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Who is interested in a new kind of BCD?

Discussion in 'Research and Development' started by trash, Mar 24, 2005.

  1. trash

    trash Angel Fish

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    Hi Andy, sure.

    I think the first version will be an add-on for divers who currently own a stab or wing BCD. However, I'll talk about an integrated version for new buyers.

    The integrated version would have a bladder jacket and tray as per usual, and one (or two) of my adjustable air chambers mounted besides the tank. A modified 'Air-2' style inflator supplies ambient pressure air for the backup (octo) mouthpiece, the adjustable air chamber, and drysuit air hose connector. It also includes a power and oral inflator for the stab-jacket. (Please don't post on how much Air-2 and stab-jackets suck.) Many variations are also possible.

    In operation, once you have adjusted your weights to be slightly negative with an empty bladder (the BCD I mean), empty air chamber, and 500 psi in your tank, you dive as follows:

    - prior to entering the water you inflate the bladder and adjust the air chamber for max buoyancy. Enter

    - with reg in mouth you dump the entire bladder contents of air and then you will tend to become horizontal from the buoyancy in the full air chamber.

    - you slide the adjustment knob down until you become negative and begin to sink.

    - if you don't use a foam rubber suit, your descent is constant and you can stop and adjust for neutal with a single change to the air chamber.

    - multi-level diving does not requirer any adjustments because your air volume is constant in your lungs, mask, air chamber and empty bladder.

    - to surface you adjust for positive bouyancy and then ascend at a safe and constant rate from the bottom to the top because the expanding air leaves through the check-valves.

    - on the surface you inflate your bladder.

    Even with a foam wetsuit or drysuit you will adjust less than with a regular bladder because the air volume you need to become neutral underwater is not subject to change by the affects of pressure. Uncontrolled buoyant ascents wouldn't happen without droping your weights; if you over adjust and start to ascend the ascent will be constant. If you add too much air under a ledge and become trapped in a slightly head-down fashion you just adjust for less bouyancy and sink away from the ledge. If a bladder based BCD traps air above the dump valve you got some work to do.

    I know the good divers out there have 'no problem' with buoyancy control, I'm just saying they could have less. tr
     
  2. Green_Manelishi

    Green_Manelishi Solo Diver

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    It costs $$$ to file a non-provisional. You can file a PROVISIONAL for much less but there are downsides; like when you file the non-provisional it had better seem to the USPTO that it's describing the same object or the provisional will not cover the idea and it could be "stolen". Or you could describe them both the same way and the patent is awarded but not on what you intended. Or, your description will not seem unique enough and the patent will be denied.

    You can check the patent and trademark office for more detail OR consult with an attorney. Do yourself a favor though and stay away from any chucklehead who promises (for a substantial fee of course) they can patent your idea.
     
  3. H2Andy

    H2Andy Blue Whale

    # of Dives: 200 - 499
    Location: NE Florida
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    thanks, i understood that great

    does the device have a max operating depth?
     
  4. jonnythan

    jonnythan Knight Scublar ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Upstate NY
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    Not to discourage you, but you're advocating adding this mechanically complex piece of gear to the diver's kit, and not even getting rid of anything you already have.

    I understand the idea and I think it may have merit, but what you're proposing simply won't work. It's endemic of the "throw gear at a non-existant problem" that seems rampant in the industry.

    If you can fabricate one of these devices that is somewhat reliable, doesn't have any failure modes that result in grave danger to the diver, and allows you to get rid of the BC bladder entirely, you might have something. Til then, you have [no offense] a bizarro idea that doesn't actually do anything for the diver.
     
  5. trash

    trash Angel Fish

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    The physics aren't much different than a bladder based BCD and should save a little air by eliminating a few dumps from manual over-corrections. The air pressure inside the chamber is always the same (isobaric) as the water pressure outside the chamber so depth has no affect on the operation of the cylinder. tr
     
  6. MSilvia

    MSilvia Solo Diver

    # of Dives: 200 - 499
    Location: Cohasset, Massachusetts USA
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    I don't think it's that bizarre an idea, but even if it could be made "bulletproof" reliable, I just don't see that the added expense of buying one is justified by the minor advantage it might provide.

    I also don't see that it would be very effective at maintaining the bouyancy of anyone diving in a cold water wetsuit, and if I still have to manually compensate for bouyancy lost to depth compression when using it, what's the point of having "automatic" bouyancy adjustment?

    It might have other applications that would be cool though. Maybe on a scooter or ROV?
     
  7. O2BBubbleFree

    O2BBubbleFree Solo Diver

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    I've been working with Ocean Sensor's OS500 APV™ Autonomous Profiling Vehicles:

    http://www.oceansensors.com/os500_apv.htm

    They dive by moving a piston to compress an air chamber, and surface by decompressing it.

    This method doesn't need a compressed air source, so would probably be better for a scooter or ROV.
     
  8. MSilvia

    MSilvia Solo Diver

    # of Dives: 200 - 499
    Location: Cohasset, Massachusetts USA
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    You win today's "Job I'd rather have" contest.
    Well there you go then.
     
  9. jonnythan

    jonnythan Knight Scublar ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Upstate NY
    10,070
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    Your physics don't add up.

    If the air pressure inside the chamber is always the same as the water pressure outside the chamber, the device will have to add or dump air as you descend or ascend.

    The only way around this is to have the absolute pressure inside the chamber constant while the water pressure increases or decreases.. ie, by having the piston totally fixed.

    Therefore, you would not save any air.
     
  10. Azza

    Azza Instructor, Scuba

    # of Dives:
    Location: New Zealand
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    Kudo's to you for trying to improve our great sport

    Not to be negative but you need to think this through more.
    Automatics are not for wimps but rather lazy people that cant drive properly. Thats a fact!
    What happens if you want to hold your speed while descending down a steep hill say in the wet? An auto will just let you run, however a manual can be chopped back a gear or two and actually hold the vehicle without the brakes needing to be applied, therfore reducing the risk of brake fade.
    Why do you think all the big rigs are manual, and have up to 30 gears?

    There is the main problem. Why make things complex? KISS.
    What happens when it fails underwater?
    What happens when it fails on the boat whilst steaming out to dive the wrecks of Chuuk Lagoon? Who is going to fix it? How much is it going to cost? Are the parts going to be available.

    My BCD/BP&W works fine. If it aint broken, dont fix it!
     

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