<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_ym18_1_1458793494416_4233"> This is my latest brushless thruster design for scrutiny.</div><div id="yui_3_16_0_ym18_1_1458793494416_4199">The last thruster I made was 2 piece with one seal.</div><div id="yui_3_16_0_ym18_1_1458793494416_4332">I machined the last version out of aluminum rod, which was expensive & difficult.</div><div id="yui_3_16_0_ym18_1_1458793494416_4331">The end pieces in this design are from solid rod but the mid section is from a stock tube</div><div id="yui_3_16_0_ym18_1_1458793494416_4371" dir="ltr">that I intend to have welded to the propeller end. The back end is bolted on.</div><div id="yui_3_16_0_ym18_1_1458793494416_4334" dir="ltr">Am I likely to get distortion when welding the two sections together? There is a sleeve</div><div id="yui_3_16_0_ym18_1_1458793494416_4333" dir="ltr">press fitting to help give it some rigidity for welding. Should I make a jig to clamp it in</div><div id="yui_3_16_0_ym18_1_1458793494416_4367" dir="ltr">for welding?</div><div id="yui_3_16_0_ym18_1_1458793494416_4372" dir="ltr">The thruster is for 500ft depth & is oil filled with a slight over pressure above ambient. </div><div id="yui_3_16_0_ym18_1_1458793494416_4490" dir="ltr">Oil filled mainly for cooling purposes, but also as a secondary defense against any leaks,</div><div id="yui_3_16_0_ym18_1_1458793494416_4555" dir="ltr">& for lubrication of bearings & seals. I am using low pressure lip seals & have a double </div><div id="yui_3_16_0_ym18_1_1458793494416_4565" dir="ltr">seal redundant arrangement. The outboard seal is orientated to keep the oil in & with the</div><div id="yui_3_16_0_ym18_1_1458793494416_4612" dir="ltr">internal overpressure should keep the water out. The outboard seal should fail first as it is </div><div id="yui_3_16_0_ym18_1_1458793494416_5135" dir="ltr">exposed to abrasives, especially in sea water. The inboard seal is oriented so that it keeps</div><div id="yui_3_16_0_ym18_1_1458793494416_5246" dir="ltr">any water out that may get past the outboard seal. </div><div id="yui_3_16_0_ym18_1_1458793494416_5265" dir="ltr">The tube coming out of the seal cavity is for pressurizing it & for collecting any water that</div><div id="yui_3_16_0_ym18_1_1458793494416_5247" dir="ltr">may get through & come out of suspension. I am thinking of putting a water sensor in there.</div><div id="yui_3_16_0_ym18_1_1458793494416_5383" dir="ltr">Any comments welcome.</div><div id="yui_3_16_0_ym18_1_1458793494416_5384" dir="ltr">Alan</div><div id="yui_3_16_0_ym18_1_1458793494416_5281" dir="ltr">p.s. if image isn't big enough keep hitting ctrl & + TO ENLARGE.</div><div id="yui_3_16_0_ym18_1_1458793494416_5112" dir="ltr"><div id="yui_3_16_0_ym18_1_1458793494416_5539"><br></div><div id="yui_3_16_0_ym18_1_1458793494416_5494" style="display: block;" itemtype="http://schema.org/ImageObject" itemscope=""><div class="yahoo-compose-assist-image-card ymail-preserve-class" id="yui_3_16_0_ym18_1_1458793494416_5541" style="width: 100%;" contenteditable="false"><div id="yui_3_16_0_ym18_1_1458793494416_5540"><img id="yui_3_16_0_ym18_1_1458793494416_5551" style="width: 100%; vertical-align: middle; max-height: 406px; max-width: 800px;" alt="motor cut away.jpg" src="cid:ZLxW1HuHGVrkxa5OaO8l" data-id="bcc25cf9-82f7-3373-115b-63c9939ad5e6" itemprop="contentUrl"></div></div></div><div id="yui_3_16_0_ym18_1_1458793494416_5542"><br></div></div></div></body></html>