Modern Tube computing

From: John Lawson <>
Date: Tue Jan 20 20:22:35 2004

On Tue, 20 Jan 2004, R. D. Davis wrote:

> Quothe Rob O'Donnell, from writings of Wed, Jan 21, 2004 at 01:51:45AM +0000:
> > >My preference is for a digital computer using water instead of
> > >electricity, but no one's mentioned one of those yet.
> >
> > Even sillier...
> That was not a "silly" idea; it was a serious idea, and I don't see why
> it isn't possible. It could have some very practical applications.

  One might suppose you folks have not heard of "fluidic logic"? I saw an
entire digital control system for a rocket-fuel blender/loader that used
compressed air as it's working medium.

  Fluidics was a 'fad' in the late 50s, but fell out of favor due to the
precision involved in making the modules, and the fact that the tiniest
particle of dirt would cause a failure.

  These devices work on aerodynamic principles - Bernoulli effects - and
boundary layer physics. For example, the flip/flop module used an internal
airfoil to guide a stream of incoming air through one of two adjacent
channels. The device was 'set' or 'reset' with a transverse stream
impingeing on the incoming 'main' stream, diverting it to the opposite
channel, where, due to capillary action and the boundary layer laws, it
stayed until it was set to the complement by another "puff" from the other
port. Bleed holes, or venturis, were then used to sense the direction of

  These were generally made of Plexiglass (Perspex) and were quite
beautiful to look at... like a bunch of square prismatic blocks nestled in
a forest of black rubber tubing.

 And this system would work on water as well, just the dimensions would
have to be altered to compensate for the different phsycal characteristics
of the working fluid.


Received on Tue Jan 20 2004 - 20:22:35 GMT

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