Do regulator heatsinks actually increase regulator freezing during ice diving?

[n3rdftw]

I've been primarily diving warm waters so far, but I'm prepping for a trip to try to do Antarctic diving. I have some environmentally sealed regulators but no special second stages, but in the prep material, I'm seeing some interesting information that I don't see anywhere else on the internet, and wanted to get some opinions before buying more second stages.

As a warning, the Dive Operations Handout state:
Bear in mind that any heat exchangers built into your regulator, designed to take heat from the water and into the regulator body, will act in reverse by further cooling the regulator, and increasing the chance of freezing, when the water temperature is below 0° Celsius.

How true is that statement? I've reached back out to the dive outfit for some clarification as well, and asked my LDS but they disagree with that statement. Either way - how much do I need to worry about a second stage? Does this mean that a normal second stage works better than a traditional "cold water" reg, since those regulators have fins and heatsinks?

Was potentially just going to grab some Sherwood Blizzard 2nd stages since those have a heat-vane but not a full metal body with heatsinks on it like some other regs like the Mares Abyss or Aqualung Legends.

 

[tbone1004]

If you are diving in the Antarctic, I would recommend using those that have been tested and proven in that environment.
There are only two regulators that have passed Norsok testing which is deep and cold, Poseidon Xstream, and Apeks XTXs. I would recommend purchasing one of those....

The heat sinks work to bring the metal to the temperature of the surrounding medium, in this case water. The reason they do that is that the surrounding medium is almost always going to be warmer than the gas you are inspiring, including when it is below freezing. The gas starts out at whatever temp the water is while it is in the tank. It is then cooled significantly in the first stage from adiabatic cooling, warmed ish back up through the hoses, then cooled again when it comes out of the second stage.
Regardless of if the metal is colder than freezing or not, it will always be warmer than the air coming out of the second stage and warmer is better. It may not be great, but it certainly won't be worse

 

[RyanT]

The heat sink is a design simply to improve passive heat exchange between the regulator and the water. If the water temperature is above freezing, then the heat sink will transfer heat from the warmer water to the regulator. In theory, if the water temperature is at or below freezing, the heat flow will be either none or indeed reverse. With that said, the air flow through a regulator can drop the temperature well below freezing. So, I suspect that in freezing waters, what you get is not actually a reversal of effect by the heat sink, but rather it just becomes ineffective for keeping the regulator freezing. What @tbone1004 said above.

 

[Schwob]

Interesting question.
Sort of like not test breathing your reg in near or sub-freecing air, but with (salt) water actually being at or a tad below freecing for freshwater (condensate)?
I would be interested in learning what it is in it's construction that would make a first or second stage resistant to freece-ups when submersed in sub 32F / 0C water?
(That seems ti be the stipulation?)
...
Related: Compressed air in tanks filled in a warmer environment: How dry is it? Dry enough to still be dry with no chance for any water to condense out of it at freezing temps?
...
Just trying to understand how a reg could gunction under such conditions...

 

[tbone1004]

@Schwob The first stages are designed to essentially turn into an ice block and still function.
This is a Poseidon MK3 after an ANSTI test and may well have been the Norsok test. The ports that aren't frozen are exposed to ambient water and won't freeze since the cooling occurs on the main body.

In the second stages, the key is keeping the ice out of the barrel if it's a "normal" design, and with Poseidon, the gas doesn't really come out near the one moving part, so the odds of it freezing are pretty negligible. The servo valve only bleeds a very small out of gas and the big diaphragm in the middle releases the rest. The ice can't form there for a myriad of reasons.
I don't know how Apeks was able to keep the barrel from freezing

 

[Schwob]

@tbone1004: Thanks.
and

I don't know how Apeks was able to keep the barrel from freezin

Yep, most curios ... and not only because that's what I happen to dive...

 

[rhwestfall]

Go for a double hose...

 

[shurite7]

The only two regs scientific divers are allowed to dive, McMurdo Station in Antarctica, are Sherwood and Poseidon which are provided by the station. According to the DSO there all other regs are not permitted because they free flowed during their testing. As tbone has pointed above, Apex passed the Norsok test, but the station will not use it because it failed. Yet, some of us up here dive underneath the ice with Scubapro, Apex, and Aqualung regs.

What I have learned about diving in cold water is to have a good first and second stage. The later is the one many people ignore for importance. While I am aware of the purpose of the heat exchangers, I'm not so convinced the ones along the hose work as well as it is claimed. I haven't heard of the exchangers acting in reverse.

With all that being stated, what is the policy of the operator where you will be diving? Will they allow you to use exchangers or are they forbidden?

 

[Schwob]

Go for a double hose...

No kidding, I was waiting for you to chime in with that exact comment ...
So, that "accomplished" ,
if it is indeed so, what then is the mechanism of operation that makes a double hose regulator better in the cold?
Is it possibly truly freeze proof for some reason?
Is it the the (acoustic) boom of the regulator that chips of any early ice onset with that unique low frequency sonic boom? If I dive close enough to you, could it even work on my Apeks then?

 

[tbone1004]

No kidding, I was waiting for you to chime in with that exact comment ...
So, that "accomplished" ,
if it is indeed so, what then is the mechanism of operation that makes a double hose regulator better in the cold?
Is it possibly truly freeze proof for some reason?
Is it the the (acoustic) boom of the regulator that chips of any early ice onset with that unique low frequency sonic boom? If I dive close enough to you, could it even work on my Apeks then?

it's completely sealed. The second stage can't really get the same amount of moisture around it because of the long loop hoses that collect most of the condensation. Only design that does that because the second stage is remote from your mouth.
I'm sure @Luis H can elaborate