The Design of an Adjustable Breathing Bag Exhaust Valve for Closed and Semi-Closed Circuit Scuba.

摘要

Existing closed and semi-closed circuit scuba breathing bag exhaust or relief valves were studied with the object of developing a standard U.S. Navy valve. A Canadian relief valve proposed as a substitute for the British CDBA relief valve was also studied. The latter valve (CDBA) was used as a starting point,and redesigned to provide a range of relief adjustment from approximately 0.4to 2.85psi. A relatively secure,manually operated dump knob which permits rapid purging of the breathing bag is provided. A hand-made,modified valve was tested and found to be superior to the available models. Detailed manufacturing drawings of the modified valve,including several design refinements such as non-magnetic materials and improved fittings,are submitted with the recommendation that prototypes be procured and field tested. (Author)