Talk:Scuba set

Queries

If an image belongs with a paragraph, I put the image description line before the paragraph's title line so that the image comes as high as possible within the paragraph, to cut down the amount that the image intrudes into the next paragraph. Anthony Appleyard 07:33, 23 Dec 2004 (UTC)

• I think that concise style implies, that images and text belong under a heading, in fact, no content in a structured article should be outside hierarchically nested headings.
  By the way -- why is the title of this article in plural? AtonX 10:31, 23 Dec 2004 (UTC)

Sorry to keep re-editing the text, but:-
Both types of scuba sets consist of

i) a breathing gas supply stored in a high pressure diving cylinder,
Not true with potassium superoxide rebreathers. Arguably not true with liquid-air scuba.

ii) a diving regulator attached to the diving cylinder
Not true with constant-flow open-circuit sets or with some rebreathers. We must cover old sets as well as modern sets.

Rebreathers also employ advanced electronics to monitor and regulate the composition of the breathing gas.
Not all rebreathers, and not old-type rebreathers. I have been in scuba diving from before divers' lifejackets were heard of.
Pony cylinders and stage cylinders are an important feature and should be mentioned.
Anthony Appleyard 00:00, 24 Dec 2004 (UTC)

Cylinders, regulators and stages

• 1. Firstly, in potassium superoxide rebreathers the scrubber filling also produces oxygen, but these rebreathers, too, contain a high pressure cylinder to top up the loop with breathing gas, which gets compressed with the depth! In liquid air scuba, the liquified breathing gas is also stored in a high-pressure cylinder.
     Thus, I argue, a high pressure cylinder is a general part of both types of scuba sets - aqualungs and rebreathers.
  2. Secondly, old constant-flow open-circuit sets as well as some rebreathers contain a constant flow regulator (more correctly - a constant mass flow regulator), whereas the aqualungs and the rest of the rebreathers contain a constant pressure regulator. Hence, generally it is a regulator which is a general part of scuba sets.
     The term demand regulator is -- in my opinion -- highly misleading. It is technically a constant gas pressure regulator combined with a demand valve.
  3. Thirdly, pony cylinders and stage cylinders are an important feature of a diver's equipment, I agree. However, they are just independent aqualung-type scuba sets attached to the diver to enhance his/her safety or gas supply, they are not parts of what this article describes - a scuba set. Logically, you can't say a scuba set is a part of a scuba set. They belong to articles on diving equipment or configuring cylinders, otherwise it is just duplicate information in the encyclopaedia.
     Similarly, wings and/or jackets are not a part of the breathing apparatus. They are attached to the harness, but so is the knife, the light canister, the weights etc. Here, they are misplaced - for the sake of logic and clarity, they belong to different articles! AtonX

  14:30, 27 December 2004 User:AtonX

• Whether we call pony cylinders part of the same set or another set, is a matter of definition. Anthony Appleyard 23:35, 10 Jan 2005 (UTC)

Duplicate sections

An edit note: there were sections of this page that were exact duplicates of previous sections. A copy-n-paste gone wrong? I'm not sure. In any case, I've removed them. Thayvian 19:57, 11 Mar 2005 (UTC)

Spearfishing?

Should we be encouraging spearfishing (by including it in the links) amongst scuba divers, esp given how many organisations dissaprove of it.

• I agree with you that some divers oppose spear fishing (personally, it's not something I do, and I prefer it not be done when I'm near it in the water), but I don't think it belongs as an italicized comment to the link. My suggestion would be to add a spear fishing segment to SCUBA to bring it up there and cite concerns. It just doesn't belong as a comment on the link. Wikibofh 6 July 2005 21:04 (UTC)
• Perhaps instead we should be linking to the spear-fishing article and debates about ethics could be brought up there? Justin 16:59, 3 January 2006 (UTC)

Nitrox

Would a bit about nitrox be ok here? Justin 17:03, 3 January 2006 (UTC)

Why not put it in Enriched_Air_Nitrox? Mark.murphy 19:27, 4 January 2006 (UTC)

Please be careful with the need for an "oxygen cylinder" for mixing Nitrox. The way this is worded makes it appear that the diver has an O2 tank in addition to the "air" tank. Also, most dive shops I know no longer use the O2 mixing method to produce enriched air. The are now "de-nitrifying" air to produce "oxygen enriched air". It is safer and does not require an O2 cleaned cylinder for the diver. I also believe that the author intended the questioned phrase to be something like, "an O2 cleaned cylinder is needed to store the Nitrox". Then a rationale could be given. In fact, an entire section just on production of oxygen enriched air might be in order. 199.244.214.30 (talk) 17:08, 24 February 2009 (UTC)--Reader:dmgambs

I've re-written the last paragraph of the section "Open circuit scuba sets" to try to remove the ambiguity. My usual dive shops still use partial pressure blending, so I suspect the phrase "common method" may vary regionally. I've changed it to reflect the lack of consensus for "the most common". Have a look at the article Gas blending as that is the most appropriate place for the section on production of oxygen enriched air (if you think the content already there could be usefully improved). --RexxS (talk) 20:17, 24 February 2009 (UTC)

Circular window

"Captain Trevor Hampton in the 1950's or 1960's designed an early single-hose aqualung with a fullface mask with a circular window which was a very big and thus very sensitive demand regulator diaphragm."

Did the circular window somehow act as the diaphragm? --Gbleem 06:53, 26 January 2006 (UTC)

External links

I've removed all external links, as none of them were appropriate for this article. This is an article on scuba equipment, and only links providing further information on equipment are appropriate. That means that links to commercial websites, local diving websites and training organisations shouldn't be there. Please read WP:EL and WP:NOT, and discuss here before restoring links. Thanks. (Of course, relevant links can still be added.) -- David Scarlett^(Talk) 22:36, 5 June 2006 (UTC)

The first 4 sentences of this article

It seems quite odd to me that the first 3 sentences of this article are about the origins of the name. Only in the fourth sentence is the name defined.

Is it really necessary to note the origins of foreign language words at all in this article? It does not seem relevant to this article - this is an English language article on a technical subject. I would probably find this information interesting if I chose to read an article about loan words, acronyms or the origins of words used in Welsh - not here. Even if it is justified, I don't think the origin of a word in any foreign language deserves such prominence on the third sentence in this article. Mark.murphy 22:45, 1 July 2007 (UTC)

Hi, all & Mark, yes, it's an oddly oblique start, and then it hit me: the intro does not say what a SCUBA does! The main function is to keep changing the delivered air pressure so that the diver can breath at a changed water depth; for example 44 psi 66 feet down in sea water and 59 psi at 100 feet. I'll change the intro; I hope the community will accept the change and make it better and briefer than I can write it.

Jerry-va (talk) 23:15, 15 June 2012 (UTC)

I have had a go at revising the whole lead section to be more accurate, and with luck more grammatically correct. Take a look and see if you agree. Peter (Southwood) ^(talk): 10:59, 16 June 2012 (UTC)

I've tweaked the bit about "stored gas is provided through regulators as required" because SCCRs tend to use fixed-rate injectors, not a demand system. Conventionally, we don't normally use guillemets, so I've replaced them with normal quotation marks. It's acceptable to use italics to delineate a definition term (<dfn>...</dfn>), and for when a word is used as a word, but shouldn't be overused, and I generally prefer quotation marks - see WP:WORDSASWORDS. The point of putting "self-contained underwater breathing apparatus" in the first sentence is that it's a common alternative title, and needs to be bold per our convention on bolding article titles and their plausible alternates - see WP:BOLDTITLE. HTH, --RexxS (talk) 14:20, 16 June 2012 (UTC)

FDA

Regarding this sentence: Exotic gas mixtures presently used in scuba are intended to prevent decompression illness in diving, but officially, the FDA appears to continue to believe that scuba divers all use compressed air.

Either the FDA "officially" recognizes something or they only appear to recognize something because it isn't official policy. Instead of conjecturing as to what their policy may or may not be, how about finding a reference? Mojodaddy (talk) 14:50, 20 November 2007 (UTC)

Added a "citation needed" to this claim. —Preceding unsigned comment added by 71.16.78.252 (talk) 14:13, 11 June 2010 (UTC)

Agreed. I can't find a source saying that the FDA appears to believe that all scuba divers use compressed air (officially or otherwise). The sentence seems to be editorial comment based on (i) The FDA designates non-air gas mixtures intended to prevent or treat diseases as drugs (sourceable); (ii) The FDA does not regulate the use of other gases in scuba diving to avoid DCI (may be sourceable, but more likely an inference from the lack of FDA regulation). That is a kind of synthesis and is WP:OR without a reliable source which states that conclusion. --RexxS (talk) 17:47, 11 June 2010 (UTC)

You can modify the wording, but you cannot escape logic. If the FDA has no regulation on scuba breathing gases intended to prevent DCI (as it certainly does on the oxygen to TREAT DCI-- look at those dive boat kits), then that MEANS it does not regulate these gases for this purpose. Lack of regulation = does not regulate. This is not a synthesis; this is a restatement of plain English. If you can't do that much, you're going to have hard time writing an encyclopedia. As for the rest, if the FDA regulates all exotic gases for the purpose of preventing diseases (as they state they do), and DCI is a disease (do you need a reference), and the FDA does not regulate exotic scuba gases for the prevention of DCA, it is a matter of simple logic to determine that the FDA either does not know about exotic scuba gases (unintentially ignoring them), or is intentionally ignoring them, or else is making a erroneous statement in its initial regulatory claims of coverage. There are no other possiblities. WP:SYN does not include arithmetic, and it does not include logical syllogism. If all men are mortal {citation provided} and Mr. X is a man {citation provided} then I can write in his bio that he is mortal and don't need a cite for that.SBHarris 18:46, 11 June 2010 (UTC)

One of the problems for a minority sport such as ours, Steve, is that we have a lack of recognised pundits and very few researchers – Peter Bennett & the folks at DAN, our own Gene Hobbs and the team at Duke come to mind; but then who? Even so a lot of the real research is a spin-off from projects on human spaceflight or aviation – there's little funding for scuba research. The result is that we don't fit Jimbo's idea of sourcing – the "if it's worthy of inclusion, somebody reliable will have said it" kind of view. That's what our policies are built around, and with the best will in the world, your chain of logic doesn't fit that scheme. All that you say is logical, and my personal view is that I'd agree 100% with the truth of it. Unfortunately, I still can't find anybody more eminent than you or I who has published the point about the FDA and breathing gases. No matter what we think, as soon as any of us put together two sources and draw a conclusion, we fall foul of the OR policy, even if it's logical (the directly and explicitly supported by the source phrase in WP:OR). We might be able to argue the exception for something being obvious (we don't need a source for "the sky is blue"), but I doubt it would hold up in this case. I've no intention of modifying the wording, but I couldn't honestly object if someone else chose to. --RexxS (talk) 23:44, 11 June 2010 (UTC)

Yes, but Wales is simply wrong, if you take him at his literal word, and the policy illustrates this. The policy WP:CALC, which is cited within WP:NOR actually proves he's wrong; is an admission that he's wrong. If he were right, there would be no reason to have the WP:CALC policy at all-- any calculation answer which is true, should be easy to find a citation for, according to what Wales says. But it isn't. SBHarris 01:30, 12 June 2010 (UTC)

Ambiguous

"Still, most semi-closed systems allow at least twice the duration of open circuit systems (around 2 hours)."

Which lasts 2 hours, the semi-closed or the open circuit? —Preceding unsigned comment added by 172.132.129.187 (talk) 00:17, 7 January 2008 (UTC)

The semi-closed. The preceding paragraph illustrated a 40 minute duration for open circuit. RexxS (talk) 01:32, 12 January 2008 (UTC)

Air Cylinders section

As this article has been around for some time, I thought I should flag up a revision I'm about to make. The article states "The drawback is that aluminium cylinders are neutrally buoyant when full, and positively buoyant when nearing empty. This results in having to monitor buoyancy during the dive more closely..." Why should a correctly weighted diver need to monitor more closely? The change in buoyancy as a cylinder empties is precisely the weight of air lost (about 1 lb for each 14 cubic foot of free air). It simply doesn't matter what the cylinder is made of. The real drawback of Al cylinders compared to steel is that they tend to be much thicker (and heavier despite the lower density of Al). This increases the total volume of the diver+set, which equates to a greater total weight to carry out of the water. RexxS (talk) 01:45, 12 January 2008 (UTC)

First and second stage, automat and dry suit

The first stage: is the section between the air bottle (using an INT or DIN-connection) and the pillar valve and serves to lower the bottle pressure to a lower (medium ? or breathing (low)?) pressure. The second stage: runs from the pillar valve to the mouthpiece (breathing/low pressure ?)

The pillar valve thus contains the valves required to reduce the air pressure.

A automat (not mentioned in article), is thus simply an air hose with a attached component.

The above needs to be integrated to the article/clarified.

Another question: there is a connection of the bottle to the dry suit (if one is used), but does this actually consume air, or is it simply hermeticly sealed. Also, I'm wondering whether air from the dry suit and from the buoyancy regulator (trimjacket) can actually be reused (to increase available air).

KVDP (talk) 14:29, 8 January 2010 (UTC)

The pillar valve is the top part of the diving cylinder. It contains a screw-valve operated by a knob which turns the supply on or off. It does not otherwise regulate the pressure. The pillar valve has a connector allowing the first stage of the diving regulator to be attached to it.

The connection between the diving cylinder and the diving regulator is an 'A' clamp or DIN screw fitting (either 5 or 7 thread for 232 bar or 300 bar equipment respectively).

The first stage is the first part of the regulator and is the part attached to the cylinder. Its purpose is to reduce the high pressure of the cylinder to an intermediate pressure (about 10 bar above ambient pressure).

The second stage is connected via a flexible hose between the first stage and the diver's mouth. The second stage (also called 'demand valve') allows air to be delivered to the diver at ambient pressure when the diver breathes in (i.e. 'on demand') and that valve is inside a casing with a mouthpiece that the diver places in his mouth.

An 'automat' is a vending machine (see the article you linked) - I know of no use of the word in a diving context.

I agree that many of these articles need to be tidied up. But read the articles I linked on diving cylinders and regulators. I think you'll find all the information in there (somewhere).

There is an hose connection to both the BCD and the drysuit. The air supplied in each case is vented on ascent and is not really reusable, other than in absolutely dire emergency. We used to teach how to breathe from a BCD or ABLJ, but the risk of microbial infection from organisms growing inside the BCD made training inadvisable. --RexxS (talk) 22:23, 8 January 2010 (UTC)

made this image File:Diving cilinder schematic.JPG

If there are any mistakes, ... let me know

81.243.183.37 (talk) 16:03, 9 January 2010 (UTC)

Thanks for the schematic. There are a few things that you could improve on the legend:

• 1 = Breathing gas cylinder
• 3 = Pillar valve knob
• 4 = Regulator first stage
• 5 = Primary second stage
• 6 = Submersible pressure gauge
• 7 = Secondary second stage (octopus)
• 8 = BCD hose
• A isn't needed (already labelled 4)
• B is wrong and not needed (second stages are 5 and 7)

And on the image:

• The first stage is larger and is fitted at 90 degrees to the pillar valve - look at File:Diving regulator DIN first stage.jpg and File:Pillar valve DIN 232.jpg for close-ups

Do you use Inkscape or another vector graphics program? Any image is much better than none, but an .svg would allow others to modify (and translate into other languages) much easier.

When you decide on the size of the thumbnail on the page, keep in mind that the page may be printed out, so the image is most useful if it can be read. In this case I'd recommend 400px or thereabouts.

Finally, wouldn't the schematic be more appropriate here at 'Scuba set', rather than using it at 'Diving cylinder' (which of course is only a part of the set). Hope that helps. --RexxS (talk) 17:36, 9 January 2010 (UTC)