From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Subject: Re: Silicone gasket material, vacuum chamber
Date: 10 Jul 1998
Newsgroups: rec.crafts.metalworking

On 10 Jul 1998 04:21:02 GMT, "Don Foreman"
<foreman_don@htc.honeywell.com> wrote:

>
>
>Jon Elson <jmelson@artsci.wustl.edu> wrote in article
><35A46219.8CB83613@artsci.wustl.edu>...
>> you
>> must have missed the high school science demo where you put a
>> 1 gal can with a little water in the bottom on the stove.  When it
>> gets to steaming, you cap it tightly and take it off the stove.  The
>> can is crushed like a soda can that's been run over by a truck!
>
>A pretty good boiler engineer at work was quite astonished to discover that
>an ASME-certified air tank, rated at 125 psi pressure, collapsed like it'd
>been stepped on by King Kong when subjected to vacuum.  We're saving the
>wreckage  for his retirement party....



On a larger scale. A state (which shall remain nameless) agency was
working on the problem of fumigating beehives with ethylene oxide to
eliminate "foul brood". At the time the only known cure was to kill
the bees and burn the hives not a desirable solution for the
beekeeper.  Assuming that it was desirable to put the hives in a
vacuum chamber (it was due to ethylene oxide properties) and also
assuming that it was better to take the vacuum chamber to the apiary
rather than the reverse (a no brainer). A smart engineer (state
employee) designed an 8x8x16 sheet metal box on a trailer.

The protocol (state agencies gotta have a protocol) was to kill the
bees, load the hives in the "vacuum chamber", pull a vacuum, and
introduce the ethylene oxide.

Unfortunately they invited a bunch of reporters and commissioners to
see the first application of this ingenious apparatus.

Fifteen psi doesn't seem like very much until you convert it to pounds
per square foot so if they got halfway to a good hard vacuum it comes
out to about 1000 pounds per square foot.The hives were shrink-wrapped
with sheet metal and the project abandoned.