Fill
the box with steam, and then freeze it?
Theory says that should get you to 6 millibars (0.6 kilopascals).
Brian -- If he has a 5 liter box at a 1,013.25 millibars, and he wants
to
get to 10 millibars, wouldn't he need to attach a completely empty
511.625
liter vacuum chamber to it in order to get both the box and the
vacuum
chamber to equalize at 10 millibars?
Finding and evacuating a 136 gallon vacuum chamber (or larger if he can
only
evacuate it to a few millibars) might not be all that cheap.
If freezing it is difficult where there is no electricity, perhaps
filling the box
with molten lead, and then emptying it through a 3 foot pipe in the
bottom
might work. The weight of the molten lead would leave a vacuum as it
poured
out into a holding basin, much like the original mercury barometers.
Lead/tin
solder could also be used, to get a lower melting point, but he would
need
a longer pipe, since the density is 8.79 instead of leads 11.34.
5 liters of solder weighs a little under 100 pounds. At $6 per pound for
80/20
lead/tin solder, that's $600.00.
He could get a cheap vacuum pump like the ones they use to reclaim
Freon
from car air conditioners for about $100, and an inverter for a car for
about
$20 (to convert the car's 12 volts DC into 120 volts AC). It might take
all day
for the pump to do the job, but it's cheaper than lead.
;-)
-----
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On Mon, Jun 6, 2011 at 3:14 PM, brian whatcott
<betwys1@...>
wrote:
?
On 6/6/2011 5:55 AM, slavkok wrote:
>
Hello...
>
> I need to make vacuum in range 5 to 10 mBar. What
device to use for that. I need to evacuate aprox 5 litre box but I do not
have electricity on place where I need to do that. What options I
have?
>
> Thanks
Prepare bottles of vacuum. transfer
them to container, on site? :-)
Brian W
Christopher Erickson