Centrifuge for continuously monitoring and measuring the colour of a massecuite over the entire height of the centrifuge basket

Abstract

The invention relates to a centrifuge (C1) for separating, in a massecuite (M), a quantity of sugar crystals (Su) from a syrup, the centrifuge comprising at least: - a centrifuge basket (1) into which the massecuite is intended to be introduced, and which has a peripheral wall (12); - a measurement device (2) comprising at least one light source (21) designed to illuminate the peripheral wall over at least 90% of its height; and a photodetection system (22) designed to detect light reflected by the peripheral wall over at least 90% of its height and to deliver photodetection measurements (201) which are representative of the massecuite accumulating on the peripheral wall or of the peripheral wall itself; and - a processing unit (3) connected to the measurement device and designed to continuously process the photodetection measurements in real time.

Description

[0001] DESCRIPTION

[0002] TITLE: Centrifuge for the continuous control and measurement of the color of a cooked mass over the entire height of the centrifugation basket

[0003] [Technical field]

[0004] The invention relates to a centrifuge used for the separation of a quantity of sugar crystals from a syrup in a cooked mass.

[0005] It relates more particularly to a centrifuge comprising a measuring device for carrying out photo-detection measurements on the cooked mass contained in the centrifugation basket of the centrifuge.

[0006] The invention also relates to a method of spinning by centrifugation in a cooked mass of a quantity of sugar crystals from a syrup using this centrifuge.

[0007] Such a centrifuge and such a process find industrial application in the sugar manufacturing cycle, by increasing the yield and improving one of its stages called the spinning stage.

[0008] [State of the art]

[0009] As is well known, the industrial production of a quantity of sugar as a finished product from a so-called sugar plant (the two main ones being sugar cane and sugar beet) is marked by several stages, all involving both equipment and processes / methods specific to them.

[0010] The sugar plant, once harvested, is first washed to remove external impurities (earth, stones, plant debris, etc.). This is followed by a stage called extraction, which consists of extracting a sweet juice from the sugar plant. The extraction process differs depending on the sugar plant in question: extraction is carried out by crushing in the case of sugar cane, and by grating and then diffusion in the case of sugar beet. The sweet juice then undergoes treatments to eliminate all impurities (mineral salts, organic compounds, etc.) and the water it may contain. Following these treatments, a juice concentrated in sugar, also called syrup, is obtained. The syrup is introduced, during a stage called crystallization / refining, into a cooking boiler under vacuum and seeded with very fine sugar crystals in order to generate and then finalize its crystallization.The crystallization process allows the sugar to be extracted from the syrup by the formation of crystals made up of more than 99% sucrose molecules. This produces a massecuite, i.e. a syrup that has been depleted of a large part of its sugar, also called "mother liquor" containing multiple small sugar crystals in suspension, and which is colored by the presence of residual impurities. The next step, called the spinning step, consists of washing and separating the sugar crystals from the syrup. The sugar crystals, once separated from the syrup and harvested, are dried and then packaged in order to be presented in the form of a finished product (in the form of powder in bags; in pieces in boxes, etc.).

[0011] The mother liquor from the first spinning stage still contains sucrose molecules that need to be extracted. This mother liquor is again concentrated in the form of syrup which is cooked to be transformed into a new / second massecuite which undergoes a new spinning stage in order to extract a light brown crystallized sugar called "second jet" sugar, which is less pure than the sugar collected during the first spinning called "first jet" sugar and which is white in color, because it contains residual impurities (including minerals such as calcium). These sugar crystals are remelted to be added to the syrup from the first jet. The mother liquor from the second spinning can also undergo a new cooking stage to transform it into a third massecuite which is subjected to a third spinning stage. A so-called "third jet" sugar is then collected, less pure than the second jet sugar and dark brown / brown in color.This sugar is commonly called brown sugar. The residual mother liquor remaining after this third spinning, called molasses, can generally not be further processed and is intended for distilling.

[0012] Spinning is generally carried out using centrifuges classified into two categories: continuous centrifuges and batch centrifuges. The type of centrifuge used during the spinning stage(s) depends on the purity of the massecuite and the expected sugar quality. Usually, batch centrifuges with a higher efficiency are used for the extraction of first-run sugar crystals, while continuous centrifuges are used for the extraction of second- and third-run sugar crystals. In the case of continuous centrifuges, during the spinning stage, the centrifuge basket is continuously fed with massecuite at a variable or controlled flow rate while it is rotated at a constant speed.In discontinuous centrifuges, the cooked mass is introduced all at once upstream at the start of the spinning cycle defining the spinning stage, it being understood that the rotation speed of the basket is not constant during the spinning cycle. The cooked mass is introduced into a basket included in the centrifuge, which basket has a peripheral wall that is permeable over its entire height, this generally being in the form of a woven filter cloth, conventionally made of stainless steel, provided with perforations and commonly called a spinner cloth.

[0013] Under the action of the centrifugal force created by the speed of the basket, the sugar crystals are separated from the syrup (mother liquor) which is evacuated through the perforations of the basket and collected in a chamber provided for this purpose. The dimensions of the perforations are such that the sugar crystals cannot pass through.

[0014] One or two clarification (washing) steps take place during the centrifugation phase to clean the crystals of their impurities and mother liquor which are stuck to their surface.

[0015] In the case of discontinuous centrifuges, the sugar crystals, when separated from the syrup, remain on the surface of the basket fabric, which is cylindrical in shape. The bottom wall is fitted with a shutter which is closed throughout the spinning process, then opened at the end of the latter in order to discharge the quantity of sugar crystals into a chamber provided for this purpose. The unloading is carried out at low speed of the basket by means of a scraper which removes the sugar over the entire height of the fabric and which makes it fall into the bottom wall which is at that moment open.

[0016] The still wet sugar crystals then fall onto a conveyor which takes them to the dryer.

[0017] In the case of continuous centrifuges, the basket is truncated in shape and has an upper edge delimiting an upper opening of said basket. During spinning, under the action of centrifugal force, the sugar crystals rise along the inclined peripheral wall of the basket and are evacuated by overflowing from the basket, at the level of the upper edge, into a chamber designed to collect them.

[0018] It is also common practice, during centrifugal spinning, to accelerate the separation of sugar crystals from the syrup by clarifying (washing) the massecuite, which consists of spraying water and / or clear syrup onto the massecuite using jets installed in the centrifuge. Clarification requires good control of the quantity of water or clear syrup sprayed onto the massecuite in order to prevent the spraying from dissolving the sugar crystals.

[0019] In order to better control the clarification stage so that the spinning gains in a more overall speed and efficiency, centrifuges can now be equipped with control / measuring devices to control: for discontinuous centrifuges, the color of the cooked mass which depends on the concentration of sugar in the syrup and also the presence of residual impurities; for continuous centrifuges, the color of the cooked mass and / or the sugar crystals deposited on the inclined peripheral wall of the basket (the lighter the color, the more it means that the sugar crystals are separated from the syrup and cleaned of any impurities).

[0020] Several control / measuring devices have been proposed in the literature such as EP2275207, EP3356051, W02020094217. The control / measuring devices proposed in these documents comprise a light source intended to illuminate the massecuite contained in the centrifugation basket, and a photodetection system intended to convert the light signals reflected by the massecuite into electrical signals, which electrical signals are intended to allow, after treatment, the determination of the color of the massecuite. For each control device, a method for measuring the color of the massecuite is also proposed.

[0021] The methods described in EP3356051 and W02020094217 also include a step of clearing the cooked mass which is triggered if the color of the cooked mass does not correspond to a set color, this set color being used to establish whether the sugar crystals are properly separated from the syrup. The control apparatus disclosed in EP2275207 finds an application for batch centrifuges (note that the apparatus is positioned inside the centrifuges); those of EP3356051 and W02020094217 for continuous and batch centrifuges, and can be placed both outside and inside the centrifuges.

[0022] However, the control / measuring devices disclosed in these three prior documents are only intended to illuminate a single restricted or localized area of ​​the peripheral wall of the basket and thus only allow the color of the massecuite to be controlled locally. Thus, in EP2275207, the RGB sensor (RGB in French; Red, Green, Blue) included in the photo-detection system is limited to an illumination zone of a few centimeters, resulting in a very local and limited measurement of the color of the massecuite. In EP3356051 and W02020094217, although capable of measuring in a very wide range of wavelengths, the control devices allow the color of the massecuite to be determined only at a restricted scale of the wall height of the centrifugation basket.

[0023] Determining the color of the massecuite locally on an area of ​​the peripheral wall of the centrifugation basket implies, at the time t of this determination, a lack of knowledge of the color on the rest of the massecuite. To observe the plurality of colors that the entire surface of the massecuite can take, it is necessary, if this is possibly feasible, to move the control device manually or automatically as many times as necessary. However, in addition to being particularly restrictive, it is conceivable that the color of the massecuite in an area already observed may have changed during the movement of the device in order to observe the color of the massecuite in another area.

[0024] In addition, in the case of the continuous centrifuge, there is a dark / light interface zone at the bottom of the basket which gives an indication of the fluidity of the cooked mass, an area which must also be controlled in order to improve the efficiency of the spinning.

[0025] Since the above-mentioned control devices only provide a very localized view of an area of ​​the cooked mass, they cannot, at the same time, control the interface area.

[0026] Another disadvantage is that the operator must rely solely on the color determination result they provide without having a way to personally control how the cooked mass evolves in the centrifugation basket. This disadvantage makes the control of the spinning stage ineffective.

[0027] In conclusion, these drawbacks are all obstacles impacting the efficiency of the spinning stage and the time required to carry it out.

[0028] [Summary of the invention]

[0029] The invention proposes to address the aforementioned problem by providing a solution to improve control of the spinning stage.

[0030] To this end, the invention provides a centrifuge for separating a quantity of sugar crystals from a syrup in a cooked mass, the centrifuge comprising at least:

[0031] - a centrifugation basket actuated in rotation around a central axis of rotation, inside which an introduction of the cooked mass is provided, said centrifugation basket having a bottom wall and a peripheral wall, said peripheral wall being permeable and having a lower edge contiguous to said bottom wall and an upper edge, and in which said peripheral wall has a height measured from the lower edge to the upper edge;

[0032] - a measuring apparatus comprising at least one light source for illuminating the interior of the centrifugation basket and a photo-detection system for detecting reflected light and delivering photo-detection measurements which are representative of the massecuite or the peripheral wall; and - a processing unit connected to the measuring apparatus for receiving and processing said photo-detection measurements; said centrifuge being remarkable in that the light source is shaped to illuminate the peripheral wall of the centrifugation basket over at least 90% of its height, and the photo-detection system is shaped to detect over at least 90% of the height of the peripheral wall, the light reflected by the massecuite or the peripheral wall; and in that the processing unit is shaped to continuously process in real time the photo-detection measurements carried out over at least 90% of the height of the peripheral wall.

[0033] According to two embodiment variants, the centrifuge proposed in the invention can be a continuous centrifuge or a discontinuous centrifuge.

[0034] The centrifuge comprises a measuring device and a processing unit which are respectively designed to measure and analyse continuously, in other words in real time, and over at least 90% of the height of the permeable peripheral wall of the centrifuge centrifugation basket, photodetection measurements.

[0035] The processing unit can thus apply image processing functions to the photo-detection measurements, ultimately making it possible to determine a colorimetric value of a colorimetric parameter which is representative:

[0036] - in the case of a continuous centrifuge, either: different viscosity states of the cooked mass which, under the effect of centrifugal force, clumps on the peripheral wall; or the peripheral wall itself, more precisely the material from which it was made, visible therefore when nothing accumulates on it (cooked mass or sugar crystals). The different viscosity states of the cooked mass correspond to the different degrees of separation between the sugar crystals and the syrup.

[0037] - in the case of a discontinuous centrifuge: a change in the color of the cooked mass, and / or its thickness.

[0038] This colorimetric value may refer to an ICUMSA color value which is a colorimetric parameter used normatively to control the color of syrup, cooked mass, and sugar.

[0039] Advantageously, the measuring device and the processing unit make it possible to optimize the spinning step and to control in real time the evolution of the cooked mass in its entirety, thus responding positively to the problem of a local measurement and its disadvantages explained above. Non-exhaustively, the measuring device and the processing unit make it possible to control the richness of the sugar, to better regulate the separation of the sugar crystals and the syrup in the whole cooked mass.

[0040] In the case of continuous centrifuges, the use of the measuring device and the processing unit allows the operator to quickly detect the formation of "fingers" on the peripheral wall of the centrifugation basket, i.e. vertical zones / traces for which cooked mass covers a quantity of sugar crystals already separated from the syrup, to then spray water vapor at the arrival of the cooked mass in the centrifugation basket in order to fluidize it and prevent the appearance of new fingers, a valve being able to be provided for this purpose. Thanks to the measurement provided by the invention, it is also possible to prevent the appearance of new fingers by modifying the flow rate of the cooked mass arriving in the basket by controlling for this the opening of a cooked mass feed valve.

[0041] Advantageously, the light source of the measuring device illuminates the peripheral wall of the centrifugation basket over at least 90% of its height, from its lower edge to its upper edge, thus making it possible to measure all of the cooked mass contained in the centrifugation basket.

[0042] According to a characteristic of the invention, the photo-detection system detects over at least 90% of the height of the peripheral wall, from its lower edge to its upper edge, light signals reflected by the cooked mass or the peripheral wall, then converts these light signals into electrical detection signals which are then sent to the processing unit.

[0043] Advantageously, the photo-detection system is designed and then arranged in such a way that it detects over at least 90% of the height of the peripheral wall all of the light signals reflected either by the entire cooked mass contained in the basket, or in areas by the peripheral wall itself if cooked mass or sugar crystals have not accumulated there. The photo-detection system then converts all of the light signals into electrical signals which correspond to the photo-detection measurements which are transmitted to the processing unit.

[0044] The light source and the photo-detection system are respectively designed to illuminate the peripheral wall of the centrifugation basket and detect the reflected light over at least 90% of the height of the centrifugation basket. Thus, they can respectively illuminate the peripheral wall of the centrifugation basket and detect the reflected light over the entire height of the centrifugation basket. In the case of batch centrifuges, a check carried out over the entire height of the basket advantageously makes it possible to check the color of the sugar in a more representative manner but also to detect whether the clearing nozzles are partially or completely blocked, and to detect whether the sugar at the bottom of the basket remains dark, which shows wear of the scraping plow of the basket whose function is to scrape the massecuite.

[0045] For continuous centrifuges, a check carried out over the entire height of the basket advantageously allows you to control the color of the sugar leaving the basket, but also: to check and optimize the operation of each clarification nozzle; to check that fingers have not formed; to check that the massecuite is being fed correctly by detecting if there are areas of the basket without sugar.

[0046] According to a characteristic of the invention, the processing unit is configured to generate a raw image over at least 90% of the height of the centrifugation basket, from the photo-detection measurements.

[0047] Advantageously, the processing unit restores in real time from all the photo-detection measurements taken over the entire height of the peripheral wall these electrical signals a raw image of the latter; also restored if visible are the filtration orifices of the peripheral wall through which the syrup is evacuated towards the chamber dedicated to its reception. From this raw image, the observer can for example determine the different viscosity states that the massecuite presents, what quantity of massecuite still needs to be treated during spinning, detect the occasional absences of massecuite in the centrifugation basket, etc.The knowledge provided by the raw image makes it possible to respond positively to the second problem set out in the state of the art, by no longer making the spinning solely dependent on the performance of the control device and by allowing the operator to be able to make decisions based on his observations / conclusions and act quickly to better control and master this stage.

[0048] According to a characteristic of the invention, the processing unit is configured to compare the photo-detection measurements with a colorimetric limit over at least 90% of the height of the centrifugation basket, and to construct a secondary image presenting:

[0049] - at least a first section of a first color in which the photo-detection measurements are lower than said colorimetric limit; and / or - at least a second section of a second color in which the photo-detection measurements are higher than said colorimetric limit.

[0050] The processing unit compares the photo-detection measurements, measured over at least 90% of the height of the centrifugation basket, with a colorimetric limit. This is a "step" limit for which any color lighter than this means that the sugar crystals are separated from the syrup in the massecuite, while a darker color means that the sugar crystals and the syrup are still grouped / mixed in the massecuite. The processing unit then constructs from the results of these comparisons a secondary image in two colors, each of the colors being able to define at least one section in which the colorimetric value is higher (respectively lower) than this colorimetric limit, i.e. a color lighter (respectively darker) than the "step" limit.

[0051] Advantageously, this secondary image allows among other things:

[0052] - to identify any defects in the peripheral wall which would reduce its capacity to filter the syrup from the cooked mass;

[0053] - in the case of a discontinuous centrifuge, to identify whether a clearing ramp arranged opposite the peripheral wall to clear the massecuite is faulty, for example because one or more clearing nozzles comprising it is / are blocked and cannot spray very hot water onto the massecuite, the secondary image then potentially highlights one or more zones of a first color corresponding to cleared zones, and one or more zones of a second color corresponding to zones where the clearing has not been correctly (or not at all) carried out (in general, these zones correspond to dark horizontal lines along the height of the centrifugation basket);

[0054] - in the case of a continuous centrifuge, to identify problems with the feeding of the massecuite to the peripheral wall, as well as to detect precisely over the entire height of the peripheral wall a clear interface line between a quantity of massecuite which has been treated, i.e. for which the sugar crystals have been separated from the syrup (or are well on the way to separation), and a remaining quantity of massecuite still to be treated, allowing rapid and effective decision-making with a view to optimizing the rest of the spinning.

[0055] According to one embodiment of the invention, when the centrifuge is a continuous centrifuge, the centrifuge comprises a vaporization system configured to send water vapor at least inside the centrifugation basket and in which the processing unit is configured to calculate a ratio between a surface area of ​​the at least one first section and a surface area of ​​the at least one second section, and to communicate a vaporization order as a function of said ratio, said vaporization order being transmitted by the processing unit to the vaporization system to trigger a sending of water vapor.

[0056] Thus, the continuous centrifuge is equipped with a vaporization system capable of sending water vapor over at least 90% of the height of the peripheral wall in order to fluidify the massecuite. Indeed, the location of the interface line in the secondary image is a function of the viscosity state of the massecuite in the basket, and therefore this ratio is a function of the viscosity of the massecuite. Thus, the vaporization system is triggered from a vaporization order sent by the processing unit to the vaporization system. The quantity of water vapor sent into the centrifugation basket, or the duration of the vaporization, advantageously depends on information contained in the vaporization order and which is a function of this ratio.

[0057] According to one embodiment of the invention, when the centrifuge is a continuous centrifuge, the vaporization system is configured to send the water vapor inside the centrifugation basket at least at the level of the bottom wall of the centrifugation basket.

[0058] The continuous centrifuge is fed with cooked mass from the feed system by means of a feed pipe which is in communication with the centrifugation basket at the lower zone. The vaporization system is positioned opposite the outlet / first end of the feed pipe in order to start fluidizing the untreated cooked mass from the feed system and promote the separation of sugar crystals from the syrup as soon as it arrives in the centrifugation basket, in order to promote the separation of sugar crystals from the syrup and make the spinning more efficient by reducing its completion time; but also to prevent the formation of fingers on the peripheral wall.

[0059] According to a characteristic of the invention, the processing unit is configured to distinguish several control zones distributed over the height of the centrifugation basket, and to associate with each of the several control zones a reference colorimetric value established from the photo-detection measurements carried out in the corresponding control zone.

[0060] According to one embodiment of the invention, when the centrifuge is a continuous centrifuge, the centrifuge comprises a feed system configured to feed the centrifugation basket with cooked mass, and for which the processing unit is configured to carry out a comparison of the reference colorimetric value with a colorimetric threshold in one of the several control zones, called the lower zone, which is closest to the lower edge of the centrifugation basket, and to communicate a feed order as a function of a result of said comparison, said feed order being transmitted by the processing unit to the feed system to feed the cooked mass.

[0061] During spinning in which the basket is rotated (for example at a constant speed in the case of a continuous centrifuge), the quantity of massecuite that was initially loaded into the basket before spinning began decreases as the sugar crystals and syrup are separated and discharged into the chambers provided for this purpose. In the case of a continuous centrifuge, the centrifugation basket may be fed with massecuite at a variable rate by a feed system while it is rotated during spinning.

[0062] The processing unit is configured to segment the height of the peripheral wall into several control zones and to associate a colorimetric value with each of them. In the case where the invention is implemented with a continuous centrifuge, one of the control zones may correspond to a zone called the lower zone located as close as possible to the bottom wall of the centrifugation basket and from which it is connected to the feed system. The processing unit compares the colorimetric value of this lower zone to a colorimetric threshold, which reflects a situation in which the centrifugation basket is almost empty. The result of the comparison is representative of the quantity of massecuite remaining in the centrifugation basket.The processing unit sends a feed order to the feeding system to feed the centrifugation basket with massecuite (if there is still some massecuite to be processed) at a feed rate proportional to the amount of massecuite remaining in the centrifugation basket.

[0063] According to a characteristic of the invention, for each of the several control zones, the reference colorimetric value corresponds to an ICUMSA value.

[0064] The processing unit distinguishes over at least 90% of the height of the centrifugation basket several control zones and will associate with each of them a colorimetric value of a colorimetric parameter. The value of the colorimetric parameter of a control zone is determined by the processing unit from the photo-detection measurement(s) measured in it. As previously indicated, the colorimetric value can designate an ICUMSA color value which is a colorimetric parameter used normatively to control the color of a massecuite and a quantity of sugar. Advantageously, the segmentation of at least 90% of the height of the centrifugation basket into several control zones allows the operator to observe and treat the massecuite locally.

[0065] According to a characteristic of the invention, the centrifuge comprises a clarification device comprising:

[0066] - at least one clearing subassembly shaped to spray a clearing liquid onto the peripheral wall of the centrifugation basket,

[0067] - a control unit connected to the at least one lightening sub-assembly and in communication with the processing unit to at least control the at least one lightening sub-assembly as a function of the reference colorimetric value of at least one of the several control zones.

[0068] According to a characteristic of the invention, for each of the several control zones, the processing unit is configured to carry out a comparison of the reference colorimetric value with a colorimetric setpoint, and to communicate a clearing order as a function of a result of said comparison, and the control unit is configured to control the at least one clearing subassembly in order to control a clearing flow rate, in response to receipt of the clearing order.

[0069] In other words, in order to clarify the massecuite, the centrifuge comprises a clarifying device which comprises at least one clarifying subassembly arranged at a certain height from the bottom wall and facing the at least one control zone. The processing unit compares the colorimetric value of the at least one control zone with a colorimetric setpoint indicating whether it is necessary in this at least one control zone to clarify the massecuite in order to separate the sugar crystals from the syrup and extract the impurities therefrom, or not because the sugar crystals are cleaned. Following this comparison, the processing unit sends a clarifying order to the control unit responsible for controlling the at least one clarifying subassembly so that it clarifies or not the at least one control zone depending on the nature of the order.

[0070] According to a characteristic of the invention, the at least one clearing subassembly comprises a valve which is connected to the control unit, and which is controlled to adjust the clearing flow rate.

[0071] The at least one clearing subassembly is designed to spray a liquid onto the at least one control zone facing which it is installed to clear the massecuite accumulating in said at least one control zone. The at least one clearing subassembly has at its inlet a valve used to allow the liquid to pass at a given flow rate / intensity or to stop it. The valve of the at least one clearing subassembly is connected to and controlled by the control unit. Thus, depending on the clearing order, the control unit gradually opens or closes the valve of the at least one clearing subassembly proportionally to the flow rate / intensity of clearing liquid to be sprayed onto the control zone associated with the at least one clearing subassembly.

[0072] According to one embodiment of the invention, when the centrifuge is a discontinuous centrifuge, the at least one clearing subassembly comprises a single clearing subassembly comprising several nozzles arranged at several heights from the bottom wall of the centrifugation basket.

[0073] In other words, in the case of a batch centrifuge, a single clearing sub-assembly covers all the control zones, meaning that when a clearing order is sent to the control unit, all the control zones are cleared. The duration and / or intensity of the clearing is / are a function of the set of reference colorimetric values ​​of each of the control zones determined by the processing unit. An advantage of such a clearing device is to ensure uniformity of the color of the sugar over all or part of the peripheral wall. Generally, only the duration of the clearing is set as required, the intensity of the clearing being maximum. The clearing is stopped during the acceleration phase of the centrifugation basket.

[0074] According to one embodiment of the invention, when the centrifuge is a continuous centrifuge, the at least one clearing subassembly comprises several clearing subassemblies arranged at different heights from the bottom wall of the centrifugation basket, facing the several control zones, each clearing subassembly being associated with a control zone among the several control zones, and in which the control unit is connected to the different clearing subassemblies and is in communication with the processing unit to at least independently control each of the clearing subassemblies as a function of the reference colorimetric value of the control zone associated with it.

[0075] According to one embodiment of the invention, when the centrifuge is a continuous centrifuge, the control unit is configured to independently control each of the clearing sub-assemblies in order to control the corresponding clearing flow rate, in response to receiving the clearing order resulting from the comparison of the reference colorimetric value of the control zone associated with it, with the corresponding colorimetric setpoint. In other words, the clearing device consists of several clearing sub-assemblies which are arranged facing the peripheral wall in such a way that each clearing sub-assembly covers one of the control zones defined by the processing unit. The clearing device, and therefore the clearing sub-assemblies, are controlled independently of each other by the control unit which communicates with the processing unit.

[0076] Advantageously, such a device makes it possible to carry out a clarification of the massecuite locally in the centrifugation basket, in the control zone(s) in which the sugar crystals are still mixed with the syrup, the state of the massecuite in the different control zones being known in particular through the values ​​taken by the colorimetric value associated with a control zone. For each of the control zones, each of the clarification sub-assemblies sprays the clarification liquid into the control zone with which it is associated according to a certain intensity / a certain flow rate depending on the result of the comparison between the colorimetric setpoint and the reference colorimetric value of the control zone.

[0077] According to a characteristic of the invention, the light source is a white light source.

[0078] By definition, white light corresponds to sunlight in broad daylight, that is to say, it covers the entire light spectrum visible to the naked eye (for a wavelength, in a vacuum, between 380 nm and 780 nm), and therefore the set of colors: red, orange, yellow, green, blue green, blue, violet, dark violet.

[0079] Therefore, advantageously, the white light source offers high chromatic efficiency for optimal rendering of the colors of the objects they illuminate.

[0080] According to a characteristic of the invention, the light source is a stroboscopic source.

[0081] By definition, a stroboscopic source allows the observation of periodic phenomena whose frequency is too high for the eye, which does not perceive the discontinuity, by alternating phases of very high light intensity (flashes) and dark phases. This source finds its interest in the real-time restitution of the image representative of the height of the peripheral wall. Indeed, the electrical signals processed by the processing unit from the light signals reflected by the height of the peripheral wall following its exposure to the stroboscopic source allow the observation with great clarity in real time, from this image, of even very rapid movements of rotation or vibration of the centrifugation basket, as well as the separation of sugar crystals from the syrup in the cooked mass.

[0082] According to one characteristic of the invention, the light source consists of at least one light-emitting diode, and for example several light-emitting diodes.

[0083] In other words, the light source is either a light-emitting diode or an arrangement of light-emitting diodes mounted together on the same circuit. The number of light-emitting diodes depends on the surface area of ​​the peripheral wall that is to be illuminated.

[0084] According to one characteristic of the invention, the photo-detection system comprises at least one image sensor.

[0085] The at least one image sensor included in the photo-detection system has the function of converting the at least one light signal reflected by the peripheral wall when it is illuminated by the light source into an electrical signal which corresponds to a photo-detection measurement.

[0086] According to one embodiment of the invention, the photo-detection system comprises at least one matrix of colored filters, for example of the RGB type.

[0087] The photo-detection system comprises at least one matrix of colored filters, for example of the RGB / RVB (Red, Green, Blue) and / or CMYG / CMYV (Cyan, Magenta, Yellow, Green) type to generate from the photo-detection measurement(s) a color image of the peripheral wall over at least 90% of its height.

[0088] According to a characteristic of the invention, the light source and the photo-detection system of the measuring device are arranged inside a closed, sealed housing fixed to an opening in a cover of the centrifuge, said housing being provided with a protective window facing the opening of said cover and such that the light source and the photo-detection system are behind said protective window.

[0089] The light source and the photo-detection system constituting the measuring device are arranged inside a closed, sealed housing fixed to an opening in the centrifuge cover provided for this purpose. The housing is provided on one of its faces with a protective glass facing the opening and such that the light source and the photo-detection system are behind said protective glass.

[0090] Thus, through the protective glass and through the opening on the hood, the light source (respectively the photo-detection system) illuminates at least 90% of the height of the peripheral wall (respectively detects all the light signals reflected by at least 90% of the height of the peripheral wall).

[0091] According to a characteristic of the invention, the housing is integral with a guide having a first end fixed to said housing, around the protective glass, and a second end fixed to the cover around its opening, said guide having at least one vent for air to enter said guide.

[0092] Thus, the housing is brought into collaboration with the centrifuge by means of a guide, for example rectangular in shape, comprising two ends, the first end being fixed on the housing around the protective glass, and the second end being fixed on the cover of the centrifuge around the opening. The guide has at least one vent for air to enter inside. The guide has an angle of inclination such that advantageously, the light source (respectively the photo-detection system) illuminates at least 90% of the height of the peripheral wall (respectively detects all the light signals reflected by at least 90% of the height of the peripheral wall).

[0093] According to one characteristic of the invention, the guide comprises at least one cleaning nozzle for cleaning the protective glass by spraying water.

[0094] Depending on the rotation speed of the centrifugation basket, it is possible that projections of sugar crystals or massecuite may splash and dirty the protective glass of the housing through the guide, meaning that the light source and the photo-detection system can no longer operate under optimal conditions, with risks of inaccurate or, in the worst case, erroneous photo-detection measurements which negatively impact the efficiency and relevance of the control of the massecuite and the separation of the quantity of sugar crystals and syrup.

[0095] So, to address this issue, it is planned that a cleaning nozzle, controlled by the control unit, opens into the guide in order to spray very hot water onto the protective glass to clean it of any splashes.

[0096] According to one embodiment of the invention, at least 90% of the height of the peripheral wall of the centrifugation basket corresponds to the entire height of said peripheral wall taken from its lower edge to its upper edge.

[0097] The invention also relates to a centrifugal spinning process for separating a quantity of sugar crystals from a syrup in a cooked mass, using a centrifuge such as those described above, and which comprises at least:

[0098] - a centrifugation step in which the centrifugation basket in which the cooked mass is present is rotated; said centrifugation spinning process being characterized in that it comprises, during the centrifugation step:

[0099] - a continuous lighting step consisting of illuminating the peripheral wall of the centrifugation basket with the light source over at least 90% of its height;

[0100] - a continuous measurement step consisting of detecting by the photodetection system over at least 90% of the height of the peripheral wall of the centrifugation basket, the light reflected by the massecuite or the peripheral wall, in order to deliver photodetection measurements which are representative of the massecuite or the peripheral wall; - a step of processing by the processing unit continuously and in real time the photodetection measurements carried out over at least 90% of the height of the peripheral wall.

[0101] According to a characteristic of the invention, the processing step implements a generation of a raw image over at least 90% of the height of the centrifugation basket, from the photo-detection measurements.

[0102] In other words, during the processing step, the processing unit generates from all the photo-detection measurements that it receives from the photo-detection system an image representative of the peripheral wall over substantially its entire height.

[0103] According to a characteristic of the invention, during the processing step, the photo-detection measurements are compared with a colorimetric limit over at least 90% of the height of the centrifugation basket, and comprises a step of constructing a secondary image presenting:

[0104] - at least a first section of a first color in which the photo-detection measurements are lower than said colorimetric limit; and / or

[0105] - at least a second section of a second color in which the photo-detection measurements are greater than said colorimetric limit.

[0106] In other words, during the processing step, the processing unit also generates, by comparing the colorimetric values ​​deduced from the photodetection measurements with a colorimetric limit defined as a parameter by the operator, a secondary image in two colors of at least 90% of the height of the peripheral wall, each of the two colors being representative of at least a first section for which the colorimetric value is greater than the colorimetric limit, meaning that the sugar crystals have been separated or are in the process of being separated from the syrup in the massecuite; and / or at least a second section for which the colorimetric value is less than the colorimetric limit, meaning that the quantity of massecuite associated with this at least one second section is not yet processed.

[0107] According to one embodiment of the invention, when the centrifuge is a continuous centrifuge, the centrifugal spinning method comprises a step of calculating a ratio between a surface area of ​​the at least one first section and a surface area of ​​the at least one second section, and a vaporization step consisting of sending at least one water vapor inside the centrifugation basket according to said ratio.

[0108] In other words, the processing step comprises a calculation step during which the processing unit calculates a ratio between the surface area of ​​the at least one first section and the surface area of ​​the at least one second section, and which is representative of an overall viscosity of the massecuite. Depending on the value of this ratio, the method then implements or not a vaporization step, during which the processing unit issues a vaporization order to a vaporization system which is configured, according to the information contained in the order, to send water vapor into the centrifugation basket in a quantity and for a duration which are a function of the value of the ratio.

[0109] According to a characteristic of the invention, the processing step implements a distinction of several control zones distributed over the height of the centrifugation basket, and an association with each of the several control zones of a reference colorimetric value established from the photo-detection measurements carried out in the corresponding control zone.

[0110] In other words, the ability offered by the processing unit to segment the height of the peripheral wall into several control zones and to measure in real time a colorimetric value for each of the control zones is implemented during the processing step of the centrifugal spinning process.

[0111] According to a characteristic of the invention, the centrifugal spinning method comprises an intermediate clarification step for spraying a clarification liquid onto the peripheral wall of the centrifugation basket, depending on the reference colorimetric value associated with at least one of the several control zones.

[0112] According to one embodiment of the invention, when the centrifuge is a continuous centrifuge, the spinning method comprises, during the treatment step and prior to the intermediate clarification step, a comparison step during which the reference colorimetric value of each of the several control zones is compared to a colorimetric setpoint, in order to spray a clarification liquid according to a clarification flow rate depending on the result of said comparison.

[0113] According to one embodiment of the invention, the centrifugal spinning method comprises, when the centrifuge is a continuous centrifuge:

[0114] - a comparison step during which the reference colorimetric value in one of the several control zones, called the lower zone, which is closest to the lower edge of the centrifugation basket, is compared with a colorimetric threshold; and

[0115] - a feed regulation step during which the centrifugation basket is fed with cooked mass according to a result of said comparison.

[0116] In other words, the centrifugal spinning process, when implemented using a continuous centrifuge, includes an additional feed regulation step involving the aforementioned feed system, which has the role of feeding cooked masses into the centrifugation basket while the latter is rotated during the centrifugation step. This step is implemented in the case where all of the cooked masses cannot be completely introduced into the centrifugation basket at one time during the loading step.The feed regulation step takes place continuously throughout the centrifugal spinning process, the flow rate of cooked mass introduced into the centrifugation basket by the feed system is variable such that it depends on the comparison result obtained following a comparison step carried out upstream during the treatment step, during which the reference colorimetric value associated with the lower zone of the peripheral wall is compared to the colorimetric threshold which reflects a situation in which the centrifugation basket is slightly full or almost empty.

[0117] [Brief description of the figures]

[0118] Other characteristics and advantages of the present invention will appear on reading the detailed description below, of several non-limiting examples of implementation, made with reference to the appended figures in which:

[0119] [Fig 1] is a schematic sectional view of a continuous centrifuge according to the invention, showing the measuring apparatus illuminating the peripheral wall of the centrifugation drum over at least 90% of its height, with the massecuite represented in hatching and the quantity of sugar represented in white, and detecting / receiving the light signals reflected by the peripheral wall; which is divided into four control zones by the processing unit controlling the measuring apparatus; [Fig 2] is a schematic sectional view of a discontinuous centrifuge according to the invention, showing the measuring apparatus illuminating the peripheral wall of the centrifugation drum over at least 90% of its height, and detecting / receiving the light signals reflected by the peripheral wall; which is divided into four control zones by the processing unit controlling the measuring apparatus;

[0120] [Fig 3] is a schematic sectional view of the centrifuge basket of the continuous centrifuge of Figure 1, for which the formation of massecuite fingers on the peripheral wall is illustrated; the hatched surface corresponding to the surface illuminated by the measuring device;

[0121] [Fig 4] is a functional diagram illustrating the environment of a centrifuge according to the invention and the different systems with which it interacts, such as the measuring device controlled by the processing unit, or the clarification system; the elements in solid lines correspond to all the devices that can interact with the continuous and discontinuous centrifuges for the implementation of spinning (the interactions between devices are represented by arrows), those in dashed lines are only present / used for spinning if the centrifuge considered is a continuous centrifuge;

[0122] [Fig 5] is an image showing the front face of the measuring device, in the center of which is visible the lens of the camera used as a photodetection system, and on each side of which is arranged a printed circuit comprising an arrangement of several light-emitting diodes which illuminate the peripheral wall of the centrifugation basket;

[0123] [Fig 6] is a schematic side view showing the guide having its first and second ends fixed respectively to the housing and to an opening in the centrifuge cover;

[0124] [Fig 7] is a flowchart illustrating the centrifugal spinning process implemented by the centrifuge;

[0125] [Fig 8] shows a flowchart describing the centrifugation step;

[0126] [Fig 9] shows a flowchart describing the processing step when it is implemented by a continuous centrifuge;

[0127] [Fig 10] shows a flowchart describing the processing step when it is implemented by a batch centrifuge;

[0128] [Fig 11] is an example of a raw image (left) and a secondary image (right) generated by the processing unit following the reception and processing of photo-detection measurements, with for the raw image the distinction by the processing unit of the four control zones over at least 90% of the height of the peripheral wall;

[0129] [Fig 12] is a schematic sectional view of the centrifugation basket of the continuous centrifuge of Figure 1, for which are illustrated the four control zones that the processing unit distinguishes on the peripheral wall;

[0130] [Fig 13] is an example of the evolution of the reference colorimetric value over time associated with each of the other control zones with the ICUMSA value taken by each of them on the ordinate; the solid curves correspond to the evolution of the colorimetric value while the dashed lines correspond to the colorimetric instructions;

[0131] [Fig 14] is a schematic sectional view of the centrifuge basket of the continuous centrifuge of Figure 1, in which massecuite / sugar gaps reveal the peripheral wall of the centrifuge basket, said peripheral wall thus being visible in these gap areas and illustrated in dotted lines;

[0132] [Fig 15] is a schematic cross-sectional view of the centrifugation basket of the continuous centrifuge of Figure 1, in which massecuite is shown in the hatched area while the part where the sugar crystals begin and then finish releasing from their mother liquor is shown in white, with a massecuite / sugar transition zone at a given height from the bottom wall, and also illustrated is the associated secondary image;

[0133] [Fig 16] is a schematic view equivalent to that of Figure 15, with a massecuite / sugar transition zone at a so-called abnormal height, higher than that reached in the example of Figure 15, and the associated secondary image is also illustrated.

[0134] [Detailed description of one or more embodiments of the invention]

[0135] The invention relates to a centrifuge C1, C2 for separating a quantity of sugar crystals Su from a syrup in a massecuite M, which are configured to implement a centrifugal spinning method P1, P2 which is detailed later in the description. In a first embodiment of the invention, the invention relates to a continuous centrifuge C1, illustrated in Figure 1. In a second embodiment of the invention, the invention relates to a discontinuous centrifuge C2, illustrated in Figure 2.

[0136] Commonly, the centrifuges C1, C2 comprise a centrifugation basket 1 (truncated cone-shaped for the continuous centrifuge C1, and cylindrical for the discontinuous centrifuge C2) into which the massecuite M is introduced. The centrifugation basket 1 has a bottom wall 11; and a peripheral wall 12 which:

[0137] - has a lower edge 13 contiguous to the bottom wall 11 and an upper edge 14;

[0138] - has a height measured from its lower edge 13 to its upper edge 14;

[0139] - is permeable over at least 90% of its height, and generally comes in the form of a woven filter cloth, typically made of stainless steel, with perforations.

[0140] The centrifuge basket 1 is rotated about a central rotation axis 10 set in rotational motion using a motorization system 1000. Several designs of motorization system 1000 are conceivable. For example, with reference to Figure 1, the motorization system 1000 may comprise a first drive pulley 1002 and a second drive pulley 1003 coupled by means of a belt 1004; such that the first drive pulley 1002 is crossed in its center by the central axis of rotation 10 and the second drive pulley 1003 is crossed in its center by a motor axis of a motor 1001. The rotation of the motor 1001 induces a rotation of the second drive pulley 1003, which causes a movement of the belt 1004 and therefore a rotation of the first drive pulley 1002.

[0141] Under the action of centrifugal force, the sugar crystals Su are separated from the syrup (mother liquor) which is evacuated through the perforations in the peripheral wall 12 and collected in a chamber 15 provided for this purpose. The dimensions of the perforations are such that the sugar crystals Su cannot pass through. In the case of the continuous centrifuge C1, the sugar crystals Su rise along the peripheral wall 12 and are evacuated by overflowing from the centrifugation basket 1, at the upper edge 14, into a second chamber 16 provided to collect them. In the case of the discontinuous centrifuge C2, the sugar crystals Su when separated from the syrup remain on the surface of the peripheral wall 12. The bottom of the basket 1 is provided with a shutter 17 which is closed throughout the duration of the spinning, then opened at the end of the latter in order to discharge the quantity of sugar crystals Su by scraping.

[0142] In the remainder of this description, it is considered, for illustrative purposes, for figures 1, 2, 3, 12, 14, 15 and 16 representing the centrifugation basket 1, that the hatched area(s) correspond to the cooked mass M, the white area(s) correspond to the sugar Su when it is separated from the syrup (in other words the part(s) where the sugar crystals begin and then finish releasing themselves from their mother liquor), and the dotted area(s) correspond to the peripheral wall 12 (the points schematizing its perforations).

[0143] Each of the centrifuges C1, C2 comprises a clearing device 4 which sprays a clearing liquid, for example hot water or clear syrup, onto all or part of the peripheral wall 12 to clear / fluidify the massecuite M, accelerating the separation of the sugar crystals Su from the syrup and cleaning the crystals of their impurities and mother liquor which are stuck to their surface. More precisely, the clearing liquid is sprayed from the clearing nozzles arranged at several heights from the bottom wall 11 of the centrifugation basket 1 and mounted on at least one clearing subassembly opposite all or part of the peripheral wall 12. The at least one clearing subassembly comprises several nozzles which spray the clearing liquid onto the peripheral wall 12.

[0144] In the case of a discontinuous C2 centrifuge, the clearing device 4 comprises a single clearing subassembly 45 for overall clearing of at least 90% of the height of the peripheral wall 12.

[0145] In the case of a continuous centrifuge C1, the clearing device comprises at least two clearing sub-assemblies arranged opposite two distinct surfaces of the peripheral wall 12, the at least two clearing sub-assemblies being shaped to spray the clearing liquid independently, i.e. either simultaneously or not. It is considered that the clearing device 4 comprises four clearing sub-assemblies 41, 42, 43, 44 responsible for clearing four distinct zones of the peripheral wall 12.

[0146] However, spraying the clearing liquid too intensely and / or for a long time may lead to a risk of dissolving the sugar crystals Su. This is why the at least one clearing subassembly comprises at the inlet a proportional control valve in order to regulate the intensity / flow rate of the sprayed clearing liquid. Thus, with reference to Figures 1 and 2, the clearing device 4 comprises:

[0147] - for the continuous centrifuge Cl, four valves 410, 420, 430, 440 located respectively at the inlet of the clarification sub-assemblies 41, 42, 43, 44;

[0148] - for the discontinuous C2 centrifuge, a valve 450 located respectively at the inlet of the clarification subassembly 45.

[0149] Unlike the discontinuous centrifuge C2 for which the massecuite M is only introduced into the centrifugation basket 1 via a feed inlet 18 during the low speed phase dedicated to this operation, massecuite M is introduced continuously and at a variable flow rate into the centrifugation basket 1 of the continuous centrifuge Cl during spinning via a feed system 5.With reference to Figure 1, the massecuite M is introduced / deposited in the bottom wall 11 of the centrifugation basket 11 by exiting from the first end 53 of a feed pipe 52 partially entering the interior of the continuous centrifuge C1 through an access provided on its cover 19; the second end 54 of the feed pipe 52, outside the continuous centrifuge C1, being connected to a proportional adjustment valve 51 at the outlet of the feed system 5, the progressive adjustment valve 51 being able to open and close progressively to allow a variable flow rate of massecuite M to pass into the feed pipe 52.

[0150] The continuous centrifuge Cl also comprises a vaporization system 6 shaped to send at least one water vapor at least inside the centrifugation basket, in order to fluidize the massecuite M. The water vapor can be sprayed at the peripheral wall 12 in order to fluidize the massecuite M depositing thereon and to accelerate the separation of the sugar crystals Su from the syrup, and also to prevent the formation of massecuite fingers 2000 (see Figure 3). In reference 1, the water vapor is sprayed onto the peripheral wall 12 from its outer face.

[0151] Water vapor can also be sprayed by the vaporization system 6 also at the bottom wall 11 in order to fluidify the cooked mass M opening into the centrifugation basket 1 from the first end 53 of the feed pipe 2.

[0152] The flow rate / intensity of water vapor sprayed onto the peripheral wall 12 and / or into the bottom wall 11 is regulated by means of a proportional control valve 61. The vaporization system 6 sprays water vapor simultaneously onto the peripheral wall 12 and onto the bottom wall 11.

[0153] The cooked mass M can optionally also be fluidized inside the supply pipe 52 itself, which then has an opening through which a conduit of the vaporization system 6 injecting the water vapor is released. According to two alternative embodiments of the invention, said conduit may or may not have a proportional adjustment valve 62 for injecting, or not, water vapor into the supply pipe 52 depending on the same flow rate of water vapor which is sprayed onto the peripheral wall 12 and the wall bottom 11.

[0154] With reference to Figure 1, Figure 2, and Figure 4, the centrifuge C1, C2 comprises a measuring device 2 configured for:

[0155] - illuminating the peripheral wall 12 of the centrifugation basket over at least 90% of its height, and therefore the cooked mass M, by means of a light source 21; - detecting by means of a photo-detection system 22 the light signals reflected by the area of ​​the peripheral wall 12 and / or the illuminated cooked mass M; the photo-detection system 22 then converting the light signals into electrical signals corresponding to photo-detection measurements 201.

[0156] In the remainder of the description, it is considered that the measuring device illuminates the entire height of the peripheral wall, from its lower edge 13 to its upper edge 14; and that it consequently detects all of the light signals reflected by the entire height of the peripheral wall 12.

[0157] Referring to Figure 5, the light source 21 of the measuring apparatus 2 consists of two arrangements of 4*8 light-emitting diodes 210, each of the two arrangements being arranged on a printed circuit and on either side of a camera 220 used as a photo-detection system 22, and comprising at least one image sensor and one matrix of RGB type colored filters. In other embodiments of the invention, the photo-detection system may comprise either at least one matrix of CMYG type colored filters, or at least one matrix of RGB colored filters and at least one matrix of CMYG colored filters.

[0158] Referring to Figure 6, the measuring device 2 is contained inside a sealed housing 9 which is closed and fixed to an opening 190 of the cover 19 of the centrifuge C1, C2. The housing 9 comprises a protective window 91 facing the opening 190 of the cover 19 and behind which is located the front face of the measuring device 2. The front face of the measuring device 2 therefore faces the opening 190.

[0159] The housing 9 is secured to a guide 92 having: a first end 95 fixed to the housing 9, around the protective glass 91; and a second end 96 fixed by screws to the cover 19 around its opening 190. It also comprises at least one vent 94 for air to enter inside.

[0160] The housing 9 cooperates with the first end 95 of the guide 92, which is rectangular, by means of hinges whose utility will be discussed later in the description. The guide 92 has two vents.

[0161] The guide 92 has an angle of inclination such that the light source 21 (respectively the photo-detection system 22) of the measuring device 2 illuminates the entire height of the peripheral wall 12 (respectively detects all of the light signals reflected by the entire height of the peripheral wall 12).

[0162] The measuring device 2 communicates, physically via connection cables or by means of a wireless communication protocol (such as WiFi® for example) with a processing unit 3 to which it transmits the photodetection measurements 201. The processing unit 3 is responsible for managing the progress of the centrifugal spinning process Pl, P2 and for initiating or not initiating steps of said centrifugal spinning process Pl, P2 depending on its analysis of the photodetection measurements 201.

[0163] Processing unit 3 comprises at least:

[0164] - a display unit 31, such as a screen, shaped to display for example: the parameters relating to the steps included in the centrifugal spinning process P1, P2; the photo-detection measurements 201 received from the measuring device 2 and their processing(s);

[0165] - an adjustment unit 32, comprising a keyboard, and / or a touchpad, and / or buttons, shaped so that an operator configures / parameterizes the measuring device 2 as well as the steps of the centrifugal spinning process P1, P2;

[0166] According to different embodiment variants and by way of illustrative and non-limiting examples, the processing unit 3 is a computer (desktop; or portable; or embedded, for example of the fanless type) or even a processor, a controller, an electronic card on which software is installed allowing the launch and execution of the centrifugal spinning process P1, P2.

[0167] With reference to Figure 7 and Figure 8, the centrifugal spinning process P1, P2 comprises a centrifugation step E1 during which the centrifugation basket 1 is rotated in order to process the massecuite M, all or part of which has been previously introduced into the centrifugation basket 1 during an initial feeding step E0. The centrifugation step E1 is implemented and managed by the processing unit 3. Following the loading of the massecuite M into the centrifugation basket and before launching the execution of the centrifugation step E1, the operator enters into the processing unit 3, during a parameterization step EP, a set of parameters allowing the configuration of the measuring device 2 and / or the management of the steps included in the centrifugation step E1.According to the embodiments of the invention, the rotation speed of the centrifugation basket 1 can be set from the processing unit 3 or from another device, such as for example a monitor / control station integrated into the centrifuge C1, C2. It can also possibly be modified manually by the operator or automatically depending on the quantity of massecuite M contained in the centrifugation basket 1 and the speed at which the sugar crystals Su are separated from the syrup.

[0168] Once launched, the centrifugation step E1 is managed automatically by the processing unit until the centrifugation spinning process P1, P2 is stopped. In a second embodiment of the invention, the centrifugation step E1 is semi-automatic, with the operator being able to intervene and change its parameters from the processing unit during its progress. In a third embodiment, the centrifugation step E1 is manual, with the operator himself triggering certain actions (clearing; feeding of the centrifugation basket 1 and vaporization for the continuous centrifuge C1) according to the information provided by the processing unit 3 after processing of the photo-detection measurements 201.

[0169] In the sense of the invention, it is provided that the measuring device 2, continuously and in real time throughout the duration of the centrifugation step E1:

[0170] - illuminates during a lighting step E21 the peripheral wall 12 of the centrifugation basket 1 over at least 90% of its height (and for example over its entire height);

[0171] - detects during a measurement step E22 over at least 90% of the height (and for example over the entire height) of the peripheral wall 12 the light signals reflected by the massecuite M or the peripheral wall 12, converts said light signals into electrical signals, and transmits for analysis the electrical signals, which correspond to the photo-detection measurements 201, to the processing unit 3.

[0172] Thus, the processing unit is designed to continuously analyze in real time, during a processing step E3, all of the photodetection measurements 201 sent by the measuring device 2 and to trigger certain actions as required (such as fluidizing the cooked mass by clearing) depending on the analysis results.

[0173] Continuous C1 and discontinuous C2 centrifuges are designed to process massecuite 24 / 7. They are only stopped if malfunctions are detected or if specific interventions are necessary (maintenance, cleaning, unblocking, etc.) or if an emergency stop is triggered. Thus, during the processing step E3, the processing unit 3 checks during a verification step Q.1, based on all the information it receives from the other systems included in the centrifuge, whether a stop is commanded manually or automatically. If this is the case, the centrifugation step E1 and the centrifugal spinning process P1, P2 end.

[0174] The processing unit 3 may, according to different embodiments of the invention, be configured to control the starting and stopping of the measuring apparatus 2 respectively at the start and at the end of the wringing step E1 by sending a starting or stopping instruction 200 to the measuring apparatus. During the processing step E3, the processing unit 3 applies image processing functions to the photo-detection measurements 201 in order to deduce therefrom the colorimetric value of a colorimetric parameter representative for example of the different viscosity states that the massecuite M or even the peripheral wall 12 may have. The colorimetric value corresponds to a color value ICUMSA.

[0175] With reference to Figure 9 to Figure 11, the processing unit 3, when it receives new photo-detection measurements 201;

[0176] - implements a generation E31 of a raw image 33, displayed on the display unit 31, of at least 90% of the height (and for example of the entire height) of the peripheral wall 12 and of the massecuite M which can be deposited thereon. The detection system 22 being a camera, the raw image 33 is a color video image in real time showing to the operator non-exhaustively, and as indicated previously: the evolution of the treatment of the massecuite M and the separation of the sugar crystals Su from the syrup, the different viscosity states of the massecuite M, to determine the quantity of massecuite M remaining to be treated (the raw image also restoring the peripheral wall 12 and its filtration orifices), makes it possible to observe the presence or the formation of fingers of massecuite 2000 on the peripheral wall 12 for the continuous centrifuge Cl, etc.;

[0177] - constructs during a construction step E32 a secondary image 34 of at least 90% of the height (and for example of the entire height) of the peripheral wall 12, similar to a map, on the basis of a comparison between the colorimetric values ​​deduced from the photo-detection measurements 201 with a colorimetric limit, the secondary image 34 having: at least a first section 341 of a first color in which the photo-detection measurements 201 are lower than said colorimetric limit; and / or at least a second section 342 of a second color in which the photo-detection measurements 201 are higher than said colorimetric limit.The at least one first section 341 (in white in the Figure) corresponds to an area for which the sugar crystals Su are separated from the syrup or for which the massecuite M is well on the way to being processed; whereas the at least one second section 342 (in black in the Figure) corresponds to an area for which the massecuite M is unprocessed or still remains particularly viscous. As previously explained, the secondary image non-exhaustively allows the operator to identify defects that the peripheral wall 12 would have (such as an obstruction of the filtration orifices), of the supply of massecuite M for the continuous centrifuge C1, or even a failure of the clarification system 4 (in particular for the discontinuous centrifuge C2).

[0178] According to the operating principle of the invention, the processing unit is configured to implement, after the generation 31 of the raw image 33, a distinction E33 during which it distinguishes several control zones, at least two, over at least 90% of the height (and for example over the entire height) of the peripheral wall 12. In the embodiment presented through all the figures, the processing unit 3 distinguishes four control zones S1, S2, S3, S4. Following this distinction E33, the processing unit associates, during an association E34, a reference colorimetric value S1, S2x, S3x, S4x with each of the control zones S1, S2, S3, S4.

[0179] In order to determine the reference colorimetric values ​​Six, S2x, S3x, S4x, the processing unit averages the colorimetric values ​​deduced from the photo-detection measurements from the light signals reflected by each of the control zones SI, S2, S3, S4.

[0180] In the presented embodiment, the reference colorimetric values ​​Six, S2x, S3x, S4x are therefore ICUMSA color values.

[0181] According to different embodiments of the invention, the several control zones may or may not be of substantially the same height and surface area. For a given height of peripheral wall 12, it is also possible for the operator to be able to define from the processing unit 3:

[0182] - the number of control zones, at least two;

[0183] - the height of each of the several control zones knowing that the lower the control zones are, the more precise the reference colorimetric value will be. For example, for the continuous centrifuge Cl, it may be interesting for the control zones close to the bottom wall 11 to be defined by a suitable height so as to determine precisely whether or not there is still some massecuite M to be treated in the centrifugation basket 1.

[0184] In the embodiment presented, for the two centrifugal spinning processes P1, P2, it is fixed in the design that the processing unit 3 distinguishes four control zones S1, S2, S3, S4; each having a given height which cannot be modified.

[0185] For the two centrifugal spinning processes Pl, P2, the reference colorimetric values ​​are used to assess the need or not to spray clarifying liquid on the control zones with which they are associated in order to clean the sugar crystals Su while minimizing their remelting. For this, the reference colorimetric values ​​are compared during a comparison step Q.2 to a colorimetric setpoint reflecting whether it is necessary in this at least one control zone to clarify the massecuite in order to separate the sugar crystals Su from the syrup and extract the impurities, or not because the sugar crystals Su are cleaned. With reference to Figure 13, the reference colorimetric values ​​Six, S2x, S3x, S4x are thus each compared to a colorimetric setpoint Slt, S2t, S3t, S4t.

[0186] According to different embodiments of the invention, the colorimetric instructions:

[0187] - are fixed at the design stage or can be configured by the operator from the processing unit 3 before the launch of the centrifugal spinning process Pl, P2;

[0188] - are all equal or can take different values.

[0189] If the processing unit 3 following the comparison step Q.2 establishes that it is necessary to implement an intermediate clearing step E4, it sends a clearing order 400 to a control unit 40 controlling the clearing system 4 so that it clears the peripheral wall 12.

[0190] According to the operating principle of the invention, a control zone is associated with at least one lightening sub-assembly that the lightening system 4 comprises. Thus, a control zone can be associated with one or more lightening sub-assemblies (two, three, etc.). If the result of the comparison between the reference colorimetric value of this control zone and the colorimetric setpoint assigned to it results in the need to lighten, then the lightening system 4 will or will be actuated (via the control unit) during the intermediate lightening step E4 the one or more lightening sub-assemblies associated with the control zone.

[0191] According to different embodiments of the invention, the operator can configure from the processing unit 3:

[0192] - the number of clearing sub-assemblies that the clearing system 4 comprises (in embodiments where the clearing system would not be included with the centrifuges C1, C2 and would have to be installed later);

[0193] - the allocation of a control zone to one or more clearing subsets.

[0194] In the presented embodiment of the invention:

[0195] - the clarification system 4 of the continuous centrifuge Cl comprises four clarification sub-assemblies 41, 42, 43, 44, each respectively associated, in the definition of the centrifugal spinning process PI, with a control zone SI, S2, S3, S4; and

[0196] - that of the discontinuous C2 centrifuge comprises a single clarification subassembly 45 associated with all four control zones SI, S2, S3, S4. Thus, and as previously explained:

[0197] - in the case of a discontinuous centrifuge C2, the clearing of the cooked mass M is carried out globally over at least 90% of the height (and for example over the entire height) of the peripheral wall 12. The clearing subassembly 45 clears the peripheral wall as soon as the treatment unit concludes for at least one of the control zones 41, 42, 43, 44 that it is necessary to clear;

[0198] - in the case of a continuous centrifuge Cl, the clearing of the massecuite M can be carried out locally, with each of the clearing sub-assemblies 41, 42, 43, 44 controlled independently of each other by the control unit 40 according to the instructions contained in the clearing order 400.

[0199] For the at least one clearing subassembly, the clearing order 400 comprises at least: a clearing duration during which the at least one clearing subassembly must clear the peripheral wall 12; and the intensity / flow rate at which the at least one clearing subassembly will spray the clearing liquid. The flow rate of sprayed clearing liquid is regulated by means of a progressive adjustment valve located at the inlet of the at least one clearing subassembly and controlled by the control unit 40. It is understood that when the at least one clearing subassembly is not spraying clearing liquid, the progressive adjustment valve is completely closed. Thus:

[0200] - for a continuous centrifuge Cl, with reference to Figure 1, each of the clearing sub-assemblies 41, 42, 43, 44 is provided at the inlet with a proportional adjustment valve 410, 420, 430, 440. The clearing order comprises a clearing duration and a clearing flow rate specific to each of the clearing sub-assemblies 41, 42, 43, 44 so as to be able to be controlled by the control unit 40 independently;

[0201] - for a discontinuous C2 centrifuge, with reference to Figure 2, the single clearing sub-assembly 45 is provided at the inlet with a proportional adjustment valve 450. The clearing order therefore only includes a clearing duration and a clearing flow rate.

[0202] The at least one clearing duration and at least one flow rate are set by the operator before starting the centrifugal spinning process Pl, P2.

[0203] According to various embodiments of the invention, the centrifuge C1, C2 is provided with at least one measuring device configured to measure the flow rate of clearing liquid at the level of the at least one clearing subassembly and to communicate the measurement 401 to the control unit 40, which then transmits it to the processing unit 3 so that it (and / or the operator if the centrifugal spinning process P1, P2 is semi-automatic or manual), as required, modifies during the clearing step E4 the clearing duration and / or the clearing intensity relating to the at least one clearing subassembly.

[0204] When the centrifuge is a continuous C2 centrifuge, the P2 centrifugal spinning process, compared to the PI centrifugal spinning process of the discontinuous Cl centrifuge, includes additional steps.

[0205] The several control zones distinguished by the processing unit 3 include a control zone located closest to the lower edge 13 of the centrifugation basket 1, called the lower zone, which corresponds in the embodiment presented to the control zone S4.

[0206] In the following explanation, the lower zone is considered to correspond to the lower zone S4.

[0207] Following the association E34 of a reference colorimetric value Six, S2x, S3x, S4x with each of the control zones SI, S2, S3, S4, the processing unit 3 executes a comparison step Q.3 during which the reference colorimetric value S4x of the lower zone S4 is compared to a colorimetric threshold.

[0208] Figure 14 presents an example of an application context which can be observed in a continuous centrifuge Cl, for which zones of lack ZM of massecuite / sugar are present in the centrifugation basket 1, these zones of lack ZM thus revealing the peripheral wall 12 (the peripheral wall 12 being represented in dotted lines in this Figure 14); such zones of lack ZM being, thanks to the invention, detectable in all the control zones SI, S2, S3, S4 and in particular in the lower zone S4.

[0209] In this context of Figure 14, the reference colorimetric value S4x is representative of the massecuite M. On the other hand, if the massecuite M is not introduced in sufficient quantity into the centrifugation basket 1 (for example if it is too viscous or there is a malfunction in the feed system), one or more missing zones ZM begin to appear on the peripheral wall 12 in the lower zone S4. Thus, the reference colorimetric value S4x is representative of the remaining massecuite M to be treated and of the peripheral wall 12. It is to this situation, for which the centrifugation basket 1 is almost empty, that the colorimetric threshold relates / corresponds.

[0210] If the processing unit concludes following the comparison step Q.3 that the centrifugation basket is almost empty, it sends a feed order 500 to the feed system 5 to feed the centrifugation basket 1 with massecuite M, thus implementing a feed regulation step E5. The processing unit 3 sends the feed order 500 under the condition that massecuite M remains to be processed. For this, the feed system 5 communicates beforehand with the processing unit 3 to send it, among a set of information 501, information relating to the presence or absence of a quantity of massecuite M still remaining to be processed.

[0211] The feed order 500 comprises at least one feed duration during which the feed system 5 must feed the centrifugation basket 1 with massecuite M, and a feed rate. Depending on the requested feed rate, the feed system gradually opens or closes the proportional adjustment valve 51 to allow a variable flow rate of massecuite M to pass into the feed pipe 52. According to an alternative embodiment of the invention, the set of information 501 communicated by the feed system 5 to the processing unit comprises the flow rate of massecuite M circulating in the feed pipe 52, so that the processing unit 3 (and / or the operator if the centrifugal spinning process PI is semi-automatic or manual) can modify / regulate the feed rate and / or the feed duration as required during the feed regulation step E5.

[0212] By default, the feed duration and feed rate values ​​are entered by the operator during the EP setup step from processing unit 3. It also defines the color threshold value.

[0213] According to different embodiments of the invention, the feed system 5 has at least one measuring device configured to measure the massecuite flow rate M feeding the centrifugation basket 1, and to communicate the massecuite flow rate measurement 501 to the processing unit 3. Depending on the massecuite flow rate measurement 501, (and / or the operator if the centrifugation spinning process PI is semi-automatic or manual) can modify the requested feed rate value and / or the feed duration during the feed step E5.

[0214] The centrifugal spinning method PI also comprises a calculation step E61 of a ratio taking place after the construction step E32 from the secondary image 34, between an area of ​​the at least one first section 341 and an area of ​​the at least one second section 342. As previously indicated, the ratio reflects a general viscosity state of the cooked mass M.

[0215] By comparing the ratio with a threshold ratio during a comparison Q4, the processing unit 3 determines whether or not it is necessary to send water vapor into the centrifugation basket 1 to thin the massecuite M. If so, the processing unit 3 sends a vaporization order 600 to the vaporization system 6 for the implementation of a vaporization step E62, during which it sprays water vapor into the centrifugation basket 1, at least at the bottom wall 11 and, as in the embodiment presented, at the peripheral wall 12.

[0216] In the example of Figure 15, the massecuite M / sugar S transition zone is located at a given height from the bottom wall, which is a normal processing height, which is reflected in the associated secondary image 34 by a ratio (that resulting from the calculation step E61) above the threshold ratio, so that no vaporization order 600 is issued.

[0217] On the other hand, in the example of figure 16, the massecuite M / sugar S transition zone is located at another given height of the bottom wall, which is a so-called abnormal height which is greater than the normal treatment height of figure 15, which this time translates into the associated secondary image 34 by a ratio (that resulting from the calculation step E61) below the threshold ratio, so that a vaporization order 600 is issued.

[0218] The vaporization order 600 comprises at least a vaporization duration during which the vaporization system 6 sprays water vapor into the centrifugation basket and a vaporization flow rate to adjust the intensity of the spray. The intensity of the spray is physically adjusted by the vaporization system which controls the proportional adjustment valve 61 according to the specified vaporization flow rate value.

[0219] In the embodiment presented, as mentioned previously, the vaporization system can also, as required, fluidify the cooked mass M circulating inside the feed pipe 52 before it arrives in the centrifugation basket.

[0220] In the case where the processing unit 3 implements the vaporization step E6 in parallel with the supply step E5, the vaporization order 600 may comprise a second vaporization duration and a second vaporization flow rate corresponding respectively to the duration and intensity of water vapor that the vaporization system 6 injects into the supply pipe; the regulation of water vapor being managed by the vaporization system 6 by means of a proportional adjustment valve 62, which is completely closed if water vapor does not have to be injected into the supply pipe 52.

[0221] The operator enters by default during the parameterization step from the processing unit 3 the vaporization duration, the vaporization flow rate, and the value of the threshold ratio. In the embodiment presented, it also enters the second vaporization duration and the second vaporization flow rate. According to different embodiments of the invention, the vaporization system 6 has at least one measuring device configured to measure at least the intensity of water vapor injected into the supply pipe 52 and / or that sprayed into the centrifugation basket 1, and to communicate the vaporization measurement(s) 601 to the processing unit 3.Depending on the vaporization measurement(s) 601, the processing unit 3 (and / or the operator if the centrifugal spinning process PI is semi-automatic or manual) can modify the requested vaporization flow rate value(s) and / or the vaporization duration(s) during the vaporization step E6.

[0222] Depending on the rotation speed of the centrifugation basket, it is possible that projections of sugar crystals Su or massecuite may splash and dirty the protective glass 91 of the housing 9 through the guide, meaning that the light source 21 and the photo-detection system 22 can no longer operate under optimal conditions. This is why the guide 92 of the centrifuges C1, C2 is equipped with a cleaning nozzle 93 opening into the guide 92 in order to spray very hot water onto the protective glass to clean it of any splashes.

[0223] The cleaning of the protective glass is carried out at regular intervals throughout the duration of the centrifugation step E1 of the centrifugal spinning process P1, P2. For this, the processing unit sends a cleaning order 930 to the control unit 40 which controls the cleaning nozzle 93 so that it sprays or not very hot water on the protective glass 91, respectively by opening or closing an on / off valve located at the inlet of the cleaning nozzle 93.

[0224] According to different embodiments of the invention, the operator can enter during the EP parameterization step from the processing unit 3 the duration of the cleaning, the time interval separating each cleaning. In the embodiment presented, the cleaning intensity is a predefined value and the time interval separating each cleaning is equal to fifteen minutes.

Claims

DEMANDS 1. Centrifuge (Cl, C2) for separating a quantity of sugar crystals (Su) from a syrup in a cooked mass (M), the centrifuge (Cl, C2) comprising at least: - a centrifugation basket (1) driven in rotation around a central axis of rotation (10), inside which is provided an introduction of the cooked mass (M), said centrifugation basket (1) having a bottom wall (11) and a peripheral wall (12), said peripheral wall (12) being permeable and having a lower edge (13) contiguous to said bottom wall (11) and an upper edge (14), and in which said peripheral wall (12) has a height measured from the lower edge (13) to the upper edge (14); - a measuring device (2) comprising at least one light source (21) for illuminating the interior of the centrifugation basket (1) and a photo-detection system (22) for detecting reflected light and delivering photo-detection measurements (201) that are representative of the cooked mass (M) or the peripheral wall (12); and - a processing unit (3) connected to the measuring device (2) for receiving and processing said photo-detection measurements (201); said centrifuge (Cl, C2) being characterized in that the light source (21) is shaped to illuminate the peripheral wall (12) of the centrifugation basket (1) over at least 90% of its height, and the photo-detection system (22) is shaped to detect over at least 90% of the height of the peripheral wall (12) the light reflected by the massecuite (M) or the peripheral wall (12); and in that the processing unit (3) is shaped to continuously and in real time process the photo-detection measurements (201) carried out over at least 90% of the height of the peripheral wall (12).

2. Centrifuge (Cl, C2) according to claim 1, wherein the processing unit (3) is configured to generate a raw image (33) over at least 90% of the height of the centrifugation basket (1), from the photo-detection measurements (201).

3. Centrifuge (Cl, C2) according to claim 2, wherein the processing unit (3) is configured to compare the photodetection measurements (201) with a colorimetric limit over at least 90% of the height of the centrifugation basket (1), and to construct a secondary image (34) exhibiting: - at least one first section (341) of a first color in which the photodetection measurements (201) are below said colorimetric limit; and / or - at least a second section (342) of a second colour in which the photo-detection measurements (201) are greater than said colourimetric limit.

4. Centrifuge (Cl) according to claim 3, wherein the centrifuge (Cl) is a continuous centrifuge comprising a vaporization system (6) configured to send water vapor at least into the centrifuge basket (1), and wherein the processing unit (3) is configured to calculate a ratio between an area of ​​at least a first section (341) and an area of ​​at least a second section (342), and to communicate a vaporization order (600) as a function of said ratio, said vaporization order (600) being transmitted by the processing unit (3) to the vaporization system (6) to trigger a sending of water vapor.

5. Centrifuge (Cl) according to claim 4, wherein the vaporization system (6) is configured to send water vapor inside the centrifuge basket (1) at least to the level of the bottom wall (11) of the centrifuge basket (1).

6. Centrifuge (Cl, C2) according to any one of claims 1 to 5, wherein the processing unit (3) is configured to distinguish several control zones (SI, S2, S3, S4) distributed over the height of the centrifugation basket (1), and to associate with each of the several control zones (SI, S2, S3, S4) a colorimetric reference value (Six, S2x, S3x, S4x) established from the photodetection measurements (201) carried out in the corresponding control zone.

7. Centrifuge (Cl) according to claim 6, wherein the centrifuge (Cl) is a continuous centrifuge comprising a feeding system (5) configured to feed the centrifuge basket (1) with massecuite (M), and wherein the processing unit (3) is configured to perform a comparison of the reference colorimetric value (S1, S2x, S3x, S4x) with a colorimetric threshold in one of several control zones (S1, S2, S3, S4), referred to as the lower zone (S4), which is closest to the lower edge (13) of the centrifuge basket (1), and to communicate a feeding command (500) based on a result of said comparison, said feeding command (500) being transmitted by the unit treatment (3) intended for the feeding system (5) to feed the mass cooked (M).

8. Centrifuge (Cl, C2) according to claim 6 or 7, wherein, for each of the several control zones (SI, S2, S3, S4), the colorimetric reference value (Six, S2x, S3x, S4x) corresponds to an ICUMSA value.

9. Centrifuge (Cl, C2) according to any one of claims 6 to 8, comprising a clearing device (4) including: - at least one clearing sub-assembly (41; 42; 43; 44; 45) shaped to spray a clearing liquid onto the peripheral wall (12) of the centrifugation basket (1), - a control unit (40) connected to at least one clearing subset (41; 42; 43; 44; 45) and in communication with the processing unit (3) to control at least one clearing subset (41; 42; 43; 44; 45) according to the reference colorimetric value (Six, S2x, S3x, S4x) of at least one of the several control zones (S1, S2, S3, S4).

10. Centrifuge (Cl, C2) according to claim 9, wherein, for each of the several control zones (SI, S2, S3, S4), the processing unit (3) is configured to perform a comparison of the reference colorimetric value (Six, S2x, S3x, S4x) with a colorimetric setpoint (Slt, S2t, S3t, S4t), and to communicate a clearing command (400) as a function of a result of said comparison, and the control unit (40) is configured to drive at least one clearing subset (41; 42; 43; 44; 45) in order to control a clearing flow rate, in response to a receipt of the clearing command (400).

11. Centrifuge (Cl, C2) according to claim 10, wherein at least one clearing subassembly (41; 42; 43; 44; 45) comprises a valve (410; 420; 430; 440; 450) which is connected to the control unit (40), and which is piloted to adjust the clearing flow rate.

12. Centrifuge (C2) according to any one of claims 9 to 11, wherein at least one clearing sub-assembly comprises a single clearing sub-assembly (45) comprising several nozzles arranged at several heights from the bottom wall (11) of the centrifugation basket (1).

13. Centrifuge (Cl) according to any one of claims 9 to 11, wherein at least one clearing sub-assembly comprises several clearing sub-assemblies (41, 42, 43, 44) arranged at different heights from the bottom wall (11) of the centrifuge basket (1), facing several control zones (SI, S2, S3, S4), each clearing sub-assembly (41, 42, 43, 44) being associated with one control zone (SI, S2, S3, S4) among the several control zones (SI, S2, S3, S4), and wherein the control unit (40) is connected to the various clearing sub-assemblies (41, 42, 43, 44) and is in communication with the processing unit (3) to at least independently control each of the clearing sub-assemblies (41, 42, 43, 44). 44) depending on the colorimetric reference value (Six, S2x, S3x, S4x) of the control area (SI, S2, S3, S4) associated with it.

14. Centrifuge (Cl) according to claims 10 and 13, in which the control unit (40) is configured to independently control each of the clearing subsets (41, 42, 43, 44) in order to control the corresponding clearing flow rate, in response to a clearing command (400) received from the comparison of the reference colorimetric value (Six, S2x, S3x, S4x) of the control zone (SI, S2, S3, S4) associated with it, with the corresponding colorimetric setpoint (Slt, S2t, S3t, S4t).

15. Centrifuge (Cl, C2) according to any one of the preceding claims, wherein the light source (21) is a white light source.

16. Centrifuge (Cl, C2) according to any one of the preceding claims, wherein the light source (21) is a stroboscopic source.

17. Centrifuge (Cl, C2) according to any one of the preceding claims, wherein the light source (21) consists of at least one light-emitting diode (210), and for example several light-emitting diodes (210).

18. Centrifuge (Cl, C2) according to any one of the preceding claims, wherein the photo-detection system (22) comprises at least one image sensor.

19. Centrifuge (Cl, C2) according to any one of the preceding claims, wherein the photo-detection system (22) comprises at least one array of colored filters, for example of RGB type.

20. Centrifuge (Cl, C2) according to any one of the preceding claims, wherein the light source (21) and the photo-detection system (22) of the measuring device (2) are arranged inside a sealed housing (9) closed and fixed to an opening (190) of a hood (19) of the centrifuge (Cl, C2), said housing (9) being provided with a protective glass (91) facing the opening (190) of said hood (19) and such that the light source (21) and the photo-detection system (22) are behind said protective glass (91).

21. Centrifuge (Cl, C2) according to claim 20, wherein the housing (9) is integral with a guide (92) having a first end (95) fixed on said housing (9), around the protective glass (91), and a second end (96) fixed on the hood (19) around its opening, said guide (92) having at least one vent (94) for an air inlet into said guide (92).

22. Centrifuge (Cl, C2) according to claim 21, wherein the guide (91) includes at least one cleaning nozzle (93) for water spray cleaning of the protective glass (91).

23. Centrifuge (Cl, C2) according to any one of the preceding claims, wherein at least 90% of the height of the peripheral wall (12) of the centrifugation basket (1) corresponds to the entire height of said peripheral wall (12) taken from its lower edge (13) to its upper edge (14).

24. A centrifugal dewatering process (P1, P2) for separating a quantity of sugar crystals (Su) from a syrup in a cooked mass (M), employing a centrifuge (Cl, C2) according to any one of the preceding claims, and comprising at least: - a centrifugation step (El) in which the centrifugation basket (1) containing the cooked mass (M) is rotated; said centrifugal spinning process (Pl, P2) being characterized in that it comprises, during the centrifugation step (El): - a continuous lighting stage (E21) consisting of illuminating with the light source (21) the peripheral wall (12) of the centrifuge basket (1) over at least 90% of its height; - a measurement step (E22) consisting of detection by the photo-detection system (22) over at least 90% of the height of the peripheral wall (12) of the centrifuge basket (1) the light reflected by the massecuite (M) or the peripheral wall (12), in order to deliver photo-detection measurements (201) which are representative of the baked mass (M) or the peripheral wall (12); - a processing step (E3) by the processing unit (3) continuously and in real time of the photo-detection measurements (201) carried out on at least 90% of the height of the peripheral wall (12).

25. Centrifugal spinning method (P1, P2) according to claim 24, wherein the processing step (E3) implements a generation (E31) of a raw image (33) over at least 90% of the height of the centrifugation basket (1), from the photo-detection measurements (201).

26. Centrifugal spinning method (P1, P2) according to claim 25, wherein, during the processing step (E3), the photo-detection measurements (201) are compared with a colorimetric limit over at least 90% of the height of the centrifugation basket (1), and includes a construction step (E32) of a secondary image (34) exhibiting: - at least one first section (341) of a first color in which the photodetection measurements (201) are below said colorimetric limit; and / or - at least a second section (342) of a second colour in which the photo-detection measurements (201) are greater than said colourimetric limit.

27. Centrifugal spinning method (PI) according to claim 26, wherein the centrifuge (Cl) is a continuous centrifuge, and comprising a calculation step (E61) of a ratio between an area of ​​at least a first section (341) and an area of ​​at least a second section (342), and a vaporization step (E62) consisting of sending at least a water vapor into the centrifuge basket (1) according to said ratio.

28. Centrifugal spinning process (P1, P2) according to any one of claims 24 to T1, wherein the processing step (E3) implements a distinction (E33) of several control zones (SI, S2, S3, S4) distributed over the height of the centrifugation basket (1), and an association (E34) to each of the several control zones (SI, S2, S3, S4) of a reference colorimetric value (Six, S2x, S3x, S4x) established from the photo-detection measurements (201) carried out in the corresponding control zone.

29. Centrifugal spinning method (P1, P2) according to claim 28, comprising an intermediate clearing step (E4) for spraying a liquid of clearing on the peripheral wall (12) of the centrifugation basket (1), according to the colorimetric reference value (Six, S2x, S3x, S4x) associated with at least one of the several control zones (SI, S2, S3, S4).

30. Centrifugal spinning process (PI) according to claim 29, wherein the spinning process comprises, during the treatment step (E3) and prior to the intermediate clearing step (E4), a comparison step (Q.2) during which the colorimetric reference value (Six, S2x, S3x, S4x) of each of the several control zones (SI, S2, S3, S4) is compared to a colorimetric setpoint (Slt, S2t, S3t, S4t), in order to spray a clearing liquid at a clearing flow rate according to the result of said comparison.

31. Centrifugal spinning method (PI) according to claim 29 or 30, wherein the intermediate clearing step (E4) implements clearing of each of the several control zones (SI, S2, S3, S4), independently, according to the associated colorimetric reference value (Six, S2x, S3x, S4x).

32. A centrifugal spinning method (PI) according to any one of claims 28 to 31, wherein the centrifuge (Cl) is a continuous centrifuge, and comprising: - a comparison step (Q.3) during which the reference colorimetric value (Six, S2x, S3x, S4x) in one of the several control zones (S1, S2, S3, S4), called the lower zone (S4), which is closest to the lower edge (13) of the centrifuge basket (11), is compared with a colorimetric threshold; and - a feed regulation step (E5) during which the centrifugation basket (1) is fed with cooked mass (M) according to a result of said comparison.

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