A Joss Research Institute
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.)
the Joss Research Institute
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Last modified: Wed Sep 17 01:46:55 EDT 2008