AVS 50th International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeP

Paper VT-WeP6
Vacuum Pump Oil Tests at the National Synchrotron Light Source to Minimize Oil Waste@footnote 1@

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: C.L. Foerster, Brookhaven National Laboratory
Authors: C.L. Foerster, Brookhaven National Laboratory
J.-P. Hu, Brookhaven National Laboratory
E. Haas, Brookhaven National Laboratory
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In order to reduce the large amount of oil waste produced during normal operation of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL), an oil-testing project was established to determine if synthetic vacuum pump oil could be used effectively with longer oil change intervals. Due to the large number of oil-sealed rotary vane pumps that are used at the NSLS, a longer oil change interval would reduce maintenance costs as well as oil waste. Initially, two basic types of vacuum pump oils, mineral and synthetic, were selected for direct comparison. Three of the same size two-stage mechanical pumps were set up to run simultaneously with the same gas load. ConvectronR gauges, cold cathode gauges, and isolation valves were connected to a central vacuum chamber having a common inlet pressure control and a sampling valve for residual gas analysis. To simulate oil degradation produced by long-term mechanical pump operation, the system air load was manually controlled with an air bleed valve on the common vacuum chamber and was periodically adjusted to run at 500 mTorr. This easily tolerated pressure range for mechanical pumps was suggested by oil suppliers to expedite the oil viscosity change, acid buildup, and pump-wear debris production. Major advantages are that the testing time will be much quicker and that any back streaming of oil is minimized at this operating pressure. The detailed test data for the resulting oil properties, oil degradation, visual comparison, vacuum conditions, and pump characteristics will be presented for comparison of the pump oils used at NSLS and for estimation of the resulting oil waste reduction.@footnote 1@ Work performed under the auspices of the U.S. Department of Energy, under contract DE-AC02-98CH10886.