Method of and apparatus for measuring the molecular weight of a gas

摘要

There is provided a meter for measuring the molecular weight of a gas, the meter comprising a housing having an inlet and an interior for receiving said gas to be measured, a sensor assembly comprising a high-frequency planar piezoelectric crystal oscillator located within said housing so that, in use, the piezoelectric crystal oscillator is in contact with said gas, said sensor assembly being arranged: to drive the piezoelectric crystal oscillator such that the piezoelectric crystal oscillator resonates at a single resonant frequency; to measure said single resonant frequency of said piezoelectric crystal oscillator to determine the density of gas; and to determine from the density, determined or pre-determined pressure of the gas and determined or pre-determined temperature of the gas, the molecular weight of the gas.

主权项

1. A method of measuring the molecular weight of a gas, the method comprising:
a) driving single high-frequency planar piezoelectric crystal oscillator in contact with the gas utilizing a drive circuit, such that the piezoelectric crystal oscillator resonates at a single resonant frequency despite changes in the Q factor of the piezoelectric oscillator; and b) measuring said single resonant frequency of said piezoelectric crystal to determine the density of gas; and c) determining the molecular weight of the gas from the density, a determined or pre-determined pressure of the gas, and a determined or pre-determined temperature of the gas based on a change in frequency being linearly proportional to a change in density.