BR112021014521A2 - GETTING DATA FROM A MOVING PARTICLE PRODUCT - Google Patents

Abstract

obtaining data from a product of moving particles. a sensor structure (10) is used to obtain data from a moving stream of particulate matter (11), with a light source (56) providing a focused beam of light (64) to illuminate the particles (11) and a light receiver (54) receiving the light reflected from the illuminated particles (11) and transmitting the light to an optical sensor. The light from the illuminated particles (11) in a small analysis zone (65) is analyzed during short intervals, so that the light from only one particle is analyzed at a time. the light from a large number of individual particles (11) is analyzed separately and an analysis result is calculated from the analysis of the reflected light from the multiple individual particles (11).

Description

“GETTING DATA FROM A MOVING PARTICLE PRODUCT” FIELD OF THE INVENTION

[001] The present invention relates to a sensor structure for obtaining data from a moving particle product. The invention is useful for flowing hot particulate products, but is also useful in many other applications, such as for products on a conveyor belt or in various other modes of transport.

BACKGROUND OF THE INVENTION

[002] The stream of calcined product flowing from a calcining furnace is at a temperature that is high enough to cause the rocks that make up the product to glow. It is desirable to be able to analyze the product flow to determine the characteristics of the product leaving the oven. This allows the oven's operating parameters to be adjusted to obtain a high quality product. Specifically, in a lime calcination process, it is desirable to optimize the amount of chemically available lime and the ratio of chemically available lime to slow reacting lime. In the industry, this is known as detecting the “burn” level of the product.

[003] Calcined comprises chunks that are known as rocks and contain dust. Rocks are of various sizes. The term "particulate" is used herein to include the form of calcined material emerging from a lime kiln - as well as various other forms of moving product comprising solid particles.

[004] The present invention provides a sensor structure that obtains spectral data from glowing rocks in a calcined lime stream.

[005] The sensor structure can be used in relation to any other product comprising a stream of rocks heated to a temperature sufficient to make them glow, or in relation to any other product comprising a stream of moving particles. .

BRIEF DESCRIPTION OF THE INVENTION

[006] According to a first aspect of the present invention, a sensor structure is provided for obtaining data from a moving stream of particulate matter, the sensor structure comprising: - a light transmitter which is adapted to produce light in a beam of focused light, to illuminate particles in the moving stream; and - a light receiver which is adapted to receive light reflected from the illuminated particles and to transmit the light to an optical sensor; - wherein the light transmitter and optical sensor are configured to analyze light reflected from the illuminated particles, or emitted by the illuminated particles, during intervals shorter than a period required for a typical sized particle to pass before the focused beam of light; - where a light transmitter focus angle and light receiver acceptance angle are configured to analyze light reflected from illuminated particles or emitted by illuminated particles, from an illumination or analysis zone of a size that is , at most, as large as the size of a typical particle in the particulate material stream.

[007] The light source can be adapted to produce light continuously and the optical sensor can be adapted to analyze the reflected light intermittently, or the light source can be adapted to produce flashes of light at timed intervals.

[008] The light source can be a laser, such as a pulsed laser.

[009] The light receiver may have an axis that intersects the focused light beam at a non-zero acute angle, so that it is adapted to receive reflected light along a path that crosses the focused light beam.

[010] The light receiver may have an axis that coincides with the focused light beam at a zero angle and without displacement, so that it is adapted to receive reflected light along at least part of the same path as the beam of light. focused light.

[011] The focused beam of light can be focused close to infinity, also known as a collimated beam.

[012] The light receiver acceptance angle can be close to zero.

[013] The light transmitter may comprise a light source, a first optical fiber and a focusing lens, the first optical fiber having an input end and an output end, and the light transmitter being configured so that the light from the light source passes from the input end of the first optical fiber to emerge at the output end, and the light emerging from the output end passes through the focusing lens to form the focused light beam.

[014] The receiver for reflected light may comprise a second optical fiber having an input end and a lens, such lens being adapted to collect the reflected light from the illuminated particulate material and launch it at the input end of the second optical fiber.

[015] The sensor structure may include a housing having an end wall including at least one window, such sensor structure being configured so that the focused beam of light transmitted from the light transmitter and the light reflected from the illuminated particulate matter pass through the window in spaced locations.

[016] The sensor structure can include two spaced windows, configured so that the focused beam of light transmitted from the light transmitter and the light reflected from the illuminated particulate matter pass through different windows.

[017] The sensor structure may comprise a collector that defines a passage for a cooling medium, such collector forming an extension of the housing and being adapted to be fixed to a flow channel into which the particulate material falls. The end wall of the housing can also form an end wall of the collector.

[018] The sensor structure can include an air inlet adapted to inject air into the manifold and the sensor structure can be configured so that the air injected through the air inlet flows inside the manifold away from the window and towards the channel. flow.

[019] In accordance with another aspect of the present invention, there is provided a method of obtaining data for analytical purposes of a stream stream of particulate product, such method comprising: - illuminating the particles in the stream stream by directing a beam of light focused on current flow; - collect reflected light from particles in the current flow; - feeding the reflected light that is collected to an optical sensor; and - separately analyzing the light reflected from a plurality of individual particles from the illuminated particles, separately analyzing the light reflected from each of the individual particles during an interval that is shorter than the period required for a typical sized particle to pass before the beam of focused light; and - calculating an analysis result from the analysis of light reflected from the plurality of individual particles.

[020] The method may include illuminating the particles at timed intervals, pulsing the focused beam of light to illuminate the particles in the current stream for periods that are shorter than the period required for a typical sized particle to pass before the beam of focused light.

[021] The method may include illuminating the particles continuously with the focused beam of light and analyzing the light reflected from the particles intermittently for periods that are shorter than the period required for a typical sized particle to pass before the focused beam of light.

[022] The method may include mounting an angle of the focused light beam to illuminate an area the size of a typical particle size or less. Instead, or in addition, the method may include molding an acceptance angle of the light receptor to cover an area the size of a typical particle size or less.

[023] The angle from which the reflected light is collected may cross the focused beam of light at a non-zero acute angle.

[024] The current flow may comprise a hot, glowing particulate product.

BRIEF DESCRIPTION OF THE DRAWINGS

[025] For a better understanding of the present invention and to show how it will be carried out, references will now be made, by way of example, to the accompanying drawings, in which:

[026] Figure 1 is a schematic representation of a first embodiment of a sensor structure according to the present invention 1; and

[027] Figure 2 is a schematic representation of a second embodiment of a sensor structure according to the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[028] With reference to both drawings, the reference signal 10 generally refers to a sensor structure to obtain data from a stream of calcined product for analysis purposes, and the same reference signals are used in both drawings for identify features that are substantially similar between the two modalities, but appendices are used to distinguish general sensor structures, such as 10.1 and 10.2, respectively.

[029] With reference to Figure 1, the illustrated sensor structure 10.1 is fitted into a flow channel, in the form of a trough 12, into which calcined lime falls from a calcining furnace. Calcined lime is in free fall, glowing and in the form of what we call “rocks”

11. There is also dust in the gutter 12.

[030] The trough 12 has an opening 14 in its side wall and a collector 16 is fixed to the trough in alignment with the opening 14. The collector 16 comprises an inner cylindrical wall 18 which is surrounded by a coaxial water jacket 20. Inside the jacket 20 there is a coil 22 that guides the flow of cooling water that enters through an inlet 24 and leaves through an outlet 26.

[031] An air inlet to the manifold is shown at 28 and a manifold end flange 16 is shown at

30. An end closure plate 32 for manifold 16 is attached to flange 30. A gasket 34 is provided between flange 30 and end plate 32 to limit heat transfer from manifold 16 to plate 32. 32 is also part of an optical scan head commonly referred to as 36.

[032] Plate 32 may have a single window, but preferably has two windows 38 and 40.

[033] The scan head 36 comprises an outer housing designated 42, within which there is a transverse assembly 44. The assembly 44 carries two fiber optic termination units 46 and 48 for two optical fibers, a first optical fiber 52 and a second optical fiber 50. Between the optical fiber end unit 48 and the window 40 of the plate 32 there is a lens 56 which produces a beam 64 of light. The beam 64 passes through the window 40 and the collector 16 so that, in use, it illuminates the calcined material 11 falling through the chute 12.

[034] Between the fiber optic termination unit 46 and the window 38 is a lens 54 which, in use, collects the reflected light from the calcined material 11 and casts it on the second optical fiber 50 in the termination unit 46.

[035] A back plate 58 of the head 36 has an opening and a hose gland 60 is fitted into this opening. A protective hose 62 is attached to the gland 60 and optical fibers 52, 50 are passed through it to 3, respectively, a light source and an optical sensor, such as a spectrometer.

[036] In use, the hot rocks 11 of the calcined lime, with a certain amount of dust, fall into the trough

12. Water is pumped through jacket 20 and circulates around coil 22 so that heat is transported and overheating of head 36 is prevented. Dust-free air is blown through inlet 28 and flows into chute 12 through manifold 16. Having a higher pressure adjacent to windows 38 and 40 causes air to flow into the manifold in a purge direction 63, away from the vents 38 and 40. windows and towards opening 14, and thereby prevents or inhibits dust from settling on windows, as well as attenuating both transmitted light beam 64 and reflected light 55 from flowing product stream 11.

[037] Light in the form of flashes is launched onto the optical fiber 52 from the light source. Light shining out of optical fiber 52 is cast by lens 56 into a beam 64 that illuminates flowing current.

[038] As illustrated, fiber optic termination unit 48 is at an acute angle to fiber optic termination unit 46 which receives light reflected from rocks 11. Light beam 64 is transmitted as a pencil-like beam and illuminates the rocks as they fall through the beam. The reflected light from the rocks is scattered in all directions, and the reflected light passing through window 38 to lens 54 is collected by the lens and focused onto optical fiber 50 at termination unit 46.

[039] As shown by the dashed area representing an illumination or analysis zone 65, light reflected from substantially the entire width of the rock stream 11 falling into the chute 12 can reach the termination unit 46 if reflected properly. The width of the analysis zone 65 is a result of the small acute angle between the emitted light beam 64 and the reflected light 55, which is collected by the lens 54.

[040] As transmitted and reflected light passes through separate windows 38 and 40, or through spaced parts of the same window (in other embodiments of the invention), the likelihood that light from transmitted light flashes will scatter dust on the window is minimized, reach lens 54 and be accepted by fiber optic 50.

[041] The received light is converted into a discrete digital matrix of intensity values by means of a digital spectrometer. Each value in the matrix represents the intensity of a photosensitive pixel that has accumulated light of a certain wavelength range. These digitized spectra are processed in computer software at regular intervals.

[042] At each interval, the digitized spectrum is correlated with a set of five predefined spectral signatures (the number of signatures may be different in other embodiments of the invention.) The five correlation results are stored as a record in a FIFO buffer ( First In First Out). An analysis result is calculated by iterating through the buffer and comparing the correlation values to the threshold values and then applying conditional logic to assess whether this spectral sample scan can be counted as a rock or not. In the case of a rock, it is further evaluated whether the rock can be counted as burned or not.

[043] An output value of "rocks" is the total amount of records in the buffer that have been evaluated and can be considered as a rock. The output value of "burnt rocks" is calculated as a percentage where the amount of records in the buffer that can be counted as "one rock" and "burnt" is expressed as a percentage of the total amount of rocks counted in the buffer.

[044] As the FIFO buffer is refreshed at regular intervals, it contains a recordset of the most recent correlation results after being filled for the first time. The sensor output values will therefore be current, and when the number of rocks counted is high enough, the output values will be based on a statistically significant number of "experiments" to be representative of the rock flow 11.

[045] The light source must have a lumen value necessary to provide the spectrometer with light of sufficient brightness to allow it to process the light and obtain useful results. If a light source that provides continuous illumination is used, then the spectrometer can be switched effectively to provide snapshots of falling rocks.

[046] It is desirable to take only one snapshot of each falling rock. Consequently, the time between flashes (or spectrometer firing) is such as to ensure that a rock that has been illuminated falls out of analysis zone 65 before the next snapshot is taken. The duration of the light pulse, or spectrometer integration time, is preferably short enough to ensure that only one rock has been illuminated and therefore examined during the duration of a single pulse or integration time.

[047] Likewise, it is desirable that each snapshot includes only one falling rock and, consequently, the illuminating light beam 64 and/or the reflected light beam 55 preferably have a size (a cross-sectional area ) that is approximately the same size, or preferably smaller than the size of a typical rock - so that the analysis zone 65 has a size that is equal to or smaller than the size of a typical rock. The size of analysis zone 65 can be kept small while preserving a small enough light transmitter focus angle and/or light receiver acceptance angle.

[048] With reference to Figure 2, a second embodiment of a sensor structure 10.2 is shown, which is similar to the sensor structure shown in Figure 1. In particular, the trough 12 and the collector 16 are identical between the two illustrated embodiments. , and so is the overall external structure of the optical scanning head, with a mount 44, termination units 46.48, fiber optics 50.52 and lenses 54.56.

[049] Instead of two separate windows in the end closure plate 32, the sensor structure 10.2 includes only a single window 39. Reference was made when describing Figure 1, where a single window could be used in the first embodiment of the 10.1 sensor structure with illuminated and reflected light passing through different locations in such a window, but the significant difference between the modalities shown in Figures 1 and 2 reveals that illuminated and reflected light passes through a single location in the second modality of the sensor structure 10.2 - thus necessarily requiring only a single window 39.

[050] A mirror 67 and a beam splitter 66 are provided on the optical scanning head 36 between the window 39 and the lens 56,54. Mirror 66 is arranged in the optical path of illuminating light beam 64, emitted from lens 56 at an acute angle. Mirror 67 is shown at a 45 degree angle, but the angle can be varied in other embodiments. The beam 64 emitted from the lens 56 is reflected by the mirror 67 on the beamsplitter 66, whereupon part of the beam 64 passes through the beamsplitter 66 and is discarded (e.g., capturing it on a matte black surface), while the remainder of beam 64 is reflected by beam splitter 66 and travels through window 39 to become illuminating light beam 64.

[051] From the light reflected from a falling rock 11 in the trough 12, the reflected light 55, which travels coaxially with the illuminating light beam 64, passes through the window 39, and part of the reflected light beam 55 passes through the separator beam 66 at lens 54 and is launched onto optical fiber 50 at termination unit 46, while the remainder of the reflected light beam 55 is deflected by beam splitter 66 and deflected by mirror 67 back to the light source. Mirror 67 is merely provided to retain the parallel arrangement between termination units 46,48 and lenses 54,56.

[052] In the second mode of the sensor structure

10.2, the illuminating light beam 64 and the reflected light beam 55 are coaxial, so that the analysis zone 65 extends across the entire chute 12 - which is beneficial because the analysis zone should preferably extend over the maximum cross-section of the trough, to maximize the probability of illuminating the falling rocks 11. However, the window 39 in the sensor frame 10.2 must be kept clean and dust-free to prevent light emitted by the lens 56 and passed through beamsplitter 66, is reflected off the dust in window 39 and travels towards lens 54 - and finally to the spectrometer.

[053] The illustrated embodiments of the invention are intended to obtain data from a calcined product stream, but the invention can be applied to various other hot or cold particulate product streams.

Claims (23)

1. A sensor structure for obtaining data from a moving stream of particulate matter, said sensor structure comprising: a light transmitter which is adapted to produce light in a focused beam of light to illuminate particles in the moving stream ; and a light receiver which is adapted to receive reflected light from the illuminated particles and transmit it to an optical sensor, said optical sensor being configured to perform spectral analysis of said light; characterized by the fact that the light transmitter and optical sensor are configured to analyze the light reflected from the illuminated particles, or emitted by the illuminated particles, during intervals shorter than the period required for a typical sized particle to pass before the light beam focused; characterized by the fact that a light transmitter focus angle and a light receiver acceptance angle are configured to analyze the light reflected from the illuminated particles or emitted by the illuminated particles, from an analysis zone with a size that is , at most, as large as a typical particle size in the particulate material stream. 2. The sensor structure, according to claim 1, characterized in that the light source is adapted to produce light continuously, and the optical sensor is adapted to analyze intermittently reflected light. 3. The sensor structure, according to claim 1, characterized in that the light source is adapted to produce flashes of light at timed intervals. 4. The sensor structure, according to claim 1, characterized in that the light source is a laser. 5. The sensor structure, according to claim 4, characterized in that the light source is a pulsed laser. 6. The sensor structure, according to claim 1, characterized in that the light receiver has an axis that crosses the light beam focused at an acute angle other than zero, so that it is adapted to receive the light reflected along a path that crosses the focused beam of light. 7. The sensor structure, according to claim 1, characterized in that the light receiver has an axis that coincides with the light beam focused at a zero angle and without displacement, so that it is adapted to receive the light reflected along at least part of the same path as the focused beam of light. 8. The sensor structure, according to claim 1, characterized in that the focused light beam is focused close to infinity. 9. The sensor structure, according to claim 1, characterized by the fact that the acceptance angle of the light receiver is close to zero. 10. The sensor structure, according to claim 1, characterized in that the light transmitter comprises a light source, a first optical fiber and a focusing lens, said first optical fiber having an input end and an output end, and said light transmitter being configured such that light from the light source passes from the input end of the first optical fiber to emerge at the output end, and light emerging from the output end passes through the focusing lens to form said focused beam of light. 11. The sensor structure, according to claim 1, characterized in that the receiver for reflected light comprises a second optical fiber having an input end and a lens, said lens being adapted to collect the reflected light from the material illuminated particulate and launch it at the input end of the second optical fiber. 12. The sensor structure of claim 1, characterized in that it includes a housing having an end wall including at least one window, said sensor structure being configured such that the transmitted focused beam of light by the light transmitter and the light reflected from the illuminated particulate matter passes through the window at spaced locations. 13. The sensor structure according to claim 12, characterized in that it includes two spaced windows, configured so that the focused beam of light transmitted by the light transmitter and the light reflected in the illuminated particulate material pass through windows many different. The sensor structure of claim 12, characterized in that it comprises a manifold defining a passage for a cooling medium, said manifold forming an extension of the housing and being adapted to be attached to a flow channel in which said particulate material falls. 15. The sensor structure, according to claim 14, characterized in that said end wall of the housing also constitutes an end wall of the collector. The sensor structure according to claim 14, characterized in that it comprises an air inlet adapted to inject air into the collector, said sensor structure being configured so that the air injected through the air inlet flows into the collector to away from the window and towards the flow channel. 17. A method of obtaining data for analytical purposes from a stream of particulate product, said method being characterized by comprising: illuminating particles in the stream of current by directing a focused beam of light into the stream of current; collecting light reflected from particles in the current flow from an area that is the size of a typical sized particle at most; feeding reflected light that is collected to an optical sensor; and separately performing the spectral analysis of the light reflected on a plurality of individual particles from the illuminated particles, separately performing the spectral analysis of the light reflected from each of the individual particles during an interval that is shorter than the period required for a particle of size typical to pass before the focused beam of light; and calculating an analysis result from the spectral analysis of the light reflected from the plurality of individual particles. 18. A method according to claim 17, characterized in that it includes illuminating the particles at timed intervals by pulsing the focused beam of light to illuminate the particles in the current flow for periods that are shorter than the period required for a typical sized particle to pass before the focused beam of light. 19. A method according to claim 17, characterized in that it includes illuminating the particles continuously with the focused beam of light and analyzing the light reflected from the particles intermittently, for periods that are shorter than the required period. for a typical sized particle to pass before the focused beam of light. A method according to claim 17, characterized in that it includes shaping an angle of the focused light beam to illuminate said area the size of a typical particle size at most. A method according to claim 17, characterized in that it includes molding a light receptor acceptance angle to cover said area the size of a typical particle size at most. 22. A method according to claim 17, characterized in that the angle from which the reflected light is collected intersects with the focused light beam at an acute angle other than zero. 23. A method according to claim 17, characterized in that the current flow comprises a hot, incandescent particulate product.