YOKE vs DIN

[iain/hsm]

I have a yoke reg designed for 4000# service before DOT regulation changed to DIN only for 3500# and above, probably to prevent someone using a 1800# service from over 3500# pressure which could cause a catastrophic accident rather than just blowing an o-ring.

Bob My guess is your going back 20 odd years here and it was an old US Divers A Clamp
you are referencing. Details and accuracy matter in these types of posts to me at least if I am involved but it would would be good if you were to verify.

My point on these 4000psi stamped rating on the US Divers Regulators is that they did not take into account the developed pressure generated of a full cylinder at 60 degrees centigrade and therefore had to reduce the service pressure rating down to 3500 psi to cover on later models.

Now by contrast the retail scuba sports market have no such requirement so the entire batch were sold to recreational divers with no problem. Saving considerable cost.
Nothing wrong with the clamp its a little thicker than the earlier XIV but made from the same material spec (Tensile Strength) and method of manufacture (Hot brass Stamping)

But for the rated stamped pressure of 4000 psi against the extrusion pressure due to deflection of the clamp was too close for the original application hence why they ended up with you lot getting to buy them.

 

[Gareth J]

Only because that was the pressure used at the time, the yoke was changed as tank pressures increased. As mentioned before, I have a yoke reg designed for 4000# service before DOT regulation changed to DIN only for 3500# and above, probably to prevent someone using a 1800# service from over 3500# pressure which could cause a catastrophic accident rather than just blowing an o-ring.

@Bob DBF

I fully accept that the yoke designs have been revised as the pressures have been increased.
The reason the Yoke is still considered an acceptable design is due to "Grandfather Rights". i.e. an old design that has been in circulation has been allowed to be upgrade.

With a clean piece of paper, with the current pressures and modern safety and design criteria, it would not have been an acceptable design. These days, I only work/design negative pressure systems (vacuum), which means a maximum pressure differential of 1bar. In the past I used to work on negative / positive pressure systems. Even at the lower positive pressures I worked with, we wouldn't have proposed a design like the Yoke design because I don't believe we would have got it past the safety people.
(Full disclosure, I am not a mechanical design Engineer, I am an Electronics and Instrumentation Engineer.)

 

[Celt]

Only because that was the pressure used at the time, the yoke was changed as tank pressures increased. As mentioned before, I have a yoke reg designed for 4000# service before DOT regulation changed to DIN only for 3500# and above, probably to prevent someone using a 1800# service from over 3500# pressure which could cause a catastrophic accident rather than just blowing an o-ring.



ABS brakes lengthen the stopping distance, but are safer because it is less likely for the driver to lose control.

Is it the clamp itself that has different working pressures. I have various clamps on different regs. Spiro US Diver Dacor. etc.

 

[iain/hsm]

Your moving the goal posts, For a yoke valve the working pressure is 232bar, the hydro test is 340 bar. There's no one using yoke at 340bar. A yoke valves used at the working pressure it's designed for will not extrude the correct oring. It will extrude an incorrect oring. Obviously a 300bar din will take more pressure than a 232 bar yoke. And they both form a seal exactly the same way. An oring sandwiched between two metal surfaces. Granted if you overpressure a yoke valve the metal yoke itself can stretch and blow the oring.

Mac.

I'm not moving any goal post quite the opposite I'm trying very hard to iron out any information that is incorrect in the event that if I don't them someone will believe the bull as truth.

Now again most of what you have said is fine but what you are failing to acknowledge
it's the fine engineering detail in design and manufacture methods of these sports divers products that are exposing you as a diver to unknown additional risk however mediated by the number of non eventful dives you do or age.

Was it not yourself who said that you fill your cylinders to 250 bar ( 3625psi)

Now consider your Italian designed (Scubapro) engineer thinking its for a working pressure of 200 bar (2900psi Euro) and 3000 psi psi for the USA market he would not necessarily
be required to design it up to the developed pressure of a 200 bar cylinder on a hot day of 60C developing 275 Bar (3987 psi) let alone the maverick here filling to 250 bar and those among us that claim the ignorance of Cave Man rights.

And yet those of us that do experience blow out at depth tend to regret buying o-rings from a dive shop with no idea of the age, the shore hardness, the compound or the polymer.

And again may I suggest consideration in your statement in an earlier post of you using the same O-ring for three years at I assume this 250 bar charging pressure.

 

[Celt]

I just pulled this old spiro aquilon yoke reg out from under my bench (haven't seen it in a while)and low and behold it has a very slight free flow, yep those old yoke regs are useless.

 

[Celt]

Mac.

I'm not moving any goal post quite the opposite I'm trying very hard to iron out any information that is incorrect in the event that if I don't them someone will believe the bull as truth.

Now again most of what you have said is fine but what you are failing to acknowledge
it's the fine engineering detail in design and manufacture methods of these sports divers products that are exposing you as a diver to unknown additional risk however mediated by the number of non eventful dives you do or age.

Was it not yourself who said that you fill your cylinders to 250 bar ( 3625psi)

Now consider your Italian designed (Scubapro) engineer thinking its for a working pressure of 200 bar (2900psi Euro) and 3000 psi psi for the USA market he would not necessarily
be required to design it up to the developed pressure of a 200 bar cylinder on a hot day of 60C developing 275 Bar (3987 psi) let alone the maverick here filling to 250 bar and those among us that claim the ignorance of Cave Man rights.

And yet those of us that do experience blow out at depth tend to regret buying o-rings from a dive shop with no idea of the age, the shore hardness, the compound or the polymer.

And again may I suggest consideration in your statement in an earlier post of you using the same O-ring for three years at I assume this 250 bar charging pressure.

On paper a din reg seems best but in practice a yoke reg is every bit as reliable and more versatile. I used the scubapro regs today and I'll use them tomorrow and for the foreseeable future, I used the spiro aquilon in the 60,s and other yoke regs continuously over 50 years for work and pleasure, I never blew an oring in the water. My scubapro yoke regs are every bit as reliable as my din poseidons. Any reg can be miss handled or abused.

 

[iain/hsm]

I just pulled this old spiro aquilon yoke reg out from under my bench (haven't seen it in a while)

Er you may want to re phrase that sentence dude.
For a moment I thought you were on about pulling something else out.
You sure its an old Spiro your pulling out and not a La Spirotechnique

For an old duffer you know how it goes with these old folk on the forum.
Can't compete with the younger fitter smarter better looking divers I guess LOL

 

[iain/hsm]

On paper a din reg seems best but in practice a yoke reg is every bit as reliable and more versatile. I used the scubapro regs today and I'll use them tomorrow and for the foreseeable future, I used the spiro aquilon in the 60,s and other yoke regs continuously over 50 years for work and pleasure, I never blew an oring in the water. My scubapro yoke regs are every bit as reliable as my din poseidons. Any reg can be miss handled or abused.

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[tursiops]

Give me strength Mac. Your as bad as that other old duffer on this thread cave fill Chairman the pair of you at your ages need to get up to speed on this. No paper needed
DIN out engineers an A clamp in every way possible save for some arthritic old dudes that can't unscrew a milk bottle carton without needing help and some rinky dink straw hut dive
shacks out in some rat infested Far East toyboy town.

At your age you don't have a tomorrow or a foreseeable future. Save to teach us to number our days.

Give yourself one last piece of pleasure in life Oh and ditch the A clamp.

The point is -- which you seem to be missing -- is that the DIN valve/reg is OVER-engineered for 99% of the divers on 99.9% of their dives. (Percentages approximate...)

 

[Bob DBF]

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Bob My guess is your going back 20 odd years here and it was an old US Divers A Clamp

My point on these 4000psi stamped rating on the US Divers Regulators is that they did not take into account the developed pressure generated of a full cylinder at 60 degrees centigrade and therefore had to reduce the service pressure rating down to 3500 psi to cover on later models.

Early '80's Sherwood 4000. A-clamp was an integral part of the reg body casting. It was designed to actually handle that service pressure, it was not an upgrade of their standard clamp.

With a clean piece of paper, with the current pressures and modern safety and design criteria, it would not have been an acceptable design.

Hindsight is always 20/20.

And actually DOT considers it an acceptable design on pressures below 3500# from its track record, even though there are still low pressure yokes still in use.