[PSUBS-MAILIST] Controle Valves

["Dan H." <machine@epix.net>]

I'm doing some of the plumbing in the K-350 I'm building.

According to the plumbing print, the Captain has designed in "Henry 6253
diaphragm valves" for controlling the air to the ballast tanks.  These
are backed up with secondary ball valves for safety. I'm not familiar
with these "Henry" valves.  I looked throughout Mc Master Carr, and they
have hundreds of valves, but don't list any diaphragm valves.

Does anyone know what these valves are like, where I can locate them,
and if they're really needed.  I think I can just use a quarter turn
ball valve for the main ballast tanks, but I'm thinking a quarter turn
valve may be to rough to control the variable ballast tank air.

I don't have any sub experience and would appreciate some input from
anyone who does or anyone else building one.

Thanks, Dan H.