<DIV style="font-family:Arial, sans-serif; font-size:10pt;"><FONT size="2" style=""><FONT face="Arial, sans-serif">I use the regulator on the O2 tank and set it at above what I consume 2.0 or 2.5 then I run that to a adjustable flow meter and dial it into my breathing consumption which is a little above 1.5 . And then watch the cabin pressure gauge and my O2 sensor.</FONT></FONT><DIV><FONT size="2" style=""><FONT face="Arial, sans-serif"><BR></FONT></FONT></DIV><DIV><FONT size="2" style=""><FONT face="Arial, sans-serif">Brian</FONT></FONT></DIV><DIV><FONT size="2" style=""><FONT face="Arial, sans-serif"><BR></FONT></FONT></DIV><DIV><FONT size="2" style=""><FONT face="Arial, sans-serif"> </FONT></FONT><BR><BR><SPAN style="font-family: Arial, sans-serif; font-size: 10pt;">--- personal_submersibles@psubs.org wrote:</SPAN><BR><BR><SPAN style="font-family: Arial, sans-serif; font-size: 10pt;">From: hank pronk via Personal_Submersibles <personal_submersibles@psubs.org></SPAN><BR><SPAN style="font-family: Arial, sans-serif; font-size: 10pt;">To: Alan via Personal_Submersibles <personal_submersibles@psubs.org></SPAN><BR><SPAN style="font-family: Arial, sans-serif; font-size: 10pt;">Subject: Re: [PSUBS-MAILIST] Bellows add</SPAN><BR><SPAN style="font-family: Arial, sans-serif; font-size: 10pt;">Date: Mon, 25 May 2020 01:39:08 +0000 (UTC)</SPAN><BR><BR><DIV style="font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 13px;"><DIV></DIV>
<DIV dir="ltr">Alan,</DIV><DIV dir="ltr">Based on what Bruce Jones said on the topic on FB, they must use solenoids also. I am assuming of coarse.</DIV><DIV dir="ltr">Hank</DIV><DIV><BR></DIV>
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On Sunday, May 24, 2020, 5:10:37 PM MDT, Alan via Personal_Submersibles <personal_submersibles@psubs.org> wrote:
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<DIV><DIV><DIV><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><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><DIV><DIV style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><DIV></DIV>
<DIV dir="ltr">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">Hank</DIV><DIV><BR></DIV>
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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:
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<DIV><DIV><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></DIV><DIV><DIV><BR>On 25/05/2020, at 8:08 AM, hank pronk via Personal_Submersibles <<A href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>> wrote:<BR><BR></DIV><BLOCKQUOTE><DIV><DIV style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><DIV></DIV>
<DIV><BR></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></DIV>
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On Sunday, May 24, 2020, 1:24:32 PM MDT, Alan via Personal_Submersibles <<A href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>> wrote:
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<DIV><DIV><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></DIV><DIV><DIV><BR>On 25/05/2020, at 1:50 AM, hank pronk via Personal_Submersibles <<A href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>> wrote:<BR><BR></DIV><BLOCKQUOTE><DIV><DIV 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><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></DIV></DIV><DIV>_______________________________________________<BR>Personal_Submersibles mailing list<BR><A href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</A><BR><A href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</A><BR></DIV></DIV>
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