Abstract:
A temperature measuring apparatus is provided for determining the temperature of a target material to be measured as compared with the temperature of a spaced reference source which has a temperature control for controlling the temperature of the reference source. A differential radiation detector having a first detector exposed to the target material and a second detector which is shielded from the target material and exposed to the reference source provides a differential output or error signal which is used to control the temperature of the reference source. When the reference source temperature is the same as the target, the temperature of the reference source is read out which is the temperature of the target material regardless of the emissivity. The differential radiation detector is positioned in spaced relation to the target material and is focused onto the target and the reference material and the error signal generated is used for controlling the temperature of the reference source. The reference source is preferably a heated plate having a step in the center thereof with a hole therein through which the differential detector means views the target as well as the plate. Using a hole prevents reflection from the target back through the plate to areas of uncontrolled temperature.
Abstract:
A pyrometer adapted to be disposed remotely from a heated diffusely reflecting target obtains a first electrical signal from that portion of target radiance which reaches the instrument. A laser beam is generated within the instrument and is directed upon the target, a portion of the beam being reflected back to the instrument. A second signal is obtain from this portion. The separation between target and instrument is measured and a third signal depending on the separation is produced. A fourth signal dependent upon the power level of the beam is produced. The instrument then computes from these signals the surface temperature of the target.
Abstract:
An improved method for measuring the surface temperature of objects, such as metals on a color coated sheet iron line, by means of a radiation thermometer, wherein a radiation source hot plate having a surface whose surface temperature is substantially constant and whose emissivity is nearly equal to unity is located opposite to an object to be measured and above that portion of the object to be measured. The temperature of the object portion below the hot plate is considerably lower than that of the portion of the object subject to direct temperature measurement by the radiation thermometer. The emissivity of the metal surface is obtained from a measurement of the reflected radiation from the radiation source hot plate off of the surface of the object, and the value of emissivity of the surface is used to automatically correct the output of the radiation thermometer to provide more accurate temperature measurements.
Abstract:
An apparatus comprising first and second thermal sensors operating at first and second temperatures and generating electrical signals in response to thermal radiation from a radiant body and from an external source irradiating the radiant body is used to remotely measure the temperature and emissivity of the radiant body independent of its radiant surface property.
Abstract:
A radiometer is disclosed for use in either ambient atmospheric air or a vacuum environment having a black body receptor cavity in a massive heat sink enclosed in a Dewar Flask. A view limiting tube outside a housing is provided with baffles, as is a muffler inside the housing, to protect the cavity from effects of wind. A compensating cavity or mass of thermal capacity is connected to the heat sink via a flange by a thermal resistance equal to a thermal resistance connecting the receptor cavity to the flange. Cold junctions of a thermopile are connected to the receptor cavity. A heating coil is provided for the receptor cavity for calibration. Modifications for various elements or features are also disclosed.