[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PSUBS-MAILIST] To Dan H. (or anybody with VBT (MBT) knowledge)



Thanks Dan!

So basicaly it's very similar to a soft tank but with a valve at the bottom (drain). My soft tanks are already configured that way but for another reason (so I can keep some pressurized air inside the tanks if I need it to resurface if I run out of air...) but I think I might built a VBT and use electric/pneumatic valves so it could be easy to adjust the bouyancy with small push from button... And also, it might be a good idea to always have the VBT at ambient pressure. It could be easyer to adjust.

As for the hatch seal, I must confess that my hatch is not as flat as I would it to be... I discovered that when welding, things tend to bent every direction they want! And the hatch as a complex shape. Also, The "flat" area is a square tubing of 0.125" thick wall... Not sure I can groove it. But thanks anyway! It is not that big a problem for me...

Pierre "VBT man" Poulin




From: "Dan H." <jmachine@adelphia.net>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: Re: [PSUBS-MAILIST] To Dan H. (or anybody with VBT (MBT) knowledge)
Date: Wed, 5 May 2004 08:24:37 -0400

Brian,

The VBT has two connections attached to it.  One is a one inch pipe that
water moves through and the other is a half inch pipe that air moves
through.

The water port is located at the rear of the tank (not important) and has an
internal elbow and pipe that goes to the bottom of the tank, so when
reducing ballast, it drains clear to the bottom.  The smaller line in
located at the top of the tank so when reducing pressure, it vents out air.

The water port has a one inch ball valve attached to it after it exits the
tank.  This is controlled from the pilots seat through linkages that pass
through a thruhull fitting.

The air port is plumbed directly into the sub and then to two valves near
the pilot seat. One of these valves allows you to blow air into the ballast
tank to pressurize it.  The other valve is a vent valve that connect to a
vent thruhull in the top of the hull. This valve allows you to bleed off
pressurizes air from the MBT to allow water to enter the water port.  To
allow water to fill the MBT properly, this venting system must be located
above the top of the MBT.  My vent is located just forward of the conning
tower in the hull.  An added advantage is that you can see the air venting
through a viewport.

To decrease buoyancy:  (go down)
Open the vent valve.
Open the water valve.
When neutral buoyancy is reached close off both valves and power down with
the thrusters. ( Of course if you go to negative buoyant, you can just sink
downward.)

To increase buoyancy:  (come up)
Open the air pressure valve to charge the VBT above ambient pressure.
Open the water valve.
When you hear air blowing out the water port, the tank is empty and you can
close all valves. (If making a miner adjustment to the positive, pressurize
and then just crack the water valve a bit until you reach the desired
buoyancy.)

I hope this helps!

Pierre, Your hatch seal really isn't a difficult problem. There is no need
to reinvent the wheel!  O-rings exist and they are perfect for your needs.
A standard Buna O-ring, with a cross section of around .200 inch or more, in a groove within two flat matting surfaces is all you need. Your "hatch hold
downs" will apply all the force you need to compress the O-ring if your
mating surfaces are flat.  A 24 inch Buna O-ring is about $10.  Cheep, off
the shelf and easy to replace anywhere if needed.

Keep It Simple, Dan H.

----- Original Message -----
From: "Pierre Poulin" <pipo305@hotmail.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, May 04, 2004 9:49 PM
Subject: [PSUBS-MAILIST] To Dan H. (or anybody with VBT (MBT) knowledge)


> Hi Dan!
>
> I know that there is a Variable Ballast Tank in a K-350. And I imagine
that
> yours have one too.
>
> Could you please tell me how this VBT is connected? Valves, vents,
drains...
> I was planning to have a pneumatic cylinder and a piston to adjust
buoyancy
> using readyly availible ambient pressure but maybe a VBT is easyer to
built
> and could do the same job.
>
> I was thinking that we could use some pneumatic push button valves for
ease
> operation...
>
> Thank you very much!
>
> Pierre Poulin
>
> _________________________________________________________________
> MSN Messenger : discutez en direct avec vos amis !
> http://messenger.fr.msn.ca/
>
>
>
>
> ************************************************************************
> ************************************************************************
> ************************************************************************
> The personal submersibles mailing list complies with the US Federal
> CAN-SPAM Act of 2003.  Your email address appears in our database
> because either you, or someone you know, requested you receive messages
> from our organization.
>
> If you want to be removed from this mailing list simply click on the
> link below or send a blank email message to:
> removeme-personal_submersibles@psubs.org
>
> Removal of your email address from this mailing list occurs by an
> automated process and should be complete within five minutes of receipt
> of your request.
>
> mailto:removeme-personal_submersibles@psubs.org
>
> PSUBS.ORG
> PO Box 311
> Weare, NH  03281
> 603-529-1100
> ************************************************************************
> ************************************************************************
> ************************************************************************
>
>





************************************************************************
************************************************************************
************************************************************************
The personal submersibles mailing list complies with the US Federal
CAN-SPAM Act of 2003.  Your email address appears in our database
because either you, or someone you know, requested you receive messages
from our organization.

If you want to be removed from this mailing list simply click on the
link below or send a blank email message to:
	removeme-personal_submersibles@psubs.org

Removal of your email address from this mailing list occurs by an
automated process and should be complete within five minutes of receipt
of your request.

mailto:removeme-personal_submersibles@psubs.org

PSUBS.ORG
PO Box 311
Weare, NH  03281
603-529-1100
************************************************************************
************************************************************************
************************************************************************


_________________________________________________________________
MSN Search, le moteur de recherche qui pense comme vous ! http://fr.ca.search.msn.com/




************************************************************************
************************************************************************
************************************************************************
The personal submersibles mailing list complies with the US Federal
CAN-SPAM Act of 2003.  Your email address appears in our database
because either you, or someone you know, requested you receive messages
from our organization.

If you want to be removed from this mailing list simply click on the
link below or send a blank email message to:
	removeme-personal_submersibles@psubs.org

Removal of your email address from this mailing list occurs by an
automated process and should be complete within five minutes of receipt
of your request.

mailto:removeme-personal_submersibles@psubs.org

PSUBS.ORG
PO Box 311
Weare, NH  03281
603-529-1100
************************************************************************
************************************************************************
************************************************************************