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From: hamish@mate.sybase.com (Just Another Deckchair on the Titanic)
Newsgroups: comp.arch,comp.misc
Subject: Re: Pneumatic computers (yes, air-pressure powered)
Keywords: Van Alyn,ancient
Message-ID: <13023@sybase.sybase.com>
Date: 28 May 91 18:36:53 GMT
Article-I.D.: sybase.13023
References: <1991May24.231620.15367@digi.lonestar.org>
Sender: news@Sybase.COM
Organization: Sybase Inc, Emeryville CA USA
Lines: 30

In article <1991May24.231620.15367@digi.lonestar.org> crichmon@digi.lonestar.org (Charles Richmond) writes:
>Fifteen or so years ago I heard that in the '60's there were
>computers constructed that ran from air pressure.  No electronics,
>just air pressure.  [...]
>
>Does anybody know about this?  Are any such computers in
>existence today?  (Hey, even if you only HEARD about it, that
>would indicate that I did not dream it . . .)

Sure - pneumatic logic (including a whole array of "gates" and logical units)
used to be (still is?) common in situations where *any* RF or current can cause
problems - oil refineries, for example.

The refinery I worked at (as a process control engineer) used a central
pneumatic "computer", itself controlled by remote Numalogic PLCs and
LSI-11s, to control remote valves with long runs of compressed air
(Nitrogen?  Probably something less encouraging to fire than air...).
The remote valves were invariably in places were the slightest
possibility of a spark had to be ruled out.

The "computer" was a giant board with a lot of transparent tubing going
into mechanical gates that looked like, well, water taps (faucets for
Americans) with rather precise plumbing fixtures implementing the
logic. The PLCs controlled an monitored these gates with position
sensors, etc.  A lot of fun....

	Hamish
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Hamish Reid           Sybase Inc, 6475 Christie Ave, Emeryville CA 94608 USA
+1 415 596-3917       hamish@sybase.com       ...!{mtxinu,sun}!sybase!hamish