HP Steel tanks with Yoke valves

[netdiver]

I'm relatively new to diving and have been doing much research on tanks and valves. I have question I hope you can help me with.

I have an Aqualung Legend LX regulator with a first stage that is fitted with a yoke valve that I use often with my own and rented aluminum 80's. I like the convenience and simplicity of this, but I'm interested in HP steel tanks. I'm hoping to gain some BT and also have an additional safety margin when I surface.

The working pressure of HP steel tanks are above 3400 PSI, but tanks like those from XS/Worthington have Yoke valves. Does the valve reduce the pressure presented to the yoke valve on the regulator to 3000 PSI? Are there special "high pressure" yoke valves for these style of tanks? Can I use my standard yoke valve on my first stage with these tanks?

I appreciate any insight the board can lend.

 

[Tamas]

You can use your current reg and current yoke valve on the HP steel tanks without problems. Most are rated to a working pressure of 3500-4000psi (or higher) and will be just ok. DIN would be the clear winner but for now your yoke's will be ok....just make sure that the o-ring is nice and new.

 

[Jay_SMART_Diver]

Most yokes are rated to 5000psi.

 

[miesemer]

Yes you can use your yoke regulator clamp on the ProValves provided as standard on the Worthington steel cylinders. However, most people I know that have used the ProValves on the HP steel cylinders with yoke connections have changed over to DIN connections due to extruded orings. I've seen some different orings supplied with the Thermo ProValves and a few different inserts. The insert oring combination that I think is the most reliable is the one that requires a 5/16 hex to remove and uses a fat oring that fills the oring pocket.

It shouldn't cost more than $50 to convert your reg to DIN.

 

[miesemer]

Most yokes are rated to 5000psi.

That's not my experience. I'm used to seeing 232 Bar.

 

[netdiver]

Thanks for quick and helpful replies.

I just checked the owner's manual provided with my reg and it is stated to support up to 3300 PSI with a yoke valve.

 

[Turtle Diver]

All my tanks and regs are din. I use an adapter whenever I rent a yoke valve tank. Never regretted going din.

That said, there are plenty of people using yoke regs with 3442 psi tanks, regardless of the yoke reg pressure rating. Most of the time you won't get a full fill anyway, and when you do, the pressure drops below 3300 pretty fast.

 

[spectrum]

Netdiver be sure to understand what you are doing here.

First of all tank valves are just valves they do not control pressure and are always used full open. Your regulator will see the full pressure. Some can do some weird stuff if left 1/2 open but don't go there.

You have identified your rig as ratted to 3300 PSI. Most current HP cylinders are rated to 3442 PSI. Remember that on occasion the air fairy may bless you with several hundred extra PSI. The same can be said for hooking up to a vehicle or sun warmed cylinder. Knowing that you have a 3300 limit it is your decision on how much design margin is in there. That being said the practice is quite common.

As for seeking more bottom time that is a function of cubic feet capacity, not pressure. If you seek more air than you have in an AL80 consider an E7 or X 100. Going to a HP steel will have some advantages. You will be 12 pounds lighter in the water and it is a true 80 CF. An AL80 with a perfect fill is only 77.4 CF.

If you have any discomfort about this I suggest getting your regulator converted to DIN. It's usually a $50 adpater that can be swapped out while you wait. You can then get a yoke converter to let you dive yoke cylinders on vacation or in a pinch. My wife and I have been HP/Steel/DIN since the beginning and it's been good.

As an asside if you begin to accumulate HP steels you will inevitably come across some used 3500 PSI cylinders that have DIN only valves, at that point you would need to convert your regulator to DIN should you buy those to use.

Pete

 

[netdiver]

Your concerns are appreciated, Spectrum, but I am not confusing pressure with volume. And it is also now clear that none of the common tank valve systems provide and sort of pressure reduction as part of their delivery.

It would seem the 3300 PSI manufacturer rating for the Legend would be for the yoke assembly itself rather than the mechanics of the first stage since the same regulator is rated to the common 300 bar with a DIN connector. That being the case, I am not very concerned about the 142 PSI differential.

Actually, I've already decided to get a DIN connector for the first stage and a yoke converter (when needed) when I order my HP steel tanks. If I go on an extended dive trip where I expect to be using rented tanks exclusively, I can reattach the yoke connector before I head out to avoid the extra bulk and "hassle" of using the converter.

 

[spectrum]

If I go on an extended dive trip where I expect to be using rented tanks exclusively, I can reattach the yoke connector before I head out to avoid the extra bulk and "hassle" of using the converter.

That's a nice way to go since you will already own the hardware. I though twice about suggesting it on the internet not knowing abilities but if you are so inclined it's not rocket science. Having the right tools to retighten the yoke is the biggest trick.

Pete