Metal Thermo Flasks: How Do They Keep Drinks Hot?

In summary, the conversation discusses metal thermo flasks and their effectiveness in keeping drinks hot for long periods of time. The speaker is familiar with the principle of vacuum flasks and has recently seen a new stainless steel version with a metal bridge connecting the inner and outer flasks. They question how the metal bridge affects the heat retention and mention the limitations of stainless steel as a heat conductor. The other person confirms that the metal bridge does decrease the insulation but is still better than having no insulation at all. They also mention the challenges of using metal in cryogenic systems. The original speaker expresses relief that they did not miss any important features of the stainless steel thermo flask.
  • #1
sven56
2
0
A question about metal thermo flasks, or metal vacuum flasks if you prefer.

I understand the principle of thermo/vacuum flasks.
Just to proofed that I read up before posting this question :-)
http://en.wikipedia.org/wiki/Vacuum_flask

But today I had a look at on of those new-isch thermo flask contraptions totally made out of stainless metal.

Its one stainless steel flask inside other with a vacuum between. But there is a stainless steel bridge connecting those two bottles at the opening. Since metal is such a good heat transfer medium – how can my drink stay boiling hot for hours?
 
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  • #2
Stainless isn't a very good conductor and the neck is only joined by a very thin ring of metal. They aren't as good insulators as a glass flask but are better than nothing.
If you build cryogenic systems it is frustrating how poor some metals are as conductors of heat when you are trying to get that last 1degree temperature difference!
 
  • #3
thanks for your prompt replay.

i was a bit worried that i missed some essential feature of this stainless steel thermo flasks- makes me feel better that i didn't. Other than that stainless steel is a bad conductor.

Thanks!
 

FAQ: Metal Thermo Flasks: How Do They Keep Drinks Hot?

1. How do metal thermo flasks keep drinks hot?

Metal thermo flasks use a vacuum insulation technology, which creates a vacuum between two layers of metal. This vacuum prevents heat from escaping and keeps the drink hot for a longer period of time.

2. What is the role of the metal in a thermo flask?

Metal has a high thermal conductivity, which means it can transfer heat quickly. In a thermo flask, the metal is used to absorb the heat from the hot drink and prevent it from escaping through the flask's walls.

3. Can a metal thermo flask keep drinks cold as well?

Yes, metal thermo flasks can also keep drinks cold. The vacuum insulation technology works both ways, preventing heat from entering the flask and keeping the cold drink from warming up.

4. How long can a metal thermo flask keep drinks hot?

The duration for which a metal thermo flask can keep drinks hot depends on various factors such as the initial temperature of the drink, the quality of insulation, and the outside temperature. However, on average, a metal thermo flask can keep drinks hot for 6-12 hours.

5. Are metal thermo flasks safe to use with hot drinks?

Yes, metal thermo flasks are safe to use with hot drinks. The materials used in these flasks are food-grade and do not release any harmful chemicals when exposed to high temperatures. However, it is always recommended to handle hot liquids with caution.

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