<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Brian,</div><div>there is this military de-classified 1972 document on pressure compensating.</div><div><a href="https://apps.dtic.mil/dtic/tr/fulltext/u2/894795.pdf">https://apps.dtic.mil/dtic/tr/fulltext/u2/894795.pdf</a></div><div>I printed it out & had it bound.</div><div>I found that the rotation of the motor was throwing the oil out of the motor</div><div>housing & up in to the compensating tube. If you dived there would be added</div><div>pressure to keep the oil in the motor housing, but this wouldn't happen transiting</div><div>on the surface. As the oil also keeps the Motor cool, there may be a danger of</div><div>the motor overheating in this instance.</div><div>As you will find in the linked manual, a minimum of 5psi over pressure is the norm.</div><div>I am going to use the same system as Cliff, with the relieving regulator dialled</div><div>up to 5psi to give an overpressure. However my system has oil in it so I get it's </div><div>cooling advantages & eliminate large air volume changes.</div><div>Alan</div><div><br>On 25/03/2020, at 11:19 AM, Brian Cox via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div style="font-family:Arial, sans-serif; font-size:10pt;"><font size="2">Seawater gets compressed up the hose, so never goes above the highest point of the hose. When oil heats up it spills into trap and cannot escape to the sea. </font><div><font size="2"><br></font></div><div><font size="2">Brian</font></div><div><font size="2"><br></font><br><span style="font-size: 10pt;">--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a> wrote:</span><br><br><span style="font-size: 10pt;">From: Øystein Skarholm via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span><br><span style="font-size: 10pt;">To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span><br><span style="font-size: 10pt;">Subject: Re: [PSUBS-MAILIST] motor oil compensator</span><br><span style="font-size: 10pt;">Date: Tue, 24 Mar 2020 22:21:15 +0100</span><br><br><div dir="ltr" style="font-size: 10pt;">You should avoid contact between the seawater and the oil. The oil will contaminate quickly and it will no longer be dielectric. <div>Just the hose from the motor to the tee is enough to compensate. You do not have to have a large volume of oil. Fill the hose with oil and cap it off, done. or make a neat yet more sophisticated solution. </div><div>Make the end lid of the motor as a flange assembly and instead of a lid, use a rubber diaphragm. This will then act as a compensator. You can even install a light spring pushing down on the diaphragm if you want a slight internal overpressure. </div><div><div><image.png><br></div></div></div><br><div style="font-size: 10pt;"><div dir="ltr">tir. 24. mar. 2020 kl. 21:28 skrev Brian Cox via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>:<br></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="font-family:Arial,sans-serif;font-size:10pt"><font size="2">Here is a drawing for my oil compensator</font><div><font size="2"><br></font></div><div><font size="2"><br></font></div></div>_______________________________________________<br>
Personal_Submersibles mailing list<br>
<a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>
</blockquote></div><br><div style="font-size: 10pt;"><br></div><span style="font-size: 10pt;">-- </span><br><div dir="ltr" style="font-size: 10pt;"><div dir="ltr"><div>Vennlig hilsen<br>Øystein Skarholm</div><div>91369599</div></div></div><span style="font-size: 10pt;">
--000000000000a6cb3105a1a055ba--_______________________________________________
Personal_Submersibles mailing list
</span><a href="/eonapps/ft/wm/page/compose?send_to=Personal_Submersibles%40psubs.org" style="font-size: 10pt;">Personal_Submersibles@psubs.org</a>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" style="font-size: 10pt;">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a>
</div></div></div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>Personal_Submersibles mailing list</span><br><span><a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br><span><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br></div></blockquote></body></html>