<html><head></head><body><p dir="ltr">The Parker O-ring Handbook includes design guidelines for such dynamic shaft seals, including maximum surface speeds and so forth. I have used this on several occasions to design rotary shaft seals.</p>
<p dir="ltr">Sean<br>
</p>
<br><br><div class="gmail_quote">On September 7, 2014 5:21:33 PM MDT, Vance Bradley via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="k9mail">Low rpm was the key. Much faster and the rubber overheats.<br />Vance<br /><br />Sent from my iPhone<br /><br /><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> On Sep 7, 2014, at 7:04 PM, hank pronk via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br /> <br /> Vance,<br /> Sounds like a good option if you have in house machining. The cartridge seal shaft is equally fussy, it took me a few try's to get it perfect. I am sure Brian is a better machinist than I am, so should be no problem.<br /> I believe the slower the rpm the better with o-ring seals.<br /> Hank <br /><hr /><br /> On Sun, 9/7/14, via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br /> <br /> Subject: Re: [PSUBS-MAILIST] Brushless Thrusters<br /> To: personal_submersibles@psubs.org<br /> Received: Sunday, September 7, 2014, 6:49 PM<br /> <br /> Hank,<br /> <br /> <br /> <br /> <br
/> Harbor Branch used o-rings on the reduced output 1<br /> 1/4 thrusters on the JSLs. The mid-body on the hard can<br /> (actually the back 25% or so of the cylinder section) was<br /> machined on the output side for planetary gears, and<br /> machined on the motor side to replace the entire output<br /> plate/bearing case for the motor itself (like a golf cart<br /> motor bolts into a differential). Pretty nice and compact<br /> for the day.<br /> <br /> <br /> <br /> <br /> <br /> The rear section of the hard can behind the gear<br /> case is a hollow sand casting shaped like the long end of an<br /> egg, webbed internally to support a 1" shaft, double<br /> bearings, with double thrust bearings, and a tapered,<br /> polished, hardened aluminum sleeve pressed in from the<br /> pressure side.<br /> <br /> <br /> <br /> <br /> <br /> The shaft itself was machined to carry double<br /> o-rings in square cross section grooves and terminated on<br /> the internal end with a
flex-coupling which mated<br /> (obviously) to the output of the planetary output. A big<br /> shaft was necessary to keep the jitters down to more or less<br /> zero. Everything needs to stay exactly centered, as the<br /> O-rings will go to pot a whole lot faster if there is any<br /> flex or vibration at all in that prop shaft<br /> shaft.<br /> <br /> <br /> <br /> <br /> <br /> Lots of development to get it right, finally, but<br /> the props turned about 275-300 rpm (I don't remember<br /> exactly, but something like that). 14" X 14" Kort<br /> style prop in a machined syntactic foam nozzle supported on<br /> a 4-legged frame welded to the aft part of the shell. I<br /> actually have a blueprint of it, somewhere around here. For<br /> those interested, the tip clearance between blade end and<br /> nozzle sleeve was about 50-thousandths. NOTE: That would be<br /> of an inch, Emile.<br /> <br /> <br /> <br /> <br /> <br /> There were no speed controls on the boats.<br />
Fwd-Off-Rev only. You just turned thrusters on or off to<br /> vary the push. When I was there, we had 5 for forward and<br /> reverse (3 in a row on the centerline with 1 each to port<br /> and starboard aft) plus a vertical and horizontal pair<br /> forward and aft for steering and fine maneuvering (fine<br /> maneuvering my ass!!!). That's right. NINE thrusters<br /> that probably with cabling weighed over half a ton. Plus two<br /> or three spares in the kit ready to bolt up at a<br /> moment's notice as replacements. We were definitely in<br /> the motor business with those babies.<br /> <br /> <br /> <br /> <br /> <br /> They were home grown but worked reasonably well,<br /> although they were a little noisy with the gear case and<br /> whatnot. That said, I never saw the electrical side flooded<br /> on one of those things. Not once. Ever. We had a routine<br /> service schedule and changed a thruster every so many hours<br /> of service. Just put a fresh one on (two people
could do a<br /> change-out in about three minutes), then tear the<br /> to-be-serviced unit down to check brushes and bearing lube<br /> and change the shaft o-rings (which would be looking a<br /> little fuzzy by then, but still worked fine--and even if<br /> they looked brand new, we changed them). It needs a really,<br /> really first rate waterproof lubricant, as the internal<br /> shaft o-ring runs hotter than the one in contact with the<br /> water, and was often in worse shape than the one primary as<br /> a result.<br /> <br /> <br /> <br /> <br /> <br /> Once the JSLs re-certified to 3000 feet,<br /> engineering redesigned the seals for better service, using a<br /> ceramic cartridge seal in place of the o-rings, but that was<br /> after my day. I'd hate to even think what<br /> one would cost today, built commercially. You wouldn't<br /> use them, probably, as a unit with twice that power is<br /> probably a third the size and weight.<br /> <br /> <br /> <br /> <br /> <br
/> Those thrusters on the Tritons,<br /> for instance, look positively tiny by comparison, and<br /> they're rated at over 2 hp. Then there's our own<br /> Uncle Dr. Phil's new mag coupled ones. Now there's a<br /> Christmas present to ask Santa for.<br /> <br /> <br /> <br /> <br /> <br /> All that aside, the o-rings will<br /> work if you plan regular service (ie, scheduled o-ring<br /> replacement) and don't wait for water intrusion. They<br /> have to be done right during construction, though. Those<br /> surfaces have to be mirror smooth.<br /> <br /> <br /> <br /> <br /> <br /> Vance<br /> <br /> <br /> <br /> <br /> <br /> <br /> -----Original<br /> Message-----<br /> <br /> From: hank pronk via Personal_Submersibles<br /> <personal_submersibles@psubs.org><br /> <br /> To: Personal Submersibles General Discussion<br /> <personal_submersibles@psubs.org><br /> <br /> Sent: Sun, Sep 7, 2014 4:51 pm<br /> <br /> Subject: Re: [PSUBS-MAILIST] Brushless Thrusters<br />
<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Brian,<br /> Vance would know better than me, but I think if you keep the<br /> rpm under 1,000 you <br /> can use an o ring for a seal. I thought Perry did that in<br /> the early subs to <br /> 1,000 feet. <br /> Hank<hr /><br /> On Sun, 9/7/14, hank pronk via Personal_Submersibles <personal_submersibles@psubs.org><br /> <br /> wrote:<br /> <br /> Subject: Re: [PSUBS-MAILIST] Brushless Thrusters<br /> To: "Personal Submersibles General Discussion"<br /> <personal_submersibles@psubs.org><br /> Received: Sunday, September 7, 2014, 4:42 PM<br /> <br /> <br /> Brian,<br /> You can use a simple<br /> mechanical seal, that is what the K subs have. An 891<br /> Chesterton mechanical seal is good fo 600 psi, that is what<br /> Gamma had when I got it. You can buy them on ebay for 100<br /> bucks. Build the shaft to fit the seal, and your<br /> sailing.<br /> Hank<hr /><br /> On Sun, 9/7/14,
Brian Cox via<br /> Personal_Submersibles <personal_submersibles@psubs.org><br /> wrote:<br /> <br /> Subject: Re:<br /> [PSUBS-MAILIST] Brushless Thrusters<br /> To:<br /> "Personal Submersibles General Discussion" <personal_submersibles@psubs.org><br /> Received: Sunday, September 7, 2014, 4:29<br /> PM<br /> <br /> I<br /> <br /> talked to a hydraulics guy a few days ago about making a<br /> seal for my motor pod. I told him I had a<br /> high pressure<br /> tank that I wanted to turn a<br /> shaft inside the tank to stir<br /> the contents<br /> at 250 psi, ( didn't want his eyes to<br /> <br /> glaze over if I mentioned submarine !) Anyway he<br /> directed<br /> me to a system using a bronze<br /> fitting that would tighten<br /> down these rings<br /> he called "cheverons" they are<br /> <br /> mating rings of a very high durometer . the bronze is<br /> for<br /> mating with stainless . I would have<br /> to machine an<br
/> assembly for this , but once<br /> I have my shaft size (1 inch<br /> most likely) I<br /> will be able to size everything<br /> <br /> accordingly. Brian <br /> <br /> <br /> ---<br /> personal_submersibles@psubs.org<br /> wrote:<br /> <br /> From: hank pronk<br /> via Personal_Submersibles<br /> <personal_submersibles@psubs.org><br /> To:<br /> personal_submersibles@psubs.org<br /> Subject: Re:<br /> [PSUBS-MAILIST]<br /> Brushless Thrusters<br /> Date:<br /> <br /> Sun, 7 Sep 2014 07:07:20 -0700<br /> <br /> Alan<br /> When I upgraded the<br /> cartridge seal in Gamma, I needed a pretty<br /> Beafy thrust<br /> bearing, it was no problem to<br /> get. have since changer to<br /> <br /> Magnetic. I think you could replace the bushing<br /> in a<br /> thruster with a ball bearing and never<br /> look back. <br /> Hank <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />
<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> From:<br /> <br /> <br /> <br /> Alan via Personal_Submersibles<br /> <personal_submersibles@psubs.org>; <br /> <br /> <br /> <br /> <br /> <br /> <br /> To:<br /> <br /> <br /> <br /> Personal Submersibles General<br /> <br /> Discussion <personal_submersibles@psubs.org>; <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Subject:<br /> <br /> <br /> <br
/> Re: [PSUBS-MAILIST] Brushless<br /> Thrusters <br /> <br /> <br /> <br /> <br /> <br /> Sent:<br /> <br /> <br /> <br /> Sun, Sep 7, 2014 1:43:49 PM <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Hi Hank,the kort<br /> <br /> nozzle on the Indonesian thruster looks a bit<br /> Naff. ( I am designing an art work<br /> here.)I could get a price for the unit<br /> without<br /> kort nozzle, butI'm wondering<br /> if I could<br /> build something for 1/2 that<br /> price.There are some<br /> reasonably priced<br /> brushless motors about.I<br /> don't know<br /> that I could just retro fit a thrust bearing<br /> inside the can of the motor.I tried to put<br />
a<br /> thrust bearing for reverse inside my<br /> brushed thrusters,<br /> butcouldn't find one<br /> with a thin enough<br /> section to fit.Also the<br /> motors are a bit<br /> expensive to just buy<br /> & hope you can fit<br /> one.How did you fit<br /> the thrust bearing on Gamma?<br /> Did the<br /> propellor shaft extend out the backof<br /> the<br /> motor?Alan<br /> <br /> Sent from my<br /> iPad<br /> On 7/09/2014, at 7:22 pm, hank pronk<br /> via<br /> Personal_Submersibles <personal_submersibles@psubs.org><br /> wrote:<br /> <br /> <br /> Allan<br /> Dont<br /> worry about<br /> thrust bearings to much. They are aesy to get,<br /> I bought one for Gamma , real heavy duty for<br /> 80 dollars. <br /> Personally I would just use a<br /> good quality bearing and<br /> replace it once a<br /> year for 8 bucks, if it is a small<br /> <br /> thruster. Are you not happy with the <br /> Indonesia thrusters?<br />
Or to pricey?<br /> Hank <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> From:<br /> <br /> <br /> <br /> Alan via<br /> Personal_Submersibles<br /> <personal_submersibles@psubs.org>; <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> To:<br /> <br /> <br /> <br /> Personal Submersibles<br /> General<br /> Discussion <personal_submersibles@psubs.org>; <br /> <br /> <br /> <br /> <br /> <br /> <br />
<br /> <br /> <br /> Subject:<br /> <br /> <br /> <br /> [PSUBS-MAILIST] Brushless<br /> Thrusters <br /> <br /> <br /> <br /> <br /> <br /> Sent:<br /> <br /> <br /> <br /> Sun, Sep 7, 2014 11:58:56 AM <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Hi people,<br /> I've<br /> spent several hours today looking at brushless<br /> thrusters<br /> & wonder if anyone else has<br /> looked at them or got any<br /> ideas. There is<br /> the Indonesian thruster I posted a few weeks<br /> back at US 2,200. There is also the Haswing<br /> Protruar 2hp<br /> that Emile has; however they<br
/> state that it's for fresh<br /> water only,<br /> & I think Emile said it was a bit noisy.<br /> The inrunner motors that have the winding<br /> on<br /> the outside, seem a good option as they<br /> cool through<br /> convection to the can. They<br /> also need higher revs for torque<br /> &<br /> require a planetary gear box or similar. ( which a lot<br /> have built in)<br /> I was<br /> looking at the<br /> option of making my own<br /> thruster, however the motor would<br /> require a<br /> thrust bearing & I don't<br /> know of<br /> any that would have one other than<br /> maybe<br /> a high powered battery operated drill.<br /> Any<br /> thoughts, suggestions thanks.<br /> Alan<br /> <br /> Sent from<br /> <br /> my<br /> iPad<br /> <br /><hr /><br /> Personal_Submersibles mailing list<br /> Personal_Submersibles@psubs.org<br /> <a
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