Instrumentarium Corporation

Timo Merilainen

Kurt Peter Weckstrom

Borje T Rantala

Kai Karlsson

Seppo Poikolainen

The invention relates to an infrared radiation source for a gas analyzer and a method for generating infrared radiation. The infrared radiation source comprises a body (6), thermal insulation material (5) adapted inside the body (6), a radiant element (1) fitted inside the insulation material (5), elements (2, 3) for feeding electric energy to said radiant element (1), and a channel (7) formed in said body (6) and said thermal insulation material (5) in order to pass the radiation generated by said radiant element (1) to the gas under measurement. According to the invention, at least the thermal insulation material (5) adapted in close proximity to the radiant element (1) has a low thermal conductivity and the emissivity of the radiant surface (11) adapted in close proximity to the radiant element (1) is greater than 0.5 at the operating temperature of the source.

Infrared radiation source for a gas analyzer and method for generating

A method for calibrating a gas analyzer (1). A gas analyzer is calibrated by measuring the zero level of the analyzer (1). The level of the analyzer is measured, after a preceding reset, whenever a temperature variation (.DELTA.T) of an infrared sensor (14) included in the analyzer (1) or of a component thermally connected in a highly conductive manner thereto exceeds a predetermined threshold value (A), or the temperature variation rate (D) of the infrared sensor (14) of the analyzer (1) or of a component thermally connected in a highly conductive manner thereto exceeds a predetermined limit valve.

Method for calibrating the zero point in a gas analyzer

The invention relates to a method and apparatus for temperature compensation in gas analyzer equipment for transient error caused by temperature change. According to the method, a radiation source (1) is used for transmitting electromagnetic radiation through a gas mixture to be analyzed, the intensity of radiation transmitted through the gas mixture being analyzed is detected by means of a thermal detector (4) comprising a radiation detecting sensor element (16) and a reference sensor element (17) for generating an output signal proportional to the concentration of gas being analyzed, the temperature of said thermal detector (4) is measured either directly or indirectly, the measured detector temperature values are recorded as a function of time, and the output signal of the thermal detector (4) is temperature compensated by a correction term dependent on the temperature rate of change (DT) of the thermal detector. According to the invention, the uncorrected output signal V.sub.mass of the thermal detector (4) is temperature compensated by adding a correction term V.sub.comp dependent on the temperature rate of change (DT) of the thermal detector to said output signal.

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Helsinki, Finland

Timo Merilainen