On the submarine, one of the emergencies we trained for was the dreaded Steam Line Rupture in the Engine Room. A large steam line rupture would undoubtedly kill everyone in the engine room nearly instantly, so one might think training for that was kind of pointless. It might be a small enough rupture that everyone had time to run away and shut the door to the Engine Room, though. That’s what we were training for.

Now, you can’t just run away from a broken nuclear power plant for long and expect it to be safe. Worse, submarines need propulsion, and engine rooms don’t run themselves, especially with a broken power plant. Someone has to go back in there. That person was often me.

As you might imagine, a confined space that just had thousands of pounds of steam poured into it is pretty uncomfortable. It’s hot, wet, slippery, a mess of debris, hot, full of sharp objects, an electrocution hazard, and hot. It’s also hot. You can’t just walk in there unprotected.

Hence, the steam suit. I’d have to put on what was essentially a whole-body oven mitt, with a helmet. Here’s a picture of a guy having one put on him.

The steam suit was fed by an air line with a quick disconnect to be plugged into air supply lines that had jacks located every so often around the whole ship. So the plan was, plug in, blow your suit up like the Michelin man, then disconnect and move to the next jack, repeating until you were where you wanted to go. Make the reactor safe, get propulsion, then make it so other people can come back into the Engine Room and help.

To cool the air going into the suit, and this is the point of the whole story, there was a little metal tube where the air came in. Room temperature air went in the side, and then somehow, cold air came out one end and into the suit, and hot air went out the other end outside the suit. Somehow this tube knew how to separate hot and cold air. I used to stare at that thing while I was waiting wondering what could possibly be inside the tube to make it do that. Doesn’t that violate a law of thermodynamics?

I finally got around to looking it up on the internet one day. It’s called a Ranque-Hilsch Vortex Tube (originally, “Wirbelrohr”, a much cooler name.) Turns out nobody is 100% sure how it works.

Here’s how to make one, though.