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Brent,
Frank
suggested a piston type looking thing that has a small diameter shaft in the
middle, and then the actual sealing plunger is like what you currently
have. Maybe take a look a large pvc spring check valve and see how
they design those valves. Your idea is just like that except it has a
control arm which opens and closes the valve. Or, something that you
may have already touched on, would be like a spring loaded check valve and
then the opening mechanism would push the valve open and the spring would do the
closing for you as you turn the handle linkage. But that might not
be what you want since it would be a momentary type control valve. The
other option is to have a actual piston which moves into a position where there
is a open passage for water/air to escape, kind of like a giant hydralic
control valve where there are passage ways for different functions like on
a fork lift or whatever. You wouldn't want too much of a bearing surface
however because of friction.
Better hurry and design it though ! 'cause I'm going to need something
like that soon.
Brian
"all this ,will someday come to pass, in Gods good
time" Cpt
Nemo
Hi Brian, Do you have
any materials in mind for the tube and piston. I can see a couple of
different configurations that have a piston riding inside a tube, with holes
at the top of the tube to allow the air out. Perhaps the piston can be
guided with spring rings, guide wheels mounted in the piston, or other
means. I can see the piston being moved by the same type of spring
loaded pneumatic actuator as we have been discussing, and having the actuator
mounted as it is on my last model. Meaning the piston would not be moving
collinear to the axis of the piston, allowing for the assembly to be in a
tighter spot as it is on my K boat.
If one has more room to work with
then I think a assembly like Jays would be easier to make and install then my
hinge type or your piston type, as I currently see them in my head. I'll make
a third assembly based on your suggestion, when I finish the other two I'm in
the middle of now.
Szybowski
From: ojaivalleybeefarm@dslextreme.com
To:
personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] MBT
valve
Date: Thu, 15 Jan 2009 09:26:23 -0800
Brent,
What about making the valve a cylinder and have a bore that it travels
in. That way you would be assured that it would seat. Just a
thought.
Brian
That's not fun. I tried
it when I'm not signed in on a PC and a Mac, and it worked good for me.
Perhaps it's one of those things were you have to hold your breath and think
good thoughts. ;)'
Your a flickr.com fan, so this
might do the trick.
http://www.flickr.com/photos/12242379@N05/
If you click on the upper
right hand corner of the pictures, you can see and download them in a better
size and quality if you wish.
http://www.flickr.com/photos/12242379@N05/3198294928/sizes/l/
Szybowski
From: bottomgun@mindspring.com
To:
personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] MBT
valve
Date: Wed, 14 Jan 2009 20:15:00 -0500
Brent,
This
URL is buried someplace within Windows Live it appears and is
inaccessible.
R/Jay
Respectfully,
Jay
K. Jeffries
Andros
Is., Bahamas
As
scarce as the truth is, the supply has always been in excess of the
demand.
-Josh
Billings
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent
Hartwig
Sent: Wednesday, January 14, 2009 7:47 PM
To:
PSUBSorg
Subject: RE: [PSUBS-MAILIST] MBT
valve
I think this
should fit the bill Hugh. I remembered that I had set my limit
mate on the plunger land sub assembly to only allow the plunger to open to
20 degrees. So here it is at 40 degrees with a touch of Photoworks
rendering thrown in for good measure.
http://cid-5085d10eb6afe47c.skydrive.live.com/browse.aspx/Open%20to%2040%20degrees
Regards,
Szybowski
From:
brenthartwig@hotmail.com
To: personal_submersibles@psubs.org
Subject:
RE: [PSUBS-MAILIST] MBT valve
Date: Tue, 13 Jan 2009 18:02:12
-0800
Hi
Hugh,
Design review is
one of the primary reasons why I posted it, so it's all good.
There is a couple
things going on in my assembly, first the material I needed to add to the
plunger above the O-ring, so It would meet the bottom of the FRP cap that I
cut out of the main FRP shell, partly gets in the way when the valve is only
opened part way as shown. Adding that material and attaching the FRP
cap, is mostly for a clean look and a touch of hydrodynamics, which I'm not
to worried about.
I did intend to open that valve farther, and there is
plenty of room to do so, but was having trouble with my mates on the
plunger land part and was not able to lock the plunger land to the MBT as I
had planned. It sits at about a 6.5031433...... angle and usually I
can mate a odd angle to other planes and/or surfaces and lock things down,
but ever since I reloaded my software I've not been able to ferret out the
glitch. At any rate your correct, and the valve needs to open
further. There is a fancy new locking mate feature on Solidworks 2008,
but as luck would have it I have 2007. But with assembly mates there
is more ways then one to skin a cat, so I'll just keep poking at it. If I
try to open the valve further as I currently have it, the plunger land
starts to move down with the plunger. Which of course is not what I need to
happen.
From:
hc.fulton@gmail.com
To: personal_submersibles@psubs.org
Subject: RE:
[PSUBS-MAILIST] MBT valve
Date: Wed, 14 Jan 2009 08:25:24
+1300
Brent,
Just
a comment on your MBT valve. If you alter the depth of the eat area so
that when it is open it has a larger gap it would help. With valves
you should have ¼ x diameter lift opening for the same area as the
hole.
Yours
appears to only have about ¼ inch opening. What is the ratio of
vertical gap to diameter in your drawing? It is what we call design
review. Hope it helps. Hugh.
.
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent
Hartwig
Sent: 13 January 2009 17:30
To:
PSUBSorg
Subject: RE: [PSUBS-MAILIST] MBT valve
Hey
Jay,
That assembly looks like it will work well to me, and
doesn't look to hard to manufacture, install, or maintain. It's good to see
some of your CAD work. It's basically along the lines of what I was
thinking of doing when I first started to think about large venting options
and from what I was thinking Vances mushroom vents might look like.
Having the closure spring inside the pneumatic actuator simplifies things
for use both. I like the sealing grooves you used. I had thought at first
that the mushroom vents would be partly above the MBT's to let all the air
out of the tanks and mount them. But both are assemblies are basically
hidden, and yet still let most of the air out. Your blue components,
namely the piston and the piston land, I think might be able to be made out
of UHMW plastic or the like, or even acrylic for that matter. But I
like UHMW for it's ease of machining, much cheaper then SS, it's light so
that helps in keeping the weight down (since these are mounted higher up in
the subs), and it's very corrosion resistant as far as I'm aware
of.
I can see how I
could blend your assembly with mine by using your type of upper rubber
gasket and grooved plunger/piston, and then just use a SS or UHMW retaining
ring to hold the gasket in place basically in the same
way you've secured the gasket on yours. The main reason
I switched over my thinking from a piston to a hinged plunger assembly was
that the top of my MBT's are right next to the knuckle curvature of the
steel heads, and my MBT's are not even close to flat on top, unless I modify
them.
"Want
to mount the complete valve assembly on the tank surface so that if there is
give between the hull and the tank surface, closing tolerances and alignment
will not be affected."
This point I believe is a good one, and this is why I
left as much thickness to my plunger land as I did. I could even add
some additional thickness to the underside of the FRP tank shell to beef
things up in that area if need be. I can see how that might be good
for your assembly as well, not for making it seal better like mine, but
primarily for keeping the FRP tank rigid over time. Also I hope to
have less trouble with my assembly from any flexing or alignment issues by
using a good large soft O-ring(s) or gasket.
Your mentioning having the complete valve assembly on
the tanks surface to better deal with alignment issues, gave me an idea of
how I could do that with my basic hinge type assembly, and not have to weld
the two SS tabs onto the pressure hulls steel heads. I would need to add
about a 1/4" of FRP to the bottom of the upper area of the MBT's to beef it
up to handle this new configuration. So that means it's back to the
salt mines to work up another assembly model. ;)' Thank goodness for
soft office chairs.
From:
bottomgun@mindspring.com
To: personal_submersibles@psubs.org
Subject:
[PSUBS-MAILIST] MBT valve
Date: Sun, 11 Jan 2009 03:23:15
-0500
Brent &
Vance,
Thanks for
taking the lead with the illustration of a MBT valve. I have taken the
liberty to play with the design some, see the 3 images at http://flickr.com/photos/bottomgun
in the MBT Vent Valve group. I believe if you have a FLICKR account,
you can view the images at a higher resolution.
Some
thoughts:
1.
Want to
minimize number of moving parts
2.
Want to
minimize the number of hinge points
3.
Want to mount
the complete valve assembly on the tank surface so that if there is give
between the hull and the tank surface, closing tolerances and alignment will
not be affected.
4.
Want seating
surfaces to mate square on to insure complete closing of valve
5.
Seating surface
material should be above the valve disk so sand or other matter doesn’t
settle on it and allow air to leak
6.
Seating
material should be a soft elastic material
7.
Operating
cylinder should fail in the valve closed position (some cylinders have
springs installed and air pressure operates against the spring below the
piston, not sure if Bimba has this capability)
Bimba
cylinders, 3-D models in various formats are available on their web
site:
http://www.bimba.com/
R/Jay
Respectfully,
Jay K.
Jeffries
Andros Is.,
Bahamas
As
scarce as the truth is, the supply has always been in excess of the
demand.
-Josh
Billings
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