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PVanscoik@ao*.co* wrote:
> 
> i saw something which may be of interest at the Draeger booth.
> a very compact twin DIN cylinder valve - 200 bar.
> 
> looking from above, looks like an *X*. rear two posts have knobs, front two
> posts are threaded in ends for DIN regs.  looked robust, well engineered &
> very compact.
> perhaps highly suitable for redundant regs on single cylinder?
>

These type of valves are not new (at least not in Germany). Two other
manufactures build this valve type as well -- Nautec and Aircon. Indeed
they are very well engineered and especially the handles run very 
smoothly. There is an addon part that allows you to make isolated
doubles
out of two singles equipt with this valve.

However, they have one very big disadvantage:

IT IS NOT OBVIOUS WHICH VALVEKNOB OPENS/CLOSES WHICH POST!!

In a situation where you want to shut down a post, but cannot reach back
to the valves your partner has a 50% chance to close the wrong one. 

Even if you "know" that the knob staight in line with a post closes this
post you might be wrong -- Here in germany they sell two versions: one
where the former mentioned closing mechanism is installed and another
one that has exactly the opposite (ie. the valveknobs close the 90deg 
rotated post).

If you use the valves for doubles it get's even worse. Now you have two
isolation valves. The chances that the isolation is closed while filling
is doubled, too. 

My advise: Stay away from these valves. 

Regards, 
Frank

P.S. I had a pair of those valves installed on 80's. Later I dived them
as doubles. As I moved further into tech diving it became obvious that
these valves are dangerous. I sold them together with a BiBo kit and
got a solid isolation manifold and SS tank bands instead. I told the
buyer about the disadvantages of the valves, but he wanted them
anyway (DSM, you know :-).
--
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