On Sat, 04 Feb 2006 20:38:30 GMT, Ignoramus28190
wrote:

Can a typical "125 PSI air tank" be used as a "buffer" of vacuum? I
have some applications in mind like desoldering, where I would use
vacuum intermittently, and it would be nice to use a tank to "store"
vacuum. I was thinking about a use of an air tank. Not sure if regular
portable air tanks can be used for vacuum, but my own feeling is that
they should be OK. Just wanted to double check. Thanks

i

In general, no. I have personally seen an ASME-rated small air tank
(portable, probably 5 or 10 gallon) collapsed by pulling a vacuum in
it.

Hi,

Obviously it will depend on the design of the tank, and I'm not sure
what these portable air tanks are like, so take Don's word here. The
risk is that the walls of the tank will buckle under compression - it's
much easier to buckle a metal sheet than it is to pull it apart in
tension. You could look at small propane cylinders instead. I am pretty
sure the smallest propane cylinders we have in England would be strong
enough to take a vacuum. And if you don't mind destroying an air tank,
you could try it. The energy storage wouldn't be huge, the steel
wouldn't shatter, it would collapse slowly, and any bits would go
inwards, so I think it would be a reasonably safe thing to try. Just
pump it down slowly with a pump which can pull a good vacuum. It might
be that you don't need a really good vacuum in your de-soldering
application, anyway.

Best wishes,

Chris