Sensormedics Corporation

Michael B Jaffe

Charles R Luper

Howard J Reid

Eric Mabry

An improved gas volume calibration method and apparatus for use in respiratory gas analyzers. A control unit monitors the flow of calibration gas through the analyzer by monitoring the electrical signals produced by a gas turbine and a breath switch. During calibration, a known volume of calibration gas is repeatedly delivered to the analyzer from a calibration syringe at each of a number of different flow rates. On the basis of the information received from the turbine and the breath switch, the control unit generates and stores a piecewise linear approximation of the nonlinear characteristic of the turbine. This stored turbine characteristic is then made available during subsequent measurements to eliminate those volume errors which are associated with variations in the rate at which the sample gas is delivered, thereby affording measurements of improved accuracy.

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Anaheim, CA, United States of America

Michael B Jaffe