Cold Wwater/Deep Water Reg.

[ajaxord]

[Think about a thermos. Whether you are trying to keep you liquid cold or hot; what works better, a metal thermos or a plastic. Metal of course.]

Oh really?

What you find in a thermos is a glass envelope holding a vacuum. Inside a thermos is glass, and around the glass is a vacuum. The glass envelope is fragile, so it is encased in a plastic or metal case. In many thermoses you can actually unscrew and remove this glass envelope.

A thermos then goes one step further. The glass is silvered (like a mirror) to reduce infrared radiation. The combination of a vacuum and the silvering greatly reduces heat transfer by convection, conduction and radiation.

So a metal casing is better than a plastic casing? Maybe in preventing the glass envelop from breaking, but can't see how the vacuum is any different when contained in metal vs. plastic.

 

[StSomewhere]

There are metal-lined thermos bottles (not just metal cases). I know since I have three, I'm too hard on the glass ones. I use them for morning coffee on the way to the quarry. <-- Lame attempt at being on topic.

I still say get a sealed Zeagle or Apex.

 

[rescuediver009]

There are metal-lined thermos bottles (not just metal cases). I know since I have three, I'm too hard on the glass ones. I use them for morning coffee on the way to the quarry. <-- Lame attempt at being on topic.

I still say get a sealed Zeagle or Apex.

Yeah, not sure that I agree with the thermos analogy either. The thought that the metal 'insulates' the moving parts is also wrong. Metal actually conducts cold better than plastic. I don't think that there was anything there that was right....

 

[darkstar]

Metal actually conducts cold better than plastic.

You mean metal conducts heat better than plastic. Cold is just a term used to describe the relative absence of heat energy.

A metal body second stage would sink heat from the surrounding water to keep the valve above freezing. Probably better in 2-3C water, because water is a better conductor than moist exhaled air.

Regs like Sherwoods and Apeks sink heat from the diver's exhaled breath and so would be better in situations like the Antarctic where the surrounding salt water may be below 0C.

I have both a Blizzard and an ATX200, but would favor the Blizzard for ice diving because the second stage is a much simpler mechanism. For everything else, Apeks all the way baby.

 

[rescuediver009]

Regs like Sherwoods and Apeks sink heat from the diver's exhaled breath and so would be better in situations like the Antarctic where the surrounding salt water may be below 0C.

You are way off. How would explain that the heat sink (the ribbed piece of metal on the outside of the reg) draws the warmth from the diver's exhaled breath? You should look at a little closer before you give advice nevermind correcting others. The heat sink works by taking the warmth from the water which no matter what is always warmer relative to the moving parts of the second stage and thus keeps them from freezing.

 

[darkstar]

You are way off. How would explain that the heat sink (the ribbed piece of metal on the outside of the reg) draws the warmth from the diver's exhaled breath? You should look at a little closer before you give advice nevermind correcting others.

Didn't mean to piss you off. Its just that talking about conducting cold is like talking about black surfaces 'conducting dark'.

You are right about the ATX200 having an external part called the "heat exchanger".

I don't think I'm "way off" though, but maybe I didn't explain my reasoning very well.

I think that the valve on the ATX also benefits from being contained in an metal assembly, with a large surface area, that is exposed to the exhaled breath. It may not be intentionally designed that way, but with every exhale, you are breathing warm air directly onto the valve spindle which contains the valve seat, spring and shuttle. In salt water that is below 0C, that would be the only way to keep the valve above 0C and frost from forming on the rubber seat. Also, if the only heat that ended up warming the reg was coming from the surounding water, then a full metal body reg (with a much larger conductive surface area exposed to the water), would capture more heat (from the water) than a half inch long ribbed tube on the outside of a plastic body. If the water was just over 0C, the full metal body reg valve would be at or below the temperature of the water, but the Apeks valve would be warmer.

On the Blizzard, there is a double metal fin in the mouthpiece of the reg that connects to the second stage valve. From the Sherwood specs on the Blizzard: "Plated fins and heat sink retain the warmth of your exhaled breath to prevent freeze-up or second-stage free flow." Even though there is also an exposed ribbed metal coupling on the Blizzard, it is definitely designed to recover heat from an exhaled breath.

Finally, the Blizzard second stage has many fewer parts. Though I don't have the Blizzard's diagram, probably less than 10 parts as compared to 31 in the ATX200. I think that in a situation where ice might form, the Blizzards simpler mechanisim has less potential points of failure. There are also a lot of divers in my area that have used Blizzard under the ice and come back to tell the tale. In every other respect, the ATX200 blows the doors off of the Blizzard which is why I bought one to replace my trusty Blizzard.

That's my reasoning. I would hope that anybody seriously considering any reg would do their own thinking.

 

[Greg Barlow]

"I think that the valve on the ATX also benefits from being contained in an metal assembly, with a large surface area, that is exposed to the exhaled breath. It may not be intentionally designed that way, but with every exhale, you are breathing warm air directly onto the valve spindle which contains the valve seat, spring and shuttle. In salt water that is below 0C, that would be the only way to keep the valve above 0C and frost from forming on the rubber seat. Also, if the only heat that ended up warming the reg was coming from the surounding water, then a full metal body reg (with a much larger conductive surface area exposed to the water), would capture more heat (from the water) than a half inch long ribbed tube on the outside of a plastic body. If the water was just over 0C, the full metal body reg valve would be at or below the temperature of the water, but the Apeks valve would be warmer."

Your assumptions on heat retention and transfer are correct from a scientific point of view. I have explained regulator heat sinks in the same manner as the cooling fins of an air cooled internal combustion engine. Heat is transfered from one medium to another, and "cold" is merely the lack of heat. A refrigeration unit doesn't actually make food cold, it instead removes the heat from the unit's contents.

Air conditioning compressors, evaporation coils, and condensation coils all work collectively to transfer heat. Absolute zero is the term which means that all heat energy has been tranfered. At this theoritical point, molecular activity effectively stops. I might add that this has never been achieved in a lab setting, as on Earth there would always be some heat transfer going on despite the amount of insulation available.

The heat sink on a reg needs to have as much surface area as feasible to offer much warming of the incoming gas. In theory, a "long hose" such as a 5' or 6' variety would also aid in slightly warming the air. Poseidon evens claims in some of their literature that they have shown this to be true.

Greg

 

[rescuediver009]

Didn't mean to piss you off. Its just that talking about conducting cold is like talking about black surfaces 'conducting dark'.

Don't worry you never pissed me off. You are just telling people something that is inaccurate.

It may not be intentionally designed that way, but with every exhale, you are breathing warm air directly onto the valve spindle which contains the valve seat, spring and shuttle.

How about with every breath you are exhaling moisture and humidity onto the metal internal parts that is constantly being cooled by the incoming air that is dry from your tank? That is the whole reason for a heat sink otherwise the parts would not stick together.

Also, if the only heat that ended up warming the reg was coming from the surounding water, then a full metal body reg (with a much larger conductive surface area exposed to the water), would capture more heat (from the water) than a half inch long ribbed tube on the outside of a plastic body.

IT would and it does. But there is only a certain amount necessary we are not trying to roast weiners here.....

On the Blizzard, there is a double metal fin in the mouthpiece of the reg that connects to the second stage valve. From the Sherwood specs on the Blizzard: "Plated fins and heat sink retain the warmth of your exhaled breath to prevent freeze-up or second-stage free flow." Even though there is also an exposed ribbed metal coupling on the Blizzard, it is definitely designed to recover heat from an exhaled breath.

I am familiar with the blizzard as well. I had one for years. The fins on the outside have nothing to do with you breath as they never touch the air. You are contradicting yourself. If the internal parts took the warmth from your breath on the apeks they would just be wicking it away into the water with the heat sink....
In the blizzard however the fins are so large inside the reg that condensation acutally forms on them humidifying the tank air.

Finally, the Blizzard second stage has many fewer parts. Though I don't have the Blizzard's diagram, probably less than 10 parts as compared to 31 in the ATX200. I think that in a situation where ice might form, the Blizzards simpler mechanisim has less potential points of failure.

Wow you actually cat down and counted them.......

There are also a lot of divers in my area that have used Blizzard under the ice and come back to tell the tale.

Lived to tell the tale??? Where did they go to the last frontier? Ice diving is cold but once your reg is under the water it is not that big a deal. I think that you would be able to "tell the tale" if you were careful and dove a brut. (Although I would always recommend diving with a cold water regulator. As for the number of parts it is like comparing apples and oranges. The blizzard is a simple design yes, but the apeks is balanced, so of course it has more parts to peroform better, and most of them only touch the incoming air and never would be able to freeze....

 

[darkstar]

...That is the whole reason for a heat sink otherwise the parts would not stick together...

IT would and it does. But there is only a certain amount necessary we are not trying to roast weiners here.....

If the only source of heat is the external heat exchanger (hence surrounding water), then why didn't the Apeks freeze in -1.7C water tests conducted by the USN?

http://www.apeks.co.uk/newsarticle.asp?Title=US Navy recommends Apeks regulator

I looked for a weinie roaster on the diagram, but couldn't find it. :1poke:

 

[rescuediver009]

If the only source of heat is the external heat exchanger ...

who said that?

The moving water keeps ice crystals from forming. I think that the horse is dead... so stop kicking.