RE: [PSUBS-MAILIST] Double O-Ring On A Hatch

[Brent Hartwig <brenthartwig@hotmail.com>]

Greetings Cliff,
 
Thank you for the good link. The first couple of drawings on the page showing the O-ring cross section being compressed, have some problems when compared to a sub hatch O-ring and groove. First the groove would need to be a little narrower then the O-ring cross section to hold the O-ring in place when the hatch is open. Then there would also be more distortion on the top and bottom of the O-ring when the hatch flange is pressing down on it.
 
In regards to spliced O-rings, I would also like to acquire standard sized O-rings when possible. But for very custom O-ring sizes like might of been needed for Krakas and the Euronauts engine room hull flanges one might need a spliced O-ring. I installed a large spliced O-ring in a hyperbaric chamber door that was spliced. I was told the splice is cut at an angle with a special cutter and then glued with a very good glue that is stronger then the O-ring material or the same as. 
 
The larger cross section O-ring I used on the hyperbaric chamber had a lower durometer reading then most smaller cross section O-rings used on subs. But I would suspect the larger cross section O-rings used on Kraka and Euronaut have a low durameter reading as well, to help seal the flanges easier if there are imperfections in a large flange, like I had on my chamber door. Also a larger cross section O-rings will give you more distance of travel between the flange surfaces before the flanges bottom out when comparing O-rings with the same hardness and/or type of material.
 

Regards,

Brent Hartwig

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Date: Wed, 8 Aug 2007 19:39:56 -0700
From: cliffordredus@sbcglobal.net
Subject: Re: [PSUBS-MAILIST] Double O-Ring On A Hatch
To: personal_submersibles@psubs.org

Brent,

 

 

I concur with Vance, Carsten and Peter ..., a single o-ring with the correct hardness is the way to go.  See technical note http://www.satoriseal.com/Technical/introduction_to_o-rings.htm on how o-ring is design to move within it's machined grove under pressure to seal.  Hatch upper and lower faces need land face to face.    If you are designing a hatch, pick a standard size so that you do not have to introduce a splice.

 

Cliff
 

Great works are performed not by strength but by perseverance.
Samuel Johnson

----- Original Message ----
From: Brent Hartwig <brenthartwig@hotmail.com>
To: PSUBSorg <personal_submersibles@psubs.org>
Sent: Tuesday, August 7, 2007 11:31:47 PM
Subject: [PSUBS-MAILIST] Double O-Ring On A Hatch

 
I finally found a double o-ring on a sub hatch. The sub on ebay right now called the Great Lake's Submarine mentioned earlier, has one. Here is the picture.
 
http://www.frappr.com/?a=viewphoto&id=4001713&pid=7375620

Regards,
Brent Hartwig