[PSUBS-MAILIST] Yet another compensator method

[Alan via Personal_Submersibles]

James,
an additional thought is that it looks to be placed right in the flow from the propellor.
You could have a much narrower tube & place it elsewhere.
Alan

> On 7/07/2020, at 8:23 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> James,
> ideal is to have a system that pressurises to 5psi above ambient as this is
> the figure that professional compensators try to achieve.
> Compensating as Cliff does with a relieving regulator does this. He was
> air compensating, but if you oil compensate with his system you have the 
> Cooling plus added security that if all the oil leaked out you would still have
> air compensation.
> With your bellows, I would reduce the air volume a lot. The oil expansion
> won't be much & you can run your motors out of water till they get hot to
> check that if you like (but don't overheat them). If you lost oil then the bellows
> could compress in to the affixed tube & rupture; so less air volume will give
> you a bit more of a reserve of oil.
> I would have also put the bellows on the bottom side. If they rip or deteriorate
> with the oil & leak, then oil being lighter than water will flow out & be replaced
> with sea water.
> You could rectify that by swapping the thrusters from one side to the other.
> If you enclose them for protection, then maybe in an acrylic tube so you can
> keep an eye on the oil level.
> Alan.
> 
> 
>> On 7/07/2020, at 1:31 AM, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Hi All
>> 
>> Getting Jodie B ready for diving in the next week or so.
>> I have changed the motor compensator yet again as the last enclosed one didnt really have a proper flexible part and I think the oil expanded a bit over time and leaked out through the seals.  Just a tiny bit, but enough to put some air back in the pipe.
>> 
>> Anyway, the new method is simply a tube with belows.  These are from a toilet flush and have been sitting full of oil for a couple of weeks to see if anything happens.  They seem good, so i have installed them. The motor is completely filled with oil and the bellows have a small amount of air.  They compress easily, so should provide pressure compensation while also allowing the oil to expand if required.
>> 
>> The bellows will be covered with an open ended tube for protection.  Just got to make a strap for those.
>> 
>> Any comments?
>> Thanks
>> James
>> 
>> <20200704_142240.jpg>
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