Din vs Yoke Tanks?

[guruboy]

It's because 99% of rental tanks are yoke. If you don't own your own tanks, you're going to need yoke regs. If you own your own tanks, you have a choice to make.

In that situation, if you own yoke regs, it is the fact that you own a yoke reg that might lead you to a tank with a yoke valve. Or if you want to use DIN regs, you would probably get a DIN valve.

To put it another way,

Statement A) makes no sense to me;
A) I am going to buy a tank so I should get a DIN valve, because if I own a tank DIN valves are better.

Statement B) I could agree with;
B) I am going to buy a tank, but because all my regs are yoke and I won't do cave diving, I will get a yoke valve.

I hope this makes my point clear.

Just OWNING a tank, in and of itself, without taking into account any other considerations, should not influence your valve choice.

 

[doctormike]

I don't know about just dismissing the advantages of a DIN tank valve.

DIN to DIN connection is VERY secure (important in any sort of diving, not just cave diving), the trapped O-ring is much less prone to breakdown than the thin little exposed O-ring in a yoke connection, and the profile is lower as mentioned above. It is less of an entanglement hazard - and that is not something that only happens in overhead environments. Also (according to the TDI advanced wreck diving manual), flow rates are significantly better through DIN regulators (not sure how much of a rec diving issue that is).

So if you are buying a tank, and get a Pro Valve, then you can use it with any regulator you have, DIN or yoke. If you have a DIN regulator, you can always get an adaptor for rental yoke tanks when traveling. And even if you are using a yoke reg now, buying a tank with a pro valve means that you can use it if you ever get a DIN regulator in the future. I suppose that a yoke valve is somewhat less expensive? Not sure.

So the bottom line is that I don't see the advantage would be of buying a tank with a yoke valve - it seems to restrict you to a lesser product. I'm also not sure what is meant by the statements that DIN is more subject to damage than a yoke, or that yoke regulators are more robust. But I guess that may have something to do with how they are treated, maintained, etc...

My 2 psi...

 

[chillyinCanada]

Ya, those damn o-rings are expensive. A person's got to take that kind of thing into consideration.

 

[gcarter]

So to sum it all up, if you are buying a tank get a convertible valve (in all 6 of mine). Done.

If you are buying regs, DIN vs yoke is a legitimate conversation. But not a legitimate conversation for tanks. Tanks have nothing to do with reg choice, and if your valves don't accomodate your reg choice it is a situation easily remedied.

This is way overthought way too often.

 

[doctormike]

Ya, those damn o-rings are expensive. A person's got to take that kind of thing into consideration.

Nah, they are really cheap! The only problem is that it's hard to buy one underwater, when you really need to replace it right away...

 

[chillyinCanada]

Nah, they are really cheap! The only problem is that it's hard to buy one underwater, when you really need to replace it right away...

I just couldn't hold it in anymore doc.

 

[herman]

I don't know about just dismissing the advantages of a DIN tank valve.

DIN to DIN connection is VERY secure (important in any sort of diving, not just cave diving), the trapped O-ring is much less prone to breakdown than the thin little exposed O-ring in a yoke connection, and the profile is lower as mentioned above. It is less of an entanglement hazard - and that is not something that only happens in overhead environments. Also (according to the TDI advanced wreck diving manual), flow rates are significantly better through DIN regulators (not sure how much of a rec diving issue that is).

So if you are buying a tank, and get a Pro Valve, then you can use it with any regulator you have, DIN or yoke. If you have a DIN regulator, you can always get an adaptor for rental yoke tanks when traveling. And even if you are using a yoke reg now, buying a tank with a pro valve means that you can use it if you ever get a DIN regulator in the future. I suppose that a yoke valve is somewhat less expensive? Not sure.

So the bottom line is that I don't see the advantage would be of buying a tank with a yoke valve - it seems to restrict you to a lesser product. I'm also not sure what is meant by the statements that DIN is more subject to damage than a yoke, or that yoke regulators are more robust. But I guess that may have something to do with how they are treated, maintained, etc...

My 2 psi...

Doc, that is one of those misconceptions about DIN. If you look at the design of the actual connection, you will find it is exactly the same with one insignificant difference. Both use a male portion (reg side) that inserts into a female receptacle (valve side), both have flat surfaces that meet within the valve and both have an oring captured between those 2 surfaces. The only difference is where the oring groove is located, in the yoke it's in the valve and in the DIN it's in the reg. The potential for extrusion is exactly the same. What is different and likely the cause of the oring superiority myth of DIN is the owner of the oring. Yoke orings, esp. on rental tanks take a lot of abuse and see a lot more service than the typical DIN reg orings before it's replaced. Since the oring of a DIN valve is part of the DIN reg, odds are the owners are much more likely to keep an eye on their regs oring not to mention it gets changed at every reg service.

As to flow, while the DIN may well have more flow capability than a yoke, it is irrelevant since the part of the assembly with the least flow rate is the controlling factor for overall flow capacity and that is the second stage. Even more to the point, the diver themselves are the biggest limiting factor in total flow. It is of little importance that one valve can flow more that the other since either are have way more than enough capacity to supply 2 heavily breathing divers.

 

[doctormike]

Doc, that is one of those misconceptions about DIN. If you look at the design of the actual connection, you will find it is exactly the same with one insignificant difference. Both use a male portion (reg side) that inserts into a female receptacle (valve side), both have flat surfaces that meet within the valve and both have an oring captured between those 2 surfaces. The only difference is where the oring groove is located, in the yoke it's in the valve and in the DIN it's in the reg. The potential for extrusion is exactly the same. What is different and likely the cause of the oring superiority myth of DIN is the owner of the oring. Yoke orings, esp. on rental tanks take a lot of abuse and see a lot more service than the typical DIN reg orings before it's replaced. Since the oring of a DIN valve is part of the DIN reg, odds are the owners are much more likely to keep an eye on their regs oring not to mention it gets changed at every reg service.

I think that we are saying the same thing... Yoke o-rings are more exposed, and prone to breakdown and failure because tanks are generally not kept in climate controlled, clean, dry bags the same way that regs are. Also, there really is a difference in the way that a DIN o-ring is trapped (but obviously, both need to trap them securely enough to ensure an air-tight seal).

But it might not have that much real world advantage if you own your own yoke tanks and take good care of them, I suppose.

As to flow, while the DIN may well have more flow capability than a yoke, it is irrelevant since the part of the assembly with the least flow rate is the controlling factor for overall flow capacity and that is the second stage. Even more to the point, the diver themselves are the biggest limiting factor in total flow. It is of little importance that one valve can flow more that the other since either are have way more than enough capacity to supply 2 heavily breathing divers.

Dunno, as I said, not sure what the implications actually are. But TDI does specifically mention this in their manual as an advantage, so I thought I would note it here...

---------- Post added September 5th, 2013 at 08:18 AM ----------

It is of little importance that one valve can flow more that the other since either are have way more than enough capacity to supply 2 heavily breathing divers.

This is not necessarily true. I'm not a mechanical engineer, so maybe someone can correct me if I am wrong, but it is definitely possible to overbreathe a regulator, even with one stressed diver on a given first stage. Certainly, flow dynamics in other systems (i.e. the upper airway) show that decreasing resistance to flow in one area can improve gas flow in a downstream bottleneck. However, I don't know for sure if throats and regulators are comperable systems!

 

[halocline]

Also (according to the TDI advanced wreck diving manual), flow rates are significantly better through DIN regulators (not sure how much of a rec diving issue that is).

I'm also not sure what is meant by the statements that DIN is more subject to damage than a yoke,.....But I guess that may have something to do with how they are treated, maintained, etc...

My 2 psi...

I would be very surprised if there were even the slightest difference in identical regulator flow rates with a DIN vs yoke connector. Flow rates for 1st stages are determined by other parts and designs within the reg. Rather, the difference would be in the tank valve itself (DIN vs yoke) and my strong suspicion is that those vary more among brand and individual valves than between DIN as a design and yoke as a design. But it's an interesting point, and I'd be curious to see some data.

The issue with DIN and maintenance is not in the regulator as much as in the tank. Yoke valves are used on rental tanks in places like the caribbean and routinely get banged around, roughly handled, tossed in trucks, filled with less-than-pristine whips in a hurry, etc. If these tanks were DIN, the valve threads would likely get pretty beat up and the valves themselves would get knocked out of round very quickly.

I agree that theoretically it's 'more secure' to have a completely enclosed o-ring that the diver-not the tank rental company- is in charge of. But as a matter of practicality, over time I'm pretty confident that there would be far more problems in a rental fleet with DIN tanks, at least in high use/abuse situations.

Every day thousands and thousands of recreational dives are done with yoke tanks. If there was a serious concern for safety or even convenience there's no way that the yoke system would have flourished as it has.

The entanglement issue is real, but most recreational OW divers are already an entanglement disaster waiting to happen. So worrying about yoke entanglement in a 'typical' PADI style OW rig with danglies and hangie-thingies everywhere is a bit like ordering a diet coke with your big mac and super-sized fries. But in a cave or other restriction, definitely DIN is much more appropriate and is the standard.

 

[victorzamora]

Doc, I believe your statement about flowrate is correct when great depth is concerned....I'm not sure that's the case within recreational limits.

About the O-ring: They are NOT the same. A lot of their design IS the same (o-ring is surrounded by metal and pressed against a flat surface), but there is at least one important dissimilarity. In a DIN reg, the o-ring has a flat metal surface in ALL directions. It gets squished. With a Yoke reg, the o-ring has a flat metal surface directly in front of it, but it can herniate around it.

The biggest difference for me is the location of the threads in relation to the o-ring. With a Yoke reg, hitting the yoke knob or the first stage causes a moment created about the o-ring, allowing herniation or other damage to occur quite readily. With a DIN reg, there is no yoke knob to provide a huge moment and hitting the reg creates a moment about the threads. The threads have a MUCH greater moment arm than the yoke fulcrum and are much more capable of sustaining an applied force/moment. Summary: You would bend the valve or reg before damaging the o-ring on a DIN reg, but even small bumps can cause blowouts on Yoke regs.

Concerning the cost of an o-ring on a Yoke tank, you don't always have the luxury of purchasing one when you need it. Underwater or 30 miles out at sea, if something happens to your o-ring, you couldn't buy one.

About "buying tanks, DIN is better" being fallacious, I agree. I think DIN is better, period. If given the choice, all of my diving would be DIN. When I buy tanks (probably in 1.5 weeks), they will be DIN. I will probably buy the convertibles JIC, but you can also buy a Din-Yoke fill adapter for like $10 if filling is a concern and you want the 300BAR valve...which is something I'm severely tempted to get.