| 摘要 |
A vacuum pump system for creating a high vacuum (below 10-7 TORR) especially useful for vacuum volumetric measurements such as are performed using a gas sorption analyzer on a particulate sample to determine particulate surface area and porosity using a dry, non-lubricant oil-free vacuum pumping system that includes a turbomolecular drag pump having its high vacuum side connected to a vessel that contains the particulate sample to be analyzed, and in series with a dry, oil-free diaphragm pump whose inlet or vacuum side is connected to the high pressure exhaust side of the turbomolecular drag pump thereby eliminating any possibility of oil vapor contamination of the sample since the turbomolecular drag pump and the diaphragm pump use essentially no oil as lubricants.
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