Anybody built a centrifuge?

[OUCH! That's hot!]

As the title says; one suitable for cleaning waste oil?
This is the sort of thing I'm thinking of:
http://www.youtube.com/watch?v=SxIr4NFl3fs

 

[Blurk99]

i've never built one but i've seen a centrfuge rotor 'let go' at 3200rpm, that scared the crap out of me, these are just for removing solid contaminants prior to making biodiesel yes? they seem like a neat idea - are they new or have they been around for a while?

jim

 

[Robotstar5]

We've got one for removing oil from water drained off from air receiver at work so water is "clean" enough to go into foul drains.

 

[OUCH! That's hot!]

i've never built one but i've seen a centrfuge rotor 'let go' at 3200rpm, that scared the crap out of me, these are just for removing solid contaminants prior to making biodiesel yes? they seem like a neat idea - are they new or have they been around for a while?

jim

Not a new idea, no... In fact some mechanics call re-cycled engine oil, "spun oil" but there is a lot more going on than just spinning out the solids which will, on its own not make the oil amber coloured again and additives are added to improve the oil. A lot of people heat workshops with old oil burners and centrifuging the oil first cuts down on injector and pump wear.

John.

 

[500e]

Old

Simca used them on car engines in the 50\60 they are used on lorry engines, I think as standard on some Detroit diesels, ships use them also

 

[octo0072000]

wooden centrifuge

here's one DIY made of wood seems to get the job done

http://www.youtube.com/watch?v=gKQK5cYin2Q

 

[julianthegypsy]

I worked for a major centrifuge maker as a service manager for four years. What do you actually want to do? The thing with centrifuges is that they are capable of quite incredible things. I have installed machines to completely clean the oil in a steel rolling mill, until it came out amber, a bank of 12 to clean dirty marine diesel before being fed to a power station, another in a winery to clarify the wine, dozens more to separate raw palm oil sludge etc etc. The thing is, if you want it to work properly at any sort of flow rate it has to hit it with huge G forces, which means spinning really fast, and I mean REALLY fast. The issue then is balance, and you can't really do it at home, if it comes unglued all hell breaks loose. You may be able to find an old one and adapt it, or even better, if you can find an old hand driven milk separator you may be able to modify it. As its hand driven of course, it won't go that fast, which means the it will be really slow, but worth doing for some things.

 

[Rick]

I worked for a major centrifuge maker as a service manager for four years. What do you actually want to do? The thing with centrifuges is that they are capable of quite incredible things. I have installed machines to completely clean the oil in a steel rolling mill, until it came out amber, a bank of 12 to clean dirty marine diesel before being fed to a power station, another in a winery to clarify the wine, dozens more to separate raw palm oil sludge etc etc. The thing is, if you want it to work properly at any sort of flow rate it has to hit it with huge G forces, which means spinning really fast, and I mean REALLY fast. The issue then is balance, and you can't really do it at home, if it comes unglued all hell breaks loose. You may be able to find an old one and adapt it, or even better, if you can find an old hand driven milk separator you may be able to modify it. As its hand driven of course, it won't go that fast, which means the it will be really slow, but worth doing for some things.

You could still make one then take it to be balanced.

 

[jugs]

i've never built one but i've seen a centrfuge rotor 'let go' at 3200rpm, that scared the crap out of me, these are just for removing solid contaminants prior to making biodiesel yes? they seem like a neat idea - are they new or have they been around for a while?

jim

Nothing new jim -

used in 1860s for separating cream from milk (skimmed milk), improved by De Laval in 1880s for cleaning oil, used extensively in chemical & food industry's

 

[julianthegypsy]

You could still make one then take it to be balanced.

Yes you could. It has to be balanced at full speed though and its not a cheap job. If you made it yourself, what would you make it from? They're normally made from spun-cast stainless-for a reason. Any slight flaw and you have a major bomb on your hands. I read an account of a latex separator coming unglued in Malaysia once, probably because it was badly maintained and they forgot to fill it before they started it, but anyway, eight dead and a major mess. Would have been worse but there weren't any more people in the building.

 

[dai]

i got a centrifugal engine oil filter on a zetor tractor

 

[Rick]

Yes you could. It has to be balanced at full speed though and its not a cheap job. If you made it yourself, what would you make it from? They're normally made from spun-cast stainless-for a reason. Any slight flaw and you have a major bomb on your hands. I read an account of a latex separator coming unglued in Malaysia once, probably because it was badly maintained and they forgot to fill it before they started it, but anyway, eight dead and a major mess. Would have been worse but there weren't any more people in the building.

It doesn't have to be balanced at full speed, infact its very rare anything is balanced at operating speeds.
Price would depend how awkward it is to balance. Its no worse than any other rotating part, i.e. something in a lathe. A large fan etc etc.

 

[julianthegypsy]

It doesn't have to be balanced at full speed, infact its very rare anything is balanced at operating speeds.
Price would depend how awkward it is to balance. Its no worse than any other rotating part, i.e. something in a lathe. A large fan etc etc.

Sorry, but it does. I've stood beside a machine with a 350 kg bowl while it was spun up to 5,000 rpm with the covers off. At that speed if a grain of sand dropped on it, it would come off like a bullet. We did not do that for fun, it takes all your nerve not to run. If it could have been extrapolated from a lower speed run we would have done it. One of the reasons is that it can get very shaky at critical speed, often at around 1000 rpm. As for the part in a lathe, how often do you get parts 2 feet across doing 5000 rpm in a lathe, or say a smaller part, maybe 25cms across, doing 17.000 rpm?

 

[NigelAylesbury]

All our machines at work do 48,000 rpm plus.
we don't balance at anything like that - more like 1500
but we don't go past critical

 

[hotrodder]

I don't get the 'balanced at speed' thing. Critical speed aside if something is perfectly balanced at 100 rpm then surely it's balanced at 1000rpm or 10000rpm. Surely the issue is that nothing is perfectly balanced and while the imbalance doesn't change with speed the forces generated by this imbalance increase by the square of speed? So taking engine bits for example... maybe something like 100g.mm will cut it for a crankshaft assembley in a shopping trolley which wouldn't be good enough for a modern sportsbike and not even remotely good enough for something like a turbo

ETA what class are centrifuges typically balanced to?