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Author Topic: My solar kettle imploded  (Read 15509 times)
wookey
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« on: September 07, 2009, 02:56:15 AM »

I have been using a tube as a solar kettle almost daily for this summer and much of last. Today it blew up as I added some more water. :-(

Not sure why this fill was any different from hundreds that went before, but it seems it is possible for it to have too much thermal shock. I guess the unusual thing was I had just poured out a tiny bit of very hot water. i.e the tube was almost empty but had got nice and hot. I poured it into a cup of tea and there was only about 15mm of water in the bttom of the mug. So I went to get some more water (from the cold tap as usual - not particularly cold it being summer) and poured it in. Tube went pop in rather impressive manner as the water touched it, clearly due to too much thermal stress. Took _ages_ to get all(?) the glass out of the lawn.

Now I've filled it up innumerable times with water from the cold tap when it's been good and hot and I just poured out some really hot water. Either this was just one hot/cold cycle too many or something about only having a smidgen of water poured out is bad.

So no more solar kettle for me until I go shopping (which might as well be spring now).

Still, as it's been kicking round the garden for best part of 18 months now I'm quite impressed that it didn't get broken sooner.

Anyone else managed to break one like this?

've got a photo I'll upload later,
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Wookey
guydewdney
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« Reply #1 on: September 07, 2009, 07:33:50 AM »

yes - on my first try....


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Pic of wheel on day 1
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Flamethrower_
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« Reply #2 on: September 07, 2009, 07:38:27 AM »

Not one I supplied I hope! Shocked
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Ivan
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« Reply #3 on: September 08, 2009, 12:15:39 AM »

Wookey,

I've always been very cautious in refilling for that very reason. On occasion I've refilled a tube quite quickly without any trouble, but I've tried to always leave a tube out of the sun once I start decanting. The reason is that without water in contact with the glass, some areas can get very hot indeed. I've read 300C,but I've not actually measured it - it will be limited only by the rate of heat transfer to steam inside the tube. If the tube is left out of the sun after decanting starts, the hottest the tube can be is 100C.

When I refill a hot tube, I hold the neck of the tube under the tap, and trickle the water in slowly whilst rotating the tube - to give it chance to cool the glass at a controlled rate. Not sure if it works, but I haven't broken one like that yet.

If you're ever near Oakham or Monmouth, I'll find you a replacement tube.


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wookey
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« Reply #4 on: April 22, 2011, 09:51:38 PM »

This year's caving conference will be in Monmouth 23-25 sept.(http://hidden-earth.org.uk/). So if you are serious about the tube I could come a-blagging then (and have a look at your house :-)

Have people tried the short 'balcony' version, which would be a rather more easy-pour (but make fewer cups/store less heat).

I was just missing my kettle today as it's ridiculously sunny for April.
« Last Edit: April 22, 2011, 09:54:03 PM by wookey » Logged

Wookey
Richard Owen
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« Reply #5 on: April 22, 2011, 10:06:53 PM »

That is some memory.
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« Reply #6 on: April 23, 2011, 09:41:06 AM »

I guess these are no longer available from our hosts? Searching the navitron shop for kettle just draws up one old news item?
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SteveH
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« Reply #7 on: April 23, 2011, 10:17:40 AM »

http://www.navitron.org.uk/product_detail.php?proID=128&catID=115

http://www.navitron.org.uk/product_detail.php?proID=127&catID=115
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Preveli, South Crete.
Ivan
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« Reply #8 on: May 17, 2011, 01:45:37 AM »

No problem, Wookey. The conference is 100yards from my doorstep!
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