<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Hi Brian.</div><div>The oil would fall out when you surfaced apart from anything else.</div><div>There are a lot of different rolling diaphragms out there.</div><div>If you do an image search on rolling diaphragm neoprene fibre reinforced;</div><div>you will see some of the options. The proffesional units that I have found</div><div>information on, are fibre reinforced neoprene. A boot might do!</div><div>For sizing you would double the volume of the diaphragm to get how</div><div>much oil it would displace through it's full range.</div><div>Looking again at the design; you could buy a diaphragm with a hole in the</div><div>centre &, using a threaded rod, clamp a washer either side with nuts as long</div><div>as it didn't leak at that point.</div><div>The switch is optional, as the rod serves as a level indicator if you mark it.</div><div>Alan</div><div><br><br><div>Sent from my iPad</div></div><div><br>On 22/02/2017, at 3:38 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;"><div>Alan, What happens if you just have the oil exposed to the water? If you turned the container ( compensator) upside down the oil would rise to the top of the container and would not be able to escape to the ocean. Wonder if that would work?</div><div> </div><div>Brian<br><br>--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a> wrote:<br><br>From: Alan James via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>Subject: [PSUBS-MAILIST] Oil Compensator<br>Date: Tue, 21 Feb 2017 10:07:32 +0000 (UTC)<br><br></div><div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><div> Hi Psubbers,</div><div>Hank got me thinking when he built his compensator from a pneumatic cylinder.</div><div> Attached is a design based on how I think the commercial compensators work.</div><div>It seems a great project for a 3D printer. </div><div>The size for a 300ml version would be roughly 10" x 6" (250mm x 150mm) excluding</div><div dir="ltr">the rod. The 10" height would be in 2 sections with the tallest being 6" (thinking of printing height)</div><div dir="ltr"> The rolling diaphragm has a flange that is clamped between the two haves of the body</div><div dir="ltr">& rolls down inside itself as the oil is depleted & it is a mirror image of it's full state.</div><div dir="ltr">It will hit the micro switch to trigger a low oil warning. Also the rod will retract giving an</div><div dir="ltr">external oil level indication. </div><div dir="ltr"> Commercial compensators offer pressure ranges above ambient; for instance 4-8psi.</div><div dir="ltr">This is because the spring has more power in it's compressed state than extended state.</div><div dir="ltr">I think the final design will be dictated by suitable 316 stainless springs & available</div><div dir="ltr">sizes of rolling diaphragms. Haven't found any diaphragms locally but there are heaps</div><div dir="ltr">in China.</div><div dir="ltr">Alan</div><div dir="ltr"><br></div></div>_______________________________________________
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