Can't pull deep vac on 2" Pope

Hi gang,

I have been trouble shooting the vacuum issue on this hand-me-down 2" Pope all week. I have disassembled and cleaned and greased every joint four times now. The O-Ring at the top of the evaporator body and the gasket at the bottom are cleaned and greased and triple checked. I highly doubt it’s my glass joints or O-ring. After triple checking the connections, I was thinking the Edwards 3 vacuum pump was the culprit, but with the gauge hooked up directly to the pump, I was able to pull 0.017 torr. However, it did take over thirty minutes for the Edwards 3 to pull this deep on the gauge. The lowest I can achieve in the Pope is about 0.180 torr with the apparatus empty and dry. With material in the column, the deepest I can get is about 0.300 torr. My first attempt at a second pass, was pulling around 0.300 torr, and I didn’t get any separation with that pressure. I’m still thinking it’s the pump. It appears the person who used the apparatus before me may have sucked resin directly into the pump. Should I try a rebuild on the pump? New/different pump? Take it apart again? I’m about ready for the sledghammer…

Inside the pump:

Took almost 20 minutes to go from 0.031 to 0.017 with gauge hooked directly to pump:

You should have no trouble getting down to 10 mtorr with the pump blanked off. Sounds like (multiple) oil change time. Or rebuild. Try oil first.

Vacuum Pumps - General Info / Maintenance Tips

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