Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/05—Means for preventing contamination of the components of the optical system; Means for preventing obstruction of the radiation path
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/0037—Radiation pyrometry, e.g. infrared or optical thermometry for sensing the heat emitted by liquids
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/026—Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/0275—Control or determination of height or distance or angle information for sensors or receivers
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/06—Arrangements for eliminating effects of disturbing radiation; Arrangements for compensating changes in sensitivity
  • G01J5/064—Ambient temperature sensor; Housing temperature sensor; Constructional details thereof
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0801—Means for wavelength selection or discrimination
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0813—Planar mirrors; Parallel phase plates
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/48—Thermography; Techniques using wholly visual means
  • G01J5/485—Temperature profile
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/60—Radiation pyrometry, e.g. infrared or optical thermometry using determination of colour temperature
  • G01J5/602—Radiation pyrometry, e.g. infrared or optical thermometry using determination of colour temperature using selective, monochromatic or bandpass filtering
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/80—Calibration
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0801—Means for wavelength selection or discrimination
  • G01J5/0802—Optical filters
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0803—Arrangements for time-dependent attenuation of radiation signals
  • G01J5/0804—Shutters
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0803—Arrangements for time-dependent attenuation of radiation signals
  • G01J5/0805—Means for chopping radiation
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0806—Focusing or collimating elements, e.g. lenses or concave mirrors
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0808—Convex mirrors
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0846—Optical arrangements having multiple detectors for performing different types of detection, e.g. using radiometry and reflectometry channels
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0859—Sighting arrangements, e.g. cameras
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0893—Arrangements to attach devices to a pyrometer, i.e. attaching an optical interface; Spatial relative arrangement of optical elements, e.g. folded beam path
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/52—Radiation pyrometry, e.g. infrared or optical thermometry using comparison with reference sources, e.g. disappearing-filament pyrometer

Definitions

• the present invention relates to a device and a method for determining the temperature inside substantially transparent materials, in particular inside molten glass.
• the technical field of the invention is that of temperature measurement.
• the use of molten glass, in particular for the manufacture of glass articles, requires temperature measurements which can in certain cases be carried out using thermocouples in situ, but in certain cases the use of these thermocouples is not possible due to the disturbances they cause in the molten or cooling glass, the shape of which they can modify.
• Optical pyrometers are then used which make it possible to measure, without contact with said molten glass, the temperature of a sample of said glass; optical pyrometers are generally used in the visible or infrared range.
• Patent application No. ⁇ FR 2 458 093 describes an example of the use of an optical pyrometer for adjusting the width of a glass ribbon produced by floating.
• Monochromatic pyrometers which give the temperature of an opaque body at the measurement wavelength, when the emissivity of the measured sample is known.
• Patent application No. FR 1 580 121 describes a pyrometer of this type.
• Bi-chromatic pyrometers are also known which make it possible to measure the radiation of an opaque body over two close wavelengths, and which make it possible to deduce therefrom by calculation the surface temperature of said opaque body without having to know the emissivity of said sample, by application of Planck's formula for black body radiation.
• the US patent ***. 708 -493 (STEIN) describes a particular bichromatic pyrometer which comprises two laser diodes capable of emitting radiation towards the target, at the measurement wavelengths.
• Known optical pyrometers are generally used for wavelengths greater than five ⁇ because between 0.5 and five ⁇ , the glass is semi-transparent, and its emissivity and its transparency depend on the temperature of the glass.
• the problem posed is therefore to provide a device for measuring the temperature prevailing within a sample of molten glass and more generally within semi-transparent materials.
• the problem posed is also to provide a method for determining the temperature inside molten glass which makes it possible to precisely determine the profile of said temperature as a function of depth, and which is suitable for use in an industrial environment.
• the solution to the problem posed consists in providing a temperature measuring device which comprises at least one depth pyrometer comprising a number N of detectors sensitive to waves in the infrared range, and comprising said number N of narrowband interference filters situated respectively on the optical axes of said detectors, upstream of said detectors, and comprising at least one selective deflection device and preferably at least one dichroic measuring blade, which selective deflection devices, preferably which dichroic blades, can respectively reflect towards said detectors part of a main light beam; advantageously, said number N is at least equal to two and at most equal to eight, and preferably said number N is equal to four.
• said narrow bands of said interference filters are disjoint and are centered on respective wavelengths (Li, ... LN) which have a value between 0.3 ⁇ and Ui and the width of said bands is between 2 nanometers and 5000 nanometers and preferably between 10 nanometers and 200 nanometers, so that said pyrometer can measure N monochromatic luminances corresponding to said wavelength.
• said detectors are photo-resistive detectors
• said depth pyrometer comprises at least one light beam switch (or modulator) and, preferably said depth pyrometer comprises a switch of said main light beam, and said switch cuts off said beam to a frequency between 10 and 5000 Hz, and preferably between 100 and 2000 Hz, so that in the time interval when said switch cuts off said beam, said detectors can measure optical background noise, and preferably, said detectors can simultaneously measure the optical background noise, and in the time interval in which said switch lets said beam pass, said detectors can measure, preferably simultaneously, at least part of the energy of said beam, for example the monochromatic luminance of the radiation emitted by a sample of molten glass and preferably so that said detectors carry out a measurement at the same instant of the same object, through the same optical path outside said depth pyrometer.
• said infrared detectors are fixed on a common support, so that said optical axes of said detectors are parallel to the longitudinal axis of said depth pyrometer and, said pyrometer deep comprises means for guiding the parts of said main light beam reflected by said selective deflection devices, towards said detectors, and preferably it comprises secondary mirrors which can guide said parts of said main beam towards said detectors.
• a device further comprises, in front of each of said detectors, a focusing objective whose focal distance is between 10 and 100 mm and preferably between 10 and 50 mm, and said detector has a sensitive part whose surf ce is less than or equal to 1 mm 2 , and preferably said detector to a sensitive part whose surface is less than or equal to 0.1 mm 2 , and which may in some cases be less than 0.01 mm 2 .
• each of said resistive photo detectors is provided with a Peltier effect cooler and with a temperature probe which allows the temperature of said detector to be measured, and said common support can be cooled by a liquid, so that each of said detectors can be maintained at a predetermined temperature, and preferably each of said detectors can be maintained at a predetermined temperature below -20 ° C, which allows to benefit from a better sensitivity of said detectors.
• a depth pyrometer further comprises an input optic located on the axis of said main light beam, which input optic is achromatic (for the wavelengths corresponding to the visible range) and transparent to infrared waves, and said input optics makes it possible to focus on objects located at a distance from said pyrometer with a depth of between 1 meter and 50 meters, using a visible beam of light observed by to an eyepiece fitted with a reticle.
• the diameter of said main beam and of said parts of said main beam has a value between 1 and 0 mm and preferably has a value between 5 and 20 mm.
• said depth pyrometer further comprises an ocular sighting device, which ocular sighting device comprises an eyepiece which can be provided with a reticle, a sighting optic, a sighting mirror, a deflection device and said sighting device.
• sighting preferably comprises a dichroxical sighting blade, which deflection device, preferably which dichroic sighting blade, can reflect towards said sighting mirror a visual part of said main light beam, which deflection device is located on said longitudinal axis of said pyrometer depth.
• a depth pyrometer according to the invention may further comprise means for transporting a shielding gas near said inlet optic, and means for forming in front of said inlet optic threads of said shielding gas which in particular allow 'r avoid fouling of said optical input by projections.
• said switch (or modulator) consists of a plane disc which can rotate about an axis parallel to said longitudinal axis of said depth pyrometer, which axis is perpendicular to said disc, by means of drive. , preferably by virtue of an electric motor (for example a brushless direct current motor), and said disc comprises transparent sectors which allow said main light beam to pass through, and said disc comprises opaque sectors which stop said main light beam, and said pyrometer depth includes means for driving said disc at substantially constant speed, and said depth pyrometer includes a sensor for measuring the rotation of said planar disc.
• an electric motor for example a brushless direct current motor
• said disc comprises transparent sectors which allow said main light beam to pass through
• said disc comprises opaque sectors which stop said main light beam
• said pyrometer depth includes means for driving said disc at substantially constant speed
• said depth pyrometer includes a sensor for measuring the rotation of said planar disc.
• a depth pyrometer comprises a substantially cylindrical housing having a longitudinal axis of said axis, which housing comprises a front bottom and a rear bottom, and said housing comprises a support for said detectors, and it comprises a support for said dichroic blades and of the supports of said interference filters, and said supports of said detectors and said supports of said interference filters and said support of said dichroic blades are rigidly linked together so as to form a drawer which can slide in said housing.
• a pyrometer according to the invention further comprises electronic means for processing the signals from said infrared detectors and from said rotation sensor, and preferably said electronic means are at least partly contained in said housing.
• Said electronic means can comprise at least one, preferably at least N sampler-blockers which can record, preferably simultaneously, the signal delivered by each of said infrared detectors and which are controlled by the signals generated by said rotation sensor, preferably by means of a device for shaping said signals from said rotation sensor.
• said electronic means comprise means for sampling said signals delivered by said detectors, in synchronism with the rotation of said switch.
• a solution to the problem posed also consists in providing a device for measuring the temperature profile inside a semi-transparent material, such as molten glass, which comprises at least one optical pyrometer according to the invention, and which comprises furthermore at least one computer, at least one device for measuring surface temperature (on both sides of a sample of said material) and at least one device for measuring the thickness of samples of said material.
• a semi-transparent material such as molten glass
• a solution to the problem posed also consists in providing a method for determining the temperature inside the glass. fade which includes the following operations:
• N estimated monochromatic luminances are calculated as a function of estimated temperatures inside said sample using a mathematical model comprising N parameters, the differences between said estimated monochromatic luminances are calculated with said measured monochromatic luminances, and if said differences are greater than at least a predetermined threshold, the said parameters are corrected and the previous operation is carried out again.
• a device according to the invention is relatively simple to manufacture, at a reasonable price, allows the luminances of the samples of molten glass to be measured with a relatively rapid rate, and allows the internal temperature profiles to be determined precisely using the methods according to the invention.
• Another advantage of a device according to the invention is that provide a device that can easily be adapted to an industrial environment and which can withstand high ambient temperatures and in particular high radiant heat input thanks to said cooling device.
• the devices according to the invention make it possible to make said luminance measurements of said samples at any distance between one and fifty meters and therefore make it possible to adapt to very diverse conditions of use.
• a pyrometer according to the invention is to allow its easy installation thanks to said ocular sighting device which makes it possible to adjust the positioning of the longitudinal axis of said pyrometer so that it is sensitive to a sample. having a determined position in space.
• Another advantage of a depth pyrometer according to the invention is to have, thanks to said protective gas and to its means of implementation, a pyrometer capable of working under difficult conditions in particular in the event of projections.
• Another advantage of a depth pyrometer according to the invention is that its mechanical structure makes it possible to carry out a large part of the factory settings and to facilitate the maintenance of said pyrometer thanks in particular to the structure comprising said drawer.
• An advantage of a device according to the invention is also to have said electronic means for processing said signals, at least in part, in the immediate vicinity of said infrared detectors, so as to avoid disturbances of said measurement signals, which disturbances in particular electromagnetic are common in industrial applications.
• the depth pyrometer and its method of use according to the invention can, for example, also be used to measure the temperature profile (close to 1400 ° C.) of the glass contained in an oven, over thicknesses of up to one meter. , or to measure the temperature profile (close to 600 ° C) within glass plates which come out of an oven, which can be of a thickness ranging from ⁇ m to 30 mm.
• FIG. 1 schematically represents a depth pyrometer according to the invention and the means for implementing a temperature measurement method according to the invention.
• Figure 2 is a longitudinal section of a particular embodiment of a pyrometer according to the invention.
• Figure 3 is a view along III-III of Figure 2.
• Figure 4 is a section along IV-IV of Figure 2.
• Figure 5 is a section along VV of Figure 2.
• Figure 6 is a simplified diagram at least part of the electronic means for processing signals from a depth pyrometer according to the invention.
• Figure 7 is a longitudinal section of a preferred embodiment of a pyrometer according to the invention.
• samples of molten glass 29 are shown which move vertically along an axis zzi, for example during their fall due to their weight, at the outlet of a device for warming up said samples, which device can deliver samples of generally cylindrical shape, sometimes called "gob" or "parison".
• the molten glass is subjected to thermal conditioning operations which consist in cooling and heating it, these operations generally being carried out in a "feeder", a sort of channel in which the glass flows; at the outlet of said "feeder”, the glass is then subjected to a mechanical action of separation of the flow of molten glass, into samples of size adapted to the articles to be manufactured.
• thermal conditioning operations consist in cooling and heating it, these operations generally being carried out in a "feeder", a sort of channel in which the glass flows; at the outlet of said "feeder”, the glass is then subjected to a mechanical action of separation of the flow of molten glass, into samples of size adapted to the articles to be manufactured.
• said electronic processing means are connected by connecting means 28 with a computer 25-
• said computer is also connected to at least one surface pyrometer 26 which can measure the radiation R2 forming part of said radiation R emitted by said sample; it is also preferable to connect to said computer 25 means 31 for triggering measurement, for example of the light barrier type, means 27 for measuring the thickness of said sample 29, which means 27 may for example consist of a sensor CCD type, as well as means 32 for measuring the humidity of the atmosphere prevailing around said samples 29.
• said electronic processing means of said pyrometer 30 according to the invention, said surface pyrometer 26, said triggering means 31, said humidity measuring means 32, and said means for measuring the thickness of said sample 27, are connected to said computer by connecting means 28.
• the spectral (or monochromatic) luminance of the radiation which emerges from the molten glass depends on the temperature profile prevailing in said molten glass sample, and depends on the spectral thermo-optical properties of said molten glass, on the thickness of said sample. and characteristics of the borders of said sample with the external medium.
• Bl and B2 being parameters depending on the material.
• the calculation of the temperature profile inside said sample from the monochromatic luminances measured therefore calls for inversion methods which consist in determining the values of the temperature inside the glass by knowing the value of an integral. dependent on said temperatures; by means of certain simplifying assumptions, it can advantageously be assumed that said temperature profile follows changes as a function of the depth of the glass, of the parabolic or logarithmic type or any other parameterized analytical solution.
• four parameters Ci, C2, C3, C are sufficient; the general form of this type of equation can then be written:
• T (x) F (T ⁇ , T2, Cl, C2, C3, C4), with
• T (x) temperature at depth x in said sample Ti and T2 temperature at the surface of said sample corresponding to the ends of the thickness of said sample along the measurement axis, Ci, C2, C3, C4 being said parameters.
• T (x) T ⁇ + C ⁇ (l-exp (-x / C2)) - C3 (exp ((x-H) / C4) -exp (-H / C4))
• T (x) T ⁇ -C ⁇ (l-exp (-x / C2)) - C3 (exp ((xH) / C4) -exp (- H / C4)) - (T ⁇ -T2 + C ⁇ (l-exp (-H / C2)) - C3 (l-exp (- H / C4))) x / H, this equation leading to a temperature profile in the form of a sigmoid curve.
• said iterative calculation is stopped when said estimated monochromatic luminances have the same value to within 0.1% as said measured monochromatic luminances, which corresponds to a precision on the calculated temperature of the order of 0.5% î taking into account errors due to causes other than said calculations, the measurement accuracy is in fact 3 to 5 ° C.
• said main light beam enters said optical depth pyrometer 30 according to the invention by said input optics 7
• said input optics 7 which makes it possible to optically focus said pyrometer according to the invention in function of the distance D3 separating said pyrometer from said sample on which the measurement is to be made;
• said main light beam FP propagates along the longitudinal axis of said depth pyrometer which is constituted by said axis xxi;
• a first deflection device 8n has been provided which is preferably constituted by a dichroic blade, which will allow part of said main light beam FP to pass and which will reflect towards an aiming mirror 11 the visual part FV of said beam, which mirror 11 will reflect said visual beam FV towards an eyepiece 9 allowing the aiming of said pyrometer to be adjusted by a operator, as well as the adjustment of the orientation of the optical axis or longitudinal axis of said pyrometer depth, i.e.
• each of said dichroic measurement blades is such that it will deflect a part of said main beam corresponding to the wavelengths less than the characteristic wavelength of said dichroic blade, which deflected beam is called secondary beam; thus, if we denote Li the characteristic wavelength of said dichroic plate 3l. if L2 denotes said wavelength characteristic of said dichroic blade 32 and L3 said wavelength characteristic of said dichroic blade 33.
• said first dichroic blade encountered by said main beam after said means for deflecting the aiming beam 8 goes deflecting to a secondary mirror 6 a secondary beam FSi which consists of the part of said main light beam whose wavelengths are less than Li; said secondary beam FSi will be reflected by said secondary mirror 6 towards tin of said infrared detectors 1; the part of said main beam FP which will not have been deflected by said dichroic blade 3l. propagates along said axis xxi and arrives on said dichroic blade 32; said dichroic blade 32 v & deflects towards a second secondary mirror 6 the part of said incident main beam corresponding to the wavelengths shorter than said wavelength L2 characteristic of said second dichroic blade 32.
• said input optic ⁇ which advantageously comprises an optic constituted by three lenses 7a, 7b, 7c î advantageously, said lenses 7b and 7c are fixed relative to a central part 16a of said front bottom 16, and a lens ⁇ a. located in front of said lenses 7b and 7c, can move in translation along said longitudinal axis xxi of said depth pyrometer, on a stroke C, in order to allow the adjustment of said depth pyrometer as a function of the distance from the measurement area.
• said lens fa is mounted on a support 7d which can move relative to said central part 16a of said front face, along said longitudinal axis xxi. It can be seen that said main light beam FP which corresponds to part of the radiation emitted by said sample, can penetrate said housing of said depth pyrometer by said input optic. It can be seen that, advantageously, said support 7d and said part 16a of said front face delimit a cavity 3 into which a cleaning gas can be blown, by means of a pipe 35 which opens out of said housing and into which can be penetrated said cleaning gas according to arrow EA.
• said support 7d has openings 7e which are advantageously inclined at an angle DEB relative to said axis xxi; in this way, said cleaning gas which penetrates into said cavity after having been conveyed by said pipe 35 "can exit from said cavity through said orifices 7e, and thus form in front of said movable lens ⁇ has a gas curtain which will be able to protect said lens 7 of possible projections which would be likely to dirty said lens.
• said main light beam FP after having passed through said lenses constituting said input optics which allows the adjustment of the focus of said depth pyrometer, passes through said depth pyrometer along said axis xxi, and successively meets said device 8 of deflection of said visual beam, and said dichroic measuring blades 3l. 32. 33 constituting the means for deflecting part of said main beam, and then arrives at one of said infrared detectors 1, after having passed through an interference filter 2 and an input optic 43 which may advantageously include two lenses.
• said device 8 for deflecting said visual beam consists of a dichroic aiming blade which deflects a part of said main beam corresponding to the wavelengths less than the characteristic wavelength of said dichroic aiming blade; said visual beam FV deflected from said main light beam, is directed towards an aiming mirror 11, which reflects said visual beam FV towards said eyepiece 9. by means of an optical sight 10.
• said aiming mirror 11 is mounted on a support 11a which is fixed to a support 11b by means of a screw 11 provided with a nut and a spring 11d; thus, the position of said support 11a of said aiming mirror 11 can be adjusted with respect to the position of said support 11b so as to adjust the direction of said visual beam reflected towards said aiming optics and said eyepiece.
• said sight optic 10 is mounted on a support 10a which is provided at its end 10b with a thread 10c which can cooperate with a thread provided in a support 5. so as to rigidly fix said sight optic in relation to said support -
• Said main light beam FP after having crossed said dichroic aiming blade 8, may pass through said dichroic measuring blades 31. 32. 33; said dichroic measuring blade 33 which is mounted substantially at 5 ° (as well as said other dichroic blades) with respect to said axis xxi, may reflect towards a secondary mirror 6 a part of said main light beam, in this case a secondary light beam FS3 corresponding to wavelengths shorter than the characteristic wavelength of said dichroic blade 33; it can be seen that said secondary beam FS3 is directed towards a secondary mirror 6 which reflects said secondary beam FS3 towards one of said infrared detectors, via one of said interference filter and one of said focusing objectives located in a housing 19.
• said secondary mirror 6 is mounted on a support 6a which is fixed by means of a screw 6c provided with a nut and a spring 6d, to a support 6b, so that the position of said support 6a can be adjusted relative to the position of said support 6b by means of adjustment 6e which can advantageously be constituted by at least three support screws, so as to allow orientation of said beam FS3 reflected by said secondary mirror.
• Said supports 6b and 11b of said mirrors, said supports I81, I82. 183, 184 of said dichroic blades can advantageously be rigidly connected to parts 20a and 20b of a drawer 20 which comprises said support 5, and which can slide in said cylindrical housing 15a of said depth pyrometer.
• said drawer 20 can be blocked by means such as screws 38 relative to said cylindrical housing, and can slide inside the said housing, when said screws 38 have been removed so as to allow easy access to said components of said pyrometer. deep for maintenance in particular.
• an electric motor 13 is provided which can drive in rotation along an axis xx2 parallel to said axis xxi, a switch 4 of said main light beam FP, which is constituted by a flat disc 12; said electric motor 13 can be fixed by a support 13a to said drawer 20.
• Each of said infrared detectors 1 is advantageously mounted on said support 5. Which can be cooled so as to maintain said detectors at a substantially constant temperature, and said housings 19 can be screwed into said support 5. opposite said infrared detectors by means of a thread 19a provided at one end of said housing.
• Each of said boxes will include an interference filter 2 followed by a focusing objective 43 advantageously constituted by two lenses; the purpose of said focusing objective is to focus said main light beam FP having passed through said interference filter 2, on the sensitive surface 1b of said detector 1 according to a focusing angle A which is advantageously greater than 30 °; each of said detectors is provided with means for connection 1a to said electronic means for processing the signals coming from said detectors, which electronic means can (at least in part) be advantageously fixed on supports 3 rigidly connected to said support 5. and located near said support , so that said connection means are as short as possible, so as to avoid the effects of electromagnetic disturbances.
• each of said housings 19 can be immobilized relative to said support 5 P ⁇ of the screws 39. after the adjustment of the focusing of said focusing objective 43 on said sensitive part 1b of said detectors has been made.
• said rear face 17 of said housing receives said eyepiece 9 allowing aiming by an operator 44, and also receives connectors 37 which form part of said connecting means 28 between said electronic means for processing said signals from said detectors, and said computer.
• said aiming optic 10 comprises at least one lens which is mounted on a support 10a provided at one of its ends 10b with a thread 10c, so that said support 10a can be screwed onto said plate forming said support 5 said infrared detectors; advantageously, said input optic 10 can consist of an achromatic doublet.
• said drawer comprises a part 20b on which are fixed supports 182, I83, I84 of said respective dichroic measuring blades 31. 32. 33; said dichroic measuring blade 33 makes it possible to extract from said main beam FP a secondary beam FS3 which contains the radiation of said main beam whose wavelength is less than the characteristic wavelength of said dichroic blade 33 î said secondary beam FS3 deflected by said dichroic plate 33 is reflected by a secondary mirror 6 towards said infrared detector, and passes through said interference filter and said focusing objective which are contained in said support 19, and which are located on the optical axis of said corresponding infrared detector, upstream thereof on the path of said beam FS3.
• means 39 such as screws are provided for locking in position said support 19 of said interference filter and of said focusing objective with respect to said support 5 and that means 38 such as screws are provided for immobilizing said support 5 and therefore to immobilize said drawer 20 inside said cylinder 15 forming said housing.
• said slide 20 can be extracted from said cylindrical housing 15a according to arrow S,; advantageously, supports 36 of electronic signal processing means can be fixed on said support 5. which electronic means will be electrically connected to the connections la of said infrared detectors 1; said electronic processing means may advantageously be connected to said computer by means of connections which may in particular include connectors 37 located on said rear face 1 of said housing.
• said drawer 20 comprises said support on which are fixed said supports 19 said interference filters and said focusing objectives; we see that on a part 20b of said drawer, are fixed said supports 6b of said secondary mirrors 6, as well as at least part of said supports
• said supports 18 are distributed along said longitudinal axis xxi of said depth pyrometer, and that said dichroic measuring blades are fixed so that their plane makes an angle B close to
• a part 20c of said drawer serves as a support for said rotation sensor 14 of said plane disc 12 forming said switch of said main beam FP.
• said rotation sensor 14 is constituted by an opto-electronic fork.
• said drawer 20 which can slide in said cylinder 15a of said housing, comprises parts 20i, 202. 2O3, 204. substantially planar, and comprises said part 20c which supports said rotation sensor 14 which can measure the rotation of said plane disc 12 forming said switch of said main beam FP;
• said flat disc comprises transparent sectors Si and S3 which are distributed alternately with opaque sectors S2 and S4; thus, during the rotation of said plane disc along said axis xx2. said sectors will successively allow passage (for transparent sectors), then obscure (for opaque sectors) said FP beam after it has crossed said focusing objective of said depth pyrometer.
• the angles at the center E of said sectors Si, S2, S3, S4 are equal and in the case where said disc is cut into four sectors, said angle is substantially equal to 90 e ; it can be seen that said rotation sensor 14 is mounted along a radius of said plane disc which forms an angle D with the axis yyi contained in the plane of FIG. 4, which axis yyi passes through the traces in the plane of the figure of said axes xxi and x2, which axes xxi and XK ⁇ are perpendicular to the plane of figure 4.
• said flat disc is shiny on its face situated on the side of the incident light, that is to say on the side of said front bottom, and said flat disc is matt black on its other face.
• said angle D is close to 45 °, and is between 30 and 60 ⁇ , in the case where said plane disc comprises four sectors of 90 ° each; thus, said rotation sensor can provide a signal when passing in front of said rotation sensor of the border separating one of said transparent sectors with one of said opaque sectors; thanks to the choice of said angle D, said signal supplied by said sensor will correspond to an angular position of said planar disc in which, as the case may be, either said main beam FP is completely obscured by one of said opaque sectors of said planar disc, or said main beam crosses without attenuations, one of said transparent sectors of said flat disc.
• said signal could serve as a means of triggering the measurement of the signals coming from said infrared detectors, which measurement will be used and / or interpreted, respectively in one or other of the above cases, either as a characteristic measurement of the radiation of the sample, or as a measurement of noise, in particular optical noise.
• an infrared detector 14 of optical axis A reconnecteur4 is located on said longitudinal axis xxi of said pyrometer, and that the other three infrared detectors 11, 12, I3 of said pyrometer are located on said support on a radius Ri; it can also be seen that a hole 44 passing through said support 5 allows said aiming beam to pass through said support and to travel towards said aiming eyepiece.
• said infrared detectors have six connections a , particularly in the case where said infrared detectors are equipped with an internal temperature probe as well as an internal cooler, for example a Peltier effect type cooler.
• FIG. 6 there is shown schematically a portion of said electronic processing means of said signals from said infrared detectors; we see that said electronic processing means 21 may comprise for each of said infrared detectors 11 and 12, respective shaping modules 42 ⁇ , 422 which are advantageously identical. It can be seen that the signal Mil delivered by said infrared detector 11 is applied to the input of an amplifier Ai; the other input of said amplifier
• Ai is brought to a reference potential Vi; an assembly constituted by a resistor Ri preferably an adjustable resistor and a capacitor Ci connected in parallel to said resistor, which assembly is connected between said input of said amplifier Ai on which is applied said measurement signal Ml and said output of said amplifier, allows the adjusting the gain of said amplifier; an amplified measurement signal Ml2 is thus obtained at the output of said amplifier Ai which is applied to the input of blocking samplers EBl and EB2; advantageously, said blocking samplers EB1 and EB2 are respectively controlled by control signals U2 and U3.
• said rotation sensor 14 comprises a phototransistor Ti which is capable of delivering a synchronization signal Ui, thanks to a power supply V2 and a resistor R3.
• Said synchronization signal Ui is sent to a device for generating synchronization signals X, which is supplied by a potential 2; said device X for producing synchronization signals generates said signals U2 and U3 which will trigger the operation of said blocking samplers EB1 and EB2; the output of said blocking samplers EB1 and EB2 can be applied respectively to the negative and positive terminals of an amplifier A2 which will make a difference between said signals from said blocking samplers.
• a cell comprising a resistor R2 in parallel with a capacitor C2 will be connected in parallel to one of the inputs of said amplifier A2 and the output of said amplifier so as to define the gain of said amplifier; in this way, one obtains at the output of said amplifier A2, a signal MI3 which corresponds to the difference between the signals measured by said detector 11, respectively during the passage of said main beam in one of said transparent sectors of said plane disc and respectively during occultation of said main beam by one of said opaque sector of said flat disc; a signal MI3 is thus obtained which is representative of the signal detected by said infrared detector corresponding to the characteristic wavelength of the interference filter placed upstream of said detector 11, in which the optical noise has been largely eliminated.
• control signals U2 and U3 are applied to said module 422 for developing and shaping the signal M2 ⁇ generated by the infrared detector 12 and that said module 422 Which functions and which is made up so identical to said module 42 ⁇ , makes it possible to deliver a preamplified M23 signal corresponding to a measurement carried out by said detector 12 in which the optical noise has been largely eliminated.
• Said signals MI3, M23 ... can then be transmitted to said computer, after possible amplification by a line amplifier, or else be digitized and then transmitted in digital form to said computer.
• said pyrometer comprises said generally cylindrical housing which has an inner wall 15a, an outer wall 15b, which inner and outer walls define channels 15c which can extend in a general shape of a helix, in which a cooling fluid such as water can circulate, which cooling fluid can penetrate according to the arrow G2 in said channels via 'an inlet orifice 15d, which fluid can exit from said channels according to arrow G3 via an outlet orifice 15e.
• said front face 16 of said housing has a general form of flange, on which are mounted supports 51. in a substantially sealed manner, which supports can receive said dichroic input blade 8, said optic d input 7, said motor 13 for driving said switch 4, as well as an additional optic 50, which is a converging infrared optic, which converges the substantially parallel beam having penetrated into said housing by said input optic, on a field diaphragm ⁇ 2 located in the image focal plane of said optic 50; in this embodiment, a second objective 53 (constituting a collimation optic) substantially identical and symmetrical to said objective 50 makes it possible to reconstruct a parallel light beam from said rays having passed through said diaphragm 52; this particular device makes it possible to further attenuate the optical noise liable to tarnish the measurements made by said detectors.
• said dichroic blades 3 and secondary mirrors 6 are located on a support mechanically connected to said common support 5 of said detectors 1 so as to constitute a drawer 20 which can slide in said housing cylindrical and which facilitates adjustments and maintenance of the device according to the invention.
• said infrared detectors 1 are mounted on said common support 5 by means of said supports 19 of said interference filters and focusing objectives; advantageously, cavities 5 ⁇ . 55 in the general shape of a torus are provided between the substantially cylindrical external face of said supports 19 and corresponding bore portions provided in said support 5. which cavities ⁇ . 55 communicate with respective conduits 56, 57.
• said aiming objective 10 is mounted on said part forming a sliding drawer 20, and that said eyepiece 9 is mounted on said rear bottom 17 of said housing, which rear bottom 17 is mounted in a sealed manner thanks to to sealing devices 60 between said rear bottom and said cylindrical housing and by means of sealing devices 59 such as O-rings located around said supply pipes for said first and second coolants of said common support and said detectors ( in particular of said line 58).
• said rear bottom 17 can be part of said sliding drawer.

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• Physics & Mathematics (AREA)
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• Spectroscopy & Molecular Physics (AREA)
• Radiation Pyrometers (AREA)

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• 1990
  • 1990-11-23 FR FR9014977A patent/FR2669732A1/fr active Granted
• 1991
  • 1991-11-19 AU AU90455/91A patent/AU9045591A/en not_active Abandoned
  • 1991-11-19 WO PCT/FR1991/000909 patent/WO1992009869A1/fr active Application Filing

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