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Title: Performance test of a ceramic rotor developed for turbomolecular pumps for fusion use

Abstract

Turbomolecular pumps with a metallic rotor have been widely used to pump out gases from plasma confinement devices. However, high magnetic fields produced by magnet coils and plasmas cause eddy current heating and rotation speed reduction of the rotor of the pumps, and as a result serious problems take place in the rotor strength and pump performance. In order to overcome these problems, the authors have been developing a ceramic turbomolecular pump and, as a first step, have manufactured a test machine. The test machine consists of a ceramic rotor assembly with high electrical resistivity, gas bearings, a gas turbine, and a spiral-groove seal. The ceramic material is silicon nitride. Using the material strength of the actual components, rupture probability of the rotor assembly was estimated at various rotation speeds. Rotational tests of the test machine were successfully performed in both stationary and pulsed magnetic fields (0.046 T and 0.02 T/ms, respectively) at the required speed of 30 000 rpm. The leak rate through the spiral-groove seal was measured for two different seal gaps and at various rotation speeds.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Japan Atomic Energy Research Institute (JAERI), Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
OSTI Identifier:
6488331
Resource Type:
Journal Article
Journal Name:
J. Vac. Sci. Technol., A; (United States)
Additional Journal Information:
Journal Volume: 5:4
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; THERMONUCLEAR DEVICES; TURBOMOLECULAR PUMPS; PERFORMANCE TESTING; ROTORS; CERAMICS; ROTATION; SILICON NITRIDES; EQUIPMENT; LABORATORY EQUIPMENT; MOTION; NITRIDES; NITROGEN COMPOUNDS; PNICTIDES; PUMPS; SILICON COMPOUNDS; TESTING; VACUUM PUMPS; 700209* - Fusion Power Plant Technology- Component Development & Materials Testing

Citation Formats

Murakami, Y, Abe, T, Morii, S, Nakaishi, N, and Hata, S. Performance test of a ceramic rotor developed for turbomolecular pumps for fusion use. United States: N. p., 1987. Web. doi:10.1116/1.574393.
Murakami, Y, Abe, T, Morii, S, Nakaishi, N, & Hata, S. Performance test of a ceramic rotor developed for turbomolecular pumps for fusion use. United States. https://doi.org/10.1116/1.574393
Murakami, Y, Abe, T, Morii, S, Nakaishi, N, and Hata, S. 1987. "Performance test of a ceramic rotor developed for turbomolecular pumps for fusion use". United States. https://doi.org/10.1116/1.574393.
@article{osti_6488331,
title = {Performance test of a ceramic rotor developed for turbomolecular pumps for fusion use},
author = {Murakami, Y and Abe, T and Morii, S and Nakaishi, N and Hata, S},
abstractNote = {Turbomolecular pumps with a metallic rotor have been widely used to pump out gases from plasma confinement devices. However, high magnetic fields produced by magnet coils and plasmas cause eddy current heating and rotation speed reduction of the rotor of the pumps, and as a result serious problems take place in the rotor strength and pump performance. In order to overcome these problems, the authors have been developing a ceramic turbomolecular pump and, as a first step, have manufactured a test machine. The test machine consists of a ceramic rotor assembly with high electrical resistivity, gas bearings, a gas turbine, and a spiral-groove seal. The ceramic material is silicon nitride. Using the material strength of the actual components, rupture probability of the rotor assembly was estimated at various rotation speeds. Rotational tests of the test machine were successfully performed in both stationary and pulsed magnetic fields (0.046 T and 0.02 T/ms, respectively) at the required speed of 30 000 rpm. The leak rate through the spiral-groove seal was measured for two different seal gaps and at various rotation speeds.},
doi = {10.1116/1.574393},
url = {https://www.osti.gov/biblio/6488331}, journal = {J. Vac. Sci. Technol., A; (United States)},
number = ,
volume = 5:4,
place = {United States},
year = {Wed Jul 01 00:00:00 EDT 1987},
month = {Wed Jul 01 00:00:00 EDT 1987}
}