----- Original Message -----
Sent: Wednesday, November 19, 2003 7:36
PM
Subject: Re: [PSUBS-MAILIST] O rings and
pressure
Brian,
Here is a dumb answer! lol
Handbooks like the Machinery's Hanbook give some information
on ring grooves. A lot of o-ring manufacturers websites also give their
reccomended dimmensions. These are critical and so is the surface finish.
Depending on what your shaft is going thru, it is generally easier to
have the o-ring and its groove on the shaft and leave the thru bore smooth,
just make sure the remaining material on the shaft is adequate for the applied
torque and make sure there is some sort of a restraint so the rod
can't be pushed into the sub. I would not use a regulator
you might need more pressure at some point. Make use of the valve on the HP
tank and route it to a ballasting valve with a pressure gauge. Make sure
your piping can handle the pressure. No need to worry about freezing, the flow
to blow doen't take very long.
Adam
Hi, I have a dumb question, I just machined my first
sub part, sort of a test part, a thru hull piece that will have a shaft
going thru it to turn a valve from the inside of the sub to the out
side. I machined an inside groove for an "o" ring, now are
there recomended specs for this "o" ring ? Like so many
thousandths thickness etc.. and should the shaft be
notched as well?
Second dumb Question: Is all of your air pressure comming
off the high pressure cylinders (2000 psi) always dropped down to a
lower pressure (200 psi) with a regulator before it is used to blow
out a ballast tank? Is that high pressure too high to use for that
(possiblly freezing up lines?)
Brian Cox