The "Tek Tip" at the bottom of the DGX web page linked to above, " How are the DGX Premium O2 Valves different from regular SCUBA valves?," says it all.
What valve is most common for 100% o2 deco bottle?
- Thread starter 211ratsbud
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
The "Tek Tip" at the bottom of the DGX web page linked to above, " How are the DGX Premium O2 Valves different from regular SCUBA valves?," says it all.
- Messages
- 20,644
- Reaction score
- 15,137
- # of dives
- I'm a Fish!
@Lorenzoid where are you going with that?
That seems kind of nice. I don't think it's worth replacing a valve, but I guess it might be worth ordering this one if you don't already have a valve for your o2 bottle.divegearexpress:
Pao
Contributor
The DGX O2 valves are also not chrome plated on the surfaces that will be exposed to O2. Will that help?
Pao
Contributor
A little bit OT. I work in a hospital. Another curiosity is that the way O2 medical cylinders and regulators are handled. They get treated with less respect than LPG/Propane cylinders over where I am from, but no accidents seem to happen. What is so special about the CGA 540 valves?
That other than DGX thoughtfully using finer threads and avoiding chrome plating on some parts, which I get the impression are nice features but not critical to safety, it's no different than any other valve, or as you put it: "a valve is a valve is a valve."
2airishuman
Contributor
I think this is a very interesting question that is probably worthy of its own thread.
Based on my reading, the answers are:
1) Cylinder, valve, and regulator accidents with medical O2 do occur but the incidence per fill or per bottle in use seems to be much lower than for technical diving.
2) It appears to me that it is uncommon for valves and regs to be rebuilt in the field. Cylinder valves on medical cylinders are typically replaced when they fail because they are so inexpensive in quantity and because their manufacturers guarantee that they are suitable for oxygen service. The regs, if they are rebuilt at all, are rebuilt by the 100s at a time, perhaps in a more controlled environment than your average scuba shop workbench.
3) There is less of a problem with contamination of fill equipment because none of it is ever used for gasses other than oxygen.
Most of the medical O2 accidents involve fires when a high-o2 atmosphere has accumulated at the point of use. Most of these are related to cigarette smoking by the patient or their family members, with the rest being generally due to surgical procedures that involve ignition sources, particularly electrocautery and lasers.
540 are actually engineered for O2, "slow opening", relatively large orifice size, with no sharp bends or areas where the gas impinges or crashes into a wall of brass.
Harrison Valve
Scuba valves are rudimentary in comparison with a comparatively tiny orifice which maximizes velocity, poor choice of interior gas passage dynamics, and much more opportunity for fleck of metal or dust to get blasted into a wall by the gas and create enough heat to trigger a fire.
Sadly we are stuck using scuba valves for a gas that they are not really designed for.
Last edited:
Similar threads
