What is the maximum extent of Vacuum that can be acheived inside a closed container ?

Question

Usual vacuum obtained inside a closed airtight container is 760 mm of Hg or 29 t0 30 inches... Can we increase this..ie., numerically reduce this value ?

Answer 1

You can indeed, by using a turbomolecular pump you can achieve a vacuum down to 6e-10 milibar.



Have a look at BOC Edwards Vacuum division.

Answer 2

Maximum extent would be simply zero absolute pressure.



29 - 30 inches of vacuum is merely the measure of the surrounding atmospheric pressure.



An interesting thought experiment involves submerging a very long test tube into a container of mercury until it is completely filled. When you lift the closed end of the tube out of the mercury straight up - the mercury will fill the tube to approx. 29 inches high - if you continue to lift the tube, to any height, the mercury will remain at 29" - yet the closed space above it will continue to increase in volume. This space increases in volume without the addition of anything - it is simply nothing, which is expanding - yet the mercury is only pushed up as much as the pressure exerted on it by the atmosphere.

Once this absolute pressure is zero, it is a good analogy to compare it to absolute zero - you simply can't extract any more heat energy from absolute zero - the same as you can't extract anymore pressure from essentially nothing.

Remember, it's a thought experiment - in reality, neither a perfect vacuum nor absolute zero can be achieved.



Added Note: "Above the column, the (absolute) pressure is the vapor pressure of mercury, 1.2 x 10-3 mm Hg, so small that it does not have to be considered."



Source: Handbook of Chemistry and Physics 56th Edition

Answer 3

Wrote a story about this as a kid! My answer is pretty much the same. If I wouldn't get arrested for trespassing and other things... I'd be roller blading. Best believe I'd set up a ping pong table too. Or a ball and a paddle to whack a ball with whilst roller blading. But didn't you know Walmart never closes? :D

Answer 4

I think you are confusing atmospheric pressure which is normally 29.92 inches or about 760 mm. If we remove all the air from a box you get what there is in space, which is 0.

Answer 5

Yes, with specialized equipment. There are some vacuum pumps capable of very high vacuum indeed.

Answer 6

yeah, there are vacuums that 10-12 mbar and below. extreme high vacuum that simulate space in a closed container. they are used to test space equipment while on earth.

Answer 7

absolute vacuum is not possible. subject to the material of construction of the container as well as its geometry. That is the container should not collapse when vac is produced.

Answer 8

nothing is emptier than empty. A total vacuum does not have anything in it thus you can not suck atything out.

Answer 9

minor correction - if you do the mercury trick, the "empty space" above 29" will be filled with mercury vapor :)