hi
was talking with my brother the other week.
he sells a few things at a small business he has.
one of them is pressure cookers.
he has some that can cook under 15psi of pressure.
so i had an idea and looked up some things, at sea level your average pressure is about 14.7 PSI where space is 0 PSI.
so if can handle 15 PSI more than sea level without failing, should be able to go other way to - 15psi, or 0 PSI.
already has a small outlet for releasing pressure with a weight put on it, and it will release a little and hover around 15 PSI.
and has a pressure gauge already fitted.
so thought could take off the standard gauge for a vacuum gauge drill some holes for spark plugs for electrical through put.
will attach a small drawing of idea.
let me know what you guys think.
(http://i1078.photobucket.com/albums/w482/Steven_Whittam/IMG_0773.jpg)
Rather than holding back pressure from the inside which tends to separate the seals, vacuum will compress the seals. So yes, it should easily hold a vacuum.