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

Paper VT-TuA5
New Calibration Apparatus for 1, 10, 100 Torr Capacitance Diaphragm Gauges

Tuesday, November 1, 2005, 3:20 pm, Room 200

Session: Calibration: Pressure and Flow Metrology
Presenter: S.Y. Woo, Korea Research Institute of Standards and Science
Authors: S.Y. Woo, Korea Research Institute of Standards and Science
I.M. Choi, Korea Research Institute of Standards and Science
Correspondent: Click to Email
Capacitance diaphragm gauges are electromechanical pressure sensors in which the displacement of a stretched thin metal diaphragm is detected by a capacitance measurement. They have gained widespread international popularity not only as high accuracy transfer standards but also as reliable replacements for many other vacuum gauges used in process industries. In order to calibrate such accurate vacuum gauges, laser or ultrasonic mercury manometers have been used. However, complexity, health concerns of mercury vapor, and cost of these manometers made it difficult to use in most calibration laboratories. As a substitute, a gas-operated pressure balance can be used with some modifications. In this article, we introduce a new apparatus for the calibration of the precise vacuum gauges. This device has a unique mass handling structure that allows masses to be changed in-situ without breaking the vacuum. It covers three pressure ranges of 1 Torr, 10 Torr, and 100 Torr. Using this apparatus, the characteristics of three commercial vacuum gauges (MKS, Model 626) were studied.