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This is a dull idea.
Pipes will sometimes burst when they freeze, because the water
expands as it turns to ice.
So, as the pumbing is being assembled, simply slide in a strip of a
closed-cell, non-toxic plastic foam. I'm imagining it would come
a roll, and would be about as thick as
Then, if the pipes do freeze, the expanding water will simply
compress the foam rather than bursting the pipe.
Issues: (1) problematic with soldered joints, as the plastic would
melt/burn (but fine with compression joints) (2) How to hold the
foam strip in place inside the pipe? This could be solved if the
strips were bonded inside the pipes at the time of manufacture.
You'd then need a little gadget to remove a piece of the strip near
the cut end of a piece of pipe, if you are using solder joints.
[ldischler, May 04 2009]
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||Re the link, you can certainly make unburstable pipes - in
fact, plastic plumbing has enough 'give' to resist bursting in
most cases. However, the idea here was to enable copper
pipes (which are preferred in many applications) to be
||I'm not sure how the "self healing elastic" would work for
plumbing. If it did burst, surely the water gushing out of the
split would prevent the edges from rejoining?
||// You'd want pipes that are bigger in diameter // Yes and
no. If you imagine a standard 15mm copper pipe (internal
diameter ?14mm?), fitted with a foam strip 6mm in
diameter. The area available for water then reduces from
154mm^2 to about 126mm^2, which I don't think would
have much impact.
||You wouldn't want this in drains (since you need a smooth
bore to avoid clogging), but they are not usually a problem
when it comes to freezing.
||Issues: 3) Getting plumbers to forego the ongoing source of income generated by burst pipes.
||Great idea. It's also interesting to note that this material would heat up very slightly as it's compressed.
||Saw something similar in new scientist in the 70s ....
t'was a plastic strip with a cross section a bit like a flying saucer which is pushed into the pipe. (Can't find no mention of it via that there google thing.)
(ie, pretty much baked)
||//something similar in new scientist in the 70s// Damn - can
anyone else trace this prior art?
||Surely it would be better to have a foam tube that lines the inside of the pipe instead? Two reasons: the ice would exert all its pressure outwards and so all its pressure on the foam, and also, the foam would act as insulation against freezing in the first place. On the other hand it would be harder to install, and different for different sized pipes.
||If you're willing to have less capacity per amount of material in your pipe, why not just roll it down to an elliptical cross section? (Leave the ends round for joints, of course)
||"This is a dull idea." thanks for pointing that out [+]
||//why not just roll it down to an elliptical cross section?
(Leave the ends round for joints, of course)// Several
reasons. First, bending elliptical pipe is a pain. Second,
you'd have to roll it down on-site (if the ends have to be
left round). Third, pipe-clips etc are all designed for round
pipe. Fourth, modifications (eg, breaking into a run of
pipe to add a T-joint) would be difficult because of the
need for leaving the jointed parts round.
||The idea of the foam strips was that you could make, sell
and install piping which would be compatible with existing
systems and just as easy to use.
||Ah - well, that pretty much bakes it, I think. Case closed.
||With "foam lined pipes" i get 2 results, which is, by the way, the lowest non-zero results count i ever had.