What Happened to Cryogenic Scuba?

[BRT]

There were articles on Cryogenic (liquefied air) Scuba developed by Jim Woodberry in the June (page 22) & December (page 28) 1967 issues of Skin Diver Magazine. Basically, liquid air was stored in Dewar flasks and warmed into gaseous air for breathing. Skin Diver's editor, Paul Tzimoulis, reported diving a prototype to 100' and the inventor diving to 200'.

The December article indicated that Mako (the air compressor manufacturer) was weeks away from finalizing the design and shipping production units. That was the last word I ever found on the subject.

So what happened? Did they discover a concept flaw, decide it wasn't marketable, couldn't deal with the weight change in the days before BCs, or there was not enough patent protection to justify bringing it to market?

The advantages are that the liquid to gaseous conversion is ~1:815 versus ~1:234 for a 3,442 PSI bottle and the operating pressure is below 250 PSI. Among the disadvantages is a pressure gauge would not indicate remaining air.

It strikes me that O2 would boil off at a different temperature than N.

Edit. Tricked into replying to something from the dinosaur era.

 

[EFX]

Where does the gasification occur? Surely not in the tank because of the large liquid volume there. If the conversion happens in the first stage regulator could the extreme cold cause parts to freeze up and not move? Are special o-rings needed to handle the cold. Any water vapor in the reg may ice over.

 

[BRT]

Where does the gasification occur? Surely not in the tank because of the large liquid volume there. If the conversion happens in the first stage regulator could the extreme cold cause parts to freeze up and not move? Are special o-rings needed to handle the cold. Any water vapor in the reg may ice over.

Gasification is typically done in the tank. I.E a propane tank.

 

[Akimbo]

Where does the gasification occur? Surely not in the tank because of the large liquid volume there.

The units described in Skin Diver magazine all had external heat exchangers, which they label a vaporizer:

Gasification is typically done in the tank. I.E a propane tank.

Liquid oxygen and nitrogen tanks that I have seen all have visible heat exchangers attached to the Dewer cylinders.

 

[runsongas]

cryogenic tanks would have horrible buoyancy characteristics due to insulation requirements. you give up the compression advantage by either having to go with relatively small usable volume or you would be wearing a boat anchor.

 

[AfterDark]

Hello!

I'm kind of new here, but I remember reading this article when I made my account a few days ago. I was reading some news articles today and came across this... I thought it might be something to go on.

Into the abyss: The diving suit that turns men into fish - Science - News - The Independent

Apparently, someone patented a suit in the not so distant past to do just that. Interesting read.

So this is like a baby in the womb breathing fluid, back to the future.

 

[AfterDark]

The units described in Skin Diver magazine all had external heat exchangers, which they label a vaporizer:

View attachment 600816



Liquid oxygen and nitrogen tanks that I have seen all have visible heat exchangers attached to the Dewer cylinders.

My first impression of this rig is that it is an entanglement accident looking for a place to happen.

 

[Akimbo]

cryogenic tanks would have horrible buoyancy characteristics due to insulation requirements. you give up the compression advantage by either having to go with relatively small usable volume or you would be wearing a boat anchor.

It doesn't appear to have been an issue if you read the Skin Diver article attached to Post #1. Note that all the images were of guys testing it without any thermal protection.

 

[broncobowsher]

I believe there was a rebreather made that used the super cold liquid oxygen to freeze out the CO2. After the dive you opened the unit, let the block of dry ice thaw out and release the CO2 that was stored. Not sure if it ever made it to production. 1970s?

I don't see a need for liquified gas rebreather. The duration of a rebreather diver is generally limited by many other factors before running out of O2. Add in the inability to store your gas. Most rebreather divers are not a fill and dive. More of a fill, and have it ready for when to dive. This is a solution to a problem that doesn't exist.

And there are some old internet videos of people putting liquid oxygen with charcoal briquettes and lighting them. Coals are ready for cooking your burgers in about 5 seconds, if the bottom of the grill didn't fall out. Makes high pressure oxygen look like a kids toy.

 

[BRT]

The units described in Skin Diver magazine all had external heat exchangers, which they label a vaporizer:

View attachment 600816



Liquid oxygen and nitrogen tanks that I have seen all have visible heat exchangers attached to the Dewer cylinders.

My bad. Logically it would have to be like that because the tank is insulated but I just thought of a propane tank. Sorry.