What Happened to Cryogenic Scuba?

[emoreira]

Attached are scans from Skin Diver's December article.

Thanks for the attachment, but unfortunatelly the images are very little and can hardly be printed or read.

 

[knotical]

There's a bit of info here: Scuba set - Wikipedia, the free encyclopedia

and a very interesting article here:
Google Translate

 

[knotical]

... images are very little and can hardly be printed or read.

You might have success reading them, as I did, by saving the thumbnails as individual jpg's, opening them in a picture manager and zooming.

 

[Akimbo]

Thanks for the attachment, but unfortunatelly the images are very little and can hardly be printed or read.

The images were scanned at 200 DPI so as knotical indicated, you probably have to download to make them readable. I tried to make a single .pdf file but it exceeded upload limits. Sorry.

 

[Crush]

Given that the boiling point of oxygen is 90 Kelvin and nitrogen is 77 Kelvin, I would have thought that a cryogenic mixture of 21% oxygen and 79% nitrogen would lead to the following dive: first the oxygen boils off and you convulse from oxygen toxicity and die, and then the nitrogen boils off and you would die from hypoxia. I'd rather die zero times instead of two times during a dive...

That is an easy fix - dive two tanks, one O2 and one N2, and mix them on the fly.

I am not certain that it is possible to indefinitely store LN2 and LO2 at ambient temperatures. While this is possible at increased pressure with some gases (e.g., liquefied petroleum gas), it may not work with LN2 and LO2. If it were possible to indefinitely store LN2 and LO2 at ambient temperatures this would likely require tanks that are rated far in excess of 3000 psi and bring in the headache of new DOT approvals.

The system seems to be rapidly growing in complexity - it might just be that a rebreather is easier, cheaper, and less prone to failure.

 

[Akimbo]

Based on the articles, they appear to have solved the differential boil-off issue with a cryrogenic air mix. Note the single Dewar flask X2 and X5 prototypes. Paul Tzimoulis wrote both articles, was editor of Skin Diver, and technically competent enough to investigate the issue. The December article discusses using a Beckman O2 analyzer to test gas before dives, which was a pretty $tandard instrument of the day.

… The system seems to be rapidly growing in complexity - it might just be that a rebreather is easier, cheaper, and less prone to failure.

The articles and photographs indicate it is much simpler than even a pure oxygen rebreather, let alone an eCCR. We have all seen vapor ware and far-out proposals that were impractical on the face, but I can’t recall anything in the diving industry with the credibility indicated in these articles. Jordan Klein of Mako was putting his own money and considerable expertise behind this project.

 

[knotical]

... I can’t recall anything in the diving industry with the credibility indicated in these articles...

And as the Russian article I mentioned in post # 12 said, a quite successful and simple system was actually developed in the 1970s and used in the 1980s. But apparently lack of infrastructure killed it around 1990.

 

[Crush]

Based on the articles, they appear to have solved the differential boil-off issue with a cryrogenic air mix. Note the single Dewar flask X2 and X5 prototypes. Paul Tzimoulis wrote both articles, was editor of Skin Diver, and technically competent enough to investigate the issue. The December article discusses using a Beckman O2 analyzer to test gas before dives, which was a pretty $tandard instrument of the day.



The articles and photographs indicate it is much simpler than even a pure oxygen rebreather, let alone an eCCR. We have all seen vapor ware and far-out proposals that were impractical on the face, but I can’t recall anything in the diving industry with the credibility indicated in these articles. Jordan Klein of Mako was putting his own money and considerable expertise behind this project.

Fair enough - I was just speculating. The mention of a dewar flask denotes cryogenic conditions and therefore may not be suitable for long-term storage...

 

[Akimbo]

... The mention of a dewar flask denotes cryogenic conditions and therefore may not be suitable for long-term storage...

That was definitely an issue. The article mentions a 6-day boil off for their X5 model. The earlier article show images of filling rigs off a larger Dewar on the back of a pickup so it would not be that big a problem for a small group of divers or a charter boat to buy bulk liquid for a week or so of diving.

Given the cost and complexity of some cave and wreck projects, I can see how the cryogenic rigs could be attractive. Most anywhere on the continental US coastline would not be a problem. It would be usable for remote dive sites like the South Pacific or Indian Ocean where gas plants were not nearby.

 

[msmchy]

Completely unrelated and sorry to derail, but anybody know how I could procure a copy of that article in Time magazine. Jim Woodberry was my father-in-law.