Why DIN?

[DA Aquamaster]

IMHO, I wouldn't advise changing the reg back and forth from yoke to DIN. It's an unecessary hassle, and if you switch a lot it will add wear to your regulator.

It's a nice theory, with a certain appeal as it appears valid on the surface, but think about it...how soon do you wear out the threads on your DIN connection or on your yoke nut? Yep...It takes an awful lot of tank changes to get any noticeable wear at all.

That's about the same lenght of time and number of cycles it would take to wear out the threads in the yoke and DIN retainer nuts and the regulator body. Actually, it would take longer as those threads stay a lot cleaner.

Over torquing is the only thing I'd be worried about and with the universal retainer used by Scubapro, the retainer comes to a stop against the outside of the regulator before it can bottom out in the regulator and stretch the threads.

As for the hassel, it takes about 2 minutes to swap them and if you store the unused yoke or DIN parts in a zip lock, no cleaning or lubing is needed when the swap is made.

It eliminates an extra o-ring compared to using an adapter and the shorter connection places less stress on the regulator and DIN retainer. I'd worry a lot more about breaking the DIN retainer from the extra leverage of a yoke adapter on the end of my DIN connection if the tank fell over on the boat than I would about ever wearing out the threads.

 

[Chad Carney]

It's a nice theory, with a certain appeal as it appears valid on the surface, but think about it...how soon do you wear out the threads on your DIN connection or on your yoke nut? Yep...It takes an awful lot of tank changes to get any noticeable wear at all.

As for the hassel, it takes about 2 minutes to swap them and if you store the unused yoke or DIN parts in a zip lock, no cleaning or lubing is needed when the swap is made.

DA,

As a qualified tech I'm sure you can exchange a yoke for a DIN with zero damage. And I'm sure there are plenty of DIY divers out there that can handle it too.

BTW, I said nothing about thread wear.

I rarely theorize. Since 1988 when the first big wave of DIN tanks hit the US, the damage I've seen on regulators coming into the shop I managed for the next 12 years, was on the yoke nuts, DIN adapters and regulator bodies. Lots of stripped out parts and missing chrome. Also lost filters and extruded internal O-rings.

Sure the same fittings get removed every year or so for service, but generally by qualified techs with good tools and brass or wood vices or boxes, but unfortunately not always. In the field however, it's often rusty channel locks and and vice grips.

There is simply no reason not to use a spin on yoke to DIN adapter, for the rare occasions a DIN tank owner, like the thread originator, will encounter while recreational diving. With a 300 bar DIN regulator fitting he can use it on any tank ever made without any tools... that's no hassle. I've been doing it for years with no bumps on my head. Many times I have been able to weasel the dive masters larger DIN tanks on the spur of the moment when overseas!

JMO, to each his own.

Happy Holidays!

Chad

 

[Lead_carrier]

I have a ScubaPro S600 yoke first stage. People tell me I should change to DIN. I don't know enough to know whether that make sense. Why do people use DIN anyway, and should I make the change? FWIW I dive on wrecks off NJ (no penetration), I use single tanks (LP steel), and I take my regs along for resort diving. Thanks!

Why bother? You'll see and hear all the arguments about they're safer, can be used for high pressure, etc. I have yet, I'm sure others have,seen a properly seated and tightened yoke fail after pressurizing. I have seen plenty of excessively corroded din regs brought in for service. If you start penatrating wrecks, cave diving, definitely go din.

 

[Rick Inman]

Another good reason for DIN: HP Tanks.

 

[Charlie99]

I have seen plenty of excessively corroded din regs brought in for service.

Did being DIN have anything to do with the corrosion?

Outside of needing an adapator when using yoke tanks in resort areas, do you see any downside to having DIN instead of yoke?

 

[Chad Carney]

Lead,

I'm really surprised you haven't seen one yet. It's commonplace in scuba courses and boat trips to have extruded o-ring incidents occur when using yoke valves with face O-rings. (Especially with rental tanks.)

My previous store and in my current instruction business we use(d) nothing but DINs for training. In 17 years I have only witnessed one DIN extrusion.

I'll bet you've seen more excessively corroded yoke regulators come in for service.
Zeagle sells about 98% yoke regulators, and I'll bet that's about the same with all the manufacturers. Many stores sell high end quality regs and BCs but only a small percentage sell top of the line quality tanks. ($$$$)

Of course DIN to yoke adapters should be removed and rinsed often, even if not being used on DIN.

Chad

 

[Lead_carrier]

Did being DIN have anything to do with the corrosion?

Outside of needing an adapator when using yoke tanks in resort areas, do you see any downside to having DIN instead of yoke?

In my opinion it did. Either water was being collected inside the valve and being blown inside the first stage or when the reg was being rinsed the first stage was sealed as completely as it should be. Which one? Who's fault? Who knows, It's not like that on all regs just about half of the ones that I've serviced.

I didn't say there was a downside. I just stated an opinion. If you'll notice, I told him if the starts doing penetration or cavern/cave, then definitely go din.

I'm really surprised you haven't seen one yet. It's commonplace in scuba courses and boat trips to have extruded o-ring incidents occur when using yoke valves with face O-rings. (Especially with rental tanks.)

My previous store and in my current instruction business we use(d) nothing but DINs for training. In 17 years I have only witnessed one DIN extrusion.

I'll bet you've seen more excessively corroded yoke regulators come in for service.
Zeagle sells about 98% yoke regulators, and I'll bet that's about the same with all the manufacturers. Many stores sell high end quality regs and BCs but only a small percentage sell top of the line quality tanks. ($$$$).

It may be common place for you to see extruded o-ring, I just said I haven't, if the reg is properly connected.
As far as number of corroded yoke regs. Yes, I have seen more of them. Percentage wise, definitely not.
As far as selling top of the line quality tanks ($$$$). That has nothing to do with the fact it has a din or yoke valve. Most tanks I've seen, from the $29 e-bay special to the newest steel tanks, will accept any valve that fits.

Myself, I'm lucky enough to have enough regs to have both din and yoke setups.

 

[DA Aquamaster]

DA,

As a qualified tech I'm sure you can exchange a yoke for a DIN with zero damage. And I'm sure there are plenty of DIY divers out there that can handle it too.

BTW, I said nothing about thread wear.

I rarely theorize. Since 1988 when the first big wave of DIN tanks hit the US, the damage I've seen on regulators coming into the shop I managed for the next 12 years, was on the yoke nuts, DIN adapters and regulator bodies. Lots of stripped out parts and missing chrome. Also lost filters and extruded internal O-rings.

Sure the same fittings get removed every year or so for service, but generally by qualified techs with good tools and brass or wood vices or boxes, but unfortunately not always. In the field however, it's often rusty channel locks and and vice grips.

I think we mostly agree on this. If you look at my post, I mention the tools needed to do it properly. I have also experienced the pure joy of removing over torqued yoke nuts that have also been rounded off by their owners attempting to remove it again themselves. Crescent wrenches, vice grips and channel lock pliers do not have a place in yoke nut removal.

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With regard to DIN downsides,

When rinsing, many DIN caps do a poor job of sealing the regulator. Some of them serve as dust covers but have no provision at all for sealing the inlet of the regulator other than the bottom of the cap sort of sealing the inlet with a less than watertight seal. Often unless you think about it and look, it is not always intuitively obvious.

You want to be sure to use a cap with a shoulder that seals against the o-ring on the DIN fitting to keep water out of the regulator.

Care is also needed to ensure no water remains in the DIN tank valve as it is a bit slower to dry and could result in greater potential for water to be blown into the tank during a fill.

There is also some misinformation about yoke valves that is taken as truth. Many DIN using divers state that the o-ring is not "fully contained" in a yoke connection. In fact, a properly designed yoke/valve arrangement has no excess space for extrusion of the o-ring and has the same near metal to metal contact as the "fully contained" DIN o-ring.

The major differences betwene the two systems are that:

1. It is virtually impossible to install a DIN connector with poor alignment, something that can happen on a yoke valve and cause an extrusion.

2. Since the DIN connector has the o-ring on the downstream (regulator) side of the conection, if you fail to adequately tighten the fitting, it just leaks immediately. On a yoke valve the o-ring is on the upstream side and if it is tightended just short of enough, it will seal just enough to extrude the o-ring.

So both connections use "fully contained" o-rings (and have to at scuba tank pressures) but the DIN connection is just more idiot proof with the yoke connection being more suceptible to operator error. In 17 years (and probably 1500 dives) using yoke valves prior to switching to DIN, I never had a tank valve o-ring extrusion. The most serious issue I had was the occassional slight hiss of escaping gas or small dribble of bubbles from a worn o-ring.

 

[Chad Carney]

I think we mostly agree on this.
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There is also some misinformation about yoke valves that is taken as truth. Many DIN using divers state that the o-ring is not "fully contained" in a yoke connection. In fact, a properly designed yoke/valve arrangement has no excess space for extrusion of the o-ring and has the same near metal to metal contact as the "fully contained" DIN o-ring.

Since the DIN connector has the o-ring on the downstream (regulator) side of the conection, if you fail to adequately tighten the fitting, it just leaks immediately. On a yoke valve the o-ring is on the upstream side and if it is tightended just short of enough, it will seal just enough to extrude the o-ring.

So both connections use "fully contained" o-rings (and have to at scuba tank pressures) but the DIN connection is just more idiot proof with the yoke connection o-ring being more suceptible to operator error.

DA,

I agree... that we agree, on most points of the DIN vs yoke system. Obviously we both use DIN today, even though they are not perfect.

However for friendly discussion, I disagree on a few points.

Yoke extrusions are often not the fault of the operator. They are frequently the fault of worn or low durometer o-rings, especially the thin ones found in aluminum cylinder valves. And sometimes they fail because of improper tolerances in the yoke and valve, due to fatigue and damage. I'm sure you remember the spindly yokes on older regulators. We had worn out several valves on our test bench, to the point where they would hold pressure for a while and then extrude the o-ring, even with new regulators. This can happen with rentals and old valves customers own as well. Tank valves are the most abused and under-serviced gear divers use.

A regulator connection is simply a seal around the flow of gas from the tank to the regulator. Upstream or downstream does not apply, as it does in regulator seats that have a closing force with or against the flow.

DIN valves can extrude after sealing, although it's very unlikely. I witnessed this once on a HP100 with a 300 bar valve, when mated with a 300 bar DIN on a new regulator. The diver made it down about 15 feet and then the o-ring extruded. He could still breathe during the ascent and massive bubble cloud. The valve had some salt corrosion in the threads and the regulator had an over-chromed male DIN part. Obviously these two parts closed down enough to seal but not for long.

DIN valves have a much larger internal bore, and it's enough to make a noticeable difference in performance.

The "captured" o-ring system in a DIN valve when properly serviced is superior to that of a yoke system. Hence the higher pressure rating capability of up to 300 bar/4410 psi. I have also witnessed one other rare event; a diver on my boat made an entire dive with no oring after over tightening his DIN.

I'd sure like to know how PST managed to get a 3442 psi DOT rating on their E-series tanks. The valve face looks beefed up compared to the typical aluminum tank valve and the o-rings are thicker, but I still have my doubts about a system that started out at 1800, then increased to 2015, 2250, 3000, 3200, 3300, and now 3442 psi.

"As far as selling top of the line quality tanks ($$$$). That has nothing to do with the fact it has a din or yoke valve. Most tanks I've seen, from the $29 e-bay special to the newest steel tanks, will accept any valve that fits."

It did until just a few years ago. All HP steel tanks in the US had 7/8" necks and would accept only DIN valves. Most of the LP steel tanks were sold with DIN valves too.

Now with the introduction of the E-series tanks there appears to be no difference, other than 58 psi, which few divers can even accurately measure.

IMO the big difference that the E-series tanks will bring is in their marketing. A major objection to steel tanks has been removed. Hence more buyers and lots more $$$$ for the tank manufacturer.

I don't believe they have gone with the best sealing system. I'll just stick with my 300 bar DINs and clean all my valves regularly.

Happy Holidays guys!

Chad

 

[DA Aquamaster]

The yoke stretching that you mention is the major limiting factor in pressure. A yoke heavy enough to with stand greater pressure (plus a suitable safety factor) gets to be excessively large and heavy. And if some stretch occurs, so will o-ring extrusion. There is no doubt that for pressures over 3000 psi, DIN is superior, especially in the 7 thread 300 bar DIN valve.