Which Liquid Gases Do Hospitals Use and Why Are They Warmed?

[DaveC426913]

On the way into work, I pass through "Hospital Alley". I saw a collection of Praxair tanks with radiating fins that were covered in ice. If you put fins on something that's cold, it will warm up faster. I was trying to figure out why they would have a system that was designed to warm up the gases.

You wouldn't want to do that with N or CO2 since their raison d'etre is as a freezing agent. Radiating fins would defeat the very thing they are trying to do.

The only one I can think of is Oxygen. That's a gas that you'd store as a liquid but use as a room temp gas.

Any others that a hospital might use?

I looked up Praxair, they are suppliers of oxygen, nitrogen, argon, carbon dioxide, helium and hydrogen.

 

[Ryan_m_b]

Depending on what they are doing in the labs CO2 might be needed (and not as a freezing agent). Not sure about the others.

 

[rollcast]

They wouldn't happen to be using argon for laser eye surgery in that building?

 

[Andy Resnick]

On the way into work, I pass through "Hospital Alley". I saw a collection of Praxair tanks with radiating fins that were covered in ice. If you put fins on something that's cold, it will warm up faster. I was trying to figure out why they would have a system that was designed to warm up the gases.

<snip>

I'm surprised there are fins on the tanks; the tanks around here definitely don't have them. AFAIK, Nitrogen is delivered in small (200 liter) dewars and is used in research, to store cells. The big external tank here is Oxygen, and there is an evaporator section to deliver the O2 as a gas:

http://www.anaes.med.usyd.edu.au/lectures/gas_supplies_clt/gas_supplies.html

Argon, CO2, and other speciality mixes are also delivered in small bottles as needed- at least they are at the places I have worked. The NASA center had liquid He and H onsite- the H was stored far away from anything else, in an array of thin horizontal tubes stacked on the back of a truck- they didn't need this anymore:

http://www.apollomissionphotos.com/apollo/hydrotank.jpg

 

[DaveC426913]

The image on that page:

is exactly it.

The fins are not on the tank, they are next to it.

 

[Andy Resnick]

Those aren't fins, exactly- that's where the O2 gas is warmed up prior to use.

 

[DaveC426913]

Those aren't fins, exactly

Physically, no. But they serve the same purpose - maximum heat exchange.

that's where the O2 gas is warmed up prior to use.

Cool. That's exactly the conclusion I came to.

Other gases, N and CO2 serve their purpose best because of their cold, so you wouldn't want to waste that. Which means whatever it is, it's a gas that they store as liquid, but want to use at normal temps. Oxygen was the only one I could think of that they'd need tanks that size for. Not sure how much they'd need of Ar, H or He.

What caught my eye was that they're not being used very efficiently if they have a three foot thick layer of snow of them. I wonder how often they have to defrost...

 

[ThinkToday]

We have them on our O2 system here. I took a look and they are on the downstream side of the tank before the lines go underground into the hospital.