[PSUBS-MAILIST] Oil Compensator

[Sean T. Stevenson via Personal_Submersibles]

http://www.finning.com/content/dam/finning/en_ca/Documents/Parts/Maintenance-Products/Grease/Marine-Grease-Datasheet.pdf

Sean


On April 10, 2017 10:15:36 AM MDT, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>I just got off the phone with the Parker guys, their elastomer seal
>group
>out of Utah.  I discussed the MK-101 application issue with them as it
>applies to my boat (air compensation, 4 psi differential, 450 fsw max
>ambient). I guided the conversation towards the KISS principle rather
>than
>evaluating more sophisticated seals such a double mechanical cartridge
>seals. The guy I spoke with said that the 1-atm gap between the two lip
>seals, as per the manufacturers original design, is very likely to
>cause
>a problem as well as seal orientation.  His recommendation was to use
>the
>two existing lip seals but to reverse them, so that the outer bound
>seal
>could handle the situation where the pressure compensation is off and
>boat
>is just sitting in the water over night and the inner seal is oriented
>so
>it can handle the normal operating condition of a 4 psi higher internal
>pressure than ambient.  He also suggested using a seawater and
>freshwater
>resistant grease between the seals rather than oil to help prevent 
>this
>barrier fluid from leaking out. He also suggested removing the
>cardboard
>spacer.  Under normal operating conditions when the thruster is being
>pressure compensated, the 4 psi is trying to push both seals out of
>the Minn-Kota Brushed End Housing part but due to the lip seal
>interference
>fit, they should stay in place.
>
>I am inclined to give this a try. Not sure what greese to try but a
>quick
>look online looks like  DuPont Marine Grease with Teflon fluropolymer
>might
>work.
>https://www.amazon.com/DuPont-Teflon-Waterproof-cartridge-DGM614101/dp/B003UTX0N2
>http://www.performancelubricantsusa.com/product/marine-waterproof-grease.php
>
>Does anyone have a better recommendation for a saltwater -freshwater
>resistant grease for this application?
>
>
>
>
>
>On Mon, Apr 10, 2017 at 9:27 AM, Jon Wallace via Personal_Submersibles
><
>personal_submersibles at psubs.org> wrote:
>
>>
>> What I've gleaned so far is that regardless of oil vs air method,
>nobody
>> has addressed the space between the shaft seals on the minn-kota so
>from
>> that perspective the methods are equal.  Regarding that void between
>the
>> seals I have to again wonder if the two seals are really necessary in
>a
>> compensated system.  I'm looking at one of my MK101 lower units and
>the
>> space between seals is about 6mm.  But for sake of argument, assuming
>both
>> seals are required, could you not simply remove the spacer and outer
>seal,
>> fill some part of the void with oil and then discard the spacer but
>install
>> the outer seal so it butts against the oil reservoir creating a
>sandwich of
>> inner-seal, oil, outer-seal.
>>
>> I really like the air compensation system that Greg and Cliff
>described.
>> While it is simplistic in theory, I am concerned that I am going to
>end up
>> with an octopus of tubing trying to retrofit it to the K-600 using
>the
>> existing hull penetrations.  However, not needing to pot the wires at
>the
>> motor or worry about fluid creep between insulating wires is
>attractive.  I
>> also notice in my unit that there is white grease lubricating the
>thrust
>> bearing and shaft seals.
>>
>> Jon
>> _______________________________________________
>> 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/20170410/1f3a3093/attachment.html>