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SOLD!!! 2 Beuchat Y-Valves

Discussion in 'Classifieds: Tanks, Valves and Bands' started by Teknadv3x, Dec 4, 2019.

  1. 2airishuman

    2airishuman Solo Diver

    # of Dives: 100 - 199
    Location: Greater Minnesota
    2,410
    1,619
    113
    The dual-dip tube Beauchat Y-valves have been sort of a legend among solo divers. I've never seen any actually come up for sale, since I started diving.

    Safe diving, particularly safe technical diving, is not solely an armchair intellectual exercise. Manifolded doubles are the gold standard for redundancy, not only because they make sense on paper, but also because they have better and longer track record for safety than any other SCUBA diving system, with millions of dives over around 40 years, and few if any serious accidents caused by failures of the manifold system.

    Whether the isolator valve in a twinset overall improves safety is an equivalent question. The received wisdom is that it does -- neck o-ring failures, though rare, do occur, as do burst disc failures. There are also have been, though rare, situations where impact has damaged both a handwheel and a regulator.

    One thing is clear, to me, though -- the Beauchat Y-valve is a huge improvement over H-valve arrangements, because the posts are better positioned, and because the gas paths are independent. I experimented with H-valves for solo diving, for a while, and came to the conclusion that they aren't useful.

    Finally, with the declining availability of LP120 and HP149 cylinders, there are few dives where a Y valve is useful. I have a 72cf twinset (144 cf total) and find that there are few dives where it is useful. More often, dives that warrant redundancy call for a larger gas supply.
     
  2. Schwob

    Schwob Solo Diver

    # of Dives: 200 - 499
    Location: Illinois
    1,821
    983
    113
    Interesting...

    Well, I take it that neck o-ring failures do occur. But those bother me. Shouldn‘t occur...

    I am troubled by the to me seemingly tribal knowledge of them occurring far more often than any manifold related failures, be that an o-ring in there or due to manifold transmitted impact or other forces.

    Ah, yes, that burst disc. I concede that..., but, see below.

    But, so, where is the knowledge that there are less manifold related or caused failures occurring than say neck o-ring failures coming from?
    Is it in deed so? Data?

    These neck o-ring failures really bother me.
    Why do they fail?
    Failure only if wrong duraneter selected or way old because not replaced with cylinder inspection (or, pending where you are, never inspected)...
    Do good, proper durameter, not old neck o-rings, properly installed in clean tanks with good thread and good valve really fail?
    How possibly? What could that failure mode be?

    And that burst disc assembly... they are supposed to protect the fill station / tank monkey if somehow the tank geht’s overpressurized only, right? Do they really blow whilst diving in a non overpressurized tank (or at least not for the disk chosen)?
    How does that failure mode look like?
    Any way to avoid it other than to dive where burst discs are not used?
     
  3. MrVegas

    MrVegas Nassau Grouper

    # of Dives: 50 - 99
    Location: Ohio
    114
    61
    28
    I don't pay attention for a few days and look what I miss. Oh well. Did these have the standard neck size for American tanks?
     

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