2nd stage shutdown valves.

[Michael_Lambert]

If the OP is talking about one of the shut-offs like Diver0001 shows, it is widely used in some tech applications, usually on Deco/Stage bottles.

I can not say i have ever seen them used in any applications around here. I could see how a new diver could see the value of it however it is nothing but yet another failure point on you gear.

Especially on a Stage/deco bottle which would be primed at the start of your dive and shut down again once the dive has started unless you are breathing off it.

If you are diving a single tank setup and have a need for a device like this i would suggest you are going beyond the intended use of your single tank rig, you should be able to manage a free flowing second stage or at least breath off it while you do your accent.

 

[sambolino44]

I always dive with one. It looks like this and works like a charm.

I have one that looks just like this and it doesn't work at all!

Oh, wait, was I supposed to put it together first?

 

[sunkmail]

I can not say i have ever seen them used in any applications around here. I could see how a new diver could see the value of it however it is nothing but yet another failure point on you gear.

Especially on a Stage/deco bottle which would be primed at the start of your dive and shut down again once the dive has started unless you are breathing off it.

If you are diving a single tank setup and have a need for a device like this i would suggest you are going beyond the intended use of your single tank rig, you should be able to manage a free flowing second stage or at least breath off it while you do your accent.

Some of the uses I eluded to are for rebreathers and a little beyond the scope of this conversation. As for many pieces of gear, there are some situations where these are handy, and many where they can be a liability.

It is not standard everywhere to prime a bottle and shut it down - some prefer to keep it on. I am not going too get into reasons for either method; it really isn't important or relevant for this thread. Just remember, different areas/environments/people/seasons/whatever sometimes necessitate different approaches.

For a typical recreational, single-tank diver, I agree - there is no real need for these.

 

[BoneCrusher]

I always dive with one. It looks like this and works like a charm.

In this configuration.... I have my doubts that it "works like a charm." My advice would be to put all the parts back together (in the correct order) and it will start to "work like a charm"!

 

[Graeme Tolton]

I can not say i have ever seen them used in any applications around here. I could see how a new diver could see the value of it however it is nothing but yet another failure point on you gear.

Especially on a Stage/deco bottle which would be primed at the start of your dive and shut down again once the dive has started unless you are breathing off it.

If you are diving a single tank setup and have a need for a device like this i would suggest you are going beyond the intended use of your single tank rig, you should be able to manage a free flowing second stage or at least breath off it while you do your accent.

I was simply curious about this product. I am not a new diver. My open water card was issued in 1997. I can manage a freeflow, however I would rather avoid the inconvenience of needing to end a dive over something that can be corrected.

 

[Cave Diver]

I was simply curious about this product. I am not a new diver. My open water card was issued in 1997. I can manage a freeflow, however I would rather avoid the inconvenience of needing to end a dive over something that can be corrected.

One thing to keep in mind with stuff like this, is will it introduce more problems than it solves? There are some applications for this type of valve, but I dont think normal OW diving is one of them.

 

[Graeme Tolton]

One thing to keep in mind with stuff like this, is will it introduce more problems than it solves? There are some applications for this type of valve, but I dont think normal OW diving is one of them.

One could also argue that manifolded double tanks with an isolation valve could be problematic. (not that I am). However, it comes down to being familiar with your equipment and practicing with it. As far as normal open water diving... we don't have a whole lot of that here. Most of my dives are in the 40 degree range, where freeflows are not an uncommon occurrence.

Diving with a sealed 1st stage, it is highly unlikely to have a 1st stage freezeup, but more likely a 2nd stage, thus reducing the risk of a burst lp hose signifigantly.

 

[Cave Diver]

One could also argue that manifolded double tanks with an isolation valve could be problematic. (not that I am). However, it comes down to being familiar with your equipment and practicing with it. As far as normal open water diving... we don't have a whole lot of that here. Most of my dives are in the 40 degree range, where freeflows are not an uncommon occurrence.

Diving with a sealed 1st stage, it is highly unlikely to have a 1st stage freezeup, but more likely a 2nd stage, thus reducing the risk of a burst lp hose signifigantly.

Totally agree on the practicing thing. I also agree that isolation valves could present a problem and I don't recommend using those when they aren't needed either.

Like I said, do they solve more problems than they introduce? In cold water where free flow is common, then they might have merit. In more "normal" diving, maybe not. Only you can decide where that balance is.

 

[rjack321]

Most of my dives are in the 40 degree range, where freeflows are not an uncommon occurrence.

Diving with a sealed 1st stage, it is highly unlikely to have a 1st stage freezeup, but more likely a 2nd stage, thus reducing the risk of a burst lp hose signifigantly.

Why are you having so many free flows in water that's "in the 40s"? (40+F presumably).

With good technique free flows should be quite rare even in the low 40sF and fresh water. They should not be happening in 40F sea water with its lower freezing point.

Relax, get your consumption down. Less gas and slower delivery = less adiabatic cooling and you won't form ice or free flow.

 

[Cave Diver]

Why are you having so many free flows in water that's "in the 40s"? (40+F presumably).

With good technique free flows should be quite rare even in the low 40sF and fresh water. They should not be happening in 40F sea water with its lower freezing point.

Relax, get your consumption down. Less gas and slower delivery = less adiabatic cooling and you won't form ice or free flow.

Pre-breathing in air temps below freezing?