Poor performance of old diff pump.

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.
Marcin Dziedzic
Posts: 5
Joined: Thu Dec 20, 2018 5:57 pm
Real name: Marcin Dziedzic

Re: Poor performance of old diff pump.

Post by Marcin Dziedzic » Fri Feb 08, 2019 5:05 pm

The pump has been dismantled, and turned out to be heavily damaged. The jest assembly is probably incomplete. The slits in jest assembly are bent in many places, and it's evident that the pump had been cleaned many times, marks from scratching with knife (!) are evident. :( The pump is not equipped with water-cooled coldcap and huge oil backstream destroyed two of my vacuum gauges (ITR90 and PTR91). I'll post a short story with photographs, for now I'm trying to replace it with new varian HS-20.

Jerry Biehler
Posts: 842
Joined: Tue Nov 24, 2009 8:08 am
Real name:
Location: Beaverton, OR

Re: Poor performance of old diff pump.

Post by Jerry Biehler » Mon Feb 11, 2019 5:12 am

The gauge heads ought to be able to be cleaned to get them working again. I would probably start by washing them out with mineral spirits to dissolve the oil and then acetone. I would be surprised if the filament on the ion gauge ever even turned on at the pressure you were getting.

Post Reply