cold water/sealed regs

[FMT]

Could you explain that further please?
T

[DRE]

Please enlighten us as you seem to have very articulate views on this topic...

[jasondbaker]

Yeow, strong words. Knowing most of the people on this thread I can comfortably say most of them have dove extreme cold. Here is Apeks' version of balanced:

Over-balanced Diaphragm Design
The heart of any regulator is the first stage. Most Apeks first stages utilize a unique Over-Balanced diaphragm design. In an over-balanced first stage design, the interstage pressure in the hose increases faster than traditional balanced models as a diver descends to greater depths. This increased interstage pressure compensates for the increased density of your breathing gas by allowing a larger volume of gas to flow through the system on demand. The result is superior breathing performance regardless of depth. The Over-balanced Diaphragm Design is found on Apeks Black Pearl, ATX 200, ATX100, ATX50, ATX 40, and TX40/DS4 first stages.

Pneumatically Balanced 2nd Stage

All Apeks second stages feature a Pneumatically Balanced Valve System. In most second stage designs, the inhalation effort of the diver opens a valve inside the regulator that is held closed by spring tension. In the Apeks pneumatically balanced design, the pressure on the second stage valve is "balanced" by allowing medium pressure air to pass through to the opposite side of the valve to help counteract the force of the spring. This reduces the inhalation effort required to open the second stage valve and substantially improves the overall ease of breathing in all diving conditions.

[tpscuba]

great Jason. I use Sherwood and they have been great Just like any other toy it's what works for you.

[freedivernd]

Hey chrisw
freediving would sure make it all a lot simpler eh?

[LKunze]

Hey chrisw
freediving would sure make it all a lot simpler eh?
[/quote]
I knew it was a matter of time before you or Jon got that one in Fred. BTW, how's the diving been up in the Detroit Lakes area this summer?

[freedivernd]

Hey Lonnie,
diving's been good. my brother has been out with me a few times and we've had a blast. he bought 2 seadoo DPV's, a good one 3.3mph and -100', and a cheapo 2.?mph and -65'. The turbo one is a hoot when you're freediving. first time I took it down, when I got to the bottom I did the usual... stop, hang, turn around, and then started for the surface, only I started for the surface the usual too, finned half way to the surface before I realized I was dragging the dpv along with me.. hey what the heck am I lugging this for, and then powered my way the rest of the trip up. habits are hard to break I guess.
vis has been getting poorer of course since this spring, but still seeing pretty good vis here and there, lot's of fish.
so busy building a house that I can't hardly get away... but am going to the freedive apalooza in wisconsin..maybe some of you folks on the board can make it down there too.. like to see ya all.
later,
Fred

[Freedive WI]

true balanced reg can't be accomplished in a diaphram reg.

I think that you've got that backwards. True balanced can't be accomplished in a PISTON regulator. However, they can make a piston regulator so fine-tuned that it becomes a mute point and will breath as well as any balanced diaphram reg.

As far as 'true cold' goes I can relate my experieneces ice diving, which isn't as cold as it sounds, and running charters on Lake Michigan in winter time- as we have a boat that can break through 3' of ice and still make it out to the wrecks in January. 8)

We have taken just about any kind of el cheapo rental reg and had it work for our ice dives in the local lakes. The following weekend we'll be running a charter and have 12, out of 14, divers have freeze-ups/free-flows and have to call their dives before they even get down.

I've seen, and had, it happen with all kinds of regulators. I stopped using my Posiden after it shot ice down my throat on such a dive. I had an Apeks freeflow on me once, but that was before they had the second stage 'severe' kits on them. I've also used Mares regs with special teflon parts that froze up on me- to which the Mares rep swore I was lying to him because his reg's "couldn't freeze".

Out on the lake your gear is more exposed and the water gets colder, due to the currents flowing which prevent the formation of ice. Dives are also much deeper than during a normal ice dive. This means that the regs have to flow more gas, thus we get more freeflows.

The best system that I have come up with so far is to drop my IP's down to around 110-120psi and use helium in my mix for dives deeper than 100'. The next best thing is to just freedive as nothing can freeflow on you.

I imagine that the rebreather crowd doesn't worry too much about this stuff since the chemical reaction of the scrubber gives off heat and reduces problems in this area.

Fred, scooters are a blast for freediving! I was using mine when diving with Jason and Lonnie on the wreck of the Milwaukee last fall and had a blast. ;D

Jon

[ghosch]

Since you've provided an opening ;D

It is true that the air you breath from a rebreather is warmer than OC. The chemical reaction warms it, as well as your body as the same air passes through your lungs many times. Rebreathing the air also moistens it leading to greater comfort and hydration. The difference is noticable after a long dive in cold water (of course, never having dove in EXTREME cold, I guess I wouldn't know).

With a rebreather traditional free flows become virtually non-existant (I suppose it is still theoretically possible) because all the regulators are doing is occasionally (or continuously in the case of SCR) injecting miniscule amounts of gas.

There are other situations on a rebreather which can lead to an unregulated flow of gas, but they aren't caused by freezing!