Regulator Roundtable Q&A

[knotical]

Ease of breathing has much more to do with adjustment than with make/model.

 

[oldschoolto]

I love my conshelf supreme XIV .. But you guys already know that...

Jim...

 

[Neilwood]

I guess regs are like cars in a way - you only notice the differences in a lot of them under extreme conditions. For day to day, there probably isn't much between them but at depth in cold climates, the very slight differences might be more apparent.

 

[halocline]

I guess regs are like cars in a way - you only notice the differences in a lot of them under extreme conditions. For day to day, there probably isn't much between them but at depth in cold climates, the very slight differences might be more apparent.

I don't think the car analogy works very well to be honest. First, cars are very complex machines with all sorts of different systems and radically different functional designs and geometry. Second, cars really have gotten much better in the last few decades; they last longer, are less polluting, more reliable, more powerful, and most importantly, they're much safer. Third, there are huge differences in function between cheap cars and expensive ones.

Regulators, in comparison, are very simple devices, some are ingeniously designed and a few do have significant differences (i.e, SP pilot vs standard 2nd stages) but mostly they're pretty similar. There have been few if any appreciable improvements over the classic designs. Many of us who really understand how these things work still choose to dive with old inexpensive regulators (I paid $80 for a MK10/D300 that I use in technical diving) despite the fact that we could easily afford the less-than-one-dive trip expense of a new high end model. There's just not that much difference between them.

Where the analogy does seem to hold water (so to speak) is in the hype and nonsense surrounding their marketing and sales.

 

[seeker242]

Which one is generally easier and cheaper to service, diaphragm or piston?
What PSI does the LP and HP ports provide?
Do you need DIN in order to use it with high pressure steel tanks?
Does orientation in the water affect breathing characteristics? For example, horizontal facing surface vs horizontal facing bottom?
Do all 1st and 2nd stages use a "poppet valve" to regulate the pressure?

 

[halocline]

Which one is generally easier and cheaper to service, diaphragm or piston?
What PSI does the LP and HP ports provide?
Do you need DIN in order to use it with high pressure steel tanks?
Does orientation in the water affect breathing characteristics? For example, horizontal facing surface vs horizontal facing bottom?
Do all 1st and 2nd stages use a "poppet valve" to regulate the pressure?

1. There's no significant difference in cost or difficulty of service for piston vs diaphragm regs.
2. HP ports provide tank pressure, LP ports provide intermediate pressure, typically around 135 PSI.
2. No you do not need DIN for HP tanks. Modern yokes are more than up to the task. Some DIN valves are not convertible, and for those tanks you do need DIN regs.
3. Yes, orientation does affect breathing characteristics. This is due to geometry issues and slight differences in depth between different parts of the regulator that change with orientation.
4. Only first stages regulate pressure, meaning they allow a specific pressure to pass through the regulator, and hold back any additional pressure. 2nd stages are "demand valve" meaning they allow air to pass on demand. The term "poppet" is used differently by different manufacturers, but here's what all regulators have in common. The first stage has a valve that is open when unpressurized. When pressure from the tank enters the regulator and reaches IP, this valve is closed, preventing further air passage. The 2nd stage has a valve that is closed when unpressurized, or more importantly, when there is a pressure balance between the inside of the 2nd stage case and the outside. When a diver inhales, he reduces the pressure inside the case, which allows outside pressure to collapse the diaphragm, which pushes a lever that opens the valve and allows pressurized air from the hose to enter the 2nd stage, until the pressure equilibrium is re-established. Any pressure excess in the 2nd stage gets vented out the exhaust valve.

 

[knotical]

... LP ports provide intermediate pressure, typically around 135 PSI. ...

and to elaborate a bit, that's 135 psi above ambient. The absolute IP increases with depth so the reg doesn't become dramatically harder to breathe from.

 

[kelemvor]

I believe some regulators have devices in the first stage to prevent water intrusion if submerged without being connected to a tank (e.g. during cleaning). It may not affect how much gas the things deliver, but I wish my regulators had that feature. Others come with swivels that reduce jaw fatigue. Supposedly, the Atomic swivels are safe (compared to aftermarket swivels that have a bad rep for breaking apart).

Maybe not a "major" change, but I think they are still valuable. I wouldn't consider either feature to be a gimmick, since they both address real problems the average diver might have with a regulator.

 

[rhwestfall]

(compared to aftermarket swivels that have a bad rep for breaking apart).

replaced many years ago by another product..... practically "urban legend" now..... but it just keeps being said....

 

[uncfnp]

So I have a question. If regulators are more alike then dissimmilar, what makes a regulator a tech regulator? When I started venturing into more advanced diving, I was required to have tech regs but never got a clear definition of what "tech" meant when it comes to regulators.