Are Atomics worth the cash?

[Luis H]

Everybody's already given the answer to couv's question: no exhaust valve = no CGF, and minimal "cracking effort."

A small clarification (for the benefit of others): eliminating the CGF does not automatically mean lower “cracking effort”. It means that the cracking effort can be “manually adjusted” lower without automatically inducing a free flow, due to pressure differential from the sensing diaphragm to the exhaust.



You are correct, that you will pre-load the diaphragm when it is in lower position (deeper) in the water column, but to do a complete and fair analysis; at this point you should introduce the rest of the breathing loop/ system… the human body.

The exhaust valve is a flexible one way membrane that opens due to minute differential pressures (into the exposed water column pressure), but the flexible nature of some of our air passages will have a similar effect (in allowing some preload of the “demand valve diaphragm” that is located deeper in the water column).




On a related but different subject (different principles), I have done some testing on double hose regulators with and without the inlet mouthpiece valve.

There has always been the debate of how much flow resistance is caused by the mouthpiece valves in the loop of a double hose regulator so I decided to tae some measurements. I tested several valves, but was most interested on the newest super flexible valves the VDH is offering.

The flow results were not surprising; yes there is some flow resistance, but it is minimal, even hard to measure in the normal flow rate range.

What was more interesting was the pressure in the breathing chamber when there was no flow. Between inhalation breaths the pressure never went back to zero. Due to the one way valve there was always a bit of a vacuum (about -0.3 inWC) in the inhalation chamber. This maintained a bit of a preload on the demand valve diaphragm.

Flow initiated when the suction was raised to about -0.6 inWC and the flow stopped at about -0.3 inWC.

This is one of those observations that make a lot of sense once I have seen it, but I never though about it before.



As I mentioned above, you start diving and playing with a double hose regulator and you will get a lot of insight into the physic of the water column.




So what is this about an Atomic regulator… The question that always had, are they radioactive?

 

[rsingler]

Don't be afraid around Atomic divers, Luis! You'll be okay, because your RAM is made out of kryptonite. You're protected.

 

[flspy]

Wow, I really got a lot of mileage out of this post. When I put it up, I was looking at the high end titanium Atomic regs. Now that everyone tells me there is no real performance difference between them, the prices are not much different. Also, I would definitely get an Atomic octo. I don't like to mix manufacturers for my reg setups.

PS- the Mares has worked very well for years, but it is getting a little long in the tooth. Technology in diving changes fast, so having the latest easy breather is important to me.

 

[Fishpie]

.......if you find something new, innovative and better breathing than your Abyss let me know.

 

[halocline]

Technology in diving changes fast, so having the latest easy breather is important to me.

Not in regulators, despite what the ads and dealers would like you to believe. There's been no real improvement in the breathing performance of regulators in decades.

 

[herman]

And there has been a great loss in durability...not that I am likely to be around to see it but I seriously doubt there will be Atomic or any other current regulator still diving 40 or 50 years from now like the ones from the 60s and 70s do now.

 

[Eric Sedletzky]

Hi rsongler,

Nice write ups. I agree with most of what you have posted… with one exception.
I don’t agree with this statement: “To me, it's the huge flows of piston regs over some diaphragms (Poseidon excluded).”
I have not seen any actual work of breathing data that shows that the huge flow makes any noticeable difference in performance… especially with a good balanced second stage, a D400 couldn’t care less what first stage it was attached to. I am sure the Atomic second stage performs just fine if it is attached to a Conshelf or its flow through piston first stage.

The breathing performance is mostly driven by the second stage… the only thing the first stage does is keep a reasonably constant IP and a Conshelf does that just fine.

BTW, I used to be very much a flow through piston fanatic back in the 70’s… it is just too bad they don’t make that regulator anymore.



I didn't want to derail this thread, but I think the OP question has been answered, so I will share my opinion about first stages.

First, flow through pistons are great… they are relatively simple (specially the Mk-5) and they have super high flow rate. But, the only practical outcome of the high flow rate is a quick IP recovery during the breathing cycle. That in theory could be noticed if you have an unbalanced second stage… with a balanced, doesn't make much difference.



Now why I like balanced diaphragm (in particular the Conshelf and all its twins)? Primary reason: reliability. It also helps that in is the same first stage (and uses all the same parts) as my 1965 Royal Aqua Master double hose. Using the same parts in all my regulators helps reduce parts inventory.

The Conshelf is the longest production first stage ever. All modern Aqua Lung regulators still use the basically the same internal design as the first Conshelf and the Royal Aqua Master.

In recent years I have purchased over a dozen vintage Conshelf. At least half of them have never been service (they had the original seat from the 60’s or 70’s) and they worked just fine. Many Conshelf first stages can easily go for 40 years without service and work just fine. Is this surprising? Not to me.

My observation is that all industrial pressure reducing regulators are of diaphragm design. Also my observation is that they never get serviced. In the very rare occasion when they fail, they normally just get replaced. Note: my observation does not include all types of industrial application. My related experience is limited to power plants, some petrochemical, marine (Navy and commercial) and a few other.

Many industrial regulators operate in environments that are much harsher than a scuba regulator, both in corrosive environments and temperature extremes.

Also the consequences of a malfunction in an industrial regulator could be much more severe than in a scuba regulator. A failure in an industrial regulator could result in an explosion or a fire or many other disruptions that could easily escalate into a major accident, involving the lives of many. Regulators that are used in a critical application can be very specialized, but everyone I have seen is of diaphragm design.


So how often do I plan on servicing my Conshelfs, Royal Aqua Master, Phoenix RAM, and now the Argonauts? Only when they need it. That could easily be tomorrow if I flood one by accident or maybe in a few decades if the first stage is not abused. At this moment I have a few hundred dives in one of my Phoenix RAM (in several years) and the first stage has not needed any service. When I upgraded the second stage with the HPR, I didn't touch the first stage.



About the flow rate scaling, I think you are in the ball-park, but I will explain more later. This is not just a straight Reynolds number scaling situation.

I was given an old conshelf XI and the last known time it was used was 1974. I took it apart, saw no corrosion - it was amazingly clean, like it had been serviced then put away, the diaphragm seemed to be fine.
So I put it back together and have been using it with the same kit in it from who knows when.
It holds perfect IP. I don't know what else to say except it has given me many great dives.

I still don't really understand why pistons exist. Not that there's anything wrong with them, but diaphragms were first and worked as well as anything would ever need to so I don't get why someone saw a reason to design the moving part with a piston which is simpler but then you have O-rings and grease and keeping salt water away from the O-ring with more grease, and the service intervals associated with keeping them lubed and crud free. When diaphragms just by design sidestep all this.
I have several piston regs and love all of them dearly, but the sealed diaphram design just makes more sense to me in the environment of salt water, contamination, and grit.

I started a thread "Scubapro vs Atomic".
I wanted to know were the differences between he two companies and their regs.
What I got out of it was that Atomics are probably a little better as far as fine tuneness and precision but who really knows.
The bigger part was about the political runnings of both the companies.

I'm over it. I don't see myself getting another piston style reg probably ever.
I lusted over the T3 for a few minutes in a moment of weakness, but I slapped myself hard when I went and looked at my MK5/109's and my collection of old Aqualung conshelfs and my DA Aquamaster. I just don't know how I could improve on those for the type of diving I do.
All I'll really need is a handfull of 900001 kits, a few second stage seats, A few MK5/109-156 kits and and I'll be set for life.

 

[Scared Silly]

One thing that I am not sure has been completely discussed regarding Atomics is the similarity across all models. The first and second stages all come out of the same mold. As has been said that means the performance is the same across the board. But from the mfg and shop perspective this helps keep costs down. Further Atomic has not made a significant change in the first and second stages since their debut in 1998. As such, one can update a 15 year old reg into one made today. Sure the second stage case has changed just a bit but not significantly that the original case can not be updated. And in the case of the first stage there have been no changes unless you want to count the piston change.

To my knowledge Atomic is the only mfg. who has has such stability. Which I find interesting and says a lot about their designs. Yeah the basic technology of a regulator has not changed but look at all the models changes from SP and others.

 

[halocline]

To my knowledge Atomic is the only mfg. who has has such stability. Which I find interesting and says a lot about their designs.

I don't know, the RAM 1st stage internals lived on through the conshelf versions into the titan, the SP s-wing poppet and other parts, including the diaphragm, work on 2nd stages from the 109 to the current G250V, both of these examples are several-decade runs. The MK25 alone has been around as long as atomic, I'd bet. It's just that atomic is a much smaller and newer company. They're being smart about streamlining their production, but some of that is simply a matter of scale.

Not that SP hasn't made some really dumb moves.....

 

[flspy]

Does anyone have the z3? Is getting the sealed version worth it if i live in South Florida and do all my diving in warm water? If it is less prone to corrosion, then yes, it is.
The b2 looks cool too, with the swivel 1st stage. It also has a different 2nd internal. Not sure the swivel makes of breaks the deal on the 1st stage (but a must have on the second.)

Have any of you actually ran the reg for two solid years without a service? that just makes me nervous. It's like the new outboard motors. One of them claim you can run hundreds of hours without a service- but try budging lower unit bolts that have been soaked with saltwater for that long!