<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_ym19_1_1487669898351_2973"> Hi Psubbers,</div><div id="yui_3_16_0_ym19_1_1487669898351_2672">Hank got me thinking when he built his compensator from a pneumatic cylinder.</div><div id="yui_3_16_0_ym19_1_1487669898351_2670"> Attached is a design based on how I think the commercial compensators work.</div><div id="yui_3_16_0_ym19_1_1487669898351_2561">It seems a great project for a 3D printer. </div><div id="yui_3_16_0_ym19_1_1487669898351_2560">The size for a 300ml version would be roughly 10" x 6" (250mm x 150mm) excluding</div><div id="yui_3_16_0_ym19_1_1487669898351_2572" dir="ltr">the rod. The 10" height would be in 2 sections with the tallest being 6" (thinking of printing height)</div><div id="yui_3_16_0_ym19_1_1487669898351_2669" dir="ltr"> The rolling diaphragm has a flange that is clamped between the two haves of the body</div><div id="yui_3_16_0_ym19_1_1487669898351_2752" dir="ltr">& rolls down inside itself as the oil is depleted & it is a mirror image of it's full state.</div><div id="yui_3_16_0_ym19_1_1487669898351_2751" dir="ltr">It will hit the micro switch to trigger a low oil warning. Also the rod will retract giving an</div><div id="yui_3_16_0_ym19_1_1487669898351_2739" dir="ltr">external oil level indication. </div><div id="yui_3_16_0_ym19_1_1487669898351_2765" dir="ltr"> Commercial compensators offer pressure ranges above ambient; for instance 4-8psi.</div><div id="yui_3_16_0_ym19_1_1487669898351_2792" dir="ltr">This is because the spring has more power in it's compressed state than extended state.</div><div id="yui_3_16_0_ym19_1_1487669898351_2793" dir="ltr">I think the final design will be dictated by suitable 316 stainless springs & available</div><div id="yui_3_16_0_ym19_1_1487669898351_2853" dir="ltr">sizes of rolling diaphragms. Haven't found any diaphragms locally but there are heaps</div><div id="yui_3_16_0_ym19_1_1487669898351_2854" dir="ltr">in China.</div><div id="yui_3_16_0_ym19_1_1487669898351_3018" dir="ltr">Alan</div><div id="yui_3_16_0_ym19_1_1487669898351_2855" dir="ltr"><br></div></div></body></html>