What to Make Of Pfeiffer Oil Viscosity?

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ian_krase
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What to Make Of Pfeiffer Oil Viscosity?

Post by ian_krase » Wed Feb 08, 2017 8:18 am

Pfeiffer officially specifies that you use their own P3 oil in their small rotary vane pumps such as the Duo 2.5 (It would be pretty funny if they recommended that you use Leybold's oil, after all!)

This is a little peculiar. P3 is a bit less than twice as viscous as the standard oil specified for most similar small pumps, about Grade 100 (ISO) It is a bit more expensive, much less available, and doesn't have the multitude of alternatives and substitutes that the common "19" oil (which is apparently ISO grade 68, sometimes more like 58) has.

On the other hand, Pfeiffer seems to give their blessing to using their own "19" oil in the Duo 2.5, and a few other vendors suggest using their particular "19" oils in this pump as well. I'm not sure what makes the Duo 2.5 different from nearly every other small 2-stage industry-grade pump with around 1 to 2 CFM.

What should I use in this pump? Should I just get my hands on the P3 once I've finished flushing the thing out?

Jeroen Vriesman
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Re: What to Make Of Pfeiffer Oil Viscosity?

Post by Jeroen Vriesman » Wed Feb 08, 2017 1:17 pm

Hi.

Look at the viscosity for the operating temperature. This will always be "low". Low enough to not influence the pump in any way.

I use P3 in my pumps, but I also have a 20L barrel of "Shell S3 RX 100", with a much lower viscosity at 25 deg. C
http://www.oqvalue.nl/Images/Products/P ... 00_TDS.pdf

It doesn't seem to matter at all. Above 40 deg. C the viscosity is always "just low".

The other properties, like vapour pressure, water content and corrosion resistance are also ok for all the oils.
I never saw any difference in pressure, noise, operating temp or anything else. The vapour pressure of the shell S3 RX 100 is much higher than the advertised vapout pressure of P3, bu teven that didn't seem to make any difference.

The only thing which did make a difference was a zeolite trap between the rotary vane pump and the turbo to prevent backflow.

ian_krase
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Re: What to Make Of Pfeiffer Oil Viscosity?

Post by ian_krase » Wed Feb 08, 2017 8:39 pm

Ok, thank you.

Looking at the table, it looks like P3 is more viscous hot, but I can see how it may not matter much.

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