"Ignoramus28190" wrote in message
. ..
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


I wouldn't suggest trying it, especially after reading this post in this NG
from "Steve" in May of 2000:

_____________________________________________

Someone passed the following message to me.
I have no idea who originated it.

Good food for thought !!

------------------
Please share this visual with all of your employees in upcoming meetings. It
is a great reminder that though many of our vessels are pressure-rated, many
will not withstand significant vacuum. A vacuum can be created by simply
draining a vessel without venting, or by steam cleaning and not venting ---
the subsequent condensing of the steam is an extremely strong vacuum. The
hotter or higher pressure of the steam, the stronger vacuum.

Even the condensing of a hot hydrocarbon, with low vapor pressure can have
similar results if the system is not gas/N2 blanketed or equipped with a
vacuum breaker.

The tank car in the linked photo is not one of ours. It is a general
purpose PYGAS car that was being steam cleaned to prepare it for some
maintenance work. The job was still in progress at the end of the shift, so
the employee decided to block it in. Problem was there was no vacuum
relief; the car cooled, the steam condensed and the car imploded."

http://www.metalworking.com/DropBox/...les/VacPwr.txt
http://www.metalworking.com/dropbox/...es/VacPwr1.jpg
http://www.metalworking.com/dropbox/...es/VacPwr2.jpg

_____________________

Note: the links have been "adjusted" to point to the current locations of
the files.

"RAM³" wrote:

"Ignoramus28190" wrote in message
. ..
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


I wouldn't suggest trying it, especially after reading this post in this NG
from "Steve" in May of 2000:

_____________________________________________

Someone passed the following message to me.
I have no idea who originated it.

Good food for thought !!

------------------
Please share this visual with all of your employees in upcoming meetings. It
is a great reminder that though many of our vessels are pressure-rated, many
will not withstand significant vacuum. A vacuum can be created by simply
draining a vessel without venting, or by steam cleaning and not venting ---
the subsequent condensing of the steam is an extremely strong vacuum. The
hotter or higher pressure of the steam, the stronger vacuum.

Even the condensing of a hot hydrocarbon, with low vapor pressure can have
similar results if the system is not gas/N2 blanketed or equipped with a
vacuum breaker.

The tank car in the linked photo is not one of ours. It is a general
purpose PYGAS car that was being steam cleaned to prepare it for some
maintenance work. The job was still in progress at the end of the shift, so
the employee decided to block it in. Problem was there was no vacuum
relief; the car cooled, the steam condensed and the car imploded."

http://www.metalworking.com/DropBox/...les/VacPwr.txt
http://www.metalworking.com/dropbox/...es/VacPwr1.jpg
http://www.metalworking.com/dropbox/...es/VacPwr2.jpg

_____________________

Note: the links have been "adjusted" to point to the current locations of
the files.

That reminds me of the science experiment we did in junior high school
many years ago.

Take a metal 1 gallon can like what acetone comes in. Put a little
water in the bottom of it and then heat it up till it is boiling.
Take it off the heat and quickly put the cap on it. The can will slowly
start to be crushed by the atmospheric pressure when the steam
condenses.

It looks like an invisible hand is squeezing it into a ball.


John