AVS 52nd International Symposium
    Vacuum Technology Tuesday Sessions
       Session VT-TuP

Paper VT-TuP4
Selection of State Variables for Diagnosing Dry Vacuum Pumps

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Vacuum Technology Poster Session
Presenter: J.Y. Lim, Korea Research Institute of Standards and Science
Authors: J.Y. Lim, Korea Research Institute of Standards and Science
W.S. Cheung, Korea Research Institute of Standards and Science
K.-H. Chung, Korea Research Institute of Standards and Science
Correspondent: Click to Email
Detection of degradation and failure-related symptoms of dry vacuum pumps has been currently hot-issued in the semi-conductor and display process lines since the loss time and costs due to abnormal malfunction are astronomically rising. The baseline for the detection is direct monitoring of all state variables from target pumps such as currents, exhaust pressure, vibration, sound pressure, purge gas, temperature, etc. However, the analyzed results show that the state variables are very closely correlated each other, and their factorization may be required for the symptom detection. Also, confusion for the selection has been frequently arisen since vacuum pumps of the same type and of about the same size offered by different manufacturers frequently have minor or even large differences in their mechanical structures. To achieve the process and pump state monitoring ability, gas-type independent vacuum gauges have been installed at the very near pump inlet to monitor the inlet pressure variation with respect to the process time. Five 600 m3/h dry vacuum pumps of the same type have been selected, and tested in the laboratory as well as the actual process line for analyzing state variables. The resultant variability coefficient of the inlet pressure was less than 3.5% above 0.05 mbar corresponding to the actual process pressure range. In the case of the power consumption, the coefficient was above 10%. This very meaningful information provides us with the inlet pressure as the most significant state variable for the detection of degradation and failure-related symptom in the pump type or size independent manner.