<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Hank,</div><div>I am using a combination. </div><div>Am having a click style paediatric flow regulator set at a flow level below</div><div>my requirements but at a level I could survive on ( as per DW) but topping</div><div>up with a rebreather solenoid valve that opens based on readings from</div><div>Three O2 sensors. A piece of electronics reads the O2 level from the three O2 </div><div>sensors & takes the average of the two with the nearest readings to each other as true.</div><div>This system will pick up when one O2 sensor is faulty.</div><div>When I saw the Triton 3000 years ago, the pilot told me they just adjusted the O2</div><div>flow from a needle valve. I could have this wrong but I did ask specifically about it.</div><div>Mind you they have a big cabin & would have lots of time to make changes.</div><div>Alan</div><div><br>On 25/05/2020, at 10:18 AM, hank pronk via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div class="ydpe64e1c6ayahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div></div>
<div dir="ltr" data-setdir="false">Alan, The problem with your scenario is there is a preset amount of O2 flowing all the time, so the altimeter would detect an air leak. Unless the air leak was identical to the lack of O2. BUT, I am not adding a bellows add because I got some good advice from a saturation dive operator in South Africa. I am going with exactly what you recommend and just pulled one out of storage. A regulator with a flow meter on it. This is much better than a paediatric regulator with set points. </div><div dir="ltr" data-setdir="false">Hank</div><div><br></div>
</div><div id="yahoo_quoted_0513305718" class="yahoo_quoted">
<div style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:13px;color:#26282a;">
<div>
On Sunday, May 24, 2020, 2:37:16 PM MDT, Alan via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:
</div>
<div><br></div>
<div><br></div>
<div><div id="yiv9469130512"><div><div></div><div>Hank,</div><div>the altimeter wouldn't help in the case of an air leak, as you could have the scenario</div><div>where the scrubber takes the C02 out of the air but instead of replacing with O2</div><div>from the bellows add, it is replaced with air from an air leak, & the cabin O2 content</div><div>would slowly diminish with the pressure staying the same (hope that makes sense).</div><div>To save space & cost & if you are the only person diving this sub, you could just have a needle valve & adjust the flow based on O2 readings.</div><div>Alan</div><div><br clear="none"></div><div class="yiv9469130512yqt0395795979" id="yiv9469130512yqt32020"><div><br clear="none">On 25/05/2020, at 8:08 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 class="yiv9469130512ydpba117209yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div></div>
<div><br clear="none"></div><div dir="ltr">Alan, I was thinking the same idea with the scuba regulator. I rely on the altimeter and am a good habit of checking it. Also I am like the canary in the mine. I get real sore ears when the pressure changes in the sub.</div><div dir="ltr">Hank</div><div><br clear="none"></div>
</div><div class="yiv9469130512yahoo_quoted" id="yiv9469130512yahoo_quoted_0610885897">
<div style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:13px;color:#26282a;">
<div>
On Sunday, May 24, 2020, 1:24:32 PM MDT, Alan 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:
</div>
<div><br clear="none"></div>
<div><br clear="none"></div>
<div><div id="yiv9469130512"><div><div></div><div>Hank,</div><div>there is a flaw with the Bellows Add system that I can see, in that if you</div><div>have an air leak that increases the cabin pressure then the Bellows Add</div><div>system won't add O2. </div><div>Ultimately you are relying on your O2 sensor & even then O2 sensors</div><div>have a large failure rate & a life expectancy.</div><div>Rebreathers use 3-5 sensors for redundancy & compare signals.</div><div>For a large sub you have a lot more time for any failure to have an effect</div><div>than you would in a sub like your 1 person or Cliff's. </div><div>Maybe if you insist on a Bellows Add system, have an extra O2 sensor.</div><div>The second stage regulator works the opposite way than what you want</div><div>with the water pressure pushing on a thin diaphragm that has a lever the</div><div>other side that opens the valve. Maybe if you glued the lever to the inside</div><div>of the diaphragm you could open a valve with it. You would only use the </div><div>regulator valve though, as the rest would be useless.</div><div>Better still, make a small sealed enclosure with a diaphragm on one face</div><div>& attach the second stage lever mechanism to the outside against the diaphragm.</div><div>That way you could make a screw in / out fine tuning adjuster as per DW.</div><div>Alan</div><div><br clear="none"></div><div class="yiv9469130512yqt4801307923" id="yiv9469130512yqt28692"><div><br clear="none">On 25/05/2020, at 1:50 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 class="yiv9469130512yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div dir="ltr">Hi All, I am looking for ideas on how to make a automatic O2 feed similar to the DW bellows add. I want a non electronic system. I was thinking about a scuba second stage regulator conversion, that senses negative pressure to release O2. Sean???</div><div dir="ltr">Hank</div></div></div></blockquote></div><blockquote type="cite"><div><span>_______________________________________________</span><br clear="none"><span>Personal_Submersibles mailing list</span><br clear="none"><span><a rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br clear="none"><span><a rel="nofollow" shape="rect" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br clear="none"></div></blockquote></div></div><div class="yiv9469130512yqt4801307923" id="yiv9469130512yqt39981">_______________________________________________<br clear="none">Personal_Submersibles mailing list<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><br clear="none"><a rel="nofollow" shape="rect" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div></div>
</div>
</div></div></blockquote></div><blockquote type="cite"><div><span>_______________________________________________</span><br clear="none"><span>Personal_Submersibles mailing list</span><br clear="none"><span><a rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br clear="none"><span><a rel="nofollow" shape="rect" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br clear="none"></div></blockquote></div></div><div class="yqt0395795979" id="yqt13223">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a shape="rect" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div></div>
</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>