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Re: [PSUBS-MAILIST] illustration is this what you mean sort of?? pressuriz...
9. Run the motor a half hour with the boat in the water and see may how the hot oil gets out of the weakest point by internal overpressure..
10. Switch of the motor and let the boat still in the water for two hours or so.
Open the engine the next weekend in you shop and found partly water in it because of the underpressure creates as the oil cool down..
The best for the seal is if it see no pressure differtial doesnt matter from which side. So logical the bladder has the same high as the motor.
A deeper installed bladder indicates a leak by oil getting out in the water, A higher install may not.
A higher installed bladder indicates maybe allready a leak onshore - and thats maybe the better solution.
The best solution is that the hose work between using device and bladder is from clear material and has a loop higher than the user and the bladder. So air in the system can be easy spotted.
See here: http://www.euronaut.org/content/upload/notes/IMG_3321a.jpg
Euronaut has seven bladders on:
- Stern Thruster (oil)
- Bow Thruster (oil)
- Anchor winch motor (oil)
- Propeller shaft (oil)
- Void space frame cave between fwd.ballast tank and pressure hull (coolant water)
- Void space frame cave between aft.ballast tank and pressure hull (coolant water)
- One bag for all three fix rudder skegs (coolant water)
- Side Rudder and Stern deeprudder are also filled with c.water but without bags.
See also the other mail I just send.
vbr Carsten
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<JimToddPsub@aol.com> schrieb:
> All,
>
> I'm having difficulty understanding the need for the bladder, and it seems
> like an additional complication and an additional point of vulnerability
> along with the line. How would this work:
>
> 1. Install a bleed valve at the uppermost point of the motor housing.
> 2. Install a fill valve at the bottom of the motor housing.
> 3. Attach a fill line (equipped with a pressure gauge) to the fill valve.
> Purge all air from the fill line prior to attaching it to the valve.
> 4. With the bleed valve open, fill the motor from the bottom until oil
> discharges from the bleed valve.
> 5. Turn the motor shaft by hand and vibrate the motor to release any
> trapped air bubbles. Close the bleed valve and allow the motor to sit for a
> couple of days undisturbed.
> 6. Open the bleed valve and add more oil to drive any residual bubbles
> out. Close the bleed valve while pressure is still being applied to the fill.
> 7. Adjust the pressure from the oil pump to the desired pressure, then
> close the fill valve.
> 8. Release the pressure on the oil pump/fill line, then disconnect the
> fill line.
>
> This seems logical to me, but I'd like to hear from the voice of
> experience. Does 14 lb. seem like a reasonable differential pressure for set up? I
> expect to start with new Minnkota motors, and I haven't addressed sticking
> with the factory seals vs retrofit seals. My intended operational depth
> is 300 feet.
>
> As always, comments and criticisms are eagerly invited.
>
> Thanks,
> Jim
>
>
> In a message dated 12/4/2010 10:07:34 P.M. Central Standard Time,
> alanjames@xtra.co.nz writes:
>
> Hi Lawrie,
> from what I can understand of the explanation on oil compensating a motor
> on the ROV site is this....
> If you have a motor with half pie reasonable seals, you just fill it with
> a suitable low viscosity oil.
> You have a drain nipple in to the bottom of the motor casing & a nipple
> for attachment of a hose
> on the top of the casing. You attach a tube from the top nipple to a
> bellows or as they suggested
> something like the bladder in a football. This is filled with oil &
> pressurized to about 15 psi so there
> is always an external pressure of the motor oil over the internal pressure
> of the sea or lake water of
> 15 psi no matter what depth you are at. You can use the one bladder for
> all your motors.
> The other option they mentioned was in the case where the motor might not
> be designed for underwater
> applications & the seal not so good. In this case you can make an
> enclosure, put a suitable shaft seal
> in the enclosure & do the same as the first option with the nipples tube &
> bladder but on the enclosure
> not the motor. The motor inside would need to be filled with oil & have an
> opening in it. There shouldn't be
> any air in these systems.
> The idea of the seals back to back seems to be an additional option as a
> safe guard.
> I bought a couple of trawling motors that I couldn't easily change the
> seals on so will be trying the oil
> bladder method & if I'm going through too much oil then maybe air
> compensation or buying some better motors.
> Regards Alan
>
> ----- Original Message -----
>
> From: _lawrie-psubs@environics.com.au_
> (mailto:lawrie-psubs@environics.com.au)
> To: _personal_submersibles@psubs.org_
> (mailto:personal_submersibles@psubs.org)
> Sent: Sunday, December 05, 2010 2:53 PM
> Subject: [PSUBS-MAILIST] illustration is this what you mean sort of??
> pressurized oil compensation bladder for motors
>
>
> Jim I created an illustration based on your concept as in outer oil
> housing and internal air housing for eletric motor.
> I have shown the location for a pressure sensor within the closed stem at
> the top of the outer housing and at the bottom a stem for the
> drain/fill/pressure up component not shown.
> Is this sort of what you mean with regards to seals and using oil to
> indicate you water passing the seal and increasing the differential pressure
> between the two housings? Lawrie
> On Fri, 3 Dec 2010 22:48:55 -0500 (EST), JimToddPsub@aol.com wrote:
> Great sites, Alan. Thanks!
>
> Lots of supplies/components when you click on the COMPANIES button.
>
> Jim
>
>
> In a message dated 12/3/2010 8:29:18 P.M. Central Standard Time,
> alanjames@xtra.co.nz writes:
>
> Dan Fjellroth's website is a good resource for home builds.
> Go to _http://www.ROV.net_ (http://www.rov.net/) then ROV FAQ and look
> for 'Build your own ROV'.
>
>
>
>
>
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