Non return safety valve - fitted to safety suits or divers suits, is made entirely out of flexible material

摘要

The valve which may be made in any suitable flexible material may be fitted to a safety suit or helmet without modification to this. It consists of a double flap. One side of the flap has a hole in the centre to connect with the inside of the suit. One side of the double flapis opened, and the other three sides are sealed closed. A rigid wire like frame fits inside the flap in order that it shall maintain its shape. When the pressure inside the suit is lower than atmospheric the edges (7) and (8) touch and the valve is closed. When the pressure is higher, the edges are parted and the valve opens.