Cleaning forepump oil out of a turbo

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
ian_krase
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Re: Cleaning forepump oil out of a turbo

Post by ian_krase » Mon Oct 09, 2017 12:37 am

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.

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Re: Cleaning forepump oil out of a turbo

Post by John Myers » Mon Oct 09, 2017 5:04 am

D-limonene is used as a solvent and might be a usable and less flammable/toxic alternative.

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Re: Cleaning forepump oil out of a turbo

Post by John Futter » Mon Oct 09, 2017 6:31 am

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

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Re: Cleaning forepump oil out of a turbo

Post by Jerry Biehler » Mon Oct 09, 2017 10:03 am

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 » Mon Oct 09, 2017 1:37 pm

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.

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Re: Cleaning forepump oil out of a turbo

Post by Jerry Biehler » Mon Oct 09, 2017 7:12 pm

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.

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Re: Cleaning forepump oil out of a turbo

Post by ian_krase » Tue Oct 10, 2017 3:11 am

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.

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Re: Cleaning forepump oil out of a turbo

Post by Jerry Biehler » Tue Oct 10, 2017 3:57 am

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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Re: Cleaning forepump oil out of a turbo

Post by Rich Feldman » Tue Oct 10, 2017 5:52 am

>> 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.
Richard Feldman

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Re: Cleaning forepump oil out of a turbo

Post by ian_krase » Tue Oct 10, 2017 8:18 am

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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