A method of measuring the absorptivity or emissivity factor of a sample at ambient temperature comprises maintaining a thermopile at a constant temperature substantially above ambient temperature and exposing the sample to radiation exclusively from the thermopile. The voltage across the thermopile is measured and provides a measure of the absorptivity or emissivity factor. The thermopile may be disposed in a temperature-controlled furnace extending into a conical cavity.
The present invention relates to a device for detecting micro-leaks of gas by directing the infrared radiation created by a thermal gradient onto a wall, which device comprises an enclosure provided with an opening equipped with sealing means designed to be placed in contact with the wall, a sealed tank separated from said enclosure by a partition wall, said tank housing an infrared camera of which the objective is situated in front of a lens which is permeable to infrared radiations, means for sealingly applying the enclosure against the wall, means for creating a partial vacuum inside the enclosure, and an insulating screen placed in the center of the opening of the enclosure and applied against said wall in order to filtrate the gas leaks drawn in by the vacuum effect, to obtain a thermal gradient detectable by thermovision.
An infrared sensing device is capable of sensing the amount of infrared radiation which is present at a given location and presenting a visual indicia of the strength of the signal. A series of led's which light up in a bar graph fashion indicate the strength of the signal. The device also has a remote sensor which allows the sensing to be done at a location away from the position of the visual signal strength indicator.
A method and apparatus for maintaining a viewing window of a detector substantially clean includes enclosing the detector within a housing, and moving a target surface relative to the viewing window to create an airflow adjacent the viewing window. The housing can include an aperture through which the viewing window of the sensor views the target surface. Motion of the target surface creates an airflow velocity adjacent the viewing window for maintaining the viewing window substantially clean. To increase the accuracy of the detector, a high emissivity area is provided on an outside surface of the housing which faces the target surface.
Body temperature measurements are obtained by scanning a thermal radiation sensor across the side of the forehead over the temporal artery. A peak temperature measurement is processed to compute an internal temperature of the body as a function of ambient temperature and the sensed surface temperature. The function includes a weighted difference of surface temperature and ambient temperature, the weighting being varied with target temperature through a minimum in the range of 96.degree. F. and 100.degree. F. The radiation sensor views the target surface through an emissivity compensating cup which is spaced from the skin by a circular lip of low thermal conductivity.
