Silicosis From Boiling Diff. Oil and Mech. Pump

[Liam David]

Early this summer I had two professors from George Washington University come over to observe my fusor setup. One of them mentioned that silicosis from my mechanical pump exhaust is an issue. Ever sense then, my dad has mentioned repeatedly that I need to do something about this. I haven't yet because of the outrageous costs of oil mist filters. Now I'm ready to test my new diffusion pump, but he won't allow me due to the boiling oil creating even more mist. How real is this silicosis from vacuum pump oil risk? If there is a risk, what material should I use to absorb the oil?
-Liam David

[prestonbarrows]

Oil mist eliminators can be gotten fairly cheap on ebay, around $50. Brand new models from Lesker start around $100-150; you don't need the $5,000 versions.
If you want to be really thorough, attach a line from the exhaust port to a dryer vent or similar to the outdoors; make sure it is fat and short enough to not add backpressure to the pump.

Most non-commercial, university labs Ive worked in at most use an oil mist eliminator and that is more to cut down the annoying plume when first roughing out a chamber from atmosphere rather than health concerns. Commercial fab setups typically have exhaust lines built into the building directly connected to the pumps; mostly to maintain 24/7 cleanliness and the fact they use corrosive working gasses. Neither of these are an issue for a hobbyist plasma setup.

Silicosis results from long-term exposure (more than 20 years) to low amounts of silica dust. Silica dust forms during mining, quarrying, tunneling, and working with certain metal ores. Silica is a main part of sand, so glass workers and sand-blasters are also exposed to silica.

I have never heard of this in relation to vacuum systems...

[George Schmermund]

Silicosis from a vacuum system?! This is laughable! What other 'plums of absurdity' did these 'professors' share with you?

[Liam David]

Not much else. They just figured out why my vacuum tube was fluorescing orange when I had plasma. Turned out to be the electrical potential difference between the ball valve and chamber. The guy who told me about the "silicosis issue" was an electrical engineer.

[Richard Hull]

I agree, no real silicosis issue with pumps, but breathing oil mist is a big no-no!

I have vented my pump's exhaust since 2000 to the outside world via a 3/4-inch copper pipe and a hole in my lab's wall. I used molding putty around the pipe to seal out weather and rain water. I also soldered on a turn down 90 degree elbow aimed at the ground. In addition, I soldered a small circular copper screen over the opening in the elbow to keep bugs out of the pump oil should they try and enter and move through the pipe where the last stop in their life cycle would be my pump oil.

Richard Hull

[John Futter]

To get silicosis you need finely divied silicon oxide /dioxide ie sand
so this is not what is going to happen unless you work in a quarry or you do stone carving with power tools for a hobby
But you can get http://en.wikipedia.org/wiki/Pleura-pneumonia from breathing hydrocarbon oil vapour that will make you very sick if you inhale enough.
Vent the pump outside just as Richard does or vent into a chamber filled with cotton wool.

[richnormand]

Early this summer I had two professors from George Washington University come over to observe my fusor setup. One of them mentioned that silicosis from my mechanical pump exhaust is an issue. Ever sense then, my dad has mentioned repeatedly that I need to do something about this. I haven't yet because of the outrageous costs of oil mist filters. Now I'm ready to test my new diffusion pump, but he won't allow me due to the boiling oil creating even more mist. How real is this silicosis from vacuum pump oil risk? If there is a risk, what material should I use to absorb the oil?
-Liam David

Silicosis? Don't think so from oil mist!
But I was getting tired of the oil smell in the basement. This is my setup and it has been working well for the past 5 or 6 years.
The mist filter is from ebay (KF-25 fittings in and out, about $35, including spare filter elements). I am still on the first one. Not so much as a filter but a way to capture the oil mist and return it to the pump as it drains.
On top you can see a copper pipe adapter (painted black) to a garden hose fitting. This hose then goes to the outside via the clothes dryer exhaust pipe. Not inside the pipe mind you but along it to the outside of the house.
No backup pressure issues , small, discreet, cheap and quiet.

[Andrew Seltzman]

See if this seller will sell just the filter real cheap, and then replace the element:

http://www.ebay.com/itm/AS-IS-LEYBOLD-D ... 460ffd14c4

[Dennis P Brown]

I too, like Richnormand, just use a water hose attached to my exhaust port (using a KF adapter and plastic hose fitting) and let the trivial amount of oil mist vent into a water drain pipe (below the water trap that isn't used for water!) In that way I don't need to deal with a hole in the wall. I just made my own anti-mist device for my large backup mechanical vacuum pump - used a large diameter plastic pipe, two end caps, steel wool (to be placed on the inside) and a pipe fitting that screwed into my pump exhaust port and used pipe glue for one cap and the screw fitting. A hand drill made the required holes for the air venting and a larger wood drill bit the access hole in the lower cap for the screw adapter for the pump. Very cheap and easy. (aside: the threads on my plastic end pipe adapter didn't exactly match my pump exhaust threads but being soft plastic, these were easy to force on by a thread turn or so resulting in an acceptable fit ... .)

The one part I do worry about is an anti-oil vapor back flow (a separator) on the vacuum side of my mechanical pump. I got one cheap on e-bay and after rinsing with alcohol, use it for my high vac system. This anti-back flow device could easily be made using new steel wool, plastic pipe tubing like I outlined above but since it must be vacuum tight, KF end fittings for both sides would offer the best adaption (maybe) for your system.

[Chris Bradley]

Yup. Ditto. Water hose. Actually belt and braces - both an oil mist filter and I pipe it to the outside.