Cleaning forepump oil out of a turbo

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ian_krase
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Re: Cleaning forepump oil out of a turbo

Post by ian_krase »

See also the great frustration about the unavailability of Freon TF, and the unsuccessful search for substitutes that are not gasoline-tier flammable.

(The maintenance manual for one Varian leak detector actually said to clean the blades of a turbo by partial immersing in Freon TF. Not gonna happen now.)

This is where a manual is essential or call the company.

I haven't had any luck getting maintenance manuals but I did have some luck talking to someone who works at Ideal Vacuum Products.

The user manual for this pump has a cutaway drawing. Assuming it's accurate, I should be able to soak the pump to a depth that will get the drag stages but not the bearings. However, the bearings don't look like they are protected by a "shaft tunnel" unless you know for sure.

In any case, I think I have an idea of a path forward.
John Myers
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Re: Cleaning forepump oil out of a turbo

Post by John Myers »

D-limonene is used as a solvent and might be a usable and less flammable/toxic alternative.
John Futter
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Re: Cleaning forepump oil out of a turbo

Post by John Futter »

After reading the fact sheet for D-limonene I certainly would not put it anywhere near a high vacuum system -- too many long chain slightly polar molecules that will stick much worse than our friend water which is bad enough for most on this site
Methylene Chloride is non flammable (not too good for the ozone layer but better than freon TF as a solvent and much much better to the ozone layer)

But be careful it is so good that nearly all plastics except teflon are dissolved by it
Jerry Biehler
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Re: Cleaning forepump oil out of a turbo

Post by Jerry Biehler »

Plus Methylene Chloride is pretty easy to get, it is used as a cement for acrylic.

You dont need to dip the turbo. Just pour a little bit down the inlet to wash the excess oil out and let it drain out of the backing port. You dont need to go crazy with this, it is really not that big of a deal.
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Dennis P Brown
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Re: Cleaning forepump oil out of a turbo

Post by Dennis P Brown »

Jerry has a good idea; also, but I would like others to weigh in before you try this - one could use an electronic tuner spray cleaner can (get these online or possibly a hardware store.) Just spray the blades vertically down through the upper throat . Allow a small pool of liquid to collect (2mm at most) at the base and then pour this contaminate liquid out the lower port. You might get the blades to turn by spraying - if not, try gently to get the blades to turn a little to expose new surface. The back surfaces should collect some of the vapor. Do this one or two more times so the lower blades see clean fluid. The bearing shouldn't 'see' any liquid. Maybe. Allow to air dry, then pull vacuum on it.
Jerry Biehler
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Re: Cleaning forepump oil out of a turbo

Post by Jerry Biehler »

Its not the oil on the blades. It is the oil in the drag section. The clearances are small in this section and the surface tension of the oil will cause drag. Just need to wash that out and everything should be fine again.
ian_krase
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Re: Cleaning forepump oil out of a turbo

Post by ian_krase »

Got some mineral spirits that I'm going to try. The hardware store didn't have any toluene or xylene but they had mineral spirits, paint thinner, mineral spirits paint thinner, paint thinner (mineral spirits) and low-VOC paint thinner.
Jerry Biehler
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Re: Cleaning forepump oil out of a turbo

Post by Jerry Biehler »

mineral spirits is generally just toluene, sometime has some xylene in it, kind of a potpourri of hydrocarbons. Either is fine, you just need to thin the oil out enough and wash it away. Its just a good non-polar solvent to have on hand for cleaning things and pumps out of the system fast.
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Rich Feldman
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Re: Cleaning forepump oil out of a turbo

Post by Rich Feldman »

>> Hexane may work to dissolve the oil. Also, keep in mind that a fair amount of these solvents (xylene, toluene, benzene, etc.) are very toxic. Make sure to take safety precautions before working with them.

It's the aromatic hydrocarbons that are most toxic.
For volatile aliphatic hydrocarbons (e.g. hexane), the IDLH levels (Immediately Dangerous to Life or Health) of the vapor are generally the same as the Lower Explosive Limit. :-)
Same for isopropanol, ethyl ether, etc. https://www.cdc.gov/niosh/idlh/intridl4.html

Nonflammable solvents are less of a fire hazard, but generally their vapors are more toxic. Water is a notable exception.
All models are wrong; some models are useful. -- George Box
ian_krase
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Re: Cleaning forepump oil out of a turbo

Post by ian_krase »

There's also Propylene Carbonate, an aprotic polar solvent notable for destroying most chemical resistant plastics and rubbers (except Kalrez and simple polyolefins) while being very safe and nontoxic.
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Re: Cleaning forepump oil out of a turbo

Post by Jerry Biehler »

That stuff is more polar than isopropyl, you're going the wrong way. Polar is bad, it helps introduce water into a vacuum system as well as not going to thin out the oil.

Found the list I usually use:

http://macro.lsu.edu/HowTo/solvents/Pol ... 0index.htm

Mineral spirits is not going to kill you, not even close. Just have good ventilation and you will be fine.
ian_krase
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Re: Cleaning forepump oil out of a turbo

Post by ian_krase »

I wasn't going to use propylene carbonate in my vacuum system. Just thought of it since it's something I ran into on my day job.
ian_krase
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Re: Cleaning forepump oil out of a turbo

Post by ian_krase »

So, I cleaned the turbo with mineral spirits as proposed. This seemed to work to get the forepump oil out of the drag stages and the controller now is willing to start spin-up.

However, I am nervous about running it. The solvent cleaning looks like it left some particles sticking to some of the stator blades, which doesn't seem good, and didn't really fully dry or drain -- I have it under forepump vacuum now, but I seem to be having a hard time getting under 1.8 torr -- is that just massive amounts of evaporating heavy fractions of mineral spirits and oil residue? Should I warm it with my bakeout heater?
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Dennis P Brown
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Re: Cleaning forepump oil out of a turbo

Post by Dennis P Brown »

If you have a low vapor point liquid remaining (maybe still some of the old oil), pumping will do little. Rather, try using the solvent again and do two or three rinses )using as little new solvent as possible.) This might help remove the particles (but if any still remain and are very low mass, the spinning blades should "throw" these off. You will know if this is an issue when it starts to spin up in a big way; if significant vibrations occur - trouble and turn it off. If it spins up smoothly, then they aren't an issue.)

A single (or even two) rinses doesn't always fully clean even a glass with a bit of dirty liquid in it - a turbo might be a bit more difficult still ...lol.
ian_krase
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Re: Cleaning forepump oil out of a turbo

Post by ian_krase »

As it turns out, my foreline was full of water and other contamination in the crevasses - was getting cold from that boiling off.
Brian Edwards
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Re: Cleaning forepump oil out of a turbo

Post by Brian Edwards »

Ian,

Did you get this system up to speed yet?
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