Here's the regulator real deal guys and gals

[JoelW]

The bit with oxygen and the soft element break down is not just a scuba gimmick. To pay for my hobby I design high power laser machining centers. One of the gases that is used for metal cutting is high pressure oxygen (100-300psi). When oxygen is used attention must be paid to the materials in the gas delivery system. Buna-n and polypropylene o-rings do not work (for long). They will break down in the presence of high oxygen concentrations. There is nothing quite like seeing flame exit where from a machine where it is not expected due to an undexpected oxygen leak.

JoelW

 

[LoCz]

Sorry i should have explained more, my fault, of course the tests are "currently fact" they are independant scientists so they have no reason to exadurate the truth etc etc.

I ment that some scuba manufacturers actually sell nitrox regs at higher prices because they are nitrox ready, and they also mislead ppl into thinking that you need a special regulator to dive nitrox. Making nitrox regulators a different colour ? i mean cmon there insulting the publics intelligence, or taking advantage of there ignorance.

Dont suppose you got those temperatures did you rainreg?
:goofy:


just an opinion

 

[rainreg]

Based on the information from the Note I previously stated in the other post here are some (AIT) Auto Ignition Temperatures based on those tests:

Plastics:

Teflon 7A ----434 Degrees C
Kel-F 81 -----388 Degrees C
Noryl --------348 Degrees C
Vespel SP-21 -343 Degrees C
PEEK ---------305 Degrees C
Zytel --------259 Degrees C

Rubbers:

Viton-A --------268 - 322 Degrees C
Nitrile Rubber -173 Degrees C
EPDM Rubber ----159 Degrees C

Well those are the temps and here is some more information:

Viton has a Higher AIT then EPDM
Viton does not perform as well as EPDM in cold environments.
If Flash-off occurs Viton produces a deadly gas where as EPDM provides a Noxious Gas.


rainreg

 

[LoCz]

Maybe im missing the point here but where in scuba diving are those temperatures found?

 

[rainreg]

The temperatures listed are where the listed items auto ignite. these temps are normally not found in regulators on a regular basis but can be achieved if flash off occurs due to particulate impact or other reasons as stated in previous post. the main point to understand is saftey and understanding. Have you contacted any of the people I recommended in the previous post? I would contact Elliot Forsyth first and discuss these issues with him as well. outside of the information I have already provided I am not sure what more you wish to know without contacting the listed individuals to verify and clarify what has already been said. Look forward to your next post.

 

[LoCz]

Thx rainreg your a star

Thats all i need to know for now, thanks for doing the research Gov. have i made the phone calls? No sorry i havnt.
I dont know where these phone numbers are, are they in the USA? Im from England rainreg so i have no intention of phoning the US for what would probably be a lengthy and very costly call. But thanks for providing those numbers im sure someone else will have use for them.

:goofy:

 

[rainreg]

Now I have a better understanding of your situation, the information you seek will be available at the DETA web site in the near future. Along with additional information on regulators, BC's, O2, Nitrox, Cleaning Procedures, and much more. this way you will be able to download the information and retain it in your own library. as far as the phone call thing I understand your situation and well I also listed e-mail addreses to those individuals so you can contact them through e-mail as well. I hope this helps you out and if you have any more questions feel free to drop a post and well I will provide you with the info you request. thanks again for your interest and stay safe in the UK.

rainreg

 

[scubadoo]

Just a quick question or some thoughts from others I was wondering what others think of the quality of us divers regs I plan on purchasing new and aways had good luck with there older gear is it still quality stuff or........

 

[Merlin]

I've been trying to follow this thread a bit but I may be getting lost in whose opinion is whose.

It seems logical to me that if we do indeed need an O2 ready reg for mixes below 40%, then we would also need an O2 ready BC and drysuit as well. I've never heard of these. I've never seen someone getting their BC O2 cleaned and certainly not their drysuit. And do you need to be careful about what you have in your pockets inside your drysuit too? Imagine if you had a sugar packet in your pocket. I'd bet the autoignition temp for sucrose under 40% O2 is pretty low relative to buna rubber. And what if you are using a lift bag?

I need to look up the MIL and ASTM specs you listed. Those look really interesting. Where I work, we dropped using MIL specs entirely but there are still some hold-outs for ASTM, simply because there are no ISO standards in some categories. Thanks for listing those.

Just a few thoughts about the idea of O2 clean regs below 40% O2.

 

[turnerjd]

Having followed the whole thread of this debate, there is one thing that no-one has mentioned.

The most simple way at looking at increased pressure of gasses is an increased concentration. So, whilst nothing much is going to happen to your reg at the surface, especially if the high pressure seat of the first stage is made of an inert material (eg mares ruby seat in some of their first stages), then the intermediate pressure is only some 9 or 10 bar greater than atmosphere. At this point all the little o-rings in the system are exposed to what can be considered are oxygen at 10 times the concentration of normal air.

Now, for every 10 metres (33 fsw) we are adding another bar pressure, and increasing the concentration of oxygen that all the o-rings experience.

Oxygen is quite a reactive gas, and what actually happens is that the oxygen oxidises impurities in the o-ring material, and to a much lower extent the rubber itself, and what happens over time is that they degrade, going brittle and hard.

The other important point is that the Oxygen won't just interact with the o-rings (and in some regs even more importantly the high pressure seat), but will also interact will ANY available material, such as oil / grease / dirt in the tank.

A good analogy of this is what happens when a steal cylinder gets moisture inside. The tank rusts. Rapidly. the tank would rust anyway, but due to the higher effective concentration of oxygen due to the pressure (the pressure obviously increases the net Oxygen concentration for air as well as nitrox) the rusting (oxidation) takes place at a much faster rate.

Really, what is the main risk is the high pressure seat being damaged. all it would take would be a small part of the seat stopping sealing, and then the intermediate pressure part of the reg (everything from the first stage valve seat until your mouth) would then be at tank pressure, not ambient + 9 bar or so.

There is probably a calculable, and reasonably small chance of this actually happening, however, as it is known that oxygen degrades the standard o-rings then the manufacturers are onto a losing streak if they were ever sued after some-one had an accident that was caused by an O-ring blowing out.

Personally, when I started diving nitrox, I took my regs to be serviced, and asked the technician to fit the viton nitrox o-rings and clean the reg for nitrox. The service cost the same as it would for a normal service. However, this does rely on you having a reg that can be bought in a nitrox disguise ('cos if they sell the nitrox version, all the correct seals are available to the technician).

As for the issue of what %Ox you need to start thinking about nitrox clean, if you can get it done at no extra cost on the next service then why not?

hope this makes things clearer

Jon T