Conshelf XIV exhaust valve?

[reefrat]

Reefrat, a lot of people don't realize that the Conshelf and Calypso regulators of that time have a metal cup at the bottom, which retains an air bubble in the regulator immediately under the exhaust valve (in most diving positions). This air bubble allows the mushroom exhaust valve to open in air, rather than water. Because of this, it opens fully, all the way around; mushroom valves with water around them only open partially, according to the U.S. Navy's Experimental Diving Unit. What this means is that underwater, this regulator's exhaust performs better than those with water contact on the exhaust valve.

SeaRat

Hey John I have never heard this before but it makes perfect sense and sounds like a case of lost ancient technology!!
Although I imagine it would work better in a slightly face-up position as facing horizontal it looks like the bubble would only be in the top corner of the valve.
Anyway, exhausts are only a few dollars so I'm going to clean up the valve seat and put in a new one plus a black silicone main diaphragm from VDH.

 

[John C. Ratliff]

Reefrat,

You can see the breathing characteristics in this report by the NEDU, titled An Evaluation of Commercially Available Open Circuit SCUBA regulators, 1987. The USD Conshelf XIV graphs start on page C-139.

SeaRat