Author Topic: Discussion about Flask with Tea found in treasury sump.  (Read 6964 times)

Offline Nigelh

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #25 on: December 05, 2017, 12:44:02 pm »
This is a great topic!! One of the best in a while!
 :coffee:

Offline alastairgott

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #26 on: December 05, 2017, 12:54:12 pm »
I'm now curious.
What then prevents the outer skin collapsing towards the inner skin when subjected to the pressure applied by the depth of the sump + 1 bar since there is a vacuum inside the outer skin?

Maj.

I think perhaps he puts it inside a daren drum with a bicycle valve in the top to increase Decrease(/stabilise) the pressure? (I think they pump it up before going through the sump?)

Offline RichardB1983

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #27 on: December 05, 2017, 12:54:33 pm »
A lot of thermos flasks have a layer of silvered glass either side of the vacuum as it's a poor conductor of heat - rather than metal. I'd guess that the glass would have to smash first before the surface shows any deformation - whereas a metal one could bend under the compression forces. The flask obviously must be designed to be strong enough to withstand the internal vacuum without the glass breaking - and no doubt will have a decent margin over that.

Offline alastairgott

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #28 on: December 05, 2017, 12:58:59 pm »
A lot of thermos flasks have a layer of silvered glass either side of the vacuum as it's a poor conductor of heat - rather than metal. I'd guess that the glass would have to smash first before the surface shows any deformation - whereas a metal one could bend under the compression forces. The flask obviously must be designed to be strong enough to withstand the internal vacuum without the glass breaking - and no doubt will have a decent margin over that.

That's it, we're going to need a circular saw to settle this one.

Then we'll have to ask the question can it be put in a blender?

Offline Roger W

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #29 on: December 05, 2017, 01:33:46 pm »
Flasks are usually cylindrical,making them pretty good at resisting pressure from the outside -think of a submarine's pressure hull.  The ends will be the weak points.

"That, of course, is the dangerous part about caves:  you don't know how far they go back, sometimes... or what is waiting for you inside."   JRR Tolkein: "The Hobbit"

Offline Maj

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #30 on: December 05, 2017, 01:52:39 pm »
Flasks are usually cylindrical,making them pretty good at resisting pressure from the outside -think of a submarine's pressure hull.  The ends will be the weak points.

Agreed, provided they have no dents in them. My 20yr old s/steel flask has a couple of battle scars/dents in the outer skin and so I feel this would significantly reduce its structural integrity (of the outer skin) if subjected to a high external pressure. I am assuming that my s/steel flask's outer most surface is the outside skin of the vacuum envelope - and NO! I'm not cutting it open to find out  :ras:.

Obviously glass envelopes won't have dents in them, and might better withstand the pressures found in deep sumps ........ if you can get them to the deep sump without breaking the glass in the first place.

Maj.
Confucius say "War does not determine who is right, war determine who is left."

Online mikem

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #31 on: December 05, 2017, 02:22:43 pm »
I believe the outer skin is a separate protective layer to the vacuum layers (same as a "normal" flask).

Mike

Offline glyders

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #32 on: December 05, 2017, 03:46:21 pm »
There was a container of rubber ducks that fell off a ship years back and the dispersion of the ducks has yielded huge quantities of data on ocean currents. They were distributed most of the way round the world!

We should buy up a job lot of flasks and dump them in various sinks. Colour-coded of course - red for one sink, tartan for another, etc.

Offline alastairgott

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #33 on: December 05, 2017, 03:56:13 pm »
There was a container of rubber ducks that fell off a ship years back and the dispersion of the ducks has yielded huge quantities of data on ocean currents. They were distributed most of the way round the world!

I believe there's a sump in mendip which has had similar treatment, fortunately/unfortunately it's a static sump!

Perhaps the idea of a Goose making it out of Peak cavern with singed wings is not so ludicrous after all  :tease: :-\

Online Benfool

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #34 on: December 05, 2017, 04:13:38 pm »
I heard a rumor that quite a lot of small foam footballs were dropped into the boulder choke at the bottom of the Rowter Hole Extensions to see if they would be found floating in the final airbell of Whirlpool Rising in Speedwell. They still haven't arrived and its been at least 6 months!

Offline ZombieCake

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #35 on: December 05, 2017, 04:24:46 pm »
Tea is mainly water, which doesn't compress. What about soup?  Would the chunky bits of carrot and potato which can be compressed under pressure reduce the structural integrity?

Offline alastairgott

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #36 on: December 05, 2017, 04:57:15 pm »
Excellent point, I like your thinking, I think that will require a name change! i'll take it at once to the next meeting, and we shall vote on a new name, The "Tea and Soup Group".

Offline Pitlamp

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #37 on: December 05, 2017, 06:10:53 pm »
Quote
Whoever leaves teabags in the flask needs a lesson on how to make decent flask tea!
Suppose that could be the subject of a workshop at the next Hidden Earth.  Surely leaving the tea bag in the flask would render it rather stewy?  Would a more fuller flavour tea such as Assam be better than say a lighter green tea in an adverse environment?

Correct, Zombiecake. It must be a good quality tea - and Assam is just about the best.

You don't get a prize - but well done!  :thumbsup:

Offline Ian Ball

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #38 on: December 05, 2017, 07:07:17 pm »
Making tea in a flask is a skill I have yet to master.

Offline cavemanmike

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #39 on: December 05, 2017, 07:22:33 pm »
Making tea in a flask is a skill I have yet to master.
flask of boiling water and add a teabag/tea to the cup

Offline ZombieCake

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #40 on: December 05, 2017, 09:02:51 pm »
Quote
... we shall vote on a new name, The "Tea and Soup Group"
Hmmm...  Tea & Soup Group = TSG.  Always thought the TSG didn't really mean the Technical Speleological Group   ;D

Offline Ian Ball

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #41 on: December 05, 2017, 10:21:41 pm »
Making tea in a flask is a skill I have yet to master.
flask of boiling water and add a teabag/tea to the cup

You struggle too I see.

Offline alastairgott

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #42 on: December 05, 2017, 10:34:48 pm »
Quote
... we shall vote on a new name, The "Tea and Soup Group"
Hmmm...  Tea & Soup Group = TSG.  Always thought the TSG didn't really mean the Technical Speleological Group   ;D

In our previous incarnation we were the Tea & Pb Users of Bacon Sandwich Appreciation.

Offline ZombieCake

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #43 on: December 05, 2017, 11:00:26 pm »
Quote
...Tea & Pb Users..
Pb - I suppose you could use lead acetate as a sweetener... :-) What did the Romans ever do for us? Congrats on the 1000'th post.
« Last Edit: December 05, 2017, 11:10:33 pm by ZombieCake »

Offline marysboy

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #44 on: December 05, 2017, 11:34:31 pm »
I know of a spare metal flask that would love to take part in an experiment for the good of cave science.

I suggest a test to destruction comprising:
  • Fill flask underwater and submerge to -50m, -75, -100...?
  • Half fill flask and repeat
  • Empty flask and repeat

Benfool - have you any deep diving trips planned?

Online Benfool

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #45 on: December 06, 2017, 12:29:31 am »
I suppose I can take a flask with me next time I'm in Main Rising!

B

Offline Pitlamp

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #46 on: December 06, 2017, 07:00:01 am »
Making tea in a flask is a skill I have yet to master.

That's what I said for years. I eventually gave up trying until one day a certain Mr. Skorupka presented me with an excellent brew from his flask after we'd done a long dive. That gave me the inspiration to try harder until I finally learned the secret technique.

Next time we bump into each other I'll tell you how it's done   :thumbsup:

People who know me well are aware I'm a helpless tea addict. Pint mugs are routine; I also own 2 x 2 pint mugs. To give you some idea of the scale of my tea consumption, last year a caving friend presented me with a 6 pint tea mug. (And yes, I've actually used it.). The local shop gets in 1 kg packs of loose tea specially; the usual small packs just don't last long enough.

So - for me - the encouragement I received from RPS, to keep searching for the secret of making good flask tea, was a very precious gift.  :)

Offline Ian Ball

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #47 on: December 06, 2017, 09:15:52 am »
  :thumbsup:

Blimey!  That is a remarkable amount of tea! 6 pint mug, string in the forearm!

Offline cooleycr

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #48 on: December 06, 2017, 02:33:27 pm »
I don't drink tea so not sure why I joined the TSG....maybe I misunderstood and thought it was the Toast and ....

Anyway, back to science..

So the inner sleeve of a Vacuum flask is usually silvered glass. There is then a vacuum between this inner and the outer skin.
Whether this is simply an insulated barrier or an actual vacuum, I am not 100% certain but, assuming the latter, we are still left with the fact that the cylinder itself is not fully enclosed and there is never a total vacuum.
There is an opening that is utilized to fill/empty the flask (generally at least 50% of the cylinder diameter) that is NOT sealed by vacuum, this is why if you were to pour a hot (or cold) liquid into said flask and left a gap, such that the container was not absolutely full, then the liquid would, in time, cool down (or heat up).

Correct me if I am wrong, but the integrity of the flask must be dictated by the quality of the stopper, rather than the container itself and that would determine how well the flask would stand up to the pressures of diving?

TSG

Offline alastairgott

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Re: Discussion about Flask with Tea found in treasury sump.
« Reply #49 on: December 06, 2017, 02:59:40 pm »
I've got a related/Unrelated Question.

Why?, When you put a small amount of Boiling water into a flask to warm it up does it create a vacuum/increase in Pressure?

I have this a lot. I've a small flask which has "pressure release" this effectively means the top flys off as I'm shaking it to warm the flask up.
 I've another with the new fangled inside button to open, outside ring to close. When I do the same, small amount in the bottom and shake. it again creates a vacuum/increase in Pressure. So when I press the inner button (to open) there is a rapid change in pressure.

What's happening and why? Chocolate Fireguard, my Physics knowledge is lacking :(

 

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