Abstract: The present invention teaches a unique laser radiometer capable of accurately measuring the radiation temperature of a radiant surface and independently measuring the surface's emissivity. A narrow-band radiometer is combined with a laser reflectometer to measure concurrently radiance and emissivity of a remote, hot surface. Together, radiance and emissivity yield the true surface temperature of the remote target. A narrow receiver bandwidth is attained by one of two methods; (a) heterodyne detection or (b) optical filtering. A direct measurement of emissivity is used to adjust the value obtained for the thermal radiation signal to substantially enhance the accuracy of the temperature measurement for a given subject surface. The technique provides substantially high detection sensitivity over a very narrow spectral bandwidth.

Abstract: An improvement for a system used to measure temperature of hot gases that are laden with entrained solids. The system involves use of a pyrometer that is mounted outside of a sight hole through the wall of a vessel containing the laden hot gases. And, the improvement concerns a projecting shelf above the sight hole to divert molten slag in order to keep the sight hole clear. Also there is a sloped recess at the bottom of the sight hole to drain any slag away from the lower portion thereof.

Abstract: A sensor unit comprising two pyrometers arranged in respective chambers disposed side-by-side and open at one end, one chamber being substantially totally reflecting and the other substantially totally absorbing. Periodically, the unit is advanced to the immediate proximity of the product, the signals from the pyrometers are received after the response time of the pyrometers has elapsed, and then the unit is withdrawn to its initial position. The signals from the pyrometers are processed so as to provide a signal representing the emissivity of the product.

Abstract: An optical probe for collecting light from a defined region in a high temperature environment employs a pair of curved surfaces and a reflective surface to couple light from the defined area into an optical fiber while discriminating against light from other regions.

Abstract: A system for the measurement of temperatures in a reactor such as those operated under high pressure and/or temperature is disclosed. The temperature is measured by the use of a pyrometer which is in optical communication with a measuring duct which can be disposed in the wall of the reactor and is in optical communication with the reactor interior. The measuring duct comprises two concentric tubes the outer one of which extends beyond the inner tube in the direction of the reactor interior and has a conical construction immediately following the termination of the inner tube. The concentric tubes are provided with a common end section such as in the form of a cone in the direction of the reactor exterior. A hermetic housing defining a safety chamber is disposed exterior thereof, the hermetic housing having two opposed pressure type and heat resistant windows in alignment with the inner tube and the pyrometer. The hermetic housing is not normally permanently attached to the measuring duct.

Abstract: An object carrier has a transparent plate with an opaque backing and carries a thin liquid crystal layer which, in turn, is covered with a 2 .mu.m glass plate carrying an object (microorganism, etc.). This carrier is placed in a microscope for photographic observation of the temperature-dependent reflectivity of the crystal layer as heat conductively coupled to the object. The average reflection of light by the crystal layer is used as a representation of its average temperature, to control backlighting of the opaque layer to, thereby, stabilize the average object temperature to at least 10.sup.-3 degrees centigrade.

Abstract: A portable automatic disappearing filament optical pyrometer having low power demand incorporating a solid state line scanner as a sensing element is controlled by a microprocessor to perform a balance between the radiation from a target and a lamp filament to provide a digital indication of the temperature of the target including compensation for emissivity of the target.

Abstract: A photoluminescent indicator apparatus having automatic feedback means to maintain the sensitivity of the indicator apparatus with respect to variations in environmental conditions. The apparatus includes a sample of photoluminescent material having a photoluminescent decay rate which varies as a function of environmental conditions. The sample is positioned in a remote location having some unknown aspect of the environment desired to be measured. The sample is optically excited with a modulating signal to generate an excitation output signal functionally dependent on the modulating signal and indicative of the unknown environmental condition. A phase detection means is provided for comparing difference in phase between a phase reference signal and the excitation output signal to generate a phase differential signal functionally related to the photoluminescent decay rate of the sample.

Abstract: A temperature responsive device, such as a fuse or a temperature measuring apparatus, is disclosed including a temperature sensor having a light reflective (or light transmissive) characteristic which varies with temperature, and a device for receiving the light reflected from (or transmitted through) the sensor and to provide an output in accordance with the state of the characteristic. As shown, the sensor (perhaps an adhesive temperature indicator) is used as a fuse and, upon its color-change, it interrupts a switch 2 connecting a power source to a load the temperature of which the sensor senses.

Abstract: A pyrometer system for the measurement of the temperature of a primary source of heat which might be contaminated by radiation from a transient spurious source of heat at a higher temperature, and in which the presence of radiation from the spurious source can be detected or identified by spectral discrimination. The received radiation is separated into two spectral components of which a second component comprises a significantly higher proportion of radiation emitted by the spurious source than does the first component. The ratio of, or the difference between, the magnitudes of the radiation in the second and first components is used to identify or detect the presence of spurious radiation and to produce an error, or flag, signal which is used to inhibit operation of the pyrometer or to cause it to hold the last received `good` reading before the occurrence of the spurious radiation.

Abstract: In order to measure the temperature of the mid-span first stage rotor blade of a gas turbine engine, an optical pyrometer is mounted in the inner casing of the gas turbine engine and includes an elongated sight tube extending from the optical lens of the pyrometer and through the wall of the engine separating the inner casing from the rotor. The sight tube includes an array of spaced apertures extending therethrough in the vicinity of the optical lens, with each aperture extending at an acute angle to the longitudinal axis of the sight tube away from the optical lens. Pressurized air within the inner casing passes through the array of apertures and effectively forms a conically-shaped fluid screen for preventing smoke, dust, fumes, or other contaminants from contaminating the optical lens.

Abstract: A multicore optical fiber having a plurality of cores positioned across the diameter of a common cladding can be so optimized to respond to either temperature or strain by the selection of materials, spacing and shape of the cores in the fiber. The cross-talk between adjacent cores in the fiber changes in response to either a change in temperature or a strain along the length of the fiber. The temperature, strain or pressure change, can be determined by measuring the relative intensity of light emerging from the different cores of the fiber. If the fiber is optimized to respond to temperature change, then a high degree of temperature sensitivity can be provided over a large unambiguous range. Alternatively, cross-talk can be made temperature insensitive so that the intensity pattern of light emerging from the various cores in the fiber is only a function of the strain exerted on the fiber.

Abstract: A radiation absorbing cone (34) affixed to an infrared pyrometer (31) has a pair of lateral apertures (36--36) therein through which a continuously moving heated wire (11) passes. The cone (34) blocks stray ambient radiation while substantially eliminating any reflected radiation from the wire (11) from impinging on the pyrometer (31) to provide an accurate and repeatable measurement of the wire temperature.

Abstract: An irradiance analysis system which includes an array of square rods that are joined together and have a flat entrance end and a polished flat exit end through which visible light is transmitted to a Fresnel lens and focused to a particular area where the image focused is photographed so that when the various frames are developed they can be analyzed in a conventional film densitometer to yield quantative data on the temporal variation of laser beam irradiance distributions.

Abstract: A viewing tube extension for an infrared radiation pyrometer includes a tube having a heater therein. The heater has a passageway so that the pyrometer sights a glass ribbon moving through a forming chamber of a flat glass making apparatus. Vapors from the heating chamber moving into the tube are maintained above their dew point as a purge gas moves the vapors out of the tube.

Abstract: A complete system for detecting and metering solar energy and recording the total integrated energy or power levels over a desired period of time.

Abstract: This invention relates to the use of a birefringent crystal as the sensing element in a probe thermometer constructed of certain basic optical components utilized in three separate modes. Thus, all of the modes of the invention are directed to a probe thermometer which uses the temperature dependence of the birefringence of certain single crystals as the temperature sensitive parameter. One such crystal is a Y-cut single crystal of LiTaO.sub.3. Alternative crystals having adequate sensitivity in the desired temperature range may be constructed from LiNbO.sub.3 or BaTiO.sub.3. Polarized light propagates through the crystal in two modes, the ordinary ray and the extraordinary ray, which have indices of refraction n.sup.o and n.sup.e. For LiTaO.sub.3 at room temperature, n = 2.2, B = n.sup.e - n.sup.o = 0.004, and dB/dT = 4.4 .times. 10.sup.-5 /.degree. C.

Abstract: The sub-surface temperature of a body of water, such as an ocean, is measured remotely by directing a laser beam into a body of water and analyzing the Raman backscatter produced by the water. The Raman backscatter contains information which, when processed, indicates the water temperature at various depths. Precise temperature measurements may be made by separately detecting and measuring the polarization ratio at different wavelength intervals throughout the Raman band and measuring the differential diffuse attenuation coefficient using range-gated Raman backscatter techniques on a wavelength by wavelength basis.

Abstract: The temperature of a metal surface is measured by positioning a radiation detector so that the angle between its optical axis and a line normal to the surface is equal to the principal angle of incidence of the radiation emitted by the surface and interposing a polarizer between surface and radiation detector adjusted to pass only radiation polarized parallel to the plane of emittance. In this way the effects of emissivity variations of the surface are greatly reduced.

Abstract: A hand-held radiometer for non-contact temperature measurement of objects is provided with a probe which is adapted to be mounted on the optical barrel of the radiometer to permit the radiometer to which it is attached to provide contact temperature measurements. The probe comprises a thin plastic film of low thermal mass which is shaped on one end thereof to be easily deformed when brought into contact with a specimen whose temperature is desired to be measured. The inner surface of the plastic film has a high emissivity, and a retainer means is provided on the other end of the thin plastic film for mounting the probe on the optical barrel of the radiometer.