Manifold will not break, we plug the burst disks, and the tank ring usually
goes slowly, but theoretically , yes. In reality the real deal is hitting
the right side hard enough to break off the knob in the on position and
dislodge or break the reg at the same time, or lose the knob and then have a
freeflow.

The isolator is there to solve those problems, but we try to cut it down to
as few as possible otherwise.

-----Original Message-----
From: Cam Banks [mailto:cam@ca*.co*]
Sent: Thursday, April 19, 2001 9:27 PM
To: George Irvine; Jiri Stetina; techdiver@aquanaut.com
Subject: Re: Isolating Manifold Question


If I'm not mistaken, there are then four failure modes that would require
you to isolate:

1) burst disk blow-out (non-issue if disks are plugged)
2) 1st/2nd stage failure PLUS knob failure (breakoff)
3) tank neck o-ring failure (pretty unlikely, but still in the running)
4) broken manifold bar (hope you only broke one side - this one scares me a
little.  It's the only one I can think of where you wish you didn't have the
manifold)

Any others anyone can think of, or anyone disagree with the above?

Also, I'm looking for a source for stainless or brass plugs to replace my
one-piece burst disks.  Any suggestions?  Or I could get a shim kit (as
George suggested) and put a shim underneath them, but I'd like some feedback
from the group that this is the right method, even for one-piece burst disk
assemblies.  Thanks.

Cam


> From: "George Irvine" <kirvine@sa*.ne*>
> Date: Thu, 19 Apr 2001 18:34:44 -0400
> To: "Jiri Stetina" <jstetina@ne*.cz*>, <techdiver@aquanaut.com>
> Subject: Re: Isolating Manifold Question
>
>
> We plug our manifolds as well. O ring failures are not even enough to call
> a dive on a proper manifold. That is a double barrel ring adjustable like
> the Sea Elite. When any of the knobs break off, this usually will not
cause
> a leak unless the bonnet o ring goes, and again, not much of a leak. The
> real failure mode is a double failure: it is when the knob and the reg
fail,
> either by freeflow freezup or by knocking the knob off and then failing
the
> reg in any fashion. That is the only failure that requires isolation. We
run
> low IP's to prevent the freezups, we run DIN regs to reduce the risk of
> breakoffs ( and in some cases replace the DIN connectors with stainless
> steel ones ), and we rig the regulators so that all of these contingencies
> including roll off break off of a knob are taken into consideration .  See
> my article on this on the WKPP web site.
>
> ----- Original Message -----
> From: "Jiri Stetina" <jstetina@ne*.cz*>
> To: <techdiver@aquanaut.com>
> Sent: Wednesday, April 18, 2001 11:25 AM
> Subject: RE: Isolating Manifold Question
>
>
>> The reasons for diving with open ISO are clear. Imagine manifold withouth
>> burst disks  - European manifold. Which situation could be solved by
>> closing isolation valve? Leaking o-ring can be solved by closing the tank
>> valve. The leaking ISO istself? Manifold o-ring failures?
>>
>> Do you have any experience that needs closing the isolation valve during
>> the dive?
>>
>> Jiri Stetina
>>
>>
>> --
>> Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
>> Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
>>
>
> --
> Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
> Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
>

--
Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.

--
Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]