Cold Wwater/Deep Water Reg.

[rescuediver009]

Good advice here but no one mentioned that the Apeks 200 and the AquaLung Titan's are the same reg., made by the same manufacturer (Apeks). Buy the one that you get the best buy on and can be supported by your local shop.

As mentioned before don't skimp on your underwater life support. Remember this is an extreme sport!

Happy New Year,

Dave

I think that no one has mentioned it because the titan and the ATX200 have absolutely nothing in common as far as design or construction. You may be thinking of the Legend, but even then a little research will show otherwise.

 

[SterlingDiver]

I think that no one has mentioned it because the titan and the ATX200 have absolutely nothing in common as far as design or construction. You may be thinking of the Legend, but even then a little research will show otherwise.

There you go,my ignorance has shown through.

 

[Vie]

There you go,my ignorance has shown through.

If it’s any consolation, they both use the Comfo-Bite mouthpiece.

 

[kazinvan]

Hello All,

I'm new to the sport and have yet to experience a free flow. I do dive in cold water (western Canada), the water right now is about 6C (43F). We covered free flow in training and did some practice, but no one really covered *why* regs free flow. So far, from this thread it seems like the second stage can freeze, is that correct? I suppose getting sand into the second stage can cause a problem as well. Regardless, can anyone give me some info on why they freeze and the best way to avoid id and deal with it if it does happen.

Thanks,
Mike

 

[rescuediver009]

Freeflow can happen when a number of factors are present. It can be anything from the mentioned sand, to frozen components to the reg just being so high performance that it creates a vacuum in the second stage and wont stop. So depending on where you get the freeflow, it can eb abad or good thing. The most common however experienced most by divers is that when the internal components freeze in cold water. They freeze by the very cold air passing by the metal parts that are covered in moisture from your breath or if the reg was dipped in the water. The parts will freeze open (because the passing air will cause it to cool to the point of freezing) and the reg will continuously purge. Not good. To combat this manufacturer have added a heat sink to the second stage. The piece of metal in contact with those of the othermetal moving parts wicks away the cold just like a radiator does the heat in a car through fins. For the most part they work quite well or at least have people convinced enough to buy them. Hopefully this helps.

 

[StSomewhere]

Jump in the water with a high performance reg that doesn't have the mouthpiece facing down. Instant freeflow.

 

[Greg Barlow]

Rescue Diver wrote:
"The piece of metal in contact with those of the other metal moving parts wicks away the cold just like a radiator does the heat in a car through fins."

Actually, the heat sink doesn't "wick away" cold. The scientific principle behind a regulator's heat sink is that the sink absorbs the heat from the surrounding water and then it is transfered to the inner moving parts. This is the same principle as that of a refrigerator or freezer. These appliances don't technically make food "cold", what they do is remove the heat from inside the unit.

The incoming gas from a tank drops in temperature each time that it expands through an orifice. This is the reason why a first stage can become covered in ice while diving in cold water. As the gas passes through the second stage it comes in contact with moisture that is always present. This cold gas flow can cause frost to form rather quickly and the ice crystals then bond to one another. The heat sink can, at best, raise the temperature of the gas to that of the surrounding water. Obviously, the water is above freezing or you wouldn't be able to swim. Many manufacturers use metal air barrels to act as a sink. Others use teflon coatings on the metal parts to lessen the chance that water can adhere to their surface. Some manufacturers are even using very "slick" internal surfaces to allow the moisture to "roll off" rather than adhering to the surface.

Mares's metal second stages work great in cold water for this very reason. The metal body acts as a large heat sink to absorb the water's heat. Synthetic parts do not conduct heat anywhere nearly as well as metals. This is the reason why we use them to insulate parts from heat.

When I began diving in the early 70's we all used metal bodied second stages, or double hosed regs. Free flows from icing were very rare.

Greg Barlow
Former Science Editor for Rodale's Scuba Diving Magazine

 

[Vie]

I read in Norbert Wu and Jim Mastro’s book, “Under Antartic Ice”, that the US Antarctic Diving Program uses the Sherwood Maximus which “had been further modified with a brass plate, which allowed our breath to warm up the regulator second stage and thus inhibit ice formation inside it.”

Is this a better way than using an all metal second stage?

 

[Greg Barlow]

I read in Norbert Wu and Jim Mastro’s book, “Under Antartic Ice”, that the US Antarctic Diving Program uses the Sherwood Maximus which “had been further modified with a brass plate, which allowed our breath to warm up the regulator second stage and thus inhibit ice formation inside it.”

Is this a better way than using an all metal second stage?

I've seen the photographs of the modified regs and they had a large brass or copper conduction plate in the center of the body. Brass and copper both conduct heat very effectively, and having such a plate in the area of warm exhaled air should work very well.

Sherwood first stages utilize a "dry" system where pressurized gas is released into the ambient chamber. This keeps the water from entering the chamber, but still allows the surrounding pressure to adjust the imtermediate pressure of the reg. The excess gas leaks out through a small port. The amount of lost gas is relatively little, despite what many unaware divers look at as a "leak".

Sherwood regs are very robust and dependable. When I worked for Rodale's we found that the first stages had a relatively low gas flow, which hampers the reg's performance on a breathing simulator. Their cold water service is excellent, but they just don't offer the low work-of-breathing that many comparably priced regs do.

Is a modified reg like this Sherwood better than a metal bodied Mares? Well, the Sherwoods didn't fail under such harsh conditions. Is that better? I don't really know the answer. It would be very interesting to modify a metal second stage in the same manner and then test it under such conditions.

BTW, I certainly hope that the relief efforts are helping with your country. My thoughts and prayers go out to all the victims.

Greg

 

[Vie]

BTW, I certainly hope that the relief efforts are helping with your country. My thoughts and prayers go out to all the victims.

Thank you. We’ll be back on our feet eventually and I’m sure everyone affected is grateful for all the kind thoughts and deeds shown by people both here and abroad. We are of course extremely grateful for all the relief efforts pouring in from all over the world. At a time like this it is a comfort to know that we have friends.