Article about OC Bail-out

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Quick disconnect for BOV or second stage regulator.

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Jakub
Golem Gear ShopKeeper
www.golemgear.com

jhaaja

I have been using Swagelok QC6 on my YBOD. I have one male end that is on the LP-hose that comes from the BOV. Then I have the females on stage reg LP-hoses.

I only use off-board to feed the BOV.

JH

nmanfield

Hi JH,

any chance you could give us the exact part number from swagelock? And some photos if you could. i searched on their site and got 140 hits!

Thanks,

Nick

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Tub 'O Lard

jhaaja

I do not have any photos at the moment but I can try to take some.

Here are the part numbers for my pieces of Swage:
Female body (used in stage reg LP-hose) SS-QC6-B-600,
LINK---->Part Number Search Results

Male stem (used in the BOV LP-hose) SS-QC6-D-600
LINK---->Part Number Search Results

Tube to hose adapters for both SS-4-HC-A-601
LINK----> Swagelok

I also bought the plugs to protect the QCs when not coupled:
Female body protector SS-QC6-BP
LINK----->Part Number Search Results

Male stem protector SS-QC6-SP
LINK----->Part Number Search Results


I clambed the tube to hose adapters to my LP-hoses at the local hydraulics workshop.

Hope this helps.

JH

nmanfield

Hi JH,

Thanks very kind - Phots would be very helpful

What I'm trying to do is to be able to standardise all my hoses so that they are the same as on my Meg. Drysuit, wing, bailout whips etc. I'd like to be able to quick connect a BOV (or 2nd stage on a FFM) so that if i have a failure I can re route any other whip / hose.

Unfortunately i don't know which connector is most suitable - all i need is a QD which has a standard female scuba 2nd stage fitting on one end and the smae nipple as on my Meg counterlungs on the other.

Wonder if anyone out there can help!

Cheers,

nick

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Amarok

Nick;
See the link in the BOV section " Golem BOV and Swaghelock threads". Mark N did some schematics and photos on an earlier post and Jakub was real helpful with the QD parts and real quick delivery. Right now set up is to offboard but once I get back from Thailand hopefully can do a set up for both off and onboard.
Cheers
Keith

Dave Sutton

Reading with interest, the QC fittings are a good solution to the quick disconnect, but not the only ones. There are any of a large number of brass QD's available for a fraction of the cost of Swagelok ones available for industrual hydraulic applications. McMaster-Carr catalog is filled with them.

Interconnection to diving hoses is best done by purchasing a standard oxgen fitting as would be threaded onto a welding regulator in the USA and doing a VERY simple modification which allows a standard second stage feed hose to attach to it exactly as it would to a second stage and buying the QC fitting the the pipe thread female that this fitting screws into.

As follows:

Purchase a 9/16-18 oxygen male to 1/4 NPT pipe thread male fitting. This is the fitting that threads into the body of a welding oxygen regulator in the USA and anywhere else where non-metric threads are used. Available from McMaster-Carr worldwide. They are always brass. The thread on the exterior (9/16-18) is the same as the thread of a second stage feed hose. All that needs to be done is to drill the inside diameter to the correct one for the O-Ring sealed stem of the supply hose to be inserted into the fitting and it is done. I can later write the drill size, must go to the shop and test it.

Thread the other end into the quick disconnect fitting of your choice using pipe tape and it is done.


From the non-technical side of the discussion, we have standardized on using *all* diluent for the loop and BOV from offboard gas. We use the small internal cylinder of the Mark-15's for suit inflation and for *emrgency diluent*, and for not a lot else. It is accessable to the rebreather thru the diluent selection valve mounted on the rig (on-board v/s off-board) but the *default* position of the valve is offboard, and the *default* assumption of the divers is that we exchange offboard bottles to change diluent for various depths and profiles and use that as the MAIN gas supply and that all internal cylinders are simply air. The internal gas feeds drysuit and can be used for decompression diluent if needed (IE: Nitrox as loop gas with air diluent). All BOV's are plumbed to offboard gas. This ends the question of how much volume is available to the BOV. One thing we do always consider is to attempt to have a viable diluent 02 percent *at the surface* so the BOV will provide a gas that will maintain diver conciousnss *at the surface* and will accept an initial loop PP02 that is rather higher upon first reaching botttom depth due to what might normally be considered a "rich" diluent for depth (IE up to 2.0 PP02), but we accept that the time duration on this gas is short (IE the excess 02 is metabolized within a short time after reaching bottom, and only then does 02 addition begin), and also that a diver on BOV breathing on the bottom will have a higher PP02 than "normal" or the short period he is at that depth. We used the US Navy LAR-V oxygen exposure tables to assure ourselves that these PP02's are OK *for the short while*. We feel it better to accept this than to accept the chance of opening a BOV on the surface and becoming unconcious immediately, and naturally the richer gas assists the OC decompression solution as well. And remember, this is in open ocean diving, where immediate ascent is available. Overhead environment diving would be a different calculus.


Should note also that I have made a manifold on the exterior of the Mark-15 from which comes internal diluent to a series of regulator-hose threaded ports. Normally only the drysuit feeds from it. But for shallow diving, the BOV hose goes to it, no external diluent is carried, and the rig is a "stand alone" with suit inflate, BOV, and all gas from internal. Makes a streamlined rig for no deco diving.


Many ways to do this, and an excellent discussion.



Dave Sutton

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"Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com

diverklondike

While I know that people have very strong views here. My approach is being able to "select the source" based on the dive....

nmanfield

I suppose this is what I'm trying to do. I would welcome any adults out there giving me any thoughts befor I kill myself!

Please bare in mind that this is a setup is with a Meg and a Drager FFM which has a second stage mounted to it. The red blobs are the 2nd stages. M denotes a male end F, female. As you may be able to see (I'm not a draughtsman!) The offboard can be plugged directly into the unit as well as having OC bailout capability. The FFM 2nd stage is plugged into the Onboard dil, but can easily be plugged into the offboard dil or O2 (rich) mix.

Anybody else using anything similar? What do people reccomend for the black hose connection?

Thanks,

Nick
(blackbelt in powerpoint)

Attached Images

Presentation1.jpg (31.7 KB, 197 views)

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pchanning

Well done Cedric.
I say the following desperately trying to avoid the perception of 'mine is better than yours' etc. I will risk the following comment as I believe that people coming to read your excellent article should see it as a concise overview [1]

The BOV's you note on the article are either not available (Nemo + Cis) , good for sports diving (????) or extremely uncommon (RB80/ Halcyon), which leaves the Golem and V4tec. A mention for Tracy at Divematics would be useful - these BOV's can have benefits over all the others when it comes to personal configuration/ reg choices and changing regs very cheaply IMVHO.

Also, perhaps you could put a list of hyperlinks at the foot of the article, it would do much to help those considering a BOV.

btw - have a blob for a great piece of work.



[1] ...unlike Mastering Rebreathers (Jeff Bozanic) and it being curiously devoid of information on the one rebreather that has outsold all!

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Cheers
Paul

The key to enlightenment... is survival.