waterproof shaft seal?
 

I am trying to waterproof a small electric motor (submerged) so that
shaft will be sticking out of waterproof enclosure. Can anyone point
me to a source of water sealed bushings or bearings for this sort of
application? I have been looking all over the net and can't seem to
come up with ideas or supplies to do this. The shaft size will be =
1/4"

Thanks!
Bailey--

waterproof shaft seal?
 

The problem here is shaft size: it's way too small for our boats and you
will not find a shaft seal in the boating supplies field.
How about industrial supplies? Shaft seals are used in all kind of tanks.


--
Jacques
http://www.bateau.com

"MBS" wrote in message
m...
I am trying to waterproof a small electric motor (submerged) so that
shaft will be sticking out of waterproof enclosure. Can anyone point
me to a source of water sealed bushings or bearings for this sort of
application? I have been looking all over the net and can't seem to
come up with ideas or supplies to do this. The shaft size will be =
1/4"

Thanks!
Bailey--

waterproof shaft seal?
 

Don't know which country you are in but check out your ag dealers. I reckon
they will have one to fit your purpose from one of those high pressure
chemical hand sprayers. In Australia look up Hardie.
Brumer


"Jacques Mertens" wrote in message
...
The problem here is shaft size: it's way too small for our boats and you
will not find a shaft seal in the boating supplies field.
How about industrial supplies? Shaft seals are used in all kind of tanks.


--
Jacques
http://www.bateau.com

"MBS" wrote in message
m...
I am trying to waterproof a small electric motor (submerged) so that
shaft will be sticking out of waterproof enclosure. Can anyone point
me to a source of water sealed bushings or bearings for this sort of
application? I have been looking all over the net and can't seem to
come up with ideas or supplies to do this. The shaft size will be =
1/4"

Thanks!
Bailey--

waterproof shaft seal?
 

In my experience submerged motors ( as used in submersible pumps) are to
be avoided if at all possible. And for a one-off design, you are putting a
lot of effort into something which will ultimately be unproven and a
potential failure point. You did not say what you are trying to achieve,
power, RPM, depth of submergence, fresh or salt .... Or what you have
available by way of power sources.
Can you go to a flexible shaft and keep the motor above the water? Can you
use pneumatics or hydraulics or a water driven system? What about a
magnetic drive? These are often used on pumps for severe chemical duty to
eliminate the seal problems.
Failing that, I think you are up for an expensive mechanical seal.

David



But I'd look at other ways of doing the job if at all possible.
"BruceM" wrote in message
...
Don't know which country you are in but check out your ag dealers. I
reckon
they will have one to fit your purpose from one of those high pressure
chemical hand sprayers. In Australia look up Hardie.
Brumer


"Jacques Mertens" wrote in message
...
The problem here is shaft size: it's way too small for our boats and you
will not find a shaft seal in the boating supplies field.
How about industrial supplies? Shaft seals are used in all kind of
tanks.


--
Jacques
http://www.bateau.com

"MBS" wrote in message
m...
I am trying to waterproof a small electric motor (submerged) so that
shaft will be sticking out of waterproof enclosure. Can anyone point
me to a source of water sealed bushings or bearings for this sort of
application? I have been looking all over the net and can't seem to
come up with ideas or supplies to do this. The shaft size will be =
1/4"

Thanks!
Bailey--

waterproof shaft seal?
 

Thanks for the tips. I should have provided more detail but it will
basically be a fractional horse low depth propulsion (similar to a
trolling motor only much smaller). In taking a trolling motor apart,
the water seal looks like nothing but an "O" ring or grommet next to
the bushing. How complicated can that be? Surely there has to be
something available to accomplish this.

waterproof shaft seal?
 

I think it's called a trolling motor ....
DF
"MBS" wrote in message
om...
Thanks for the tips. I should have provided more detail but it will
basically be a fractional horse low depth propulsion (similar to a
trolling motor only much smaller). In taking a trolling motor apart,
the water seal looks like nothing but an "O" ring or grommet next to
the bushing. How complicated can that be? Surely there has to be
something available to accomplish this.

waterproof shaft seal?
 

DF,
I made reference to "much smaller" than a trolling motor. How then is
this a conventional trolling motor?

waterproof shaft seal?
 

On 14 Nov 2003 08:46:58 -0800, (MBS) wrote:

I am trying to waterproof a small electric motor (submerged) so that
shaft will be sticking out of waterproof enclosure. Can anyone point
me to a source of water sealed bushings or bearings for this sort of
application? I have been looking all over the net and can't seem to
come up with ideas or supplies to do this. The shaft size will be =
1/4"

Thanks!
Bailey--

I passed your request several times - this is not a topic for
beginners to lightly undertake - but what the hell.
Go to a bearing distributors (look in the phone book)
Ask what shaft seals they have in 1/4 inch.
Pick a likely candidate, and find some tube that will fit the outer
diameter of the seal.
Place three in series in the housing, and fix the housing on the motor
in some waterproof way. This will put you in with a chance.

Brian W Altus OK
p.s. The seals go with the lip facing *outwards*

waterproof shaft seal?
 

Sorry, missed that ...
If it's that small, I'd be looking at magnetic drive. Try looking for
magnetic drive pumps.
David
"MBS" wrote in message
om...
DF,
I made reference to "much smaller" than a trolling motor. How then is
this a conventional trolling motor?

waterproof shaft seal?
 

waterproof shaft seal?
 

Brian Whatcott wrote:

Place three in series in the housing, and fix the housing on the motor
in some waterproof way. This will put you in with a chance.

That is not a very promising approach.

If keeping the motor dry is important, filling the housing with a light
oil under slight positive pressure via a compensating bellows is the way
to go. A standard lip seal will keep junk out and the oil in. The
compensating bellows will allow operation to any depth with no fear of
flooding the housing.

Rick

waterproof shaft seal?
 

Hmmm....a trolling motor uses a single seal and no depth compensating
bellows.

Still, for decent depths, rather than the shallow depths the
questioner mentioned, this would be a sensible suggestion.
Either way, lip seals
have lips facing the higher pressure side, to prevent lift off, or
they face both ways in some applications....

Brian Whatcott Altus OK

On Sun, 23 Nov 2003 19:56:48 GMT, Rick
wrote:

Brian Whatcott wrote:

Place three in series in the housing, and fix the housing on the motor
in some waterproof way. This will put you in with a chance.

That is not a very promising approach.

If keeping the motor dry is important, filling the housing with a light
oil under slight positive pressure via a compensating bellows is the way
to go. A standard lip seal will keep junk out and the oil in. The
compensating bellows will allow operation to any depth with no fear of
flooding the housing.

Rick

waterproof shaft seal?
 

This is a completely theoretical, uninformed suggestion, so take it for what
it's (not) worth...

Put the motor in a totally sealed chamber. The motor turns a large disk,
which is positioned adjacent to the rear wall of the chamber. Strong magnets
are placed around the edge of the disk. On the other side of the (thin as
possible) rear wall is a matching disk, with magnets around its rim. This
second disk is hooked to the prop shaft. If the magnets are strong enough,
wouldn't this setup transmit enough torque to spin the prop, while keeping
the motor in a totally sealed chamber?

Remember: theoretical, uninformed! (g)

Alex

waterproof shaft seal?
 

Brian Whatcott wrote:

Either way, lip seals have lips facing the higher pressure
side, to prevent lift off, or they face both ways in some
applications....

The technique I mentioned is what we used on the thrusters of manned
submersibles working down to 2000 meters. We used two lip seals, back to
back, on the shaft to keep the oil in and water out.

Rick

waterproof shaft seal?
 

http://www.pyiinc.com/?section=pss_shaft_seal&sn=4


"MBS" wrote in message
m...
I am trying to waterproof a small electric motor (submerged) so that
shaft will be sticking out of waterproof enclosure. Can anyone point
me to a source of water sealed bushings or bearings for this sort of
application? I have been looking all over the net and can't seem to
come up with ideas or supplies to do this. The shaft size will be =
1/4"

Thanks!
Bailey--

waterproof shaft seal?
 

"Paul" wrote in message
news:PxVwb.309584$Fm2.326329@attbi_s04...
http://www.pyiinc.com/?section=pss_shaft_seal&sn=4


"MBS" wrote in message
m...
I am trying to waterproof a small electric motor (submerged) so that
shaft will be sticking out of waterproof enclosure. Can anyone point
me to a source of water sealed bushings or bearings for this sort of
application? I have been looking all over the net and can't seem to
come up with ideas or supplies to do this. The shaft size will be =
1/4"

Thanks!
Bailey--


Just an idea...

Would it not be possible to submerge the whole electric motor unit in a kind
of container completely filled with a nonconductive (non toxic) oil. If e.g.
the container is kept upright with the shaft protruding downwards and the
oil being lighter than water, it seems to me that the motor could be safely
operated without expensive water sealed bearings and/or bushings. As the
container would remain opened to the surrounding water, the hydrostatic
pressure inside and outside would be equal. Fluids can not easily be
compressed so this unit could be used in any depth of water with only a
lightweight protective container and a closely fitting shaft-tube leaving a
small enough opening for pressure compensation but too small to allow the
spilling of the oil when tilted. The only setback would be that the motor
could only be tilted a little less than 90° from the upright position and
that the internal turbulence caused by the rotor (at higher rpm) would
certainly slow down the motor (depending on the construction of the motor).
With this system one could easily insulate the motor completely from the
container/vessel. (No maintenance, no galvanic effects)

JP

waterproof shaft seal?
 

Condom?

runs away

;-)

OK now i know this post is quite old & you've long since solved your problem but ive taken it upon myself to do the exact same thing without buying expensive purpose-made stuff, just to use the stuff i already have lying around or cheaply bought!

Stumbled across the link below that ive tried out and it works very well, i can settle for a 95% waterproofed shaft seal as my little project is making a liquid pump, but its a very good way of keeping water/liquid out the motor!

I also will be making a submarine next year some-point so i'll try to reverse-engineer an expensive-type shaft-seal (on the cheap of course!) as long as i can find and understand the basic principal of one online, i mean, the schematics gotta be on the web somewhere !

Hope this helps you & everyone else!

http://members.tripod.com/robomaniac_2001/id197.htm

Merry Xmas & a Happy New Year to All !!!

;-)