What's in a heatpipe?

[blueonblack]

So ever since I first saw these things I've wondered, what is inside them? The ends are soldered as though to contain something.

I was a refrigeration tech for a few years, so I know something about thermodynamics. Air is a terrible conductor of heat overall so I have to assume there is something else inside the copper pipes.

I have not had any spares to chop up and see what was in there. I've never examined any that sloshed like there was liquid in there (though if the pipe were completely full it wouldn't). Can anyone kill this curiosity itch and tell me what's inside the copper pipe?
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Gm ls engine

[killergamer]

A heat pipe is a heat transfer mechanism that can transport large quantities of heat with a very small difference in temperature between the hotter and colder interfaces.
Inside a heat pipe, at the hot interface a fluid turns to vapour and the gas naturally flows and condenses on the cold interface. The liquid falls or is moved by capillary action back to the hot interface to evaporate again and repeat the cycle.



I got this info from here.
I kinda get the drift of how this works.

[blueonblack]

I'm familiar with the concept, it's exactly the way refrigeration works, but I had no idea the actual evaporation/condensation process could happen on such a small scale.

On a simpler note, why don't they slosh?
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Chevrolet Avalanche Specifications

[crenn]

Because of their internal wick most likely. Just don't hold a match near a broken heatpipe.

[Drum Thumper]

They probably do slosh a bit. Chances are you can't hear it due to either the scale or over the case fans.

[blueonblack]

Come to think of it, I DO have a spare heat pipe! I just replaced the crappy stock cooler on my 8800GT. It has a heat pipe. Muuuuuahahahahaaaaaaa!!

Now where did I put my Dremel?
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Yaris

[OvRiDe]

wirrrrrrrrrrr... griiiiiiiiiiiinnnnnnd.... SPARK! ....

Ahhh.. My EYES!!!!!

[Eclecticos]

There is nothing inside.
I know because I have twisted several of them up. I couldn't help it.

Some of the aftermarket cpu coolers have water in them that supposedly
turn's to vapor, and then back to water when not in use.
I think after a while it just dissipates all together.

[FrooP]

there is water in them, you put the empty heatpipe in boiling water, insert water, close the heatpipe. now we have a vacuum inside the heatpipe which makes the water condensate at about 45°C, principe after condesating explained above

[Zeus]

Is it water in there? I thought is was another liquid with a lower boiling point and better heat transferability.