Talk:Gas blending for scuba diving

Reader feedback: The problem of mixed gas str...
95.177.57.136 posted this comment on 20 July 2013 (view all feedback).

"The problem of mixed gas stratification (and therefore literally mixing) seems to be a little vague, whilst literally deadly important to the ensuing gas analysis. Are there any 'rules' empirical or otherwise considering either time or physical agitation of a 'nitrox' diving bottle for example?"


 * From personal experience I find that inverting a trimix cylinder half a dozen times seems to work, but that is original research and so I cant say so without some other reference. Nitrox is more tricky as the oxygen and air are of very similar density, so inversion does not provide much driving force for mixing. In this case I prefer to roll the cylinder back and forth on the floor which would provide some acceleration and movement due to rotational inertia and mixing by friction with the walls, which with a bit of luck will generate turbulence in the mixture. I don't know how efficiently this works or how long it should be done. The final test is if there is no change in readout on the analyser after an agitation session. The time required for complete mixing by diffusion alone would be a function of temperature, but other than that I have no idea. &bull; &bull; &bull; Peter (Southwood) (talk): 19:09, 31 July 2013 (UTC)


 * Calibration gases which must be extremely thoroughly mixed are typically rolled for 2 to 4 hours. &bull; &bull; &bull; Peter (Southwood) (talk): 12:49, 24 August 2014 (UTC)

Title too generic
The title: "Gas Blending" is very broad and describes more than just blending breathing gases for diving applications. For example, gas blends are used for industrial, pharmaceutical, and food processing applications. I propose the article name be changed to reflect the diving aspect of this article. Perhaps "Gas Blending (Diving)" is more appropriate. It should also be mentioned that the terms "gas blending" and "gas mixing" are generic terms that the diving community likens directly to dive gas mixing. Outside of dive gas mixing, the term can apply to non diving gas blending processes. Thaddeusw (talk) 20:54, 20 August 2014 (UTC)
 * Adding a parenthetical qualifier to an article title is reserved for disambiguation on Wikipedia. As there's no other article on gas blending that could be confused with it, there are no grounds for disambiguating this article at present. The best course of action would be to add content to this article covering the areas that you outline, as such content clearly belongs under this title. If the article ever grows large enough to split off daughter articles, then a case could be made for "Gas blending (diving)", "Gas blending (pharmaceutical)", etc. --RexxS (talk) 21:34, 20 August 2014 (UTC)
 * Thaddeusw has a point. I have never been entirely happy with the title, but also never sufficiently unhappy to change it. The content is exclusively about blending for scuba, with nothing about blending for surface supply, so not even "Gas blending for diving" is sufficiently specific. "Blending breathing gases for scuba diving" would be accurate, but perhaps a bit cumbersome. "Blending breathing gases for diving" would include surface supply gases and saturation habitat gases, including the maintenance of chamber gas quality, a much wider scope.  A more generic article is possible, even desirable, but I don't have the specialist knowledge to write some of it. &bull; &bull; &bull; Peter (Southwood) (talk): 19:52, 21 August 2014 (UTC)
 * With the recent stories of edits by children, trolls and stoned college students showing up in academic research I think it prudent we ensure the content is as accurately descriptive as possible. The first sentence of this article is false. That right there should be enough to get the ball rolling. Thaddeusw (talk) 22:24, 22 August 2014 (UTC)
 * The title is bothersome because it is misleading. I should have stated this earlier but I was in a rush and could not articulate my point properly. Just read the first sentence: "Gas blending or gas mixing is the filling of diving cylinders with non-air breathing gases such as nitrox, trimix and heliox." That is blatantly false information as it misleads people into thinking that gas blending or gas mixing is only used for diving. &bull; What about a gas mix for welding? what about a gas mix for processing steel or packing food? Hacking up this article to shoe horn in other uses of gas blending is the wrong route to take. As far as I am concerned, this article is perfectly acceptable for the content it covers. It just needs to be tweaked. &bull; The only way to properly fix this is to rename the article to specifically state that the article is about mixing gas for diving, one of many uses of blended gas mixtures. A new article that is titled gas blending or gas mixing should be a general article on the process of mixing gases for the various industries. Content can include a general description, uses, methods of gas mixing (eg thermal mass flow, pressure proportioning) etc. A pretty decent article can be made and of course under uses diving gas will be mentioned with a link tho this article. I am not an expert in the area but I have been doing a lot of research for building a thermal mass flow mixer for metering gas into a glovebox for laser hermetic sealing. If I have time, I could start writing a template article with a few uses. But I would have to have my ducks in a row and have some solid references first. Thaddeusw (talk) 22:24, 22 August 2014 (UTC)
 * No, the title is "Gas blending" and all of the content is sourced and related to gas blending. There is nothing in the article at present that does not belong in an article entitled "Gas blending". What's misleading about "Gas blending or gas mixing is the filling of diving cylinders with non-air breathing gases such as nitrox, trimix and heliox."? That certainly is one definition of gas blending and it doesn't say "this is the only meaning of gas blending". Now, if you want to see a broader definition, provide one. You want to discuss a gas mix for welding, for processing steel or packing food? Fine; find the sources and write the text. That's how things work on Wikipedia. There is absolutely no reason to change the title of this article - otherwise we end up with something like Gas blending for scuba diving and a redirect Gas blending pointing to it. How does that improve things? Wikipedia should have an article on "Gas blending" and if the only sourced content is derived from scuba diving, then that's the article we get.
 * You say we should have "a general article on the process of mixing gases for the various industries" - ok, then find the sources and write it, but don't expect somebody else to do the work. But unless it's too big (see Article size), it will include gas blending for scuba diving because that's part of what gas blending is about. There's no value whatsoever in having dozens of tiny, stubby articles on every separate aspect of what is essentially the same topic, when we can a have one quality comprehensive article on that topic. --RexxS (talk) 00:00, 23 August 2014 (UTC)
 * ReXX,
 * "What's misleading about "Gas blending or gas mixing is the filling of diving cylinders with non-air breathing gases such as nitrox, trimix and heliox."? That certainly is one definition of gas blending and it doesn't say "this is the only meaning of gas blending"."
 * It is misleading because the article mentions *no other use*. Don't you think that can be misleading to the casual reader? You also missed the bit where I stated I would do the research and see what I can come up with. So relax. Thaddeusw (talk) 17:41, 23 August 2014 (UTC)
 * I look forward to seeing the products of your research and I am willing to collaborate in a generalised article on gas blending if you provide an adequate lead (like providing sufficient suitable references to work from). Whether the new article should start as a stand-alone or be built as an extension of this one is open to discussion, though I think it would be less work in the long run to create a separate new article and rename this one. Let me know when you start. &bull; &bull; &bull; Peter (Southwood) (talk): 19:22, 23 August 2014 (UTC)
 * I have started a new generic article for Gas blending, so I am going to rename this one and bring the new article into mainspace. I hope this satisfies everyone in principle, and that you will both give the new article a critical review and fix anything that needs fixing that you can. It can use some expansion, more references and probably has assorted typos and spelling errors. &bull; &bull; &bull; Peter (Southwood) (talk): 12:59, 24 August 2014 (UTC)

Assessment for B-class
Assessed as B-class, please explain why if you disagree. &bull; &bull; &bull; Peter (Southwood) (talk): 09:49, 3 July 2016 (UTC)

To do
Add a summary section on automatic gas blending in ECCRs and link to Rebreather diving.

I plan to do this sometime, but welcome anyone else making a reasonably useful start. &bull; &bull; &bull; Peter (Southwood) (talk): 07:04, 9 May 2017 (UTC)

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