Patent ID: 7365352
Filing Date: 2008-04-29
Classification: G01J,G01N

Abstract:
1. A gas flux measuring device, wherein said gas flux measuring device comprises: at least one light source oscillating a laser beam of an absorption wavelength natural to a measuring object gas toward a measuring region, a laser output controller controlling an output action of said light source, a wavelength modulation controller putting out a modulation signal for adding a modulation to an oscillation wavelength of the laser beam oscillated from said light source as well as putting out a reference signal synchronized with the modulation, a first light receiver receiving the laser beam transmitted through the measuring region and putting out a signal corresponding to a received light strength thereof, a first direct current component detector removing an alternating current component as a modulation signal out of the signal put out from said first light receiver and putting out a direct current component of the received light strength, a first wavelength modulation demodulator detecting, based on the reference signal from said wavelength modulation controller, an even number order harmonic component of the wavelength modulation signal added to the laser beam out of the signal put out from said first light receiver and putting out a signal in proportion to a concentration of the measuring object gas in the measuring region, an optical system distributing the laser beam oscillated from said light source to two or more portions, a reference cell enclosing the measuring object gas of known concentration and being arranged at such a position that the laser beam, distributed by said optical system so as not to be directed to the measuring region, is transmitted through the enclosed gas, a second light receiver receiving the laser beam transmitted through the enclosed gas in said reference cell and putting out a signal corresponding to a received light strength thereof, a second direct current component detector removing an alternating current component as a modulation signal out of the signal put out from said second light receiver and putting out a direct current component of the received light strength, a second wavelength modulation demodulator detecting, based on the reference signal from said wavelength modulation controller, an even number order harmonic component of the wavelength modulation signal added to the laser beam out of the signal put out from said second light receiver and putting out a signal in proportion to the concentration of the enclosed gas in said reference cell, a third wavelength modulation demodulator detecting, based on the reference signal from said wavelength modulation controller, an odd number order harmonic component of the wavelength modulation signal added to the laser beam out of the signal put out from said second light receiver and putting out a laser wavelength fixing signal as a standard signal for fixing the laser beam wavelength to the absorption wavelength of the measuring object gas, an analyzer calculating, based on the signals put out from said first direct current component detector, first wavelength modulation demodulator, second direct current component detector and second wavelength modulation demodulator, the gas concentration and a solid particle concentration in the measuring region and putting out a calculation result thereof, an adder adding the modulation signal from said wavelength modulation controller to the laser wavelength fixing signal from said third wavelength modulation demodulator and putting out an addition signal thereof as an external control signal into said laser output controller, a temperature measuring means measuring a temperature in the measuring region and putting out a signal corresponding to a measured value thereof into said analyzer, a pressure measuring means measuring a pressure in the measuring region and putting out a signal corresponding to a measured value thereof into said analyzer, and a flow velocity measuring means for directly measuring horizontal 2-directional flow velocity components and a vertical flow velocity component of a gas flow in the measuring region and putting out measurement signals thereof into said analyzer, wherein said analyzer carries out an analysis based on the eddy correlation method using the signals inputted from said flow velocity measuring means and, by calculation using an analysis result thereof, obtains a momentum flux in the measuring region, a concentration flux of the measuring object gas and the concentration of the measuring object gas.