That Time of Year - Freeflows

[Vertigo]

I am not as concerned about freeflows..because I know my good old buddy will be there with a reg or an extra stage if needed. Once in a while.. all regs will go in water that cold

 

[dave4868]

For what it's worth, there have been some great threads about "free flowing" including lots of physics explanations. Some here, some on OD. There are definitely people out there who know the real science of this stuff. I guess it just a guessing game still since we cannot "yet" monitor in real time the physics of what is happening to our regs in cold water (I mean really cold).

The issue as water gets closer and closer to the freezing point is that the temperture gradient is smaller and heat transfer is reduced.

The air expanding inside the regulator requires heat which is drawn from the regulator. In turn, the regulator has to draw heat from the surrounding water if it is to remain above freezing. If the surfaces of the reg fall below freezing, the water in contact with them can form ice on the surface which then insulates it and further reduces transfer. This rapidly causes an increase in ice and unless the first stage is environmentally sealed, eventually the ice will form in or spread to an area where it impedes the movement of the piston or the diaphragm causing the first stage to fail in an open position.

I wouldn't say there's any guessing involved, except perhaps guessing exactly when the various factors finally cause the freeze-up and free flow. See DA Aquamaster's excellent description of the process. The mechanism of the process is well-understood.

I've never had a 1st stage freeze or free flow with my Sherwood Blizzard. I like the dry-air bleed design with its dry ambient chamber.

Here's a link to Antarctic diving that might be interesting reading, including regulator performance in such conditions.

Diving Under Antarctic Ice

Dave C

 

[owlbill]

I wouldn't say there's any guessing involved, except perhaps guessing exactly when the various factors finally cause the freeze-up and free flow. See DA Aquamaster's excellent description of the process. The mechanism of the process is well-understood.

I've never had a 1st stage freeze or free flow with my Sherwood Blizzard. I like the dry-air bleed design with its dry ambient chamber.

Here's a link to Antarctic diving that might be interesting reading, including regulator performance in such conditions.

Diving Under Antarctic Ice

Dave C

That is what I meant with the guessing, just "when" it will happen.

 

[b1gcountry]

I started another freeflow thread here if anyone is interested.
http://www.scubaboard.com/forums/ontario-fresh-water-freaks/220403-freeflows.html#post3373118
This one was very interesting until it became not about freeflows...

Tom