Bertin & Cie

Gaz De France

Gerard Pelous

Yves F Guern

Michel Ayraud

Jean-Claude Noack

Laurence Juen-Grenier

Jean-Jacques Pinvidic

Mario D'Amico

Natural gas whose calorific value is to be determined is illuminated with a light beam that is applied by a measurement head and that defines three measurement bands with different wavelength ranges each having a bandwidth of 10 nm to 20 nm and all situated in the near infrared. The intensity of each light beam is measured after it has passed through the gas, and the calorific value of the natural gas is computed in situ and in real time on the basis of the optical absorption values obtained by measuring the intensities of the light beam after it has passed through the gas.

Method and apparatus for determining the calorific value of a natural

A method and apparatus for remote optical detection of a gas present in an observed volume using a thermal imager or camera including one or more sensitive elements which are sensitive to radiant fluxes in a determined band of wavelengths, two filters interposable on the optical axis of the camera, the filters having similar transmission bands, one of which includes an absorption line characteristic of the looked-for gas, while the other of which is complementary to said absorption line, and signal processing means for taking the difference between the radiated fluxes received from two points at different temperatures in the volume as observed first through one of the filters and then through the other filter, for taking the ratio of said differences, and for deducing therefrom whether the gas is present in the observed volume.

Method and apparatus for remote optical detection of a gas present in an

Method and device for comparing two variable analogue signals

Method and apparatus for surveillance of a determined space in which a camera lens enables an image of said space to be formed on a set of photodetectors associated with information processing means, the set of photodetectors being a linear strip of photodetectors, for example, mounted so as to be fixed relative to the lens which is itself mounted to rotate about a transverse axis and which is displaceable by drive means to occupy predetermined angular positions about said axis.

Method and apparatus for surveillance of a determined space such as a

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Aix-en-Provence, France

Gerard Pelous