Method for the measurement of the molar mass of gases or gas mixtures and an apparatus for the performance of the method
First Claim
1. A method of measuring a molar mass of a gas or gas mixture, comprising:
- flowing the gas or gas mixture through a holder on which one or more sonic or ultrasonic transmit and receive cells are arranged to define a baseline,wherein the sonic or ultrasonic transmit-receive cells radiate a pulsed sonic signal,measuring transit times of sonic pulses of the sonic signal along the baseline,performing temperature compensation measurements, anddetermining the molar mass from the transit times of the pulses of the sonic signal and the temperature compensation measurements,wherein the molar mass M is determined using the equation;
##EQU3## wherein k1 is a dimension-related constant, kA is a dimensionless constant for adiabatic exponent correction, T is a mean temperature along the baseline, and t1 and t2 represent transit times along the baseline reduced by time used for assembly and measurement.
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Abstract
The invention relates to a method for the measurement of the molar mass of a gas or gas mixture and an apparatus for the performance of the method. The gas or gas mixture to be investigated is passed through at least one holder, on which at least one sonic or ultrasonic transmit-receive cell is arranged defining a baseline and preferably arranged obliquely to the axis of the tube. The sonic or ultrasonic transmit-receive elements radiate a pulsed sonic signal, which measures the transit times of the sonic pulses along the baseline. Using a temperature probe for instance the variations in gas temperature along the at least one sonic transmission path is determined. From the transit time of the sonic pulses and the measured or assumed temperature the molar mass is found. The apparatus in accordance with the invention may be employed with advantage in pulmonary function diagnostics.
78 Citations
29 Claims
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1. A method of measuring a molar mass of a gas or gas mixture, comprising:
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flowing the gas or gas mixture through a holder on which one or more sonic or ultrasonic transmit and receive cells are arranged to define a baseline, wherein the sonic or ultrasonic transmit-receive cells radiate a pulsed sonic signal, measuring transit times of sonic pulses of the sonic signal along the baseline, performing temperature compensation measurements, and determining the molar mass from the transit times of the pulses of the sonic signal and the temperature compensation measurements, wherein the molar mass M is determined using the equation;
##EQU3## wherein k1 is a dimension-related constant, kA is a dimensionless constant for adiabatic exponent correction, T is a mean temperature along the baseline, and t1 and t2 represent transit times along the baseline reduced by time used for assembly and measurement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of measuring a molar mass of a gas or gas mixture, comprising flowing the gas or gas mixture through a holder on which one of more sonic or ultrasonic transmit and receive cells are arranged to define a baseline, wherein the sonic of ultrasonic transmit-receive cells radiate a pulsed sonic signal, measuring transit times of pulses of the sonic signal along a baseline, performing temperature compensation measurements and determining the molar mass from the transit times of the pulses of the sonic signal and the temperature compensation measurements,
wherein the molar mass M is derived using the equation: - ##EQU4## wherein k2 is a dimension-related constant, kA is a dimensionless constant for adiabatic exponent correction, T is a mean temperature along a baseline in a flow duct, determined using a temperature sensor positioned along said baseline, and t1 and t2 are transit times along the baseline reduced by time used for assembly and measurement, t3 and t4 are transit times of the pulsed sonic signals, reduced by time used for assembly and measurements, along parts of the baseline not in the flow duct.
- View Dependent Claims (27, 28, 29)
Specification