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Title: An instrument for gravimetric calibration of flow devices with corrosive gases

An instrument was developed for the calibration of mass flow controllers primarily used in the production of semiconductor wafers. Almost all other types of such calibrators require measurement of temperature, pressure and volume. This instrument measures the weight of gas collected in a container and makes measuring those thermodynamic variables unnecessary. The need to measure the weight of the gas container is eliminated by submerging it in a liquid (presently water) and balancing its weight with the force of buoyancy. The accuracy of this Gravimetric Calibrator is unaffected by the pressure and temperature of the gas. The Calibrator can also measure reactive, corrosive, and non-ideal gases. The container remains connected to the process by a torsion capillary, and a load cell measures the changing gas weight continuously throughout the measuring process. A prototype was designed for gas flows ranging from 1 sccm of hydrogen to 10,000 sccm of tungsten hexafluoride, constructed, tested, and used to calibrate flow devices. Experience with the prototype and results are presented, and plans for further developments are discussed. Design of a version for the flow range from 0.1 sccm to 100 sccm is in progress.
Authors:
;
Publication Date:
OSTI Identifier:
52825
Report Number(s):
CONF-9505201-2
ON: DE95009700; TRN: AHC29515%%96
DOE Contract Number:
AC05-84OR21400
Resource Type:
Conference
Resource Relation:
Conference: 41. international instrumentation symposium, Auora, CO (United States), 7-11 May 1995; Other Information: PBD: [1995]
Research Org:
Oak Ridge National Lab., TN (United States)
Sponsoring Org:
USDOE, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; MEASURING INSTRUMENTS; DESIGN; FLOW REGULATORS; CALIBRATION; INTEGRATED CIRCUITS; FABRICATION; SEMICONDUCTOR MATERIALS; TEMPERATURE MEASUREMENT; PRESSURE MEASUREMENT