Psi Rating of the RA Yoke?

[capn_tucker]

My knowledge (although improving fast) of the Royal Aquamaster's tech specs is limited; what I'd like to know is the max psi rating. Is a 2250psi 72 the best that can be used, or can 3000psi tanks be safely used?
I downloaded off this site the PDF for a RA rated at 3500psi. The yoke is totally different from other RA's I've seen, and has a stock number of 1079, as opposed to the 1046 on my RA.
Was this some extremely limited production from the last year or two before DBL's were discontinued?

[YankDownUnder]

I have two Royals and use them routinely at 3000 psi. The tanks are often pumped higher, but by the time I get into the cold water near my home, 3000 psi is all there is. Both have the earlier long yoke and not the heavy yoke, similar to that on the Phoenix and modern single hose regulators.

I cannot imagine you having any troubles at 3000 psi. 3000 psi tanks were common at the time the Royal was sold. I also have a set of triple 44, USD broxton tanks, that are rated at 2650 psi and they date to 1954, many years before the Royal and the long yokes.

Good luck.

[capn_tucker]

I have two Royals and use them routinely at 3000 psi. The tanks are often pumped higher, but by the time I get into the cold water near my home, 3000 psi is all there is. Both have the earlier long yoke and not the heavy yoke, similar to that on the Phoenix and modern single hose regulators.

I cannot imagine you having any troubles at 3000 psi. 3000 psi tanks were common at the time the Royal was sold. I also have a set of triple 44, USD broxton tanks, that are rated at 2650 psi and they date to 1954, many years before the Royal and the long yokes.

Good luck.

Thanks for the info. The LDS folks I learned to dive from way back when weren't very cooperative with my questions about double-hose regulators. Of course, they were in the business of selling brand new single-hose stuff; steering people towards double-hoses didn't benefit them.
And in the days before the internet, it wasn't easy to find out much.
On charter boats I never saw anyone use a double, and they wouldn't let you use one without gauges, BC etc anyway. Despite all that, I eventually scared up a couple of old doubles, but could only use them on beach dives or lake dives. But noone else had one, so they were a short-lived novelty for me.
It's only been in the last year I've discovered the vintage sites like VDH and VSS; an eye-opening experience! Only bad thing about all this is it's created a monster (a double-hose breathing one)...

[pescador775]

I used the long yoke RAM with 3000 psi triples for about 25 years. Never had a problem.

[capn_tucker]

I used the long yoke RAM with 3000 psi triples for about 25 years. Never had a problem.

I wish I had run into some you guys back then! All those missed opportunities. But I'll be making up the lost time with a vengeance now..

[Nemrod]

The very last year or so of the round label RAM they were equipped with a heavy yoke and marked for 3,000 psi from the factory. Apparently a few round label DA Aqua Masters were also equipped with this heavy yoke.

You may use the heavy yoke at 3,500 psi without fear. You may use the standard duty yoke of short or long length with up to 3,000 psi, with some caution and common sense with no problems.

The Phoenix, as you have learned, comes with a 232 BAR heavy yoke.

VSS, Dan, occasionally sells a machined, modified SUPER duty Dacor sourced yoke for the RAM/DA. This yoke will not work with the Phoenix but will with a standard DA/RAM nozzle. The Phoenix nozzle has a threaded yoke, the DA/RAM are slip on type.

James

disclaimer, I know nothing, I am insane, diving any of this stuff will kill you

[JES]

... VSS, Dan, occasionally sells a machined, modified SUPER duty Dacor sourced yoke for the RAM/DA. This yoke will not work with the Phoenix but will with a standard DA/RAM nozzle. The Phoenix nozzle has a threaded yoke, the DA/RAM are slip on type. ...

Here's the link to VSS where Dan lists the Dacor yoke: http://www.vintagescubasupply.com/hoses.html

Contact Dan regarding the availability of this item.

[Bryan]

If you are handy with a lathe or know someone that is, you can take any late model Conshelf yoke and do a relief on the bottom side that will allow it to fit over the DA/RAM body and it will work fine as well. That's the way mine was done.

[Ductapeman]

So, is the yoke the part that limits the pressure that the regulator sees? I had always been under the impression that it was the high-pressure seat-- but I am by no means an expert. So what exactly are the limiting factors?

[luis]

So, is the yoke the part that limits the pressure that the regulator sees? I had always been under the impression that it was the high-pressure seat-- but I am by no means an expert. So what exactly are the limiting factors?

In a non-balanced first stage, the seat can be a limiting factor, specially in a single stage regulator like the Mistral.

In any balanced first stage that I can think of, it would be the yoke.

In some balanced pistons regulators like the old MK-5, the clearance for the HP O-ring can also cause the O-ring to tend to extrude at very high pressures; somewhere above 3500PSI IMHO.

[capn_tucker]

The very last year or so of the round label RAM they were equipped with a heavy yoke and marked for 3,000 psi from the factory. Apparently a few round label DA Aqua Masters were also equipped with this heavy yoke.

You may use the heavy yoke at 3,500 psi without fear. You may use the standard duty yoke of short or long length with up to 3,000 psi, with some caution and common sense with no problems.

The Phoenix, as you have learned, comes with a 232 BAR heavy yoke.

You say the last year of the RAM they were rated 3000 psi from the factory. I'm looking at a PDF of an instruction sheet for the model 1079 RAM which states it is a 3500 psig service regulator. I'm assuming the yoke on that one was rated at 3500?

[Nemrod]

NO, I am saying that the very last YEARS of the RAM and possibly the DA, they came with the heavy yoke rated for 3,000 psi stamped on the yoke.

The limiting factor in terms of pressure for the DA Aqua Master and the Royal Aqua Master is the YOKE and NOT the seats or internal parts and most especially for the RAM. This statement only applies to these two regulators that I have experince with. It probably also applies to the Voit Navy. This is also intended to reference pressures up to about 3,500 psi. Beyond that there may be other issues that I cannot comment on since I have never attempted to run them higher. Most people understand that the yoke connection of any sort above 3,500 psi is failure prone. The standard yokes, do OK up to 3,000 but not above. Obviously, and I doubt anyone would argue otherwise, the standard yokes while satisfactory up to about 3,000psi are considerably weaker than the heavy yokes as on the Phoenix and last Aqua Masters and modern regulators. Mostly that small diamter screw is the culprit. I have bent them hitting my tank agaisnt a solid object. The heavy yokes have a screw twice or more in diameter, they are HUGE in comparison and much stronger as a result.

The limiting factor for pressure with a Mistral is the seat and the mechanical design. The yoke is not the limiting factor because most divers find the Mistral breaths increasingly stiff and poor much above 2,000 psi. At 3,000 is is quite stiff and possibly abusive of the seat.

Note, many do run their Mistrals at high pressures and since Bryan has new high tech seats, I may as well.

Concerning the DA at 3,000 psi or even 3,500. The thing I have run into is trying to tune it to breath well over such a large range of pressure. I simply cannot set the regulator up like I would wish. The unbalanced first just makes dialing it in over these pressures challenging. With the RAM, the second sees the same IP from 150 to 3,500 psi tank pressure, not with the DA, it varies inversely. This makes tuning a RAM much easier than a DA--at least to me.

You can worry yourself into a frenzy over all this or you can just go diving, pump the tank to 3,000, slap your DA or RAM or such as that on there and go dive. If it blows up--disclaimer--I am insane, my wife says I am insane, I have no idea what I am saying, I am off my meds and likely to be commited for my non PadI compliant thoughts.

Nemrod

[capn_tucker]

Nemrod, I'm not worried about it; found out what I wanted to know about useable tank pressures. I'm just curious to know more about this "Model #1079 RAM" from that data sheet.
Does anyone have one of those? I'd love to see some pics of one..

[pescador775]

The Phoenix is OK to use at 3500 psi. The use of a late production HP seat and the heavy yoke make the difference. At 3500 psi, the old, short yoke will elongate about 0.007+1. That is too much and is enough to extrude an O ring. Only modern yoke valves along with thick yokes can be used at this pressure and they depend on FIRM screw torque to maintain a good seal. My tests of the Phoenix indicate elongation of 0.002+1 which is a safe number. Aqualung's latest HP seats, those made from about ten years ago to present, are adequate for high pressure. The old, neoprene seats may blow out of the poppet. You don't want that.

[capn_tucker]

The Phoenix is OK to use at 3500 psi. The use of a late production HP seat and the heavy yoke make the difference. At 3500 psi, the old, short yoke will elongate about 0.007+1. That is too much and is enough to extrude an O ring. Only modern yoke valves along with thick yokes can be used at this pressure and they depend on FIRM screw torque to maintain a good seal. My tests of the Phoenix indicate elongation of 0.002+1 which is a safe number. Aqualung's latest HP seats, those made from about ten years ago to present, are adequate for high pressure. The old, neoprene seats may blow out of the poppet. You don't want that.

More good info to know. Thinking about getting steel 117s or 130s @ 3442 psi. Or aluminum 3000 psi 100s @ 10% overfill. Phoenix should be fine with that...