[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PSUBS-MAILIST] Diver Lockout.... serious question here!!
Where the volume of the lockout chamber is insignificant in comparison to the
volume of the rest of the sub, then the lockout may be vented into the sub.
This will result in a pressure increase over 1 atm, but this may be
acceptable if the difference is slight and/or the exposure time is low before
an opportunity to vent the sub to atmosphere arises. If this is not the
case, then the lockout chamber gas needs to be compressed to reduce the
pressure. This compressed gas may be vented to sea, or reclaimed into
storage bottles. In the case of deep lockout operations, and depending on
the volume of the lockout, reclaiming the gas may be more cost effective.
It is certainly dangerous to reduce the lockout pressure too fast when persons
are inside. A good lockout design might incorporate small diameter through
hull gas fittings to the compressor system, such that in the event of a valve
or piping failure, the pressure reduction in the lockout would not exceed the
maximum permissable ascent rate under normal operating conditions, until the
failure could be isolated. You still run the risk of exceeding the
decompression ceiling in the event of a failure, but provided you notice and
respond to it quickly, this would reduce the risk of barotrauma events.
-Sean
On July 28, 2007 21:29:06 Lil Brother LLC wrote:
> I've got into some pretty serious questions lately......and I've done a
> little reading about diver lockout (archives), but the archives raised a
> question.
>
> If you have a 1 atm sub, with a diver lockout........how do you lock a
> diver back in?
>
> Are there any 1 atm subs with a lockout?
>
> If there are......if the lockout has been pressurized to the outside
> pressure........what method is used to depressurize it back to 1 atm?
> (these questions are redundant I know)
>
> And the last....the important one.....is this on the dangerous side? If
> you depressurize to fast......the bends.
>
> I was reading about the nice sub.....(the Krata I think.....please don't
> quote me ....I've had a very long two days)......but I didn't notice if it
> was 1 atm or not.
>
> Some one learn me on this. :-)
>
> (Hey....at least I know what a VBT is for now.)
>
> James Long
> Owner/Designer
> Lil Brother LLC (Instrument Division)
>
>
>
>
>
> ************************************************************************
> ************************************************************************
> ************************************************************************
> The personal submersibles mailing list complies with the US Federal
> CAN-SPAM Act of 2003. Your email address appears in our database
> because either you, or someone you know, requested you receive messages
> from our organization.
>
> If you want to be removed from this mailing list simply click on the
> link below or send a blank email message to:
> removeme-personal_submersibles@psubs.org
>
> Removal of your email address from this mailing list occurs by an
> automated process and should be complete within five minutes of
> our server receiving your request.
>
> PSUBS.ORG
> PO Box 53
> Weare, NH 03281
> 603-529-1100
> ************************************************************************
> ************************************************************************
> ************************************************************************
************************************************************************
************************************************************************
************************************************************************
The personal submersibles mailing list complies with the US Federal
CAN-SPAM Act of 2003. Your email address appears in our database
because either you, or someone you know, requested you receive messages
from our organization.
If you want to be removed from this mailing list simply click on the
link below or send a blank email message to:
removeme-personal_submersibles@psubs.org
Removal of your email address from this mailing list occurs by an
automated process and should be complete within five minutes of
our server receiving your request.
PSUBS.ORG
PO Box 53
Weare, NH 03281
603-529-1100
************************************************************************
************************************************************************
************************************************************************