2400psi yokes... 3000psi fills?

[northernone]

Do we have consensus on the risk (real or speculative) of using yokes from an era which had 2250/2400psi service pressure now at 3000 psi service pressure?

I've believed the speculation most yokes are significantly over engineers and the failure presssure is far more than 3000psi, still leaving an acceptable (personally decided) safety margin.

Particularly interested in accounts of catastrophic failure... Are those common?

Speaking of ones such as the left. Side curiosity, the visually identical middle and left yoke... 3000 psi and 4000 psi stamped. Are they any different from each other?

 

[Bryan@Vintage Double Hose]

Even on the remote possibility it would extrude, the Oring would let go and relieve the pressure before any force could be transferred to the yoke.
Navy used early yokes on 3000psi cylinders as soon as they were available.

 

[northernone]

Even on the remote possibility it would extrude, the Oring would let go and relieve the pressure before any force could be transferred to the yoke.
Navy used early yokes on 3000psi cylinders as soon as they were available.

Thank you.
Cameron

 

[Luis H]

Some of the earlier yokes in some cases would flex enough that allowed the O-rings to extrude and blow an O-ring. The metal flexing is purely elastic and I have never seen any permanent deformation.

I surely have never seen or heard of any yoke developing a fracture or rupturing. The O-ring will let go releasing the pressure with just elastic flexing of the yoke.

The number of yoke flexing and blown O-rings has been “blown” out of proportion. It has happen and that is why the yoke connection has gotten a bit of a bad reputation. But my observation is that user error contributes to these events more often that the old thin yokes.

The 3000 psi and 4000 psi yokes are exactly the same. They have just added a bigger “safety factor” for whatever reason…

 

[macado]

Another data point but I have used plenty of 2400psi yokes on 3000psi tanks. As Luis and Bryan said, you could get o-ring extrusion.

It's not enough for me to worry.

 

[2airishuman]

Side curiosity, the visually identical middle and left yoke... 3000 psi and 4000 psi stamped. Are they any different from each other?

I concur with Luis H's assessment.

Older Conshelf yokes were stamped 4000 psi. Newer ones were stamped 3000 psi, during the era when it was thought that a yoke connection was necessary for use at over 3000 psi and DIN was thought to be the only acceptable connection at such pressures. There is no difference other than the markings.

 

[northernone]

Exactly what I was hoping to hear. (I was biased)

I'll put the question back to bed. Interesting the poll demonstrates a lack of consensus though. Maybe my question doesn't formulated identically?

Thanks,
Cameron

 

[captain]

Exactly what I was hoping to hear. (I was biased)

I'll put the question back to bed. Interesting the poll demonstrates a lack of consensus though. Maybe my question doesn't formulated identically?

Thanks,
Cameron

Probably most of the negitives were from divers who weren't alive before PADI.

 

[Ojai Diver]

I would go by what was marked on the yoke.

I doubt there would be a catastrophic failure, but my old 3000 psi yoke Conshelf would blow o rings regularly when filled to 3500 psi.

It was not a nice feeling waiting for one's o ring to blow, so I upgraded to DIN.

 

[captain]

I am yet to have an O ring blow even on my 2250 psi yokes at 3000 psi The Navy was the first with 3000 psi aluminum tanks in the mid fifties. They used the cylinders with stock USD DA Navy Approved and USD Aquamasters when the 2250 psi steel 72 was the norm for civilians. Photo from the 1958 Navy diving manual. 3000 PSI non magnetic aluminum cylinders and DA Navy Approved US Divers regulator.used buy UDT.

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