A Joss Research Institute
Informal Report:

Three Diffusion Pumps
and a Small Surprise

(13 September, 2008)

The Balzers Diff 650

This is the oldest of the three diffusion pumps that we seem to have here; it was recently given to us.


As you can see, it is designed to pull 700 Watts at 110 V; I have no idea how much fluid it takes, or even what the proper fluid is.

The Big Varian in the Vacuum-UV Spectrometer

This pump actually seems to have a gatevalve on it, but I don’t think there’s a roughing pump in the box with it. It appears to have about a 6" throat.


The Leak Detector

We seem to have a partly-disassembled leak detector. Here are some views of the guts:


The label is scratched up, and a bit difficult to read; the pump is a [rather old] Edwards SpeediVac 403A. It is water-cooled, has a 4" throat, takes 100 cc of fluid, and pulls 500 W at 240 V. (I can make 240 V with a step-up transformer, and the heater shouldn’t care about the frequency.) I have checked the heater; it has reasonable resistance, and is not shorted to the case. So far, so good.

The surprise about this unit is that there is actually a roughing pump in there as well:


It’s a bit strange, and we will have to replace the motor if we can; it wants 240 VAC at 50 Hz. I checked, and the shaft turns freely, so there is at least some chance that the pump itself is more or less intact. (There is also a chance that I can get away with running the motor on 60 Hz power, if I get the voltage close enough and if there isn’t too much work for it to do.)

This work was supported by
the Joss Research Institute

Contact Information:

Email: a@b.com, where you can replace b with joss (as in Joss Research Institute), and a with my first name (no “h”, only 3 letters).

Phone: +1 240 604 4495.

Last modified: Tue May 9 13:27:55 EDT 2017