Possibility of PCB Oils in old Diffusion Pumps?

[jasonlee112]

TL;DR

Is there a possibility that these pumps have PCB based oil inside?

I recently found three old vintage diffusion pumps left over by the previous lab owners:

1. Veeco EP 2A
2. Veeco EP 2A-1
3. Edwards Speedivac F203

Is there a possibility that these pumps have PCB based oil inside? I do not have access to PCB oil testing at the moment. Also any further information about these pumps in terms of manufacturing date? Since that would give a good idea about the presence of PCB oil.

 

[berkeman]

Welcome to PF.

What have you found with Google searches so far?

 

[jasonlee112]

Welcome to PF.

What have you found with Google searches so far?

Thank for for the welcome. So far no information about any of these vacuum pumps except eBay listings. I found that some diffusion pumps supposedly contain PCB oils but little to no information beyond that. It looks like this information may have come before the days of the internet so I'm wondering if anyone here has any experience.

 

[Dullard]

I don't know about the intended composition of old DP oil, but (depending on the old process) it could be contaminated with almost anything.

 

[kuruman]

During my servitude as grad student in the seventies I changed diff pump oil several times using what was lying around. I am mentioning this to indicate that the make of the pump does not dictate the kind of oil it contains. Considering that diff pump oil can be easily abused (@Dullard's comment is well taken), I think your best bet would be to change the oil yourself in the pumps you inherited and start afresh. Perhaps you could also make a note saying what kind of oil you used and save it somewhere for posterity.

 

[jasonlee112]

During my servitude as grad student in the seventies I changed diff pump oil several times using what was lying around. I am mentioning this to indicate that the make of the pump does not dictate the kind of oil it contains. Considering that diff pump oil can be easily abused (@Dullard's comment is well taken), I think your best bet would be to change the oil yourself in the pumps you inherited and start afresh. Perhaps you could also make a note saying what kind of oil you used and save it somewhere for posterity.

I see, thank you for clarifying. I was under the impression that a specific pump needs to use a specific oil. Was it common back then to use PCB based oils for research grade diffusion pumps? If there is a chance they do have PCB I'm not sure I want to risk it by continuing to use them even with replaced oil.

 

[Klystron]

I don't know about the intended composition of old DP oil, but (depending on the old process) it could be contaminated with almost anything.

Experience here with high voltage transformers and high-speed motors manufactured before 1970's containing PCB oils.

Dioxin was identified as extremely dangerous component of PCB's depending, among other factors, on temperatures during preparation. The unanswered question at that time concerned operating temperatures.

Would high temperatures during normal ops produce more dioxin or other carcinogens?

PCB oils appeared elusive, seeming to migrate past seals and valves. Did dioxin vaporize or the oils become aerosolized during and after operation?

https://www.epa.gov/dioxin/learn-about-dioxin

https://www.epa.gov/pcbs/learn-about-polychlorinated-biphenyls-pcbs

 

[Klystron]

This excerpt from EPA document on PCB lists known health effects of exposure.

Health Effects of PCBs​

PCBs have been demonstrated to cause a variety of adverse health effects. They have been shown to cause cancer in animals as well as a number of serious non-cancer health effects in animals, including: effects on the immune system, reproductive system, nervous system, endocrine system and other health effects. Studies in humans support evidence for potential carcinogenic and non-carcinogenic effects of PCBs. The different health effects of PCBs may be interrelated. Alterations in one system may have significant implications for the other systems of the body. ...

 

[kuruman]

I see, thank you for clarifying. I was under the impression that a specific pump needs to use a specific oil. Was it common back then to use PCB based oils for research grade diffusion pumps? If there is a chance they do have PCB I'm not sure I want to risk it by continuing to use them even with replaced oil.

I cannot answer your question because back then a lot of hazardous materials were not on anybody's radar screen and PCBs were one of them. I used "GE varnish" a lot, for gluing platinum thermometers, thermocouples, etc. to metal blocks that were taken down to liquid helium temperature and below. GE varnish was great because It is a good electrical insulator, a good thermal conductor and doesn't crack at cryogenic temperatures. Years later I found out that it contains PCB. I also found out that toluene, which mixed 50-50 with ethanol is the recommended GE varnish solvent, can cause loss of consciousness, respiratory depression and death none of which I experienced.

While I'm at it I might as well mention that I routinely moved lead bricks and lead sheets around with my bare hands to use for shielding without worrying about lead poisoning. The only hazardous material that has caused known damage to me (so far) is asbestos. A fellow grad student asked me to help him with a furnace he wanted to build with an asbestos wall for insulation. So we took a great big sheet of asbestos, 1.5" thick to the machine shop, put it on the band saw table and started cutting out a rectangle at one corner. Asbestos dust was flying all around us but nobody cared because, you see, asbestos was not hazardous back then. The damage to me was inflicted when we tried to turn the heavy sheet 90° for the second cut. The other fellow dropped his end and the asbestos sheet came crashing down and broke the great toe of my right foot. I was on crutches for the next three weeks. The fellow said he was sorry and I generously forgave him.

The moral of the story here is that you can't be too careful with hazardous materials because you don't know when or how they might turn around and bite you in the rear end. Better be informed and know your enemy. It's a good thing that you worry about PCB in your diff pump oil.

 

[berkeman]

The damage to me was inflicted when we tried to turn the heavy sheet 90° for the second cut. The other fellow dropped his end and the asbestos sheet came crashing down and broke the great toe of my right foot. I was on crutches for the next three weeks.

I hadn't seen that hazard documented on the MSDS before...

Glad you survived all that exposure to all those things. You probably managed to eat a lot of dirt back in the day -- that served as an effective prophylactic for many of us.

 

[berkeman]

Summary:: Is there a possibility that these pumps have PCB based oil inside?

I do not have access to PCB oil testing at the moment.

It's starting to sound like getting a test kit (with capacity for at least 3 tests) will be important. Even if you are careful to drain the oil that has PCB in it, how you dispose of the oil will likely depend on whether PCB is detected in the oil or not. My local Household Hazardous Waste facility is fine taking motor oil and similar, but I don't think they'd appreciate receiving PCB laced oil from an old transformer or other device...

 

[f95toli]

Indeed, some old diffusion pumps can contain some rather nasty oils.
Also, do be aware that some early diffusion pumps used mercury. They were widely used for e.g. cryogenic systems until relatively recently (oil based pumps are not great for cryogenic system they tend to contaminate and block the coldest parts), certainly until the late 90s and maybe even longer.
I'm pretty sure this isn't the case for any of these pumps, but I bet you could still find some of old mercury based pumps in storerooms at various universities; if nothing else because they are presumably a complete nightmare to dispose of.

Anyway, please do be careful when working on old systems