Question Mares Regulator Performance Data

[Zef]

That's really the essence of my new interest in Mares. Watching a CAD-CAM video of the Twin Balanced Piston in action was fascinating!
While it's anxiety provoking to think of an untethered diaphragm (which is really what the lower piston is) transmitting opening force to the push pin and poppet, it's not much different from how a piston head works in the wet ambient chamber of a Mk25.
I don't think of the environmental diaphragm as the "only" diaphragm. The lower piston is a really novel "main diaphragm" that happens to float. It's quite ingenious.
I was intrigued because of my known dislike for unsealed pistons (e.g., the famous Mk25). Though Mares has not been high on my preference list of brands, this might conceivably check two key boxes:
1) sealed mechanism;
2) diaphragm style poppet and valve, where gas only has to make a 90° turn out of the orifice, compared with a piston's 90° + 180° turns from tank to knife edge and knife edge to piston bore. This means less sandblasting of the sealing surfaces.

If the environmental seal fails, the reg just becomes an unsealed diaphragm, with the floating lower piston taking the place of the tethered diaphragm. The o-ring of the lower piston is a proven seal for the valve mechanism, with decades of piston history to support it. The only thing that's reversed is the position of ambient pressure area vs. IP chamber.

I can't argue with the size and looks of the turreted 82X, but compared to my SP Mk19 EVO, it looks to be a wash. Neither are compact beauties.

In one fashion or another, I think I'm going to give the Twin Balanced Piston a try.

I have no hands on experience with the TBP, just diagrams and videos from a few years ago and It has been quite awhile since I had seen/read anything on it. I just looked at some of the "newer" videos on youtube, and they show a lot more detail than the older clips I had previously watched. I can see now how the lower piston seals the chamber below it, and your explaination helped me better understand the design.

Thanks.

-Z

 

[Zef]

As I look at the form factor, if I'm going to try the TBP, while I wanted to be able to switch back to the standard diaphragm configuration, the 82X TBP is maybe too big.
The 28XR is TBP only (not soft main diaphragm), but is a lot trimmer.

Check the 62x...it can be purchased with/without the TBP. And I edited my post above in response to your question to note that both the 62X and the 15X can be outfitted with the TBP (the 52X can be as well).

-Z

 

[Antothoro]

I hear that Mares equipment is simple compared to other brands. The more simple something is, the fewer failure points it has and it's easier to work on, etc. Thoughts?

 

[lowwall]

I hear that Mares equipment is simple compared to other brands. The more simple something is, the fewer failure points it has and it's easier to work on, etc. Thoughts?

This only applies to their unbalanced stages.

They sell an unbalanced piston first stage, the current one is called the 2S, that is a very simple design. It's primarily intended for fleet sales to shops for rentals and classes. It's cheap, has a low parts count and is very simple to work on. As an unbalanced first, its performance suffers at depth and at low tank pressures.

OTOH, their diaphragm first stages are balanced and are pretty much like everyone else's in terms of general design. They do have excellent internal geometry and tolerances which results in very consistent performance. This is needed because their classic seconds stages are unbalanced which means divers would be able to feel performance differences if the delivery of intermediate pressure gas from the first stage varied.

Which brings us to the main thing that is simpler in their lineup, the classic downstream, aka unbalanced, second stages like the Abyss and Prestige/Rover. Mares stuck with downstream second stages decades after everyone else switched to balanced for everything except maybe compact octos.

This worked fine given the high quality of their balanced first stages, but had become a marketing liability so they added balanced second stages to their line several years ago and are slowly removing their classic seconds. All the seconds with "Adj" in the names (ex. Dual Adj and Epic Adj) are balanced and externally adjustable. The non-Adj Fusion and Ultra are also balanced.

 

[Antothoro]

Regs "being properly tuned" has come up a few times here. What does that mean to ya'll? How do I know if my regs are "properly" tuned?

 

[rsingler]

Thread 'Regulator Inspection and Checklist (Rev-8)' Regulator Inspection and Checklist (Rev-8)

 

[buddhasummer]

Thread 'Regulator Inspection and Checklist (Rev-8)' Regulator Inspection and Checklist (Rev-8)

God bless.

 

[Luis H]

I don't think of the environmental diaphragm as the "only" diaphragm. The lower piston is a really novel "main diaphragm" that happens to float. It's quite ingenious.


In one fashion or another, I think I'm going to give the Twin Balanced Piston a try.

Using a piston device to perform the same function as a diaphragm is nothing new. White Stag did a very similar design in the 60’s.

The US Divers (now Aqua Lung) UDS-1 triple tank system has a what they called a Conshelf 1st stage regulator built right into the triple tank manifold. But instead of a diaphragm it actually had a sliding piston to perform the diaphragm function. It appears that it was done to facilitate assembly in to the valve.
The UDS-1 is fully functional now!! | Vintage Scuba Diving Community Forum

I don’t have a UDS-1 (I wish I did), but I do have that section of the manifold. I will try to take pictures at some point.

Didn’t Dacor did some similar designs at one time? And I think there were others.

In any case this is nothing new. But it is a great solution, for a non-existing problem (IMHO).

I like diaphragms… they work so well that we use them in all current production second stages (we did use some bellows is some second stages in the 50’s). Try using a piston on a second stage and let me know how that works for you. The reason it doesn’t work may not be intuitively obvious, but that is a different discussion.


BTW, calling this design a Twin Balanced Piston is (IMHO) a marketing misnomer. I only see one piston. The intermediate pressure (or internal) is a piston with a sealing O-ring. The piston looking device used with the environmental sealing chamber doesn’t appear to have an O-ring and it really should not be sealed. The sealing device I see is the external diaphragm. The piston looking device appears to be just a push rod, the same as in any of my environmental sealed Conshelf's and Aqua Lung Titans.

The outer push rod probably helps keep the inside piston in alignment to keep it from binding, so it may also perform the function of a sliding guide, but not a pneumatic piston (no differential pressure).

 

[rsingler]

Ah! Leave it to Luis to bring me back to reality.

Nothing new under the sun...

 

[Nemrod]

I hear that Mares equipment is simple compared to other brands. The more simple something is, the fewer failure points it has and it's easier to work on, etc. Thoughts?

And Scubapro still has an unbalanced combo or two. The R195 and Mark 2 Evo combination for one, both stages are unbalanced. The R195 is a large diaphragm, unbalanced, classic downstream second stage. They are tough and reliable with their Nylon and 30% glass cases (same case as the balanced and adjustable G260). The Mark 2 was improved significantly with the Evo introduction and performs well even at the limits of recreational depth (or deeper) and low tank pressure, with very few parts and a compact body.

Mares classic unbalanced downstream seconds evolved from the Voit MR12, at least in part, that is where the Vortex assist aspiration tube comes from. It works much like the soldered in vane inside the USD/AL 1085 second stage, maybe even better. And Kirby Morgan took the 1085 and added an adjustment knob to allow for the working diver to adjust second stage spring tension to accommodate different supply pressure. Which would be a great thing to have with an unbalanced first stage. If there was a currently made such a regulator, a good unbalanced piston first coupled with an adjustable (but not balanced) downstream second, I would like one.

But there was another such a thing, no longer manufactured, the Scubapro 109 (non balanced) Adjustable. My two were converted to a balanced adjustable decades ago. A lot of these older (brass) downstream seconds suffered from small exhaust valves, the USD 1085 being an exception. The composite Mares regs did have large exhaust valves and I enjoyed mine. I had dived the Hole in the Wall (air dive then at about 150 feet max depth) with it (Mares MR12). On the boat (about 1998) during the return another fellow diver kept gushing over the set saying it was his most favored regulator and he went on so that when I pulled it from the tank I just handed it to him. It had a graphite colored case with a hint of metal flake and red accents. It was pretty but then and now I prefer the 1085 between those two designs and over the much admired 109.