Brian,
You can put a first stage scuba regulator on the air tank. If the air tank
outside, the pressure will not rise over 10 bar +outside pressure. Control
is then also better.
A pressure gauge on the VBT is also useful.
But I also like a relief valve. If somebody put HP air on the VBT, the
result can be deadly!
Emile van Essen
_____________________________________________
Van: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] Namens Brian Cox
Verzonden: maandag 16 februari 2009 8:00
Aan: Personal_Submersibles@Psubs. Org
Onderwerp: [PSUBS-MAILIST] over pressure hard tank
Question for some experienced submariners,
I'm wondering if this is something that is commonly done, say
you have your hard ballast tank partially or half full. Now the bottom vent
for expelling water is closed, at this point hp air is injected into the
hard ballast tank, since no water can get out the bottom of the tank, air in
the top of the tank increases in pressure and approaches what ever pressure
is in the hp tanks. Since the bubble in the hard ballast tank cannot grow
any larger no increase in buoyancy for the sub would take place. Then one
would be able to cruz around like this until it was desireable to ascend.
So at this point if the bottom vent were to be opened then the bubble inside
would be able to expand and thus creating more buoyancy. Am I understanding
this right ?
This is assuming that the hard ballast tank can handle a significant amount
of pressure, not as much as the HP tanks but up there. It would have a
relief valve that wuld pop before it's max pressure rating.
Thanks,
Brian
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