<div dir="ltr">I have to admit this one really befuddles me. What if you were to have two (independent) pressure sensors/gauges, one for cabin pressure and one for ambient pressure, but the gauges were linked at the needles with a one-way gate. This way, the gauges would both be free to move independently, but the gate would only open (and unlock the hatch lock-out via a switch) when both needles were lined up in tandem indicating equal pressure, be it at the surface or underwater. I think actually designing and building such a device would prove very difficult. <div>
<br></div><div>Is this what they are talking about, or am I confused? </div><div><br></div><div>Because if so, I'm not sure I would ever want to implement such a device on my vessel. If a malfunction of this system were to occur during an emergency egress, how much more time would it take to bypass the hatch lock-out? 3 seconds is a long time when you are dying! </div>
<div><br></div><div>With pressure gauges alone I will have a pretty good idea of where I stand in terms of equalization. </div><div><br></div><div><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">
On Wed, Dec 11, 2013 at 9:53 AM, Joe Perkel <span dir="ltr"><<a href="mailto:josephperkel@yahoo.com" target="_blank">josephperkel@yahoo.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<table cellspacing="0" cellpadding="0" border="0"><tbody><tr><td valign="top">Alan<br><br>No definitive answer but we can postulate that both sensing and actuation are involved. <br><br>On sensing, differential pressure on either side of the hatch is translated to a impulse to actuation.<br>
<br>On actuation, a method of locking out the operator from physically un-dogging the hatch, is the only way to meet the standard as per your O.P.<br><br>Joe<a href="http://overview.mail.yahoo.com?.src=iOS" target="_blank"><br>
<br>Sent from Yahoo Mail for iPad</a></td></tr></tbody></table> <div>
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Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>>; <br>
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Re: [PSUBS-MAILIST] G.L. summary Pressure Hull <br>
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Wed, Dec 11, 2013 2:36:26 PM <br>
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<td valign="top"><div style="font-size:12pt;font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif"><div><span>Alan,</span></div><div><span>Is this equalization from overpressure inside the hull? or external pressure. </span></div>
<div><span>Hank </span></div><div style="display:block"> <br clear="none"> <br clear="none"> <div style="font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:12pt"> <div style="font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:12pt">
<div><div dir="ltr"> <font face="Arial"> On Wednesday, December 11, 2013 1:23:21 AM, Alan <<a href="mailto:alanlindsayjames@yahoo.com" target="_blank">alanlindsayjames@yahoo.com</a>> wrote:<br clear="none"> </font> </div>
<div><div><div><div>Can
anyone enlighten me on what sought of mechanism</div><div>is used that renders the opening of the
hatch possible only after</div><div>equalisation, as per G.L. Requirements?</div><div>Thanks</div><div>Alan<br clear="none"><br clear="none">Sent from my iPad</div><div><div><br clear="none">On 11/12/2013, at 3:01 PM, Alan James <<a rel="nofollow" shape="rect">alanlindsayjames@yahoo.com</a>> wrote:<br clear="none">
<br clear="none"></div><blockquote type="cite"><div><div style="font-size:14pt;font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif"><div>Hi,</div><div>I'm not covering much in this section because if I started on construction</div>
<div>regulations, I would just be duplicating what was printed.</div><div>G.L. wants you to have manufacturer certificates for every non structural
screw.</div><div>Any company you contract to do your welding has to have their facilities, personal</div><div>& supervision approved by G.L..</div><div>Some points of interest are.... hatches need to be opened from both sides, they need</div>
<div>to be able to be secured open, they need to be designed in a way that opening of the</div><div>hatch is only possible after equalization. Two measures are required to guarantee that</div><div>the hatches are closed & secured before diving; one measure is to be visibly noticeable.</div>
<div>Mechanical
measures for stopping a banging of the hatch is required.</div><div>Any external through hulls are to be protected against damage by appendages or covers.</div><div>If you are doing calculations on a computer you have to prove that the program is suitable.</div>
<div>Alan</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">Personal_Submersibles@psubs.org</a></span><br clear="none">
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