<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px"><div><span></span></div><div dir="ltr" id="yui_3_16_0_ym19_1_1487329442592_5786">Alan,</div><div dir="ltr" id="yui_3_16_0_ym19_1_1487329442592_5786">I didn't wast a cylinder, I made a compensator for under 40 dollars. The whole project took about an hr including making a bracket to hold the compensator in place. </div><div dir="ltr" id="yui_3_16_0_ym19_1_1487329442592_5673">The most time consuming part was filling it with oil. That was easy also because the motors have two ports, one for filling and connecting the hose and one for venting air. </div><div dir="ltr" id="yui_3_16_0_ym19_1_1487329442592_5673">Hank</div> <div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"><font size="2" face="Arial"> On Thursday, February 16, 2017 7:34 PM, Alan James via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br></font></div> <br><br> <div class="y_msg_container"><div id="yiv7378056102"><div><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"><div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2805"><span>Hank,</span></div><div dir="ltr" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2812"><span id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2811">why waste a good pneumatic cylinder when you can have</span></div><div dir="ltr" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2807"><span id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2806">one of these. (sauce syringe) All you need is a stainless spring to put inside it for</span></div><div dir="ltr" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2810"><span id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2809">overpressure, a compatible hose fitting, & maybe replace the piston</span></div><div dir="ltr" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2808"><span id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2827">o-ring. I have only seen them up to 100ml in volume & aren't sure whether </span></div><div dir="ltr"><span>that would be enough.</span></div><div dir="ltr" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2820"><span>Alan</span></div><div class="yiv7378056102qtdSeparateBR" dir="ltr" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2819"><img id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2829" alt="Image result for sauce syringe 100ml" src="http://i.ebayimg.com/images/i/251310920781-0-1/s-l1000.jpg"><br clear="none"><br clear="none"></div><div class="yiv7378056102yahoo_quoted" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2759" style="display:block;"> <div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2758" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2757" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div class="yiv7378056102yqt8700940842" id="yiv7378056102yqt50632"><div dir="ltr"> <font face="Arial" size="2"> </font><hr size="1"> <b><span style="font-weight:bold;">From:</span></b> hank pronk via Personal_Submersibles <personal_submersibles@psubs.org><br clear="none"> <b><span style="font-weight:bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br clear="none"> <b><span style="font-weight:bold;">Sent:</span></b> Thursday, February 16, 2017 1:25 PM<br clear="none"> <b><span style="font-weight:bold;">Subject:</span></b> Re: [PSUBS-MAILIST] thruster compensation<br clear="none"> </div> <div class="yiv7378056102y_msg_container" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2756"><br clear="none"><div id="yiv7378056102"><div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2755"><div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2754" style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;background-color:rgb(255, 255, 255);"><div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2760"><span>Alan,</span></div><div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2753"><span>The port is open to the water and acts on the piston directly.</span></div><div id="yiv7378056102yui_3_16_0_ym19_1_1487204576291_11080"><span>Hank</span></div> <div class="yiv7378056102qtdSeparateBR"><br clear="none"><br clear="none"></div><div class="yiv7378056102yahoo_quoted" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2801" style="display:block;"> <div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2800" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;"> <div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2799" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div class="yiv7378056102yqt2104983558" id="yiv7378056102yqt35563"><div dir="ltr"><font face="Arial" size="2"> On Wednesday, February 15, 2017 3:44 PM, Alan via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br clear="none"></font></div> <br clear="none"><br clear="none"> <div class="yiv7378056102y_msg_container" id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2798"><div id="yiv7378056102"><div id="yiv7378056102yui_3_16_0_ym19_1_1487298503108_2797"><div>Hank,</div><div id="yiv7378056102AppleMailSignature">in hindsight there is a problem in that when the external water pressure</div><div id="yiv7378056102AppleMailSignature">pushes on the rod & tries to make the piston move down the cylinder</div><div id="yiv7378056102AppleMailSignature">there is a vacuum created behind the cylinder that needs filling with oil.</div><div id="yiv7378056102AppleMailSignature">Not sure if that's the right terminology.</div><div id="yiv7378056102AppleMailSignature">If water can move in to that void through one of the ports, it would work. </div><div id="yiv7378056102AppleMailSignature">Or the rod & piston were the same diameter. You may have already thought </div><div id="yiv7378056102AppleMailSignature">through this. I encountered this when trying to compensate linear actuators.</div><div id="yiv7378056102AppleMailSignature">Alan<br clear="none"><br clear="none">Sent from my iPad</div><div class="yiv7378056102yqt4490275195" id="yiv7378056102yqt60160"><div><br clear="none">On 16/02/2017, at 11:25 AM, hank pronk via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote type="cite"><div><div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;background-color:rgb(255, 255, 255);"><div id="yiv7378056102yui_3_16_0_ym19_1_1487196591451_9111"><span>Brian,</span></div><div id="yiv7378056102yui_3_16_0_ym19_1_1487196591451_9111"><span><br clear="none"></span></div><div id="yiv7378056102yui_3_16_0_ym19_1_1487196591451_9111"><span>The piston is mid way.</span></div><div id="yiv7378056102yui_3_16_0_ym19_1_1487196591451_9111"><span>Alan,</span></div><div dir="ltr" id="yiv7378056102yui_3_16_0_ym19_1_1487196591451_9111"><span>I was going to install an internal spring to create internal pressure but I only have one seal oriented to keep oil in. I will try this first and see where it leads.</span></div><div dir="ltr" id="yiv7378056102yui_3_16_0_ym19_1_1487196591451_9111"><span id="yiv7378056102yui_3_16_0_ym19_1_1487196591451_9285">I have tried this in the past on Gamma's prop shaft and it did not work- I am sure it is because of the seal orientation.</span></div><div dir="ltr" id="yiv7378056102yui_3_16_0_ym19_1_1487196591451_9111"><span>Hank</span></div> <div class="yiv7378056102qtdSeparateBR"><br clear="none"><br clear="none"></div><div class="yiv7378056102yahoo_quoted" style="display:block;"> <div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;"> <div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div dir="ltr"><font face="Arial" size="2"> On Wednesday, February 15, 2017 3:21 PM, Brian Cox via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br clear="none"></font></div> <br clear="none"><br clear="none"> <div class="yiv7378056102y_msg_container"><div id="yiv7378056102"><div><div style="font-family:Arial, sans-serif;font-size:10pt;"><div>Hank, where is the piston situated in the cylinder upon start up of operation ? Half way ?</div><div> </div><div>Brian<br clear="none"><br clear="none">--- <a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a> wrote:<br clear="none"><br clear="none">From: hank pronk via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none">To: Personal Submersibles General Discussion <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none">Subject: [PSUBS-MAILIST] thruster compensation<br clear="none">Date: Wed, 15 Feb 2017 21:32:47 +0000 (UTC)<br clear="none"><br clear="none"></div><div class="yiv7378056102yqt2109697325" id="yiv7378056102yqt98587"><div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;background-color:rgb(255, 255, 255);"><div dir="ltr">I have just installed my two additional motors on Gamma that are mounted to the manipulator assembly borrowed from Elementary 3,000. To compensate them I used a single air cylinder 1.5 in bore with 4 in stroke as the compensation bladder. The cylinder is filled with light hydraulic oil and the motors are filled with WD40. There are hydraulic hoses connecting the cylinder to the two motors. I reversed one seal in each motor so the one seal keeps water out and one seal keeps oil in. There is a tiny bit of air in the system but that makes no difference because the cylinder piston has enough travel to compress the air. I think oil enters compensated motors because the oil spinning creates pressure from centrifugal force and the seals are oriented to keep water out. The oil can then escape, that is why I have turned one seal around. I will be testing in a month or so, and we will see, I guess.</div><div dir="ltr">Hank</div></div></div>_______________________________________________
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