Submersible One Way Relief Valve...

[montucky]

I hope this is in the correct location...

So I am working on an autonomous submarine for a senior capstone project at school. Basically, I made a large pressure vessel that houses our computer systems as well as our pneumatics system. It is an acrylic tube that is glued to two aluminum flanges with O-ring seals and outer plates that clamp down on the rings to create a seal.

This vessel does not experience very significant pressures as it only needs to be rated to about 15 feet of depth, and it has been tested to those limits so far multiple times.

The trouble I am having is with our pneumatics system. We have a torpedo launching mechanism that is driven by a small paintball gun tank full of CO2. The C02 enters into the pressure vessel where it is input into a manifold and distributed electronically when we want our torpedos to fire.

I am concerned about a leak in the manifold or any connections that might cause pressure to build inside of the pressure vessel, and could potentially cause it to fail. To that end, I have been researching one way release valves.

We have procured a couple of samples from Halkey Roberts, and the one that is most interesting to us is this 1.5psi release valve.

In an ideal world, this valve would release pressure inside the sub once a 1.5psi pressure differential was found, and hopefully release and re-seat without letting water come in and potentially compromise our electric systems.

My thoughts on testing this were to create a small PVC pressure vessel, and install this valve as well as a Schroeder valve on the PVC ends. I would then take it into something like a bathtub and let it release pressure for a while, then take it apart and check for leaks.

Am I missing anything? Any advice.

Thanks so much,

graeme

And here is a picture of the sub, click to enlarge...

 

[gr2vessels]

Have a small seal chamber installed on the PRV outlet, like an open caisson. The gas will be relieved into the chamber, from there the excess it will bubble away. The water will never contact the PRV outlet.
Hope this trivial answer helps.
Cheers,
gr2vessels

 

[chicopee]

I would've had a smaller ,lower pressure intermediate tank fitted with a pressure regulating valve for the discharge of the high pressure CO2. This intermediate PV would inside the larger acrylic vessel and would be connected to the torpedo launching mechanism. Water infiltrating into this intermediate tank could be drain back into the "ocean" with a valve arrangement. The pressure inside that intermediate tank should be enough to drain it. The actuation of the drain valve could be problematic and piping connection thru the acrylic tank would be liquid tight. The intermediate tank could also be positioned outside the acrylic vessel.