What Happened to Cryogenic Scuba?

[Akimbo]

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

No worries. Dewar cylinders are more like vacuum flasks or Thermos bottles than propane tanks. For reference, liquid oxygen or LOX has a boiling point of 90.19 K, −182.96° C; or −297.33° F. Every hospital and most large welding shops have LOX tanks. They are always outside so any unused gas that boils off won't accumulate and create a fire risk. They are usually easy to see through a chain link fence if you are interested and want to see one.

 

[BRT]

No worries. Dewar cylinders are more like vacuum flasks or Thermos bottles than propane tanks. For reference, liquid oxygen or LOX has a boiling point of 90.19 K, −182.96° C; or −297.33° F. Every hospital and most large welding shops have LOX tanks. They are always outside so any unused gas that boils off won't accumulate and create a fire risk. They are usually easy to see through a chain link fence if you are interested and want to see one.

Yep, I've been around them but never thought about the fact that if you started to use the product it would quit boiling and producing adequate pressure. Here we have a few orchardists that have massive propane tanks for orchard frost control. They use them on cold nights so they put heaters around the tanks so the propane will continue to come out at pressure.

 

[runsongas]

X-5 system 6.3 liter nominal capacity, 4.4 liter (70% limit) fill capacity per CFR 173.316 for cryogenic nitrogen, approx 132 moles of liquefied air, 2957 liters at STP, or 104.4 cf.

2 dollars a liter refill cost at a supplier for liquid nitrogen, possibly 3 to 4 retail at a dive shop.

i just don't see this replacing a standard hp100.

 

[Bob DBF]

Yep, I've been around them but never thought about the fact that if you started to use the product it would quit boiling and producing adequate pressure. Here we have a few orchardists that have massive propane tanks for orchard frost control. They use them on cold nights so they put heaters around the tanks so the propane will continue to come out at pressure.

Propane turns to liquid at around 125 psi at room tempature. O2 cannot be liquefied by pressure alone.

 

[Old Krakken]

Just in case anyone wanted a closer look at an existing Cryogenic SCUBA unit.
Cryo Pjotrr

 

[Old Krakken]

This is curtesy of the US Patent Office.

 

[John C. Ratliff]

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

Download the images to your desktop, and read them in Preview, or another program where you can magnify the images. It works.

SeaRat