From meed@mbari.org Wed Mar 3 10:33 PST 1993 Received: from hp850.mbari.org by otter.mbari.org with SMTP (16.6/15.6) id AA04003; Wed, 3 Mar 93 10:33:38 -0800 Return-Path: Received: by hp850.mbari.org (15.11/15.6) id AA21178; Wed, 3 Mar 93 10:30:35 pst Received: by hp850.mbari.org (15.11/15.6) id AA21174; Wed, 3 Mar 93 10:30:30 pst From: Ed Mellinger Subject: Re: vacuum To: kiwi@hp850.mbari.org (William Kirkwood) Date: Wed, 3 Mar 93 10:30:29 PST Cc: meed@hp850.mbari.org (Ed Mellinger) In-Reply-To: from "William Kirkwood" at Mar 3, 93 10:07 am Mailer: Elm [revision: 66.25] Status: RO Hi Bill - No problemo senor. The hard vacuum (0 psia) is only a temporary condition, however the vapor pressure of FC-72 is only about 4 psia at room temperature, and only rises to 15 psia (1 atm) at about 60 C. So all the various seals and things will see pretty strong negative pressure whenever the vehicle is off, i.e. most of the time. I guess this might be kind of a nasty regime to try to seal against... low, alternating, positive and negative pressure? I suppose there's a modest chance we could avoid the positive pressure condition by keeping the tube walls (i.e. condenser surface) cool enough. But I'd be hard pressed to say in practical terms how cool that means, or what we might have to supply in the way of on-deck cooling to the power can. -Ed