Sorry I didn't get to this sooner (my
year end finals start Monday)....
You want the edge to be proud enough to keep the O-ring from
catching on the lip, but also such that there is room to give the
O-ring a good squeeze. (they don't need to meet, but they will as
you pump down anyway)
If you feel the need, and have a lathe or mill big enough then a
groove to secure the O-ring won't go astray, but I have a bell jar
(16" ID x 25" tall) that has the lip ~3/8" high before the flange,
I use a 1/2" thick viton O-ring, I tighten down till I can
anymore, but after pump down the lock downs are all lightly loose
anyway.
Thomas.
On 21/10/2012 4:32 AM, Russ Thornton wrote:
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?
Thomas,
Another question occurred to me. ?Do
you design the O-ring size and proudness of the
wall(s) so that there is a gap between the top and
bottom wall or do you?squeeze?the flanges until the wall edges touch?
Thanks,
Russ
