Solenoid Valves

[Phil Nuytten <72020.572@compuserve.com>]

Re: solenoid valve(s) for pressure application: use any high-end, open coil
(not potted) valve and run oil-filled. The usual method is to machine or
fabricate a metal or plastic box just like a camera housing .Connect the
Solenoid valve male tube fitting (Swagelok best!) to a double male bulkhead
fitting ( O ring sealed) by means of a short piece of double female tubing.
(easier to find than a solenoid with a thru-hull built-in!). The bulkhead
goes thru the 'lid of the box and is accessed from the outside. Install a
bulkhead electrical connector ( we use mostly 'Impulse' and 'EO'-style) and
wire the solenoids to it (them) to power the coils from a switch/button
inside the sub . Fill the whole thing with a suitable oil such as 'Telus' -
the oil make is not critical but some motor-type oils will damage potting
compound ( hence, open-coil, non-potted)and/or wire insulation ( best to
use TFE covered wire) It's not a bad idea to  tap the plexi box with a pipe
thread - say, 1/8th NPT, screw in a double male elbow, and force a short
length of capped surgical tubing onto it ( 6" or so, long) to handle
thermal expansion/contraction ( silicon tubing best) - not strictly
neccesary, but seal on box lid will often weep in hot sun, otherwise - and
can also put structural strain on box when passing thru a thermocline. Hope
this helps.
Nuytco