How often to Heat Pipe Cooling Systems Fail?

I am trying to rule out a failed (or failing) heat pipe cooling system in a Toshiba M45 S359 laptop that is exhibiting overheating symptoms.

I have read that (in this article) heat pipes use water as a working fluid.

My concern is that if the water is not completely sterile, bizarre things can happen to it (well, grow in it) over long periods of time.

(In particular, you know those water filled shakable snow globes that some people collect? It turns out that maybe 1/2 of them do not use sterile water and in time, the water turns to a nasty yellow.

and then there is the scandal about the stolen Rubycon electrolyte formula that was missing a key component (probably the preservative) that resulted in billions of bad capacitors coming out of Taiwan.

and of course, stuff growing in fuel tanks in storage that causes the fuel to gel - this would be kiss of death for a heat pipe.)​

Any thoughts would be most helpful, and of course
Thanks in Advance,
Tom

 

Do you have the link to the article?

 

http://gaming.ocmodshop.com/ocmodshop.aspx?a=721

 

Thanks Tinderbox!

I was glad to see that water was one fluid so at least I wasn't talking through my hat which I guess comes from the "mad as a hatter" due to hat makers mercury poisoning.... which is also another working fluid!

Actually the last paragraph of the URL article was quite shocking: If allowed to overheat (perhaps from lint and dust clogging the "condenser" end, the result is the working fluid goes to 100% gaseous and the heat pipe ceases to function resulting in about 2 orders of magnitude reduction in cooling.

So it is possible that although the laptop shuts down from high heat, this could already have damaged the CPU. In particular the heat soak that occurs just after shutdown would result in an even high peak temperature.

________________________________________


Which leads me to a 4th fluid failure. This one concerning mercury.

I worked for Robershaw Controls Company where we made controls for mostly gas appliances such as stoves. Safety valve mechanisms were based on a device called a diastat which was a capillary with a bulb on one end and a metal diaphram on the other. It was filled with mercury.

The bulb was located where a pilot flame would impinge on it. The resulting expansion of the mercury displaced the diaphram on the other end and operated the mechanism.

or so we thought.

Contaminants in the mercury resulted in a clogging of the capillary at the bulb end. The contaminents literally decomposed from the high flame heat exposed to the mercury (the bulb would usually glow orange) resulting in a black, burnt, crud which "stop leaked" the capillary. The diaphram ceased to move and the control acted as no pilot flame was ever present.

But there was an even worse and more dangerous condition:

Sometimes the plugging would allow a slow seepage that was enough to operate the diaphragm. The problem was that if the flame was extinguished and the safety control was supposed to shut down the gas valve in a few seconds, this shutdown could take many minutes and in some cases never happen!

So how we had a safety valve that was failing OPEN. Very nasty business.

Hope I didn't bore you,
Thanks for replies,
Tom

 

Its usually not just water, its a system of fluid with a low evaporation temperature making the liquid go to a gas, and then condenses in the heat sink and turn back to a liquid making gravity pull it back down to the heat source.

I have only heard of one defective heat pipe in my whole life, its far more likely the heat sink is not mounted properly, or that your fans or something are not working right.

 

ViciousXUSMC,

Do you have any details about the one heat pipe failure you heard of?

Thanks
Tom

 

Not sure what you mean by details, it was just a person that had gotten a defective unit right from the factory.

As for a heat pipe breaking while in use I have not seen that happen yet. I guess if you had a very very small leak it could slowly degrade performance over time.

 

This is encouraging. I could easily see a mistake in the manufacturing process. Due to the rather large size of the heat pipe, it should be impossible for it to become clogged. And due to wall thickness, a small leak should be nearly impossible.

I'm going to focus on the incredibly bad conduction surface of my particular heat pipe.