GB1446881A - Diving masks - Google Patents

Abstract

1446881 Respiratory appliances J W HEISTAND 10 Dec 1973 [16 March 1973] 12701/73 Heading A5T A full facial diving mast comprises a rigid gun-metal shell 10, with a transparent polyvinyl chloride or polycarbonate viewing portion 76, supplied with breathing gas under pressure from a main hose connected to and rotatable through 180‹ with respect to manifold 14, said shell containing a demand valve 24 through whose diaphragm 32 and flap 40 gas is exhausted to ports 34. The valve 24 and diaphragm 32 are located in recess 82 of shell 10 and when the diver inhales, reduced pressure in an oral-nasal mask 42 and hence in the demand valve housing causes diaphragm 32 to move inwards for lever 104 to move seal 94 from nozzle 92 admitting gas from pipe 18 into mask 42. On exhalation, flap 40 opens and gas passes through the centre of the diaphragm and through ports 34 to the outside of the shell. If diaphragm 32 ruptures, the diver seals ports 34 with finger and thumb. Non-return valve 16 prevents evacuation of the mask if the main hose severs. Spigots protruding through holes 114 and 120 secure the manifold 14 to the shell and supply gas respectively via pipe 18 inside the shell to the demand valve 24 and via the free flow valve controlled by knob 26 to a distribution nozzle. A closed cell neoprene hood 48 and an open cell foam ring, through which the diver's face protrudes to be sealed sealed by a neoprene layer 52, is attached to the shell 10 by holes 72 through a rubber strap 70 fittting over posts 66 on a clamp 54, 56 which rests on a flange 64. A hose for a reserve gas supply or to power auxiliary equipment e.g. to inflate underwater lifting devices may be connected to and be rotatable with respect to manifold 14, the flow to or from the manifold controllable by needle valve 22. Water is expelled via valve 36. Communication terminals 46 are provided.