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<DIV><FONT size=3>Brian: from 6-18-2015</FONT></DIV>
<DIV><FONT size=3>Jim</FONT></DIV>
<DIV> </DIV>
<DIV>
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<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial'">
<HR>
From: JimToddPsub@aol.com<BR>To: personal_submersibles@psubs.org<BR>Sent:
6/18/2015 2:51:21 P.M. Central Daylight Time<BR>Subj: Over Pressure
Valve<BR></DIV>
<DIV> </DIV><FONT style="BACKGROUND-COLOR: transparent" color=#000000
size=2 face=Arial><FONT color=#000000 size=2 face=Arial>
<DIV><FONT size=3>If the pressure differential exceeds the preset cracking
pressure, the valve will open on its own to relieve the excess pressure.
If the pressure differential is less than the cracking pressure, it would have
to be opened manually. If the differential were only slightly greater
than the preset cracking pressure, I suppose opening it manually
would open it wider for more rapid equalization on many types of
valves.</FONT></DIV>
<DIV><FONT size=3>Jim</FONT></DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 6/18/2015 2:40:58 P.M. Central Daylight Time,
personal_submersibles@psubs.org writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>
<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: Arial, sans-serif">
<DIV>Jim,</DIV>
<DIV> In that
case is it necessary to bump the sealed check valve to make it
open?</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>Alec, I guess what I meant to say was if the check valve is left
in an open line to the outside all the time, rather than being isolated by
another valve.</DIV>
<DIV> </DIV>
<DIV>Brian <BR><BR>--- personal_submersibles@psubs.org
wrote:<BR><BR>From: via Personal_Submersibles
<personal_submersibles@psubs.org><BR>To:
personal_submersibles@psubs.org<BR>Subject: Re: [PSUBS-MAILIST]
Idea..?<BR>Date: Thu, 18 Jun 2015 14:53:15 -0400<BR><BR></DIV><FONT
color=#000000 size=2 face=Arial>
<DIV></DIV>
<DIV><FONT size=3>Brian, it also has to do with cracking pressure.
When you surface the sub might be slightly over pressure but not with enough
differential to open the valve automatically. That's when you open it
manually. That would also equalize pressure if you have negative
pressure in the sub to make it a whole lot easier to open the
hatch.</FONT></DIV>
<DIV><FONT size=3>Jim </FONT></DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 6/18/2015 1:40:32 P.M. Central Daylight Time,
personal_submersibles@psubs.org writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>
<DIV dir=ltr>It is nothing but a T shape sealed by a spring. If internal
pressure builds up, it pushes the spring and the valve opens. So it is a
normally closed valve... but I suppose you could say its "open all the
time" in the sense that anytime pressure builds up, it will open.</DIV>
<DIV><BR>
<DIV>On Thu, Jun 18, 2015 at 2:35 PM, Brian Cox via Personal_Submersibles
<SPAN dir=ltr><<A title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>></SPAN>
wrote:<BR>
<BLOCKQUOTE
style="PADDING-LEFT: 1ex; BORDER-LEFT: rgb(204,204,204) 1px solid; MARGIN: 0px 0px 0px 0.8ex">
<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: Arial,sans-serif">
<DIV>Couldn't you, theoretically, have that valve open to the
outside all the time? </DIV>
<DIV> </DIV>
<DIV><SPAN>Brian <BR><BR>--- <A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>
wrote:<BR><BR>From: Alec Smyth via Personal_Submersibles <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR>To:
Personal Submersibles General Discussion <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR>Subject:
Re: [PSUBS-MAILIST] Idea..?<BR></SPAN>Date: Thu, 18 Jun 2015 12:15:57
-0400<BR><BR></DIV>
<DIV>
<DIV>
<DIV dir=ltr>I think most have an OP valve, and I'd strongly encourage
any who don't to put one in. If you read Kittredge's book, the lack of
an OP valve was the cause of the only K-boat accident so far.
Fortunately nothing happened to him, but Kittredge had a slow cabin air
leak during his dive and upon surfacing blew out the dome when just
below the surface. He was blown out himself with it. The sub sank, and
he proceeded to re-float it without losing beat. I use the OP
valve routinely to equalize pressure so I can open the hatch easily.
Just a little push on the stem does it. One thing about OP valves, they
have to be capable of handling large flow rates. Don't use a little
Swagelok check valve or such small thing.
<DIV><BR></DIV>
<DIV>Best,<BR><BR>Alec<BR>
<DIV><BR></DIV>
<DIV><BR></DIV></DIV></DIV>
<DIV><BR>
<DIV>On Thu, Jun 18, 2015 at 10:55 AM, Brian Cox via
Personal_Submersibles <SPAN dir=ltr><<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>></SPAN>
wrote:<BR>
<BLOCKQUOTE
style="PADDING-LEFT: 1ex; BORDER-LEFT: rgb(204,204,204) 1px solid; MARGIN: 0px 0px 0px 0.8ex">Also
Alec, I noticed your check valve overpressure valve in the
photo section. That seems like a great solution to the
problem! I guess I was not aware of that, does everybody
have one of those?<BR><BR><BR>Brian<BR><BR>--- <A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>
wrote:<BR><BR>From: hank pronk via Personal_Submersibles <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR><SPAN>To:
Personal Submersibles General Discussion <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR>Subject:
Re: [PSUBS-MAILIST] Idea..?<BR></SPAN>Date: Thu, 18 Jun 2015 05:25:30
-0700<BR>
<DIV>
<DIV><BR><BR>personally, I always avoid welding a machined part to the
hull. I weld a flange or nipple to the hull then bolt or thread
the machined part to that. This is my solution to a lack of
tooling and expertise.<BR>Hank
--------------------------------------------<BR>On Thu, 6/18/15, James
Frankland via Personal_Submersibles <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>>
wrote:<BR><BR> Subject: Re: [PSUBS-MAILIST] Idea..?<BR> To:
"Personal Submersibles General Discussion" <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR> Received:
Thursday, June 18, 2015, 4:58
AM<BR><BR> Hi<BR> Alec\Brian, Yes, maybe it
would<BR> push in. A flat step would probably be better
like you<BR> say. But maybe im over thinking it as
usual. Probably<BR> not required. Brian, I used
the<BR> 5\8ths bar because that's what was specified on
the<BR> plans. However, its also convenient for using a
16mm<BR> reamer for the
bore. <BR> regardsJames <BR> On 18 June 2015
at 03:04,<BR> Brian Cox via Personal_Submersibles <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR> wrote:<BR> Oh
cool ! Thanks Alec<BR> ! I owe you
much over the years<BR> ! Brian<BR> --- <A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A><BR> wrote:<BR><BR> From:
Alec Smyth via<BR> Personal_Submersibles <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR> To:
Personal Submersibles General Discussion<BR> <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR> Subject:
Re: [PSUBS-MAILIST] Idea..?<BR> Date: Wed, 17 Jun 2015 16:40:56
-0400<BR><BR> Hi Brian,<BR> I tend to use quite
thick<BR> through-hulls because its easier for me to machine
the<BR> O-ring grooves into the shaft than into the insert. In
my<BR> case its just a matter of the tooling I have on hand. If
you<BR> have the tooling to put the grooves in the insert, half
an<BR> inch is fine for many
applications.<BR> Best,<BR><BR> Alec <BR> On<BR> Wed,
Jun 17, 2015 at 3:22 PM, Brian Cox via<BR> Personal_Submersibles
<<A title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR> wrote:<BR> Alec,
James, I'm<BR> using mostly 1/2" stainless rod through-out
for most<BR> all of my hull penetrations ( for valves and
flaps) , I<BR> noticed in the example it was a 5/8"
rod, Why such a<BR> heavy duty thickness? Was that
for a particular<BR> function? Brian<BR><BR> --- <A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A><BR> wrote:<BR><BR> From:
Alec Smyth via<BR> Personal_Submersibles <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR> To:
Personal Submersibles General Discussion<BR> <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR> Subject:
Re: [PSUBS-MAILIST] Idea..?<BR> Date: Wed, 17 Jun 2015 14:03:17
-0400<BR><BR> Hi James,<BR> I think<BR> with the taper,
this would tend to push in and jam. The idea<BR> is neat,
however, and would probably work fine with a step<BR> instead of
a taper. On the other hand, does an O ring
sealed<BR> through-hull ever fail catastrophically? I've had
the<BR> odd drip, but that's all I've bad as
I've<BR> seen.<BR> Best,<BR> Alec<BR> On<BR> Wed,
Jun 17, 2015 at 12:26 PM, James Frankland
via<BR> Personal_Submersibles <<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>><BR> wrote:<BR> Hi
All Seeing as its a<BR> bit quite I thought I would show
this idea. Its super<BR> simple.... I have been
thinking how<BR> you could stop a leaking through hull.
Thinking of K boat<BR> type 5\8th through hulls as in
the<BR> plans. I believe Scott had a leak<BR> when he
did his deep test due to a faulty O ring?<BR><BR> Anyway, here is
my idea. It<BR> would take a little bit more machining, but
not much. <BR> Machine the 5\8ths bar with a taper on the
protruding<BR> part and a taper on the top to help push the bar
through. <BR> (I did that on mine anyway). The handle
is made with a cam<BR> type end. <BR><BR> If you get
a<BR> leak, you can pull the handle up. The bar would be
pulled<BR> up, forcing the taper to jam into the penetrator,
hopefully<BR> stopping most of the leak. I suppose you
could even<BR> machine a matching taper into the start of the
through hull<BR> to match? I suppose the bar could
get<BR> pushed through and jam on its own. That's
a<BR> possibility. Pic<BR> attached. Kind<BR> RegardsJames <BR> <BR><BR> _______________________________________________<BR><BR> Personal_Submersibles
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