
The Tesla Valve: One Way Flow With No Moving Parts - iamwil
http://blog.makezine.com/2012/01/05/the-tesla-valve-one-way-flow-with-no-moving-parts/
======
kragen
The whole field of fluidics is fascinating, including entire digital logic
families that operate at kHz rates with no moving parts and no electricity,
just air. I wrote a kragen-tol post about this in 2002
[http://lists.canonical.org/pipermail/kragen-
tol/2002-April/0...](http://lists.canonical.org/pipermail/kragen-
tol/2002-April/000706.html), when Air Logic still sold actual logic gates that
ran on air, but since then Google Books has archived this June 1967 Popular
Mechanics article, "How They've Taught a Stream of Air to Think":
[http://books.google.com.ar/books?id=jSEDAAAAMBAJ&pg=PA11...](http://books.google.com.ar/books?id=jSEDAAAAMBAJ&pg=PA118&lpg=PA118&dq=taught+air+to+think+fluidics&source=bl&ots=Qt70QlAjgX&sig=axEWaqYpR8KHH76sJ4LOfIRTDoI&hl=es-419&sa=X&ei=evQtT861JomDtge7qoWNBg&ved=0CCYQ6AEwAA#v=onepage&q&f=false),
and of course fluidics has become practically very important for on-chip
microarrays. There's also a Wikipedia article now:
<http://en.wikipedia.org/wiki/Fluidics>

~~~
gjm11
See also: <http://catb.org/jargon/html/G/glitch.html#crunchly73-06-04> and
follow the next-cartoon chain from there. I particularly like
[http://catb.org/jargon/html/N/number-
crunching.html#crunchly...](http://catb.org/jargon/html/N/number-
crunching.html#crunchly74-12-25) .

------
imperator
I'm the one who made that 3D printed Tesla Valve shown in the pictures and
video. I'm currently inventing a jet engine with no moving parts. If anyone
wants to ask questions about the valve's workings or about Tesla, go right
ahead.

~~~
ChuckMcM
Very cool, it would be interesting to build one (large) which would be wave
pumped. You could cast it out of concrete I suspect. The idea being that waves
would push into the end and then the flow back out would be self resisted,
this would allow the wave energy to pump seawater up a bit. Then you provide a
drain which runs through a micro-hydro station.

Would be fascinating to see what rate of wave action you would need to keep
the flow going up hill.

On a pure art level building a pool on the beach that was filled with wave
action like this would be kind of fun.

~~~
akkartik
It's a cool idea, but you might want to just build it with a traditional
valve. I think the Tesla valve relies on _moving_ fluid. If you just submerged
it half way water would leak out in the wrong direction. So it won't work well
for applications in the style of Maxwell's Demon.

~~~
mikeknoop
Not moving water, but the potential for moving water, a pressure gradient.

~~~
seclorum
The kind you get in ocean currents, where such things a self-constructing
Tesla valves are probably out there, somewhere, already ..

------
thusly
My late-night reading currently consists of the book "Wizard: The Life and
Times of Nikola Tesla; Biography of a Genius" by Marc J. Seifer. For anyone
looking to learn more about the man, this seems to be the most comprehensive
biography available. While only half through it so far, it's been an enjoyable
and enlightening read.

The author's occasional dry humour is also quite welcome. Here's a sample:
"Due to his meager funds and general inability to budget himself, Tesla had
but one suit, which had withered from use. It was the time of a religious
festival, and Szigeti inquired what Tesla would be wearing. Stuck for an
answer, the youthful inventor came upon the clever idea of turning his suit
inside out, planning thereby to show up with a seemingly new set of clothes.
All night was spent tailoring and ironing. But when one starts with a wrong
premise, no amount of patching can right the problem. The outfit looked
ridiculous, and Tesla stayed home instead."

~~~
bane
_My late-night reading currently consists of the book "Wizard: The Life and
Times of Nikola Tesla_

I'd recommend "The Prestige" <http://www.imdb.com/title/tt0482571/>

which has a fascinating portrayal of Tesla as a kind of mad techno Wizard
(played by David Bowie of all people).

~~~
thret
The Prestige is complete fiction that merely uses his name because he is
recognisable as a practical genius.

~~~
tomelders
Yeah, but a good film none the less, and for those who know about Tesla, it
was a very pleasant surprise to see him turn up.

Also, in some weird way, having Tesla as the inventor leant an air of
credibility to an other wise ludicrous plot point.

~~~
bane
Right, I thought the idea of Tesla, as a _wizard_ of science among mere
squabbling magicians, a fun plot notion. That they dealt with him, almost
alone and in his secret keep, surrounded by the mysteries of his work, a
wonderful spin on the mythos surrounding Tesla.

It helps that Tesla's personality was bit off in real life, and he did things
that even today we think of as a kind of magic.

Of course in the movie what he built _was_ impossible, but the notion that
"any sufficiently advanced technology is indistinguishable from magic" kept
creeping into my mind.

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megaman821
How Telsa came up with most the things he did are beyond me. I have always
thought he was the smartest man that has ever lived.

~~~
backprojection
I have the feeling that, to an engineer/researcher who is well versed in
fluid-dynamics, this sort of thing wont seem as ingenious - my guess is that
it's at the analogous level of a waveguide.

No doubt that Tesla was a bright person though.

~~~
Arjuna
_"[...] my guess is that it's at the analogous level of a waveguide."_

In the field of fluid dynamics, it is referred to as a _check valve._ [1][2]

[1] <http://en.wikipedia.org/wiki/Check_valve>

[2] [http://www.spiraxsarco.com/resources/steam-engineering-
tutor...](http://www.spiraxsarco.com/resources/steam-engineering-
tutorials/pipeline-ancillaries/check-valves.asp)

~~~
marshray
Well the _function_ of restricting flow in one direction is well known.

But those sources you list describe several types of check valves, all of
which have moving parts.

~~~
Retric
They also work. The Tesla valve allows a fair amount of bleed through, and
unlike valves with moving parts you can't prevent that from stacking them. In
other words it becomes less efficient as the presser differential decreases.

~~~
marshray
That bleed is also a function of viscosity.

There might be some interesting applications for a device that passes two
things, say a fluid and a gas, in one direction and resists the fluid (but not
the gas) in another.

------
stretchwithme
That's pretty cool. The curved side channel actually pushes the main flow into
the next side channel.

I wonder if a fractal version of this would work better. And what if there
were side channels on the top and bottom too.

Of course, this will always pass some fluid. but if you need a complete
shutoff valve, combining it with the tesla valve would allow you to use a
smaller one and makes its failure less traumatic.

~~~
imperator
In regard to a fractal design being more efficient, you have to check out
these topology optimized valves. They are really beautiful and peculiar, and
have many branching channels to optimize their efficiency.
[http://www.senlin41.org/topology-optimization-of-tesla-
type-...](http://www.senlin41.org/topology-optimization-of-tesla-type-
microvalve/)

~~~
stretchwithme
nice. thanks!

------
damoncali
From the comments:

Reminds me of <http://en.wikipedia.org/wiki/Vortex_tube> Another simple yet
fascinating device

~~~
imperator
I find that device fascinating too. That's why I designed the 3D printed Tesla
Valve in the article. Things with no moving parts are amazing. Especially the
esoteric ones that seem forgotten by time because other technologies
progressed ahead of them.

------
meric
Just imagine the day we get cheap 3D printers. We see this article on the
internet on the Tesla Valve and want to try it out ourselves, so we download
the blueprint and send it to our personal printer, which prints a copy of the
Tesla Valve and then we play with it ourselves. I am guessing there are so
many (expired) patents out there that, just like this one, can be converted to
a blue print and everyone would get to experiment with it, instead of only
large companies with enough cash to customise expensive equipment for it.

~~~
imperator
If you are still waiting for that day, you can get the valve 3D printed now
from my shop: <http://www.shapeways.com/model/292339/tesla_valve.html>

And if you already have a 3D printer, you can get the files free here:
<http://www.thingiverse.com/thing:16919>

------
mrstinton
That's very elegant. It's amazing (and a little terrifying) to think that he
may very well have been able to mentally visualize the fluid dynamics to some
extent. It's not like he was consciously solving navier-stokes, but it's still
incredible what some human minds are capable of.

But then, he was thinking a lot about electron flow and built up a good
intuition that had wider application. That doesn't make it any less amazing to
me though. I'd like to be able to do that.

~~~
gcb
a patent is a record of the working device, not the process used to get to it.

thinking of anyone as a supernatural genius is nonsense. most of the time.

~~~
jacquesm
In the case of Da Vinci, Einstein, Tesla and a select number of others I think
that thinking of them that way is well justified.

The general idea is that if the time is ripe for an idea then someone
somewhere will have it, and if that someone would not exist someone else will
have the idea a short while after.

But for the men mentioned above I highly doubt that would be the case, they
were both way ahead of the curve at the time.

------
learc83
From the video it looked like there was still some airflow in the reverse
direction.

~~~
blahedo
Yes, it seems better as a technique to introduce bias to flow than to restrict
it altogether---valve-like, but not exactly a valve. Sufficient for a lot of
valve applications, though, and the lack of moving parts is reeeeeally nice.

~~~
backprojection
Looks like the shape tries to maximize turbulence in one direction, and
minimize it in the other.

Probably it would be an effective mixing device too.

~~~
imperator
The Tesla Valve is a leaky valve, which is why we still use one way valves
with moving parts. The amount of leakage depends on the design of the valve
and how well it suits the incoming fluid. A faster fluid will result in a
different looking valve compared to a slower fluid. The valves design would
also change based on the viscosity of the fluid.

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mikeknoop
Is the unidirectional flow property dependent on the pressure gradient at both
ends? It seems that at low pressure differences you could still get flow in
the reverse direction. Yet, at high pressures I imagine you would see some
leakage, too. Does it only work for medium pressures?

~~~
imperator
In will work in many regimes. In the microfluidic literature, the valve is
judged by its diodicity. Different flow rates, sizes, and viscosity, results
in different geometry for the tesla valve.

------
rbanffy
Does it work with incompressible fluids? Can someone test one with water?

~~~
imperator
Yes. It also works with incompressible flows. I have yet to give mine a test
with water. I want to build an acrylic window for it first, and ink the
incoming water.

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Tycho
Can someone post a link to the desktop version? Site is unreadable on iPad.

~~~
mdonahoe
Scroll down and turn off The mobile version of the Wordpress theme.

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georgieporgie
If you haven't read Tesla's autobiography[1], I highly recommend it.

<http://www.tfcbooks.com/special/my_inventions_index.htm>

[1] I'm a bit confused as to whether it was genuinely an autobiography, or a
compilation of articles. Either way, it was interesting to read, though very
light on technical details.

~~~
acqq
It is a collection of articles for the "Electrical Experimenter" magazine:
<http://en.wikipedia.org/wiki/Electrical_Experimenter> The articles were
written by Tesla and they are autobiographical.

There are also some versions on the internet which include fake sentences
inserted later by some religious zealot mentioning "God, Divine Being." Take
care not to link to those.

