Re: [PSUBS-MAILIST] O rings and pressure

["Adam Lawrence" <adteleka@in-tch.com>]

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