[PSUBS-MAILIST] Thruster bladders

[Rick Patton via Personal_Submersibles]

Hi Alan, would love a drawing if you don't mind as I am not clear how you
will use the motor when underwater and not have all the stuff you show on
the ladder?
Thanks
Rick

On Wed, Sep 15, 2021 at 11:58 AM Alan James via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Hi Rick,
> This is a home built brushless thruster. I have attached a photo of a pool
> test.
> It's not that clear but I have one tube coming off the motor that also
> contains the wiring.
> The tube is going to an oil compensator (big aluminium thing sitting in
> the plastic box).
> At a point along the tube I have a plummers T fitting where the wires are
> potted & come out from. Another tube is attached at 90 degrees & leads to
> the compensator.
> So I fill the motor up with 5cst silicone oil and don't worry about
> getting every bubble of air out. Then attach the hose & fill the rest of it
> from a fill port on the compensator.
> I have done away with that compensator and are using an air pressure
> regulator set at 5psi with a relieving valve set at 7-8 psi.
> The regulator has to be mounted upside down & have a hole in the handle
> area. The seawater comes in through the hole and compresses the air on to
> the regulator diaphragm, giving your set pressure of 5psi plus ambient
> water pressure.
> You could have a separate nipple on your motor for the air compensation
> tube.
> You fill the oil partially up the tube which acts as your oil level
> indicator. The beauty of having oil pressurised by air, is that if the oil
> leaked out the air will replace it & still keep
> the seawater out.
> BTW Karl Stanley has been to 2000ft with an
> air compensated system, using a 1st stage regulator that he has removed
> the spring from to give ambient pressure.
> I don't like the system where people wrap a tube around the motor &
> connect to two nipples. We discussed this at length & thought that the
> plastic tubing may not collapse to give ambient pressure till about 100psi.
> So you are basically relying on the motor seals.
> I can do you a dwg of how my system will be if you like!
> Alan
>
>
> On Thursday, September 16, 2021, 09:14:18 AM GMT+12, Rick Patton via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Hi Alan,
> You mentioned oil being flung up the feed tube and that it is clear and
> gives you an idea of the oil level. I am confused on how you have your feed
> tube set up? Does it come out of the top and back into the bottom of the
> can or is there only one hole in the can with a clear tube coming out a
> foot or so with a plug on the end and there must me air in the plastic tube
> to be able to give you an oil level and I didn't think you were supposed to
> have any air in the system at all?
> Rick
>
> On Tue, Sep 14, 2021 at 6:35 PM Alan James via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Hi Rick,
> I am pressurising the oil in my thrusters with air at 5psi above ambient.
> Have found that without a bit of pressure the oil gets flung out of the
> motor housing & up the feed tube.
> The feed tube to the thruster is clear & gives me an indication of the oil
> level.
> I have spent a lot of time on the compensator issue, even 3d printing one
> & using a second stage regulator.
> I am currently ordering a stainless 316 pressure regulator with a 0-25psi
> output range and a stainless brewers over-pressure valve set at between
> 6-8psi. This is similar to what Brian Hughes is doing & a modification on
> what Cliff was using. Cliffs relieving type regulator couldn't cope with
> the back pressure build up.
> One advantage of going this route is that if you want to copy the Psubs
> electric manipulator (am working on my own version) you need to air
> compensate it & you can do both off this same unit.
> I am running a hose from the regulator to a manifold, from which hoses
> will go to 4 thrusters, the electric manipulator and over-pressure valve.
> Let me know if I can help.
> Alan
>
>
>
> On Wednesday, September 15, 2021, 04:14:32 PM GMT+12, Rick Patton via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> I am re thinking what to use for my oil expansion bladder. Would love to
> hear from everyone who chose to go with an oil filled thrusters on what
> they used and how they liked it. I remember someone saying that they used a
> squeeze ball gas tank primer which I like because it is small but I just
> spoke with someone who didn’t use a bladder and had never had a problem.
> Rick
>
> Sent from my iPhone
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20210916/f6d49de2/attachment.html>