Recently I bought a tube of three tennis balls, and much to my surprise, they were vacuum-sealed. [Managed to cut my
finger on the sharp edge of the lid, as well. LAWSUIT! :D]
Anyhoo, I just figured someone here might know why they vacuum-seal tennis balls. Is it to keep the rubber from
drying out? That’d be my guess but I’d like to be sure.
The first return on entering “Vacuum tennis balls” is: http://van.hep.uiuc.edu/van/qa/section/Cool_stuff_about_Air/Pressure/908135162.htm
I’m sorry that I don’t know the coding to make that cleaner.
I believe that is all.
Tretorn used to package 4 tennis balls in a box that were not air pressured. They were harder and lasted a pretty good time without any air pressure. I don’t know how they did it, but you may want to search under Tretorn. I don’t know if they still exist.
There is sold a little tube in which you can stick the balls into after you’ve open the tennis can, and then pressurize it by turning a screw or some such gizmo. I have an older version in which the balls sit in little cubby holes in a round gizmo and the top is tightened with a turnscrew. It helps a little, not much.
They’re not actually vacuum-sealed, they’re pressure-sealed: The air in the canister is at a higher pressure than outside, not lower. Apparently, many or most tennis balls have slow leaks (if “leak” is the right word; I think it’s an osmotic process), but if you keep their environment pressurized to the same level as the interior, there’s no problem.