[Date Prev][Date Next]
[Chronological]
[Thread]
[Top]
[PSUBS-MAILIST] Pressure compensation
Wade,
I know this is an off-topic post, but I feel that all that read your
comments should also read this.
I in no way attempted to be negative about you using an oil, even fish
oil in your gearbox. I think the idea is a good and highly inovative one
especially if you have to have a bio-degradable form of oil. I thought it
was creative. I just could not resist the joking comment about the smell
which you brought up to start with. You took the joke at first as I
intended it, without seeing it as casting a dispersion. I have no idea
what you read looking back in the thread that made you think I was
attacking your idea.
If I offended, I sincerely apologize, cause I had no intent. It was
simply the kind of joke my colleagues at school would exchange freely and
laugh at the pun. Maybe it's a Southern thing but we joke like that all
the time down here with no underlying meaning or negativity.
Once again I hope you will accept what I am saying. I have never seen
a "dumb" idea from any of your posts.
Gary Boucher
>Gary,
>I just read the Unconventional UW thread backwards. Although it was
>extremely entertaining, I suddenly understand your concern about making fun
>of my fish oil. However, I am the first to admit that I have many many very
>stupid ideas and only the occasional good one. But as long as I keep having
>the occasional good one I will continue to blurt out the dumb ones. Which
>then means I need a clever fellow like your self to tell me that it is a
>dumb idea so I don't have to suffer through finding that out myself. So I
>beg of you, next time just come right out and say it, it will save me time
>and effort in the long run (even if I don't find it very funny at first).
>Where I live, we now have three brand new and thoroughly useless, but very
>expensive ferries. They were built because nobody really bothered to stand
>up and say exactly what they thought of the whole idea. And by the way, you
>can never squash creative thinking, no matter how bad the joke.
>Actually, the whole reason I'm writing this is that now I'm imagining that
>you could have come up with a really good joke and I'm missing it.
>Cheers,
>
>Wade
>
>-----Original Message-----
>From: owner-personal_submersibles@psubs.org
>[mailto:owner-personal_submersibles@psubs.org]On Behalf Of Gary R.
>Boucher
>Sent: Saturday, August 12, 2000 8:44 AM
>To: personal_submersibles@psubs.org
>Subject: RE: [PSUBS-MAILIST] Pressure compensation
>
>
>Wade,
> I was going to joke with you and tell you that I thought your idea to
>use fish oil stunk. But, I would get more negative mail saying that I
>squashed creative thinking. I like your idea, I just don't know if I could
>go with the fish oil. Does it really smell like fish? I think for those
>not entering contests they might try submersible pump oil. Was this for
>man powered wet subs? I can see where they would not want to recreate the
>Exxon Valdez (Sp?) scenario on a smaller scale.
>
>GB
>
>
> >Gary,
> >I've actually compensated a drive train in this way before. Granted it
> >wasn't a trolling motor but it did work in my application. I used a high
> >viscosity oil made from fish (so it was biodegradable which fit with the
> >rules of the competition I was in). It smelled terrible, but it was cheap
> >and worked really well. Unfortunately, it was discovered that you still
> >need do put on some sort of compensation device (we used a sturdy balloon)
> >because it is very difficult to get all of the air out of the system and
> >even the tiny bubbles will contract and suck some water through the seal if
> >you don't. However, the balloon only needs to be very small. It actually
> >improved the efficiency of our drive train because it lubricated all the
> >parts (there were lots of gears and no long shafts). Anyways, the point is
> >if the losses aren't too significant it is a very simple and very cheap way
> >of fixing the problem.
> >
> >Wade
> >
> >-----Original Message-----
> >From: owner-personal_submersibles@psubs.org
> >[mailto:owner-personal_submersibles@psubs.org]On Behalf Of Gary R.
> >Boucher
> >Sent: Friday, August 11, 2000 11:23 PM
> >To: personal_submersibles@psubs.org
> >Subject: Re: [PSUBS-MAILIST] Pressure compensation
> >
> >
> >Jon,
> > You're right in that the mentioned method is a much better way of
> >compensating. I wonder if anyone has ever been successful at using a low
> >viscosity oil in a trolling motor. It would be an interesting experiment
> >in the direction of a low cost compensated thruster. It almost makes me
> >want to go get a trolling motor and experiment. I wonder if the armature
> >would have too much drag against the oil and how much power you would loose
> >in the process. I would think that cooling would not be a big problem. I
> >would suspect that real thrusters for submersibles that are compensated in
> >this way have special armatures. Probably the same oil used in submersible
> >pump applications would work.
> >
> >GB
> >
> >At 08:16 PM 8/11/00 , you wrote:
> > >On Fri, 11 Aug 2000 22:00:37 -0700, "Gary R. Boucher" <protek@shreve.net>
> > >wrote:
> > >
> > > > The trick is having the pressure inside the motor the same as the
> > > > outside pressure, or at least close. If you set the pressure inside
>the
> > > > motor at a certain value and ascended the pressure inside is greater
> >than
> > > > outside. If you dove beyond the set pressure you have more pressure
> > > > outside. One method of pressure compensating a motor is to place a
> >rubber
> > > > bladder with air in the water close to the motor and run a tube from
>the
> > > > bladder to the motor housing. As the sub dives the pressure on the
> > > bladder
> > > > increases and so does the inside motor pressure.
> > >
> > >Just as a point of interest...
> > >
> > >In deep professional-quality thrusters, they typically fill the thruster
> > >housing (and thus the motor) with oil, which makes the whole deal
>basically
> > >non-compressable. Instead of using a seal, they use a magnetic coupling
>to
> > >turn the propeller. This gives a thruster that can be used to full ocean
> > >depths.
> > >
> > >Later,
> > >Jon
> > >
> > >--------------------------------------------------------------
> > > Jon Hylands Jon@huv.com http://www.huv.com/jon
> > >
> > > Project: Micro Seeker (Micro Autonomous Underwater Vehicle)
> > > http://www.huv.com