Do regulator heatsinks actually increase regulator freezing during ice diving?

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The United States Navy Experimental Diving Unit: Testing in Antartica


"At its inception in 1947 (through the US Naval Support Force Antarctica) through 1967 the USAP diving program issued double-hose regulators to NSF scientific divers. In 1991, double-hose regulators were retired from service and replaced with single-hose, modified Sherwood Maximus SRB3600 regulators. A heat retention plate was fitted over the second-stage exhaust valve and around the air delivery lever and the intermediate pressure detuned from 145 to 125 psi to reduce the probability of free-flow in supercooled sea water at -1.86oC in McMurdo Sound. The decision to investigate replacement regulators was influenced by the age of the 1991 Sherwood models, their less than optimal breathing characteristics, and the lack of continued parts availability in 2008 to avoid potentially catastrophic regulator failure."

So the US Navy issued double hose regulators from approximately 1947 until their retirement in 1991 for its divers in Antarctica. Good enough for me. I've never had any issue with my Phoenix equipped DAAM, nor Argonaut when ice diving. 44 years of Navy use means something.
 
So the US Navy issued double hose regulators from approximately 1947 until their retirement in 1991 for its divers in Antarctica. Good enough for me. I've never had any issue with my Phoenix equipped DAAM, nor Argonaut when ice diving. 44 years of Navy use means something.
If I were headed for the Antarctic, the Argonaut or a similar double hose regulator would be my first choice. My understanding of the reason for the Navy to go away from the older Royal Aquamaster was that they became so banged up over the years that the cases developed leaks, and they did have some freeflows after these regulators leaked water into the cases; that and the non-availability of parts from Aqualung. The Argonaut has a plastic case, ensuring watertight integrity throughout its lifetime (there are U.S. Divers Company Jet Air regulators with plastic cases which are still as watertight as when manufactured over 50 years ago).

Double hose regulators with certain designs have their first stage inside the case (DA Aquamaster, Royal Aquamaster, Phoenix-equipped DA Aquamaster, Mossback Mk3, and Argonaut). Some others do not have this design (Sportsways Hydro-Twin, Nemrod Snark III, both of which have water-exposed first stsges). When the entire valve mechanism is enclosed in air, freeze-up is virtually eliminated. Also, with the. Double hose concept, water vapor from respiration is in a separate exhalation hose loop, and never gets to the demand (second stage) valve. This is why for cold or under ice diving, double hose regulators were preferred for half a century, and now that at least one is again available (the Argonaut), they should be reconsidered for Antarctic diving ops.

There seems to be misconceptions about "heat sinks" and "heat vanes" in this discussion too. Heat sinks seem designed to bring water temperatures into the metal o for the regulator, and my perception is that this pertains mainly to the first stage. Heat vanes in the second stage, such as seen on the Sherwood Blizzard, do something different; they transfer heat from the diver's breath to the valve mechanism for the second stage using copper metal to directly conduct this heat to the valve. This keeps the valve well above the freezing temperature of water, thereby minimizing the potential for ice to develop internally on the valve.

The Sherwood Blizzard also had a sealed first stage. There was a tiny hole that constantly bled air from the first piston stage into the ambient compartment, which had another hole plugged but a rubber stopper with a very small hole in it too, so that this entire chamber was sealed from the water. That is why, when observing this regulator in action Underwater, a very tiny stream of bubbles is noted coming from the first stage. This is normal to this regulator, and represents probably the first single hose regulator air sealed from the water surrounding it.

SeaRat
 
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If I were headed for the Antarctic, the Argonaut or a similar double hose regulator would be my first choice.
I wouldn’t. I would make use of the various organizations that run carefully controlled evaluations run by experts and buy ones that pass their tests. Comments by guys who run cold water regulator tests are the relatively small changes in a regulator, ones that are sometimes slipstreamed into production without a model number or part number change, can have very dramatic effects on freeze ups. That’s apparently been a problem that the Navy has encountered in the past.

Spending a fortune on going on a polar diving trip and then choosing a regulator based on “well, it should work” instead of relying on tests by experts to find regulators that are known to reliably work in polar diving seems crazy. And a path to having a really expensive and frustrating non-diving trip.
 
I wouldn’t. I would make use of the various organizations that run carefully controlled evaluations run by experts and buy ones that pass their tests. Comments by guys who run cold water regulator tests are the relatively small changes in a regulator, ones that are sometimes slipstreamed into production without a model number or part number change, can have very dramatic effects on freeze ups. That’s apparently been a problem that the Navy has encountered in the past.

Spending a fortune on going on a polar diving trip and then choosing a regulator based on “well, it should work” instead of relying on tests by experts to find regulators that are known to reliably work in polar diving seems crazy. And a path to having a really expensive and frustrating non-diving trip.
Kevin,

This is a pretty normal response for those unfamiliar with the workings of a double hose regulator. If I could prove that the double hose regulator is better using math, would you reconsider? Here's a quote from the symposium on diving in Antarctica:
The likelihood of regulator free-flow (Clarke, 1999) is dependent upon the probability of water gaining entry to the inside of a regulator second stage (Pwe), and the probability of low temperatures in the second stage (PlT). PlT is in turn governed by a balance between adiabatic processes producing regions of low temperature, and heat flux towards those cold regions. In general terms;

Pf = Pwe x Pit

where Pf is the probability of regulator failure caused by freezing. The probability of water entry into the second stage (Pwe) is a function of exhaust valve design (controlling the ease of exhaust valve leakage) and the magnitude of negative pressures. Negative pressures are, in turn, generated by high ventilatory rates and high gas densities related to depth when a diver works against inspiratory resistance (another feature of regulator design). Therefore, Pwe = f(VE , D, and C1...n) where VE is expired ventilation, D is depth, and C is a number of manufacturer determined parameters (e.g., C1 = exhaust valve leakage pressure, C2 = inhalation resistance, etc.).
https://www.oceanfdn.org/sites/default/files/International Polar Diving.pdf
page 37
Note that the factor, Pwe is the probability of "water gaining entry to the inside of a regulator second stage. If that Pwe factor is zero, the whole equation goes to zero and there is no probability of regulator freeze-up. This is how a double hose regulator works, as both the first stage and the second stage are isolated from water, inside the "can" of the regulator. The diver's breath is isolated from the second stage valve mechanism by a mouthpiece mushroom non-return valve, and therefore cannot get to the regulator second stage too. The whole exhalation hose loop is isolated from the second stage, and exits outside the demand diaphragm. This is how a double hose regulator prevents freeze-up. (See the diagram from the NEW SCIENCE of SKIN and SCUBA DIVING, Conference for National Co-operation in Aquatics, Copyright 1957, 1959, 1962, page 97.

Dacor, in the 1970s, took their double diaphragm two-hose regulator to Antarctica and showed no freeze-ups. "...(used by Divers at both North and South Poles and proven efficiency in tests to 83 degrees below Zero)..."* (I have checked that figure, from a Dacor publication on the R-4 "Dial-A-Breath" Regulator, not dated in my file).

SeaRat
*To be more accurate, I'm pretty sure Dacor meant to say in the Arctic and Antarctic, rather than the North and South Poles, as I'm almost positive they weren't at the North Pole, and the South Pole has no liquid water that I know of.
 

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If they are not actually being widely used by people who dive in the arctic professionally I wouldn't use it. If it can't pass their tests or the manufacturer isn't willing to submit it to testing then I would decline to be the person who finds out why that is.
 
If they are not actually being widely used by people who dive in the arctic professionally I wouldn't use it. If it can't pass their tests or the manufacturer isn't willing to submit it to testing then I would decline to be the person who finds out why that is.

I agree, so I started pounding the pavement everywhere - I even got Dan Orr of DAN fame who wrote this blog post about his experiences at Antarctica to respond to me on LinkedIn... (unsure if he has a scubaboard account to credit him with!)

For posterity - here's his feedback, and what made me pull the trigger on saving a several hundred bucks by getting a pair of Sherwood Blizzards to put towards upgrading the rest of my undergarments instead! Although based on the number of hours I spent researching this topic and reading papers on this, I might have been able to work some extra hours to bank the money for nicer regs from the beginning anyways.....

"Depending upon the time of year you go, you may expect water temperatures anywhere from 32 degrees (F) to 28 degrees (F). The water temperature when I was there (February) was consistently 32 degrees (F) throughout the water column. Before deciding on a regulator, I reviewed the literature regarding regulator performance in extreme temperatures (including this The Best Cold Water Regulators You Can Buy Right Now [Review]) and talked with friends and colleagues who have dived both the Arctic and Antarctic. In the end, it boiled down to the 4 discussed in the referenced article. I also talked with my local dive store (probably the best source of practical information) and chose to go with the Sherwood Blizzard Pro. That regulator performed well but, in reality, I believe any of the 4 referenced regulators would work well. Also, depending upon who you go with, we were required to have two separate regulator systems with make good safety sense. We also used an "H" valve to accommodate two regulators. I hope this helps."
 
come up here and see us dive under the ice then its see with your own eyes what works and what doesn't , not many free flows with the regs we use and set up in real conditions not lab results . That's why I put a low number on what a lab says and only use it as a guide , then try it myself . any one who takes our ice course get to see it and try it .....situation
 
~snip~
Double hose regulators with certain designs have their first stage inside the case (DA Aquamaster, Royal Aquamaster, Phoenix-equipped DA Aquamaster, Mossback Mk3, and Argonaut). Some others do not have this design (Sportsways Hydro-Twin, Nemrod Snark III, both of which have water-exposed first stages). When the entire valve mechanism is enclosed in air, freeze-up is virtually eliminated. Also, with the Double hose concept, water vapor from respiration is in a separate exhalation hose loop, and never gets to the demand (second stage) valve. This is why for cold or under ice diving, double hose regulators were preferred for half a century, and now that at least one is again available (the Argonaut), they should be reconsidered for Antarctic diving ops.
SeaRat

One thing I've always wondered about the 'classic' RAM style balanced double hose design with the first stage separated from ambient water pressure.

In a similar balanced diaphragm Conshelf 14 ambient water pressure can act directly on the first stage HP diaphragm as well as the second stage LP diaphragm to deliver air balanced to depth.

In the RAM double hose ambient water pressure acts on the larger surface area diaphragm and delivers air so pressure in K (referring to the NEW SCIENCE of SKIN and SCUBA DIVING diagram) matches ambient water pressure L.

Water acts with a known force at depth (for example 4 ATM at 30m it is 405.3 kPa or 58.8psi at 98.4 feet) directly on the HP diaphragm in a Conshelf 14.

However in a RAM sealed double hose system, ambient compressed air in K is delivering the same force to the HP diaphragm. Surely this compressed air is more 'springy' vs ambient hydrostatic pressure and less able to act on the HP diaphragm consistently?
Is that why the Sportsways Hydro-Twin and Nemrod Snark III engineers chose to have water-exposed first stages for their double hose designs? Though to me the Snark III looks like a variation on the sealed RAM... cannot see the ambient water entry point.
Nemrod Snark 3 detail.PNG

It is entirely possible I have missed something bleedin' obvious here... I'm still learning about the intricacies of double hose regulator design and operation :wink:
 
One thing I've always wondered about the 'classic' RAM style balanced double hose design with the first stage separated from ambient water pressure.

In a similar balanced diaphragm Conshelf 14 ambient water pressure can act directly on the first stage HP diaphragm as well as the second stage LP diaphragm to deliver air balanced to depth.

In the RAM double hose ambient water pressure acts on the larger surface area diaphragm and delivers air so pressure in K (referring to the NEW SCIENCE of SKIN and SCUBA DIVING diagram) matches ambient water pressure L.

Water acts with a known force at depth (for example 4 ATM at 30m it is 405.3 kPa or 58.8psi at 98.4 feet) directly on the HP diaphragm in a Conshelf 14.

However in a RAM sealed double hose system, ambient compressed air in K is delivering the same force to the HP diaphragm. Surely this compressed air is more 'springy' vs ambient hydrostatic pressure and less able to act on the HP diaphragm consistently?
Is that why the Sportsways Hydro-Twin and Nemrod Snark III engineers chose to have water-exposed first stages for their double hose designs? Though to me the Snark III looks like a variation on the sealed RAM... cannot see the ambient water entry point.
View attachment 515097
It is entirely possible I have missed something bleedin' obvious here... I'm still learning about the intricacies of double hose regulator design and operation :wink:
Actually, you are correct, the Snark III does not have the first stage exposed to the water; that was a miss-statement on my part. But it does have a vulnerability, in that the second stage is situated so that the ORV (overpressure relief valve) is out there and exposed. While this probably won't directly affect its breathing characteristics, it could cause the ORV to be stuck so that it doesn't function. Think of a big block of ice on the whole backside of the regulator. If that occurred, and there was a high pressure leak from the first stage, there could be bad things happening to the regulator. That is why I included it in the list of regulators not as good for the Antarctic as the DA Aquamaster, Royal Aquamaster, and Argonaut Kraken.

SeaRat
 
Thanks for the clarification SeaRat, I can see that the ORV could become encased with ice and lock up in extreme conditions!
What are your thoughts on the HP diaphragm being actuated by compressed air (to match ambient water pressure) in a RAM vs directly by the water in a Conshelf 14?
Any appreciable difference?
 
https://www.shearwater.com/products/perdix-ai/

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