeve 9 is made longer to house a valve of the flutter type secured to a tubular fitting having a flange secured similarly to that of the valve 8. In a further modification, the outer end of the sleeve 9, instead of being flared as shown, is contracted and made to open in an upward direction for ready transmission of speech to a telephone transmitter. The parts 4 and 9 may be replaced by a short valve casing screwed into the sleeve 3 from the outer side of the mask and a short valve-retaining sleeve closed at its outer end and having a ring of apertures in its cylindrical surface, thereby converting the mask into one for ordinary use.