Patent ID: 6332348
Filing Date: 2001-12-25
Classification: G01F

Abstract:
A method for gas flow calibration, comprising:setting a first mass flow controller (MFC) such that a gas flows through a mass flow meter (MFM) and the first MFC at a first rate, wherein the first MFC is connected in series to the MFM;recording a first reading from the MFM while the gas flows through the MFM at the first rate;setting a second MFC such that the gas flows through the MFM at a second rate, wherein the second MFC is connected in parallel to the first MFC, and wherein the parallel combination of the first and second MFC is connected in series to the MFM;recording a second reading from the MEM while the gas flows through the MFM at the second rate; andcomparing a difference of the second and first readings to the setting of the second MFC to determine a calibration of the second MFC.