Re: [PSUBS-MAILIST] O ring groves

["Alan James" <alanjames@xtra.co.nz>]

Thanks for all the good advice,

I downloaded the Parker Handbook (292 pages of it)

On page 100 it has half dovetail grooves.

It doesn't seem to state what direction the force is coming from.

I'm guessing that the force would be coming from the dovetail side

& pushing the O ring into the vertical side of the grove as this would be

kinder on the o ring. This would be the opposite of the K250 design wich

doesn't have so close a tolerance to hold the o ring under the dovetailed grove.

This grove on the outer side is how Jim has just explained he has his grove set up.

The handbook also states that the design assumes metal to metal contact.

Is this what we are trying to achieve?

Is the K350 design the same as the 250?

Thanks

Alan 

 

----- Original Message -----

From: ShellyDalg@aol.com

To: personal_submersibles@psubs.org

Sent: Wednesday, August 18, 2010 6:31 AM

Subject: Re: [PSUBS-MAILIST] O ring groves

All good advice. I used the Parker book but used a "straight" gland ( =groove ).

I recommend the dovetail groove. My "O" ring can slip out if disturbed.

There are a couple of other important aspects to the groove like the bottom corners being rounded.

Dimensions and tolerances are given for each application. 

The Parker book recommends no more than a 5 degree "dovetail".

It's a great book with pictures, graphs, and charts for the many different applications and sizes. Easy to understand. It's free to download.

Also has a section on the different types of material used in the making of "O" rings.

Definitely worth the effort to print and save in your files.

Frank D.