h a l f b a k e r yOn the one hand, true. On the other hand, bollocks.
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For those of you who haven't heard of mechanical
steam compression clothesdryers, they work like this:
First, the tumbler and the clothes are heated up to
100C; the steam that's initially produced displaced all of
the air, resulting in a steam-only atmosphere inside the
machine. Some of that
steam is taken out, compressed
(raising it's temperature), passed through the inside of
the condenser; the resulting liquid water exits the
condenser via either a float valve or a pressure release
valve, and is discarded down a drain. Some of the
steam from the tumbler is pulled out via a blower, sent
around the outside of the condenser (which superheats
it), then blown back into the tumbler.
Such machines are both energy efficient and fast at
drying clothing, but have one really big downside: They
operate at a range of 100C - 120C, and are not suitable
for heat sensitive clothing types.
I propose modifying this existing technology, by putting
the components into a vacuum chamber, and adding a
gas/liquid separator, an additional compressor, and a
pump.
When the system is initially turned on, air is pulled from
the dryer by the primary compressor, passed through
the separator, then the secondary condenser, then
vented.
A float valve in the gas/liquid separator will, when
liquid is present, turn off the secondary condenser and
turn on the condensate pump; this pump pulls water out
of the separator and discards it.
As with a regular MSC clothes dryer, a blower pulls gas
(either air or steam, depending on the drying phase) out
of the tumbler, past the condenser, and back into the
tumbler.
In addition, there is a thermocouple, with one end
inside of the gas/liquid separator, and the other on the
outside of the machine. If the temperature in the
separator is below the temperature of the room, the
secondary compressor is turned off, even when there's
no liquid in the separator. This keeps the system's
overall temperature close to ambient, which maximizes
efficiency. This also keeps system temperatures well
above the freeze-drying range.
As a result, we now have a clothes dryer which is just
as fast and efficient as MSC, but which operates at near-
ambient temperatures, and should be suitable for all
types of clothing.
Caution: If you accidentally put a pen in the dryer with
your clothes, it's guaranteed to explode and make you
unhappy, as the pressure drop will make the ink boil and
expand out of the pen.
Optional: A feature to run the system with the tumbler
not spinning, so it can be used to make homemade dried
foods. Use of a battery powered fan for circulation is
suggested. Cleaning or replacing the filter when
switching from making dried food to drying clothes is
strongly recommended (unless of course you *want* to
smell like jerky).
Previous posting
Combo_20Washer_20and_20Freeze-Dryer You have described something very similar to "freeze drying". And a washing machine especially a front-loader, has the seals and most of the toughness needed to stand up to air pressure when doing vacuum-drying. [Vernon, Jul 15 2011]
Degreaser dip
Degreaser_20dip With acetone! Would probably also work to dry clothes. [bungston, Jul 15 2011]
[link]
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This device would be useful for those who want to dry their clothes / make beef jerky without detection by unmanned aerial drones with infrared cameras. Bun for consideration of people who want to smell like jerky. |
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Could use ether rather than water in the wash - has a lower boiling point so a normal machine could opperate at the lower temp:O) |
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/ether/
see Degreaser dip, linked. |
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Vernon, thanks, your idea was actually part of the
inspiration for this one. My apologies for forgetting to
link to it. |
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However, in my idea, the "freeze" aspect of "freeze
drying" never occurs. The majority of the drying is
accomplished by blowing superheated steam through
the clothes. |
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Bungston, dipping clothing in acetone would certainly
remove the water -- but that isn't really drying, since
the acetone is of course a liquid, and thus the clothes
are still wet (just with acetone instead of water). The
acetone would need to be removed from the clothes
after doing that. |
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Conveniently enough, my idea would not only remove
the acetone from the clothes, but recover the vast
majority of the acetone as a liquid. |
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Come to think of it, this idea would be just as fast and
energy efficient for the final stage of drying for dry-
cleaning, as it is for the drying of water-dampened
garments. The drying stage of a modern dry-cleaner is
done by a the same mechanism as a "heat pump dryer,"
which is as efficient as (but half as fast as) mechanical
steam compression drying. |
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I just thought of a way to make a dryer using this idea
slightly cheaper to construct: instead of having two
compressors, have one. |
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When there is no liquid in the gas/liquid separator, the
compressor will *either* move gas from the dryer into
the condenser, *or* move gas from the separator into
the atmosphere, depending on whether the temperature
in the separator is below or above the ambient temp. |
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The system would be the same as I first described in all
other ways. |
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Naturally, it would take a little longer than the original
version to get one's clothes dry, but I don't believe the
increase in running time would be particularly extreme. |
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Super critical co2 would be my choice for washing clothes. Any liquid co2 left after the spin down would just boil away. Of course that means the feeling of using a fresh hot towel from the dryer will be lost to future generations |
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