[PSUBS-MAILIST] Flush Mount Valves in MBT's
jimtoddpsub at aol.com
jimtoddpsub at aol.com
Sun Dec 8 18:26:17 EST 2013
Hi Joe,
I'm trying to keep the top of the MBTs as sleek as possible, so the vent valve will either be flush with the exterior or have only a slight bulge. I can live with a liter or so of residual air, but I would like to minimize it. The main reason is that it will compress to 1/3 of that at 100 feet and 1/10 at maximum depth. It would certainly be nicer to have as little residual air as possible so you wouldn't have even that much change in buoyancy as you descend. I have a couple of VBTs as well.
Two other design solutions are (a) taper the top of the MBT toward the vent, or (b) if the top of the MBT is flat, add just enough non-compressible material to the inside top of the tank to exclude an air pocket. Taper it. Syntactic foam would be great.
Yup, CAD is certainly the eighth wonder of the world. I think the greatest benefit is being able to alter one number and have the recalc flow all the way through without having to redraw. By the way, Wilbur only lived nine years after the first flight in 1903, but Orville lived to see operational jet aircraft. He died in 1948.
Jim
-----Original Message-----
From: Joe Perkel <josephperkel at yahoo.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Sun, Dec 8, 2013 4:07 pm
Subject: Re: [PSUBS-MAILIST] Flush Mount Valves in MBT's
Jim,
I don't know quite yet, I just know I would want it clean and as low profile as possible. I'm toying with two separate designs, one that incorporates significant exostructure, the other less so. The fleet boat manual shows how the vents were routed high up into and hidden within the casing, something I could consider for saddle MBT's on an Alvin Jr type of configuration. For a reduced scale Seehund replica, (the other design), a flush mount is more of a consideration. At first glance, the extra reserve buoyancy makes the Alvin Jr. design a better choice for my conditions, the Seehund is really just an enjoyable distraction.
Good points both ref reliability and residual air allowances. I can pinpoint such volumes quite accurately in the software. I just love CAD, everyone from the Wright Brothers to John Holland and everyone in between would say we have it too easy now!
Joe
On Sunday, December 8, 2013 4:00 PM, "jimtoddpsub at aol.com" <jimtoddpsub at aol.com> wrote:
Joe,
Minimizing residual air in an MBT would be a consideration for me, but it would be the last consideration after first determining the best valve design for function, controlability, durability, and maintenance. At that point you can set the air vent as close to the top of the tank as possible and allow for any residual air in your design calculations. I expect the size of the bubble will be minimal. In your design, how much of a consideration is the amount the valve assembly projects above the top of the tank?
Jim
-----Original Message-----
From: Joe Perkel <josephperkel at yahoo.com>
To: personal_submersibles <personal_submersibles at psubs.org>
Sent: Sun, Dec 8, 2013 2:13 pm
Subject: Re: [PSUBS-MAILIST] Flush Mount Valves in MBT's
Hi Alan,
That's similar to a Kingston isn't it? That shape would assure complete venting, one would have to be assured of fail safe reliability in whatever was used. I would like a normally closed fail safe mode in whatever style best assures sealing.
Joe
Sent from Yahoo Mail for iPad
From: Alan <alanlindsayjames at yahoo.com>;
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>;
Subject: Re: [PSUBS-MAILIST] Flush Mount Valves in MBT's
Sent: Sun, Dec 8, 2013 7:10:19 PM
Hi Joe,
While thinking about the ballast valve, it occurred to me that
the drain pop up plugs found in modern bathrooms, are very
similar to what we want.
https://www.google.co.nz/search?client=safari&hl=en-gb&biw=768&bih=928&tbm=isch&sa=1&ei=47ukUvT-EsqhkwWt04DoAQ&q=drain+pop+up+waste&oq=drain+pop+up+waste&gs_l=img.3...46028.57398.0.58014.39.28.0.2.2.0.324.3866.8j5j4j5.22.0....0...1c.1.32.img..27.12.2132.cLok805IcCc
Hope that link came out OK. It was an image search on DRAIN POP UP WASTE
They would need to work upside down for our application, so they would be flush on the
inside of the ballast tank (eliminating an air trap) but extend a bit above the ballast tank.
Some models look like you could just stick an air line straight on to them, & with a spring
In them, they would work.
There may be some model that is ideal.
Alan
Sent from my iPad
On 8/12/2013, at 2:09 PM, Joe Perkel <josephperkel at yahoo.com> wrote:
I need a little help understanding the installation ofremotely operated pneumatic valves in soft tanks. I’ve been looking at variousproducts on the Net, and from what I see, there doesn’t seem to be an off theshelf remotely operated valve that would install flush and fully vent the tank.What I’m looking for is a flush mount and a clean installation which eliminatesthe exterior tubing routed to the conning tower.
Am I missing a valve type or installation that wouldaccomplish this?
Thanks
Joewith
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