Piston or Diaphragm

[Superlyte27]

While you guys are all arguing to prove who is smarter, the OP is trying to get some answers...



The Atomic regulator are excellent. I have and use many. If you are going to be wanting to service your own regs I highly suggest you look at the HOG regs. HOG is the only manufactures that allows users to service their own regs once they complete a HOG regulator Service Class. I dive, sell, and service HOG regs as well as teach the HOG Regulator Service Class. I will be happy to answer any question you might have.

Maybe you've confused us with your personal relationships, but this isn't arguing. This is a discussion. A good discussion where more than one person is learning something. Who is smarter never came into the conversation, but since you asked, I am.

With that said, no one knows everything, despite what they think. I'm leaning towards thinking that what I thought I knew regarding unbalanced piston regs isn't factual. Dude, if that's not worth the price of admission, then why are we here?

We're all here to learn or educate. Sometimes we get both.

 

[PfcAJ]

Gas density is a real thing at those depths. Passing a dense gas (like argon) is going to happen slower than a high helium mix, esp through a restricted orifice like a drysuit inflater. Its not designed to for the gas to move through it quickly, and you're cramming more gas through it at depth. Think molasses vs water moving through a crazy-straw.

 

[Superlyte27]

I don't use argon.

 

[PfcAJ]

Do you use air? Cuz thats denser than any trimix, also

 

[Superlyte27]

For drysuit, yes.
I don't have issue filling drysuit with my FDX-10, but certain did with the sp5

 

[herman]

This best advise I can give is to buy, study and understand Regulator Savvy. I have read it multiple time as well as Maintenance and Repair of Scuba Regulators, multiple regulator manuals and taken several good reg courses. I have spent hours doing the math to make sure I understand the physics involved. I understand how a reg works and the physics behind them. Most reg techs have no idea of the physics behind the regs they work on, they just put parts in.

Balancing a first stage has nothing at all to do with depth compensation or how well a reg breaths at depth, the purpose of balancing a first stage is to keep IP constant (and thereby keeping work of breathing constant) as tank pressure changes PERIOD. Depth compensating is what keeps a reg breathing the same as depth increases. Overbalancing, which is actually over depth compensating is a totally different subject and has nothing at all to do with balancing regardless of the sales BS....and I did the math on it as well. ALL scuba (breathing)regs compensate for depth and maintain IP at a given amount over ambient, anyone who tells you otherwise simply does not understand how regs work.
To put it in a basic formula - IP = spring force+ambient pressure. The ambient pressure is exerted on the diaphragm in a diaphragm reg and on the spring side face of the piston in a piston reg and as ambient pressure increases, IP does as well to compensate, following the increase in ambient pressure. If you don‘t believe it, hook your environmentally diaphragm sealed reg up to a tank, install an IP gauge and then press on the seal to “ increase ambient pressure“, the IP will increase in proportion to how hard you press on the seal. It’s a lot harder to do but reaching in and pressing on the face of the piston in a piston reg will do the same thing.

 

[Bombay High]

I used Kirby Morgan regulators very deep, but now use Scubapro MK25 and MK17. One is piston (MK25) and one is diaphragm (MK17).
They are both spectacular.
So was the Kirby Morgan, but I dont have to sell my house to get the Scubapro's serviced.

---------- Post added July 17th, 2013 at 09:56 AM ----------

BTW - I also use Poseidon Cyklons - and they are phenomenal when you are deep. But expensive to maintain, where I am. They are also extremely rugged and reliable. If you have Poseidon service close by, I would suggest you try them.

---------- Post added July 17th, 2013 at 10:21 AM ----------

Supelyte - This is from the Kirby Morgan literature. All our non rebreather bailouts are piston 1st stages, and this one is dive tested to over 1,600 feet.

I like the disclaimer at the end about sport diving ​

For anyone interested - this is the KM Superflow, and I have two for sale to anyone in India who is interested. Very good performance.

"We’ve taken the demand regulator from the world renowned SuperLite 17B deep sea commercial diving helmet, and made it accessible to scuba divers. This second stage regulator has been dive tested to over *1600 feet. It is fully adjustable with our Dial-a-Breath control, and is available in metal or plastic. Coupled with our 305-161 high flow, piston first stage, made with design principles from our Kirby Morgan Air Control Systems, these regulators offer the scuba diver the same reliable, high performance that commercial divers have put their trust in for over thirty years. ​

*We do not recommend sport diving deeper than 130 feet. "​

 

[burak]

I actually read at least 7 or 8 different articles. Honestly, I'm not trusting any of them. They are about 50/50. I quit caring. Here's what I do know.... my SP5 suck to breath on the deeper I get. I can't understand how pressure increases on the piston because the airspace on the other side of the piston is so much smaller. But, I will concede that I really don't know.

But, talking to several Oceanic repair techs, I'm convinced that lots of people don't know. At least I'm not alone.
I called 4 people who don't know each other, who have been working on Oceanic for decades, and they all told me that the SP5 only puts out 140psi, regardless of depth.

I would love to test this, but I don't have anything I can build a pressure pot out of (yet).

Hi,
I'm not familiar with the SP5 but I know the SP MKII.
The internal pressure is always 140psi above the ambient pressure and not absolut. Through the little holes water comes in at different depths with different pressures and helps to build up greater intermediate pressures at depth.

A regulator which doesn't regulate the the intermediate pressure to the absolute pressure is not a regulator, is it?

I'm guessing the misunderstanding comes from the difference between how high the middle pressure related to absolute and actual ambient pressure is.