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Mcgyver
05-23-2010, 02:13 PM
I want to build a disk type tramp oil skimmer and would like ideas/advice on powering it. Can't quantify the load other than suspecting its light, turning a 12" disk through a couple of squeegees at 10 rpm.

Aside from doing the job, I want it cheap to make and run forever....I have no experience with small motors so I don't how feasible a continuous duty is. if its not, or if its big bucks, I even had the crazy idea of powering it somehow via the submersible pump as I've been told they almost do last forever.

Ideas?

CCWKen
05-23-2010, 02:32 PM
Best bang for the buck on low rpm motors is Rotisserie Motors for barbeque grills. They have a pretty high torque and you can get them for less than $15. I bought two spares to have on hand but they're still in the boxes. I use one for certain electroplating setups. I've used the one for over three years now and it keeps going. Granted, I don't run it 24/7 but it's never failed to start. The only thing I've found is that they can start-up in either direction. Not a problem for me but you can stop it and restart it until it runs in the right direction for you. I don't know for sure but you might be able to add a capacitor to make it run in one direction. Some of the Electron-Gurus might be able to answer that.

Bruce Griffing
05-23-2010, 04:47 PM
Try the Surplus Center. Here is an example of something I would consider from them.

https://www.surpluscenter.com/item.asp?item=5-1712&catname=electric

wierdscience
05-23-2010, 05:51 PM
Ice cream churn motors,cheap orphans can be had at the local thrift stores for $5 or less.

Buy the motor one week,pickup the tub and paddle the next and you could have a dual use tool,just make sure the water sol is gone before you add the condensed milk:D

Mcgyver
05-24-2010, 08:32 PM
thanks for ideas guys....

next order of business is a disk. must be the weather, crazy ideas abound....maybe an old record (as in 12" vinyl, remember them)? I know it has grooves, but i still think it would it would squeegee a lot off. I could use a motorhead album and it would help kill the bacteria.

I read somewhere that its best to use a disk of polypropylene as it attracts oil, whatever that means. I did some quick experiments and just about all materials if drawn through the sump have oil stick to them, so how important (or not) is the disk material.

any great ideas on that one - material source for disk and squeegee?

RobbieKnobbie
05-24-2010, 09:14 PM
for the disk you could use just about anything you've got laying around... PE, HDPE, UHMW, sheet metal would probably work just fine.

For the squeegies you could just go with two squeegies stolen from a distracted window washer, or maybe two thin strips of plain black 1/8" rubber. Make sure you have a little container for the oil to run off the squeegies into... elsewise you're letting it run back into your sump :eek:

Duffy
05-25-2010, 12:31 AM
Mcgyver, you THOUGHT that you wanted a 12" disc, but what you REALLY wanted is a circle cut from an IKEA thin cutting board, (2 for$4.00.) It will be close enough, and if you splurge and change your windshield wipers BEFORE they are shredded, you will have squeegees. Old record changer motor and pulley will get you 33 1/3 rpm for starters and you only have to drop it 1/10 more. If you are REALLY nice, I have a heavy-duty 10 rpm gearmotor that you MIGHT talk me out of. e-mail me. Duffy

Marc M
05-25-2010, 04:57 AM
Our synthetic coolant destroys rubbers and plastics over time. I replace the usually thin plastic wipers with strips of shim stock. I've seen minimal wear on the disk (stainless) and the wipers last forever.

For the disk, I'd try to find an old 14"-18" saw blade, or just make a belt type skimmer due to it's simplicity.

The gear motors are a different story. Due to the relatively heavy overhung weight of the disk or belt, the bushings simply don't hold up and wear oblong causing the disk/pulley to droop, and ultimately the rotor will start to contact the motor frame. I'll press the bushings out and turn them 180* to get more life. After it wears a second time, the internal gear train is usually worn out so the whole thing gets replaced (McMaster, Grainger, MSC). If you're designing from scratch, support the disk on both sides so the gear motor doesn't have to support the weight of the skimming element.

Marc -

Mcgyver
05-25-2010, 04:20 PM
thanks again. i like the saw blade and shim stock idea...I have everything in stock for that. Plan was always to have the disk on its own axle & bearings and drive via some sort of belt

Duffy, email sent!