EP1678364A1

EP1678364A1 - Method and device for controlling a dyeing machine

Info

Publication number: EP1678364A1
Application number: EP04805270A
Authority: EP
Inventors: Georges Cornuejols
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-10-21
Filing date: 2004-10-21
Publication date: 2006-07-12
Also published as: US20070234486A1; WO2005040482A1

Abstract

The invention relates to a device for controlling a dyeing machine (100), into which a dye is introduced for a period of time D. Said device comprises a sensor (140), for measuring the transparency of a liquid contained in the bath, said sensor being adapted to provide a signal representative of the bath transparency for at least one spectral range and control means (148), for determining a reference point for the bath transparency change, which corresponds to the transparency of the bath without any dye uptake for the period of time D. Preferably, the reference point is determined by interpolating the transparency change at the beginning of the introduction, the interpolation being carried out over the period of time D during which a dye is introduced into the dye bath.

Description

METHOD AND DEVICE FOR CONTROLLING A DYEING MACHINE

The present invention relates to a method and a device for measuring transparency and controlling baths. It applies, in particular, to the control of exhaustion of dye baths for the textile industry. Numerous systems for measuring the exhaustion of dye baths are known. These systems include specific pumping means which impose a high manufacturing cost. In addition, when the dye is introduced into a bath, the dye begins to fix on the fabric to be dyed before the end of the dye introduction, which prevents correct calibration of the exhaustion measurement systems. baths. Finally, no system is known to control the rinsing of a dyeing machine. The present invention intends to remedy these drawbacks. According to a first aspect, the present invention relates to a dye bath monitoring device in which a dye component is introduced for a period D characterized in that it comprises: - a sensor for the transparency of the liquid contained in said bath suitable for providing a signal representative of the transparency of said bath for at least one spectral range; - control means adapted to determine a reference point for the evolution of the transparency of the bath corresponding to the transparency that the dye bath would have had if no dye absorption had taken place during duration D. Thanks to these provisions , the fixing of dye which takes place during the duration D does not prevent the calibration of the device and the monitoring of the transparency as a function of the reference point. According to particular characteristics, the control means are adapted to determine said reference point by interpolation of the change in transparency at the start of the introduction, interpolation carried out over the duration D of the introduction of dye into the dye bath. . Thanks to these provisions, the determination of the reference point is easy. According to particular characteristics, the control means are adapted to determine said reference point as a function of the product of the transparency derivative at the start of the duration of the introduction of the dye into the dye bath, by the duration D^'. Thanks to these provisions, the determination of the reference point is easy. According to particular characteristics, the control means are adapted to determine the duration D by measuring the duration of decrease of the transparency of the bath. Thanks to these provisions, the determination of the duration D is easy and autonomous: it is not necessary, for this determination, to use a sensor other than the transparency sensor. According to particular characteristics, the control means are adapted to determine a reference point of evolution of transparency of clear water or white bath by memorizing a value representative of the signal emitted by the sensor during a passage of water. clear or white bath in the sensor. Thanks to these provisions, the evolution of transparency can be treated according to two extreme reference points. According to particular characteristics, the control means are adapted to control the stopping of dyeing as a function of the evolution of the transparency of the bath and of at least one reference point of evolution of transparency. Thanks to these provisions, the duration of the dyeing phase can be optimized and energy, machine and water savings can be made. According to particular characteristics, the control means are adapted to determine the stopping of dyeing when the derivative of the value of the transparency is less than a predetermined value. Thanks to these provisions, the end of the dyeing time is easily determined. According to a second aspect, the present invention relates to a process for monitoring a dye bath in which a dye component is introduced for a period D characterized in that it comprises: - a step of capturing the transparency of the liquid contained in said bath during which a signal representative of the transparency of said bath is supplied for at least one color; a step of determining a reference point for the evolution of the transparency of the bath corresponding to the initial transparency if the entire dye component had been introduced and mixed with the dye bath in a fraction of the duration D and at the start of the duration D. The particular characteristics, advantages and aims of this process being similar to those of the dye bath monitoring device as succinctly explained above, they are not repeated here. According to a third aspect, the present invention relates to a dye bath monitoring device characterized in that it comprises: - a transparency sensor of the liquid contained in said bath adapted to supply a signal representative of the transparency of said bath for at least a spectral range; - Control means adapted to determine the end of a duration of rinsing of said bath as a function of the evolution of the transparency of the bath. Thanks to these provisions, the duration of the rinsing phase can be optimized and energy, machine and water savings can be made. According to particular characteristics, the control means are adapted to control the end of the rinsing time of a dyeing machine comprising said dye bath. Thanks to these provisions, the rinsing stop is automatic. According to particular characteristics, the control means are adapted to determine a reference point of evolution of transparency of clear water or white bath by memorizing a value representative of the signal emitted by the sensor during a passage of water. clear or white bath in the sensor. Thanks to these provisions, the evolution of transparency can be treated according to an extreme reference point. According to particular characteristics, in a dyeing phase, a dyeing component is introduced for a period D and the control means are adapted to determine a reference point of evolution of transparency of the bath corresponding to the initial transparency if the whole of the dye component had been introduced and mixed with the dye bath in a fraction of duration D and at the start of duration D. Thanks to these arrangements, the fixing of dye which takes place during duration D does not prevent the calibration of the device and monitoring of transparency as a function of the reference point. According to particular characteristics, the control means are adapted to determine the end of the rinsing period as a function of the evolution of the transparency of the bath and of at least one reference point of evolution of transparency. Thanks to these provisions, the duration of the rinsing phase can be optimized and energy, machine and water savings can be made. According to particular characteristics, the control means are adapted to determine the end of the rinsing time when the derivative of the value of the transparency is less than a predetermined value. Thanks to these provisions, the end of the rinsing time is easily determined. According to a fourth aspect, the present invention relates to a dye bath monitoring method characterized in that it comprises: - a step of capturing the transparency of the liquid contained in said bath during which a signal representative of the transparency is provided said bath for at least one color; a step of determining the end of a duration for rinsing said bath as a function of the evolution of the transparency of the bath. The particular characteristics, advantages and aims of this process being similar to those of the dye bath monitoring device as succinctly set out above, they are not repeated here. According to a fifth aspect, the present invention relates to a dye bath monitoring device intended to be coupled with a dye machine comprising at least one circuit for circulating the liquid making up the dye bath, characterized in that it comprises: - A transparency sensor of the liquid contained in said bath adapted to provide a signal representative of the transparency of said bath for at least one spectral range; a means for positioning the transparency sensor in a said circuit for circulating the liquid making up the dye bath. Thanks to these provisions, it is not necessary to provide a dye water circuit specific to the transparency sensor, the water circuits generally present on the dyeing machines being used to position the transparency sensor. According to particular characteristics, the positioning means comprises a sensor support adaptable to said circuit. Thanks to these provisions, the positioning means can be welded or screwed, for example, in said circuit. According to particular characteristics, the positioning means comprises a means for moving said sensor adapted to move the sensor in or outside the initial circuit of liquid making up the dye bath. Thanks to these arrangements, the sensor can be placed in the liquid flow or protected from said flow, depending on the operating phases of the dyeing machine. According to particular characteristics, said displacement means comprises a piston placed transversely with respect to said liquid circulation circuit. Thanks to these arrangements, the means of movement is easy to manufacture and inexpensive. According to particular characteristics, the control means are adapted to control the stopping of dyeing as a function of the evolution of the transparency of the bath and of at least one reference point of evolution of transparency. Thanks to these provisions, the duration of the dyeing phase can be optimized and energy, machine and water savings can be made. According to particular characteristics, the control means are adapted to determine the stopping of dyeing when the derivative of the value of the transparency is less than a predetermined value. Thanks to these provisions, the end of the dyeing time is easily determined. According to particular characteristics, the control means comprise means for controlling the sensitivity of the sensor as a function of the opacity of the liquid making up the dye bath. According to particular characteristics, the control means comprise means for controlling the optical path traveled by a light ray generated by the sensor in the liquid making up the dye bath as a function of the opacity of the liquid making up the dye bath. According to particular characteristics, the device as briefly described above further comprises a means for adjusting the thickness of the dye bath water sample, the transparency of which is picked up by the transparency sensor and the means control are adapted to control the thickness adjusting means such that the sample thickness is an increasing function of the transparency of the bath. Thanks to these provisions, by adjusting the thickness of the sample, the transparency measurement is carried out by favorably exploiting the dynamics of the sensor. Indeed, any capture means provides a signal which comprises "noise", that is to say a disturbance or a random interference and, thanks to these arrangements, the signal leaving the capture means has a fairly high intensity for that the signal / noise ratio is favorable. According to particular characteristics, the control means comprise means for controlling the capture time of the sensor as a function of the opacity of the liquid making up the dye bath. According to particular characteristics, the control means comprise means for slaving a means for amplifying the signal / noise ratio of the signal leaving the sensor, as a function of the opacity of the liquid making up the dye bath. According to particular characteristics, the thickness adjustment means is adapted to move, relative to one another, a light source and at least one optical fiber. Thanks to these provisions, the sensor, positioned at the other end of the optical fiber is protected from the flow of liquid composing the dye bath, on the one hand, and the dimensions of the parts of the device placed in the path of this liquid are on the other hand. According to particular characteristics, the control means are adapted to implement the Bert-Lambert law. According to particular characteristics, the control means are adapted to control the acidity and / or the salinity of the dye bath as a function of the change in the transparency of the liquid making up the dye bath. According to particular characteristics, the control means are adapted to control the bath temperature as a function of the evolution of the transparency of the liquid making up the dye bath. According to particular characteristics, the control means are adapted to control the quantity of clear water introduced into the dye bath as a function of the change in the transparency of the liquid making up the dye bath. According to particular characteristics, the control means are adapted to control the quantity of dye introduced into the dye bath as a function of the change in the transparency of the liquid making up the dye bath. According to particular characteristics, the control means are adapted to control the quantity of chemical compounds introduced into the dye bath as a function of the change in the transparency of the liquid making up the dye bath. For example, the chemical compounds are salts or alkaline liquids. According to a sixth aspect, the present invention relates to a dye bath monitoring method intended to be implemented in a dye bath monitoring device coupled with a dyeing machine comprising at least one circuit for circulating the liquid composing the dye bath, characterized in that it comprises: - a step of positioning a transparency sensor in a said circuit for circulating the liquid composing the dye bath and a step of capturing the transparency of the liquid contained in said bath, during which a signal representative of the transparency of said bath is provided for at least one color. The particular characteristics, advantages and aims of this process being similar to those of the dye bath monitoring device as succinctly set out above, they are not repeated here. The inventor has found that the measurement of the transparency of the dye bath is often disturbed by the presence of bubbles or foam in the dye bath. The present invention intends, according to some of its aspects, to remedy these drawbacks. To this end, the present invention aims, according to a seventh aspect, a dye bath monitoring device intended to be coupled with a dyeing machine comprising at least one circuit for circulating the liquid composing the dye bath, characterized in that '' It comprises: - a means of taking a dye bath sample, - a means of separating said sample from the dye bath and putting said sample to rest, - a transparency sensor of the sample separated from the dye bath dye suitable for providing a signal representative of the transparency of said sample for at least one spectral range and - a means for rinsing the sensor. Thanks to these arrangements, once the sample is separated from the dye bath and put to rest, the bubbles that may be present in the sample gradually separate from the liquid and the sensor can measure the real transparency of the liquid. According to particular characteristics, the sample taking means comprises a piston set in motion. According to particular characteristics, said piston can take at least one position in which the sample is in the bath and a position in which the sample is separated from said bath. According to particular characteristics, the sample taking means is adapted to take the sample in the circuit for circulation of the liquid composing the dye bath. According to particular characteristics, the sensor is positioned in said liquid circulation circuit. According to particular characteristics, the sensor rinsing means includes a pressurized clear water circuit. According to particular characteristics, the sample taking means and the rinsing means are adapted so that, during the taking of the sample, the sensor is rinsed. According to particular characteristics, the device as succinctly described above comprises means for controlling a thickness of the sample between said sensor and a light source. According to particular characteristics, the sample thickness control means comprises a piston. According to particular characteristics, the thickness control means comprises a spring. According to particular characteristics, the device as succinctly described above comprises two light sources adapted to emit different quantities of light opposite said sensor and a switching means between said light sources. According to particular characteristics, the device as succinctly described above comprises an anti-foam filter positioned between the position of the sample at the time of sampling and the position of the sample removed from the dye bath. According to particular characteristics, the device as succinctly described above comprises a piston which is adapted to take at least three positions in which, respectively: - a water passage is open opposite the pressurized clear water circuit, - the water passage is opposite the circulation circuit of the liquid composing the dye bath and - the water passage is closed and opposite the sensor. The dye bath exhaustion measurement devices present a significant optical complexity, using several chromatic filters and several brightness sensors associated with these filters. The cost of manufacturing and maintenance and the risk of breakdown are therefore very high. The present invention aims, according to some of these aspects, to remedy these drawbacks. To this end, the present invention aims, according to an eighth aspect, a dye bath monitoring device, characterized in that it comprises: - a chamber for measuring the transparency of liquid coming from the dye bath comprising a light source adapted to successively emit light in a plurality of different spectral bands, - a single optoelectronic sensor adapted to receive the light rays coming from the light source after their passage through the measurement chamber and to emit a signal representative of the quantity of light received by said sensor and - a demodulator synchronized with the light source to successively process the signals coming from the sensor to provide results corresponding to the different spectral bands successively emitted by the light source. Thanks to these provisions, a single sensor is necessary to process the different spectral bands used for the measurement of bath transparency and for monitoring the exhaustion of the dye bath or the course of rinsing. According to specifications. particular, said light source comprises a plurality of light sources adapted to emit light in a plurality of different spectral bands between the different light sources and a modulator adapted to cause an alternation of ignition of said light sources. Thanks to these arrangements, powerful light sources can be used. According to particular characteristics, said light source comprises at least one light-emitting diode. Thanks to these arrangements, the light source does not cause significant heating and has a long service life. According to particular characteristics, the light source comprises at least one electro-optical transducer whose emission spectral band depends on a characteristic of the electrical signal applied to it and a modulator adapted to modify said characteristic by alternation. According to particular characteristics, the light source comprises a light-emitting diode whose emission spectral band depends on the voltage applied to it. Thanks to each of these arrangements, a single electro-optical transducer, for example the light-emitting diode, can successively emit light rays according to different spectral bands by the simple modification of the signal applied to it. According to particular characteristics, for each light source, after each ignition corresponding to the same spectral band emitted, the signals from the sensor corresponding to the same time interval are processed, with respect to the ignition instant. Thanks to these provisions, the variations in wavelength or light power emitted do not disturb the comparison of the successive results of treatment carried out with the same light source and for the same spectral band. The particular characteristics, advantages and aims of the various aspects of the process which is the subject of the present invention, succinctly set out above, being similar to those of the corresponding devices as succinctly set out above, they are not repeated here. The particular features of each of the aspects of the present invention constitute particular features of all the aspects of the present invention. However, for the sake of brevity, these particular characteristics have not been copied with regard to each of the aspects mentioned above. The various aspects of the present invention are preferably combined with one another to carry out a method and a device for measuring transparency and controlling baths, benefiting from the advantages, aims and particular characteristics of these different aspects. Other advantages, aims and characteristics of the present invention will emerge from the description which follows, given, with an explanatory and in no way limiting aim, with reference to the appended drawings in which: - Figure 1 shows, schematically, a first mode of realization of the device object of the present invention, - Figure 2 shows a flowchart of steps performed by the embodiment of the device illustrated in Figure 1, - Figure 3 shows a transparency curve as a function of time and of the measurements made or calculated with the device illustrated in Figure 1 putting using the logic diagram illustrated in FIG. 2, - FIGS. 4A to 4G represent, diagrammatically, sensors which can be implemented in the device which is the subject of the present invention, - FIG. 5 represents, diagrammatically, a second embodiment of the device object of the present invention, - Figures 6A and 6B show, schematically, two embodiments of light sources capable of being incorporated in the embodiment of the device object of the present invention illustrated in Figure 5 and - Figure 7 represents a flow diagram of steps carried out by the embodiment illustrated in FIGS. 5, 6A and 6B. Throughout the description, the terms "sensor" and "capture means" are used interchangeably. Similarly, the terms "derivative" or "variation over a predetermined period" are used interchangeably. Finally, the terms "the dye" or "the dyes" are used interchangeably. In FIG. 1, we observe: - a dyeing machine 100 controlled by a programmer 105 and filled with a dyeing bath 110 during dyeing phases, this dyeing machine circulating the bath around the piece of fabric or the spools yarn to be dyed, the movement of the bath being caused by a circuit for circulating the dye bath 120, comprising a pump 122, a pipe 124 taking bath water in the bath 110 and re-injecting it into the bath 110 , - an analysis chamber 130 comprising a piston 132 driven by a motor 134 inside a cylinder 133, the piston 132 displacing a means of capturing transparency 140 comprising a light source 142 supplied by an electrical supply 111 (FIGS. 4A to 4G), and a bundle of optical fibers 144, the output of which is opposite a sensor 146 connected to a digitizer 148, - means 136 for moving the input of the bundle of optical fibers 144 from or to the light source era 142 (see FIGS. 4A to 4D and variants in FIGS. 4E to 4G), - control means 149 comprising:. a signal analysis means 150 receiving the digitized signals from the digitizer 148 and providing an analysis result,. a means for controlling the acidity and / or the salinity of the bath 160,. bath temperature control means 162,. a means for controlling the supply of clear water 164 into the bath 110,. a means for controlling the injection of dye into the bath 166,. a means 170 for controlling the engine 134 of the piston 132 and . a control means 172 of the displacement means 136 and. a means of communication (not shown) with the programmer 105, for exchanging operating data of the dyeing machine and allowing the programmer 105 to store or transmit traceability data of the dyeing operations. The dyeing machine 100 and the composition of the dye bath 110 are of the type known in the textile industry. Preferably, the place of introduction of dye is located near the entrance to the circulation circuit of the dye bath 120 so that the dye is dissolved in the water present in the piping before reaching the textile piece or the threads. to dye. If the place of introduction of the dye is in the pipe 124, the analysis chamber is located downstream of this place, according to the direction of circulation of the liquid of the dye bath in this pipe 124. The circulation circuit of the bath 120 dye already exists in many dyeing machines. The pump 122 and the piping 124 are of known type and already exist in many dyeing machines. They serve to ensure the relative movement of the piece of textile to be dyed with respect to the dye bath. They consist of materials which do not risk polluting the dye bath or distorting its analysis. The pump 122 preferably has a constant flow rate, possibly adjustable. The cylinder 133 constitutes a means of positioning the transparency sensor 140 in the circulation circuit 120 of the liquid making up the dye bath. This positioning means comprises a sensor support adaptable to said circuit, for example by drilling the piping 124 then gluing, riveting and / or screwing an adapter (not shown) or by replacing an element of the piping 124. The positioning means comprises a means 132 for moving the sensor 140 which moves the sensor in or outside the initial circuit of liquid making up the dye bath, initial circuit defined by the piping 124. In the example illustrated in FIG. 1, said displacement means comprises a piston 132 placed transversely to the liquid circulation circuit. The analysis chamber 130 consists of part of the piping 124 and of the piston 132, set in motion by the motor 134 under the control of the control means 170. Thanks to this piston mechanism, it is no longer necessary to provide specific piping for the dyeing machine control device and the complexity and the manufacturing, installation and maintenance costs of this device are greatly reduced. When the piston 132 is in the deployed (or high) position, the transparency capture means 140 is placed in the analysis chamber 130 which comprises, opposite, the light source 142 and the bundle of optical fibers 144, is placed in the analysis chamber 130 (FIG. 1, 4A, 4C and 4D) of the piping 124. The analysis chamber 130 also includes means 136 for moving the entry of the bundle of optical fibers 144 from or towards the light source 142. For example, the displacement means 136 comprise a stepping motor controlled by the control means 172. The spacing between the entry of the beam of optical fibers 144 and the light source 142 preferably varies at least over the range of values from 0.1 mm. at 7 mm. When the piston 132 is in the retracted (or low) position, the transparency capture means 140 is placed in the cylinder 133, outside of the piping 124, opposite a clear water inlet coming from a pipe. 175 and destined for a clear water outlet towards the continuation of pipe 175. The circulation of water in pipe 175 has two functions. This circulation makes it possible to clean the transparency capture means 140 and, in particular, its optical elements. As a variant, this circulation also makes it possible to measure the transparency of clear water. This circulation, controlled by a solenoid valve 174 is controlled by the control means 149 (as illustrated in FIG. 1), by the programmer 105 of the dyeing machine 100 or, as a variant, manually by an operator. As a variant, the piston acts as a shutter for the line 175 and the solenoid valve is not used. The light source 142 is, for example, an incandescent bulb, a halogen lamp or a light emitting diode emitting white light. The digitizer 148, of known type, digitizes the signal leaving the sensor 146. This digitization can be carried out on a single channel and represent a wide spectral range, for example visible light. This digitization can also be carried out on several channels representing different spectral ranges, for example, red, green and blue lights, the sensor 146 then comprising several sensors reacting in the different spectral ranges, for example by being fitted with optical filters of known type , each channel being connected to one of these sensors. Digitization can be carried out by a single digitizer connected, via a multiplexer, to each of the sensors dedicated to a particular spectral range (for example, red, green and blue) or by as many digitizers as there are sensors. The signal analysis means 150, which receives the digitized signals from the digitizer 148, implements the logic diagram illustrated in FIG. 2 to: - calibrate the transparency capture means then - to provide an analysis result in the form of '' a transparency value for each spectral range used, - during the dyeing phase, to provide a comparison of the derivative of each of these transparency values with at least one predefined threshold value, possibly depending on the composition of the bath dye and / or its reference points and - during the rinsing phase, to provide a comparison of each of the transparency values with at least one predefined threshold value, possibly depending on the composition of the dye bath and / or its reference points. It is observed that the predefined threshold values may depend on the spectral range considered. As a variant, during the dyeing phase, the signal analysis means 150 compares the transparency values with predefined threshold values, possibly functions of the composition of the bath and / or its reference points. Likewise, as a variant, during the rinsing phase, the signal analysis means 150 compares the derivatives of the transparency values with at least one predefined threshold value, possibly depending on the composition of the dye bath and / or its reference points. The signal analysis means, for example, consists of a computer programmed to implement the steps illustrated in FIG. 2. It includes a user interface (not shown) comprising a display screen, a keyboard and, optionally, a pointing device, for example a mouse. The means of enslavement^" bath acidity and / or salinity 160, the bath temperature control means 162, the clear water inlet control means 164 and the dye injection control means in the bath 166 respectively control, depending on the results provided by the signal analysis means, the operation of at least one valve for injecting chemical compounds into the bath, the operation of a heat source, for example consisting of a heat exchanger or water vapor piping, a clear water inlet valve, a dye injection valve in the bath. It is observed that the term "valve" does not prejudge the state, liquid, solid or gaseous, of the dye (s) and / or of the other chemical compounds, for example alkalis which can be injected into the dye bath. In FIG. 2, there is a succession of steps carried out by the embodiment of the device illustrated in FIG. 1, in the case where the textile fibers to be dyed are placed in the dyeing machine before the dyes are introduced into them and in the case where the dyes are likely to cause a "first strike" phenomenon. Those skilled in the art readily know how to adapt the steps described below to other cases of use of a dyeing machine. They are therefore not detailed in the present description. It is admitted that initially, the dyeing machine is filled with clear water and any products intended to promote the smooth running of the dyeing operations. This bath, which does not yet contain dye, is called "white bath". We also admit that the initial white bath is already at the desired dyeing temperature. Otherwise, as soon as the clear water is introduced, heating of the dye bath is then started, until it is at the desired temperature. During an industrial process selection step 200, a user selects a dyeing process by providing a value for the weight of the material to be dyed, an identification of the dye (s) to be used and an amount of dye to be injected into the dye bath. . During step 202, the movement of the transparency sensor relative to the light source is controlled, as a function of the dye selected and the amount of dye to be introduced into the dye bath. Alternatively, to avoid having to receive the data indicated above, a white bath transparency measurement is carried out for each (for example three) predetermined thickness and, during the dye bath transparency measurement comprising the dyes, a transparency measurement is carried out for each predetermined thickness. As a variant, as a function of the transparency measurement, the thickness of the sample is varied during dyeing, the transparency of which is measured as a function of this transparency, by then applying a correction coefficient to the measurement carried out, depending on the thickness of the sample. The device object of the present invention can thus be fully automatic. During a step 203, the sensor being in the high position, in the piping 124, white bath water is circulated in front of the sensor and after a period of cleaning of the transparency capture means 140, we measure the transparency of the clear water circulating in the transparency capture means 140, for each spectral range used. Preferably, several numerical values are acquired and it is their average (after a possible exclusion of the values too far from the average value) which is considered as the result of the measurement and serves as a complementary reference point ("white bath measurement" ) changes in the transparency of the dye bath. During a step 204, the piston 132 is deployed to position the transparency capture means 140 in the circulation circuit of the dye bath 120. As a variant, in addition to step 203 which then only serves 'When the transparency capture means 140 is cleaned, during a step 205, the sensor is placed in the low position, in the piping 175 and the passage of clear water is triggered in front of the sensor. During a step 210, clear water passes through the analysis chamber 130 and the transparency of the clear water circulating in the transparency capture means 140 is measured. Preferably, several numerical values are acquired and this is their average (after a possible exclusion of values too far from the average value) which is considered as the result of the measurement and serves as a complementary reference point for the evolution of the transparency of the dye bath. This variant is preferably implemented when a chemical compound capable of influencing the transparency of the dye bath is introduced into the dye bath before the introduction of dyes. Following one of the steps 203 or 205, during a step 215, the analysis means stores the result of the measurement corresponding to the transparency of the clear water or white bath. This measurement is called a "white bath" measurement. Then, during a step 220, the movement of the dye bath is triggered with respect to the textile fibers to be dyed (piece or thread) and the introduction, into the dye bath (initially consisting of a white bath) dyes and, optionally, additional chemical compounds intended to activate or supplement the dyeing of the textile product in the dye bath. During step 220, of duration D, the analysis means stores a succession of numerical values representative of transparency leaving the digitizer for each spectral range implemented (for example three spectral ranges of the visible domain, as illustrated in the figures 4A to 4D). When the initial introduction of dyes and chemical compounds is completed, during a step 225, the analysis means determines, for at least one spectral range used: - the reference point (315, FIG. 3) of the curve of the values to come, for each spectral range and - the rate of "first strike" (which one can translate in French by "cold dyeing"), for each spectral range. The reference point 315 for changing the transparency of the bath preferably corresponds to the transparency that the dye bath would have had if no dye absorption had taken place during duration D. The reference point of the curve is, in a determination method suitable for cases where the dye is introduced at constant flow rate, into the dye bath circulation circuit 120, upstream of the transparency capture means 140, as a first approximation, a transparency value (ordered) in one point of the tangent, at the start of the introduction of dye, of the transparency curve as a function of time (see FIG. 3), point which corresponds to the time of the end of the introduction of dyes into the dye bath (abscissa ). In a mode of determining the reference point suitable for cases where the dye is introduced, at constant flow rate, into the dye bath remote from the dye bath circulation circuit 120, a first multiplier coefficient experimentally determined is applied to the slope of the tangent indicated in the previous paragraph to determine the reference point as indicated above. For example, if the slope of the tangent is equal to - 4% of the value of the initial transparency ("white bath") per minute of introduction of dye, this tangent is brought to - 5% if, for the textile product to be dyed and for the initial temperature and pH of the dye bath, it has been determined that 20% of the dye is absorbed by this textile product before the dye bath passes in front of the transparency capture means 140 at the start of the phase. introduction of dye into the dyeing machine. In a method of determining the reference point suitable for cases where the dye is introduced, at a non-constant flow rate, into the dye bath, a second multiplying coefficient inversely proportional to the instantaneous dye flow rate is applied to the slope at each point of the tangent indicated above to determine the reference point as indicated above. For example, if the slope of the tangent is equal to - 4% of the value of the initial transparency ("white bath") per minute of dye introduction with a flow rate of 1 liter per minute, this tangent is reduced to - 2% for each minute of introduction of dye with a flow rate of 0.5 liters per minute. The transparency (abscissa) of the reference point is thus constituted by a succession of linear interpolations. As a variant of these different methods of determining the reference point, at least one non-linear interpolation is applied taking into account the development of the physical phenomena used, during the period D (for example, a coefficient of absorption of dye by the product textile according to the absorption already carried out and / or capacity of the dye to be absorbed by the textile product as a function of its concentration in the dye bath) and of the dye parameters (pH and temperature of the dye bath, for example) to determine the reference point. Whatever the method of determining the reference point 315, the "first strike" rate is then equal to the ratio of: - the difference between the transparency represented by the reference point and the value of the transparency on the curve at the time from the end of the introduction of dye, on the one hand, divided by - the difference between the transparency of clear water ("white bath") and the transparency (ordered) of the reference point. For example, if the transparency at the end of the initial introduction is equal to the value of the transparency of the reference point, the "first strike" rate is zero. Thus, at least one preferably linear interpolation is carried out of the value of the transparency at the start of the dye injection in order to determine a reference transparency value at the end of the dye injection in order to determine the rate of " first strike ". If the "first strike" rate is greater than a predetermined value, for example 40%, the user is provided with an alarm signal, for example by displaying a message on a user interface (not shown), triggering beacon and / or bell, so that the operator can take into account the risk of non-uniform coloring of the textile product and, possibly, stop the dyeing process, empty the dye bath and the textile product to be dyed and start a new dyeing cycle on another part or modify the operating parameters of the dyeing machine 100, for example the insertion time D, for the part being dyed or for the next part, of the same material weight , which will be tinted with the same dye. As a variant, during step 225, the value or the rate of first strike is estimated throughout the duration D and, in the event that this value or this rate is greater, in absolute value, than a value predetermined limit, the flow of dye introduced into the dyeing machine is reduced. The control means 149 are then adapted to control the flow of dye introduced into the dye bath as a function of the change in the transparency of the liquid making up the dye bath. During a step 230, each spectral range for which the variation in transparency is, during step 220, less than a predetermined limit variation rate (for example 30%) is eliminated. As a variant, implemented as an alternative to the above elimination procedure or in the event that it leaves at most one spectral range, a predetermined number of spectral ranges (for example one) is eliminated for which the variations in transparency are, at during step 220, the weakest. It is observed that the spectral ranges of interest are often the spectral ranges complementary to the spectral ranges of transparency of the dyes used. It is also observed that several dyes can react differently with the fibers to be dyed and influence several different spectral ranges. Then, during this step 230, for at least one spectral range not eliminated, a transparency measurement cycle is carried out, for each spectral range considered and the difference between the measured value and a nominal value given by a curve is compared ( time) nominal predetermined calculated according to the value or rate of first strike and the transparency of white bath or clear water, with a predetermined value. If the difference between the nominal value and the measured value is less than the predetermined value, we go to step 240. As a variant, we perform step 230 for each predetermined sample thickness and then choose the one of the measurements that corresponds to the best dynamics while avoiding saturation of the sensor. Otherwise, during a step 235, the following are controlled: - the bath acidity or salinity control means 160, - the bath temperature control means 162, - the arrival control means of clear water 164 and / or - the means for controlling the injection of dye into the bath 166. in order to restore the progress of the dyeing process so that the value of transparency approaches the predetermined nominal curve, according to known automatisms, and we return to step 230. For example, if the rate of exhaustion of the bath, which is represented by the transparency captured by the capture means 140, is less than the nominal value given by the nominal curve, it is possible, in known manner, to initiate heating of the bath or a modification of its hydrogen pH potential, in order to increase or reduce the rate of exhaustion of the dye bath. As a variant, during step 235, at least one computer alarm (signal representative of a dyeing anomaly), visual (for example a flashing light) or audible (for example a buzzer) alarm is triggered in order to alert an operator or a computer system so that one of them can, on the one hand, ensure the traceability of the event and / or, on the other hand, correct operating parameters of the dyeing machine in order to reduce the consequences of this anomalies. During a step 240, the variation, over a predetermined duration (for example one minute), of the transparency is determined. Then, during a step 245, this variation is compared to a predetermined value which is preferably a function of the value of the reference point 315 and of the calibration value with clear water ("white bath") and , if the variation is greater than the predetermined value, we return to step 230. Otherwise, the dyeing process is considered to be completed and the user is supplied with a signal indicating the completion of the dyeing process, for example by text on the user interface. During a step 250, the user initiates the rinsing of the textile product by draining the dye bath and by constantly introducing clear water into the bath. Alternatively, during step 250, the rinsing is automatically triggered. During a step 255, the difference between the measured value and a nominal rinsing value, which preferentially depends on the transparency of the clear water ("white bath"), is compared, for each spectral range not eliminated (see step 230). ") measured during step 215, of the transparency at the start of rinsing and / or of a predetermined nominal rinsing curve. For example, the nominal rinse value is equal to the transparency measured during step 215. If the difference between the nominal value and the measured value is less than a predetermined value (for example 2%), we go to l step 260. During step 260, the variation, over a predetermined duration (for example fifteen seconds), of the transparency is determined. Then, during a step 265, this variation is compared to a predetermined value, which, preferably, depends on the transparency of the clear water ("white bath") measured during the step 215, of the transparency at the start of rinsing and / or of a predetermined nominal rinsing curve and, if the variation is greater than the predetermined value, we return to step 255. Otherwise, the dyeing process is considered to be completed and the user a signal indicating the completion of the process, for example by a text on the user interface. During a step 270, the user triggers the stopping of the rinsing of the textile product. As a variant, during step 270, the rinsing is automatically stopped by stopping the supply of clear water and the movement of the textile piece or the dyed threads and draining the dyeing machine 100. As a variant, it eliminates one of steps 255 or 265 in such a way that rinsing is considered to be completed either when the variation is less than the predetermined value defined for step 265 (step 255 eliminated), or when the difference defined for step 255 is less than the value determined for step 255 (step 265 eliminated). The steps 250 and following described above are adapted to the case of overflow rinsing. As a variant, adapted to the case of rinsing in cycles, following step 245, during a step 275, a first rinsing cycle is triggered by draining the machine from the dye bath and filling it with 'clear water. When it is full, during a step 280, the difference between the measured value and a nominal rinsing value, which depends on the transparency of the water, is compared for each spectral range not eliminated (see step 230). clear ("white bath") measured during step 215, transparency at the start of rinsing and / or a predetermined nominal rinsing curve. For example, the nominal rinse value is equal to the transparency measured during step 215. If, at the end of a predetermined duration, the difference between the nominal value and the measured value is less than a predetermined value, we go to step 285. Otherwise, we repeat step 275.^' During step 285, the variation, over a predetermined duration (for example the duration of a cycle), of the transparency is determined. Then, during a step 290, this variation is compared to a predetermined value, which depends on the transparency of the clear water ("white bath") measured during step 215, of the transparency at the start of rinsing and / or nominal rinse curve predetermined and, if the variation is greater than the predetermined value, step 275 is repeated. Otherwise, the dyeing process is considered to be complete and the user is supplied with a signal indicating the completion of the process, for example by text on the user interface. During a step 295, the user triggers the stopping of the rinsing of the textile product. As a variant, during step 295, the rinsing is automatically stopped by stopping the cycles of arrival of clear water and the movement of the textile part or of the dyed threads and by emptying the dyeing machine. As a variant, one of the steps 280 or 290 is eliminated in such a way that the rinsing is considered to be completed either when the variation is less than the predetermined value defined for step 290 (step 280 eliminated), or when the difference defined for step 280 is less than the value determined for step 280 (step 290 eliminated). As a variant, during the rinsing step and / or during the dyeing step, the thickness of the sample is varied, the transparency of which is measured, as a function of the evolution of the transparency of the bath. rinse or dye bath and, preferably, a correction coefficient is applied to the measurements made. This maintains a high transparency measurement accuracy. It is observed that, in the case where a display is provided, the curve for the evolution of the dye concentration which is obtained by applying the Bert-Lambert law is preferably displayed. FIG. 3 represents a transparency curve as a function of time and of the measurements carried out or calculated with the device illustrated in FIG. 1 implementing the flow diagram illustrated in FIG. 2: - the curve 300 represents the measured value of the transparency; - the tangent 310 represents the line for determining the reference point 315; - the dye introduction phase, of duration D, is shown in 320; - the end of dye determination phase is shown at 330 - the end of rinse determination phase is shown at 340 and - the complementary reference point for clear water transparency ("white bath") 345. It is observed that the abscissa of the reference point 315 serves as the zero value of the abscissas and that the predetermined values of variation or of absolute value of transparency are preferably determined as a function, on the one hand, of the transparency of the clear water ("white bath ") and, on the other hand, the transparency of the reference point. For example, the rate of exhaustion expected at the end of the dyeing phase (used during step 230) corresponds to a transparency equal to the transparency of clear water ("white bath") minus 30% of the difference the transparency of the clear water and the transparency (abscissa) of the reference point 315. For example, the variation, over a period of five minutes, of the transparency expected at the end of the dyeing phase (used during the step 240) corresponds to 2% of the difference in transparency of clear water ("white bath") and transparency (abscissa) of the reference point 315. For example, the transparency expected at the end of the rinsing phase (used during step 280) corresponds to a transparency equal to the transparency of clear water ("white bath") minus 2% of the difference between the transparency of clear water ("white bath") and the transparency (abscissa) of the reference point 315. By example, the variation, over a period of five minutes or over a rinsing cycle, of the transparency of the dye bath expected at the end of the rinsing phase (used during step 290) corresponds to 1% of the difference of the transparency of the clear water ("white bath") and the transparency (abscissa) of the reference point 315. It is observed that, in the example given in FIG. 3, the determination of the end of dyeing and that of the end of rinsing, are each carried out by detection that the variation of the transparency, over a given period e is less than a predetermined value. It is observed that the process and the device which are the subject of the present invention can, as a variant, analyze the changes in the concentration of dye in the dye bath, rather than the change in the transparency of the dye bath. In this case, the determination of the dye concentration as a function of the transparency preferably uses the Bert-Lambert law, according to known techniques. The curve represented in FIG. 3 is a curve which corresponds to an overflow rinse rather than a curve corresponding to a rinse by cycles, in which case, the variation of the transparency during the rinsing would have inflection points defining a curve. having "stair treads", that is to say alternately rapid (during a cycle change) and slow (during the duration of a cycle) variations in transparency. In FIGS. 4A to 4G, only sensors have been described using three spectral ranges. In other embodiments, a greater number of spectral ranges is implemented. In FIG. 4A, the positioning of the sensor in the circuit 120 is observed when the piston 132 is deployed and the thickness of the sample, defined by the motor 136 is an average value (for example 0.9 mm.). In FIG. 4B, the positioning of the sensor is observed outside of the circuit 120 when the piston 132 is retracted and that the clear water circulates in the piping 175. It is observed that, preferably, this circulation of clear water is carried out in the direction reverse of the direction of circulation of the dye bath, with respect to the transparency capture means 140, for detaching the textile fibers which could have caught on by the transparency capture means 140. FIG. 4C shows the positioning of the sensor in circuit 120 when the piston

132 is deployed and that the thickness of the sample, defined by the motor 136, is a minimum value (for example 0.1 mm.). In FIG. 4D, the positioning of the sensor in the circuit 120 is observed when the piston 132 is deployed and the thickness of the sample, defined by the motor 136, is a maximum value (for example 7.2 mm.) . It is observed that the thicknesses preferentially define a substantially geometric series, that is to say that the ratio of two successive thicknesses is substantially constant (here 9, then 8). We observe, in FIG. 4E, the light source 142, vis-à-vis with three bundles of optical fibers 144A, 144B and 144C placed at different distances from the light source, for example 0.2 mm., 1 , 2 mm. and 7 mm and separated optically by opaque partitions (not shown). The other end of each bundle of optical fibers faces: - a photo-transistor 405 which captures the blue wavelengths, for example - a photo-transistor 410 which captures the red wavelengths, for example and - a photo-transistor 415 which captures the green wavelengths, for example. Preferably, the transistors 405 (respectively 410 and 415) are placed in parallel behind the same interference filter, opposite the optical fiber bundle which corresponds to them and optically separated from the other bundles of optical fibers in order to avoid a cross influence. The photo-transistor supply circuits are controlled by multiplexers (not shown) as a function of the intensity of the signals received by these photo-transistors. The outputs of the photo-transistors are connected to the digitizer by multiplexers 425 (connections not shown). The choice of channels A, B or C is made to optimize the dynamics of the signals received. Optionally, this choice depends on the identification of the dye (s) to be used and an amount of dye to be injected into the dye bath supplied during step 200. As a variant, all of the bundles of optical fibers corresponding to the same thickness lead to the same image sensor, for example a sensor with charge transfer device (DTC or in English charge coupled device or CCD) or C-MOS provided with colored filters. In FIG. 4F, a bundle of optical fibers 450 is observed, placed in the piping 124, opposite a prism 452 forming two successive mirrors placed at 45 ° to the axis of the bundle of optical fibers 450 for lighting and the axis of a beam of the axis of a bundle of optical fibers 458 the output of which faces: - a photo-transistor which captures the blue wavelengths 460, - a photo-transistor which captures the lengths red wave 461 and - a photo-transistor which captures the green wavelengths 462. The light rays coming from the optical fiber bundle 450 are directed, through the prism 452, towards the entry of the optical fiber bundle 458. The outputs of the photo-transistors are connected to the digitizer by a multiplexer 465. In FIGS. 4E and 4F, the capture of transparency has been represented in three spectral ranges and by three photo-transistors for each thickness of sample. However, the invention is independent of the number of spectral ranges used, in the visible range or not. For example, one can use four spectral ranges of the visible domain, defined by four interference filters. We observe, in FIG. 4G, in the analysis chamber 130, an image sensor 500, for example a C-MOS image sensor (which has a very large dynamic, compared to the charge transfer device), next to the light source 510, for example an exit from a bundle of optical fibers or a light-emitting diode so that the light source is located, depending on the point (or pixel) of the surface of the image sensor , at different distances and / or at different solid angles in proportions ranging from at least one to ten. For example, the light source is positioned at 0.2 mm. of a corner of the image sensor so that the opposite corner is positioned several millimeters from this light source. An image processing is then carried out to select the signals coming from the points of the image sensor which exploit the dynamics of the image sensor and which are not influenced by image points undergoing too high illumination, to determine the transparency of the dye bath. It can be seen that an image sensor comprising colored filters or a light source capable of successively emitting light rays can be used in different spectral ranges, as explained, with reference to FIG. 6B. In the case of a C-MOS sensor or any other type of sensor in which electrical charges accumulate at points of the image sensor as a function of the illumination of these points, and in which these charges are extracted by point-to-point addressing, preferably, the charges of the points of the image sensor closest to the light source are more often emptied than the charges of the points of the image sensor furthest from the light source. The frequency of discharge of the charges is, for example, at each point of the image sensor, proportional to the illumination of this points. In this way, the most illuminated points are not liable to be damaged by excess electrical charges and these do not risk disturbing the transparency measurement. Optionally, measurements corresponding to points of the image sensor are added which exploit the same part of the dynamic range of the sensor to improve the signal / noise ratio of the measurement. As can be seen with regard to FIGS. 4A to 4G, the control means 149 comprise means for controlling 136 the sensitivity of the sensor 140, as a function of the opacity of the liquid making up the dye bath. In the case shown in the figures: - the control means 149 comprise means for controlling 136 the optical path traveled by a light ray generated by the sensor in the liquid comprising the dye bath, as a function of the opacity of the component liquid the dye bath; a means for adjusting (here the displacement means 136) the thickness of the dye bath water sample, the transparency of which is picked up by the transparency sensor, is controlled by the control means 149 in such a way that the sample thickness is an increasing function of the transparency of the bath; - The thickness adjustment means is adapted to move, relative to each other, a light source and at least one optical fiber; As a variant, illustrated in FIG. 4G, the control means 149 comprise: - means for controlling the capture time of the sensor as a function of the opacity of the liquid making up the dye bath and / or - means for controlling a means for amplifying the signal / noise ratio of the signal leaving the sensor, as a function of the opacity of the liquid making up the dye bath. As a variant of the embodiments set out above, at least two light sources are used which are adapted to emit different quantities of light opposite the sensor and a switching means controls the ignition of only one of said light sources. both, depending on the expected transparency or measurement of the dyeing or rinsing bath. FIG. 5 shows a device 500 implementing at least one aspect of the present invention, associated with a dyeing machine 505, filled with a bath 510, and which comprises: - a circuit for circulating the dye bath 520, comprising a pump 522, a pipe 524 taking bath water into the bath 510 and re-injecting it into the bath 510, a clear water circuit 536 parallel to the dye bath circulation circuit 520; an analysis chamber 530 movable in a piston 532 moved by a motor 534 in a cylinder 533, and comprising a transparency capture means 540 comprising a light source 542 (see FIGS. 6A and 6B) and at least one optical fiber 544, the output of which is opposite a sensor 546 connected to a digitizer 548, - control means 549 comprising:. a signal analysis means 550 receiving the digitized signals from the digitizer 548 and providing an analysis result,. a means for controlling the acidity and / or salinity of the bath 560,. a bath temperature control means 562,. a means for controlling the supply of clear water 564,. a means for controlling the injection of dye into the bath 566,. a multiplexer 568 adapted to control the emission, by the light source 542, of light rays in successively different emission spectra and to transmit a demultiplexing signal by means of signal analysis 550 and. a control means 570 for the motor 534 of the piston 532. The dyeing machine 505 and the composition of the dye bath 510 are of the type known in the textile industry. The circulation circuit of the dye bath 520 already exists in many dyeing machines. The pump 522 and the piping 524 are of known type and are made of materials which do not risk polluting the dye bath or distorting its analysis. The pump 522 preferably has a constant flow rate, possibly adjustable. The mobile analysis chamber 530 is moved by the motor 534 in at least three positions. In a first position, the highest, the mobile analysis chamber 530 is in fluid communication with the dye bath circulation circuit 520 and receives a dye bath sample. In a second, middle position, the mobile analysis chamber 530 is in fluid communication neither with the dye bath circulation circuit 520, nor with the clear water circuit 536 so that the sample can rest , that the bubbles it contains can escape outside the optical field of the sensor 546 and that the transparency capture is performed, in each spectral optical band of interest. In a third position, the lowest, the mobile analysis chamber 530 is in fluid communication with the clear water circuit 536 and is purged of the sample. Thanks to this piston mechanism, it is no longer necessary to provide specific piping for the dyeing machine control device and the complexity and the manufacturing, installation and maintenance costs of this device are greatly reduced. In the analysis chamber 530, the spacing between the entry of the optical fiber bundle 544 and the light source is preferably constant, in the range of values from 0.2 mm. at 7 mm. Under the control of the multiplexer 568, the light source 542 is adapted to successively emit light rays in different spectral bands. The light source 542 comprises, for example a plurality of light-emitting diodes the sum of the emission light spectra of which preferably covers at least the visible spectrum (see FIG. 6A). As a variant, the light source 542 comprises a light-emitting diode whose emission light spectrum varies as a function of an electrical characteristic which is applied to it (see FIG. 6B). For example, the voltage applied to the light source 542 varies its emission light spectrum. As a variant, the light source 542 is an incandescent bulb or a halogen lamp to which a variable voltage is applied so that the emission spectrum varies during an analysis cycle. The digitizer 548, of known type, digitizes the signal leaving the sensor 546. The signal analysis means 550, which receives the digitized signals from the digitizer

548 implements the logic diagram illustrated in FIG. 7 to calibrate the transparency capture means and then to provide, from the demultiplexing signal transmitted by the multiplexer 568 and signals from the digitizer 548, an analysis result in the form of at least one transparency value and a comparison of this value with predefined threshold values as a function of the composition of the dye bath. The signal analysis means 550 is, for example, made up of a computer programmed to implement the steps illustrated in FIG. 7. It includes a user interface (not shown) comprising a display screen, a keyboard and, optionally , a pointing device, for example a mouse. The bath acidity and / or salinity servo means 560, the bath temperature servo means 562, the clear water inlet servo means 564 and the injection servo means dye in the bath 566 respectively control, according to the results supplied by the signal analysis means, the operation of at least one valve for injecting chemical compounds into the bath, the operation of a heat source, for example consisting of a heat exchanger or a steam inlet, a clear water inlet valve, a valve for injecting dye into the bath. It is observed that the term "valve" does not prejudge the state, liquid, solid or gaseous, of the dye (s) and / or of the other chemical compounds, for example alkalis which can be injected into the dye bath. It is observed that the control of these different actuators, carried out in the description, under the control of the signal analysis means 550 can be carried out by a programmer external to the device, a programmer generally already present on dyeing machines. This other programmer is then programmed to control the actuators as a function of signals from the signal analysis means 550 .. We observe, in FIG. 6A, the analysis chamber 530 movable in the piston 532 mu by the motor 534. In FIG. 6A, the light source 542A comprises seven light-emitting diodes 605, placed in staggered rows, a central diode being in contact with six diodes forming a ring equidistant from the central diode. The sum of the emission light spectra of the light-emitting diodes 605 covers the visible light spectrum. For example, each diode 605 has a spectrum width of about 50 nanometers. All the diodes 605 cover substantially the same solid angle surrounding the entry of the optical fiber 544, the axes of the light-emitting diodes all being oriented towards the center of the entry surface of the optical fiber 544. We observe, in FIG. 6B, the analysis chamber 530 movable in the piston 532 moved by the motor 534. In FIG. 6B, the light source 542B comprises a single light-emitting diode 655, placed opposite the input of the optical fiber 544, to which is applied a sawtooth voltage signal synchronized by the multiplexer 568. The sum of the successive emission light spectra of the light-emitting diode 655 covers the visible light spectrum. FIG. 7 shows a succession of steps carried out by the embodiment of the device illustrated in FIGS. 5, 6A and 6B. During an industrial process selection step 700, a user selects a dyeing process by providing an identification of the weight of material to be dyed and an identification of the dye (s) to be used and an amount of dye to be injected into the dye bath. . As a variant, these data are not implemented, as explained with reference to FIG. 2. During a step 702, the displacement and the positioning of the piston 532 are controlled to position the transparency capture means 540 in the dye bath circulation circuit 520. During a step 704, the introduction of clear water is triggered in the dye tank. As a variant, steps 702 and 704 are replaced by step 706 during which the movement and positioning of the piston 532 are controlled to position the transparency capture means 540 in the clear water circuit 536 and step 718. indicated below. During a step 710, clear water (or the "white bath") passes through the analysis chamber

530 and, during seven successive steps 711 to 717, the multiplexer 568 successively controls the emission of light by the light source 542 in seven different spectral ranges or emission spectra preferably covering the entire visible spectrum. For each emission spectrum, in a predetermined time interval following the start of its emission, the analysis means stores the digital value leaving the digitizer during the passage of clear water. The start and duration of this time interval can vary depending on the emission spectrum for example to compensate for the differences in light power emitted and sensitivity of the sensor for the different spectral ranges. Preferably, several digital values are acquired and it is their average (after a possible exclusion of values too far from the average value) which is memorized for each light spectrum. During a variant step 718, the displacement and positioning of the piston 532 is controlled to position the transparency capture means 540 in the circulation circuit of the dye bath 520. Then, during a step 720, the introduction into the dye bath is initiated of dyes and, optionally, chemical compounds intended to activate or complete the dyeing of the textile product in the dye bath and heating of the dye bath is initiated. During step 720, of duration D, several sampling cycles are carried out, in the high position of the piston, resting of the sample, in the middle position, measurement of transparency for different emission spectra of the light source, in the middle position of the piston and purge of the transparency capture means, in the low position of the piston. For each cycle, the analysis means stores the digital value leaving the digitizer, for each light spectrum of emission from the light source, controlled by the multiplexer 568, respecting the same predetermined time intervals as those used in the during steps 711 to 717, each time interval, which corresponds to an emission spectrum being defined: - by the duration which separates the start, from this time interval, on the one hand, of the spectrum change command transmission transmitted by the multiplexer 568, on the other hand and - by the duration of the time interval. When the initial introduction of dyes and chemical compounds is completed, in the course of a step 725, the means of analysis determines: - the reference point of the curve of the values to come and - the rate of "first strike" ( which can be translated into French as "cold dyeing"). The reference point of the curve is the point of the tangent to the transparency curve as a function of time (see Figure 3) at the time of the end of the initial introduction of dyes and chemical compounds. The "first strike" rate is equal to the ratio of the difference between the transparency represented by the reference point and the value of the transparency on the curve at the time of the end of the initial introduction, on the one hand, on the difference between the transparency of clear water ("white bath") and the transparency represented by the reference point. Thus, if the transparency at the end of the initial introduction is equal to the value of the transparency represented by the reference point, the "first strike" rate is zero. Thus, a linear interpolation of the value of the transparency at the start of the dye injection is carried out to determine a reference transparency value at the end of the dye injection in order to determine the "first strike" rate. If the "first strike" rate is greater than a predetermined value, for example 40%, the user is provided with an alarm signal, for example by displaying a message on the user interface so that the user can take into account the risk of non-uniformity of coloring and, possibly stop the dyeing process, empty the dye bath and the textile product to be dyed and start a new dyeing cycle on another piece. According to the variants, a mathematical combination of the results is carried out to determine an overall result or the highest value is taken. During a step 730, a transparency measurement cycle is carried out, for each light spectrum emitted, respecting the different positions of the piston and the different measurement time intervals and the difference between the measured value and a value is compared. nominal value given by a predetermined nominal curve with a predetermined value. If the difference between the nominal value and the measured value is less than the predetermined value, we go to step 740. Otherwise, during a step 735, we control: - the acidity control means and / or bath salinity 560, - the means for controlling the bath temperature 562, - the means for controlling the arrival of clear water 564, - the means for controlling the injection of dye into the bath 566, and / or - the means for controlling the injection of chemical compounds into the bath 568 in order to restore the progress of the dyeing process, according to known automatisms and we return to step 730. As a variant, we do not nominal curve work but the regulation is carried out as a function of the transparencies measured when the derivative of the transparencies tends towards zero. We then use a nominal program. During a step 740, the variation, over a predetermined duration (for example fifteen seconds), of the transparency is determined. Then, during a step 745, this variation is compared to a predetermined value which can be a function of the value of the reference point and of the calibration value with clear water ("white bath") and, if the variation is greater than the predetermined value, we return to step 730. Otherwise, the dyeing process is considered to be completed and the user is provided with a signal indicating the completion of the process, for example by a text on the user interface. During a step 750, the user initiates the rinsing of the textile product by draining the dye bath and by introducing clear water into the bath. Alternatively, during step 750, the rinsing is automatically triggered. In a step 755, a transparency measurement cycle is carried out for the different emission spectra and compares the difference between the measured value and a nominal rinsing value, which depends on the transparency of the clear water (" white bath ") measured during steps 711 to 717, of the transparency at the start of rinsing and / or of a predetermined nominal rinsing curve. For example, the nominal rinse value is equal to the transparency measured during steps 711 to 717. If the difference between the nominal value and the measured value is less than a predetermined value, we go to step 760. During from step 760, the variation, over a predetermined duration (for example fifteen seconds), of the transparency is determined. Then, during a step 765, this variation is compared to a predetermined value, which depends on the transparency of the clear water ("white bath") measured during the steps 711 to 717, of the transparency at the start of rinse and / or a predetermined nominal rinse curve and, if the variation is greater than the predetermined value, we return to step 755. Otherwise, the dyeing process is considered to be complete and the user is provided with a signal indicating the completion of the process, for example by a text on the user interface. During a step 770, the user triggers the stopping of the rinsing of the textile product. Alternatively, during step 770, the rinsing is automatically stopped. Steps 750 to 770 described above are adapted to the case of overflow rinsing. As a variant, adapted to the case of rinsing in cycles, following step 745, during a step 775, a first rinsing cycle is triggered by draining the machine from the dye bath and filling it with 'clear water. When it is full, during a step 780, a measurement cycle is carried out for each spectral range considered and the difference between the measured value and a nominal value is compared for each spectral range not eliminated (see step 230). rinse, which depends on the transparency of the clear water ("white bath") measured during step 715, the transparency at the start of the rinse and / or a predetermined nominal rinse curve. For example, the nominal rinse value is equal to the transparency measured during step 715. If, at the end of a predetermined duration, the difference between the nominal value and the measured value is less than a predetermined value, we go to step 785. Otherwise, we repeat step 775. During step 785, the variation, over a predetermined duration (for example the duration of a cycle), of the transparency is determined. Then, during a step 790, this variation is compared to a predetermined value, which depends on the transparency of the clear water ("bath white ") measured during step 715, of the transparency at the start of rinsing and / or of a nominal predetermined rinsing curve and, if the variation is greater than the predetermined value, step 775 is repeated. Otherwise , the dyeing process is considered complete and the user is provided with a signal indicating the completion of the process, for example by a text on the user interface. During a step 795, the user initiates the stopping the rinsing of the textile product. As a variant, in step 795, the rinsing is automatically stopped by stopping the cycles of arrival of clear water and the movement of the textile part or of the dyed threads and by emptying the machine As a variant, one of the steps 780 or 790 is eliminated in such a way that the rinsing is considered to be completed either when the variation is less than the predetermined value defined for step 790 (step 780 eliminated), or when the difference defined for step 780 is less than the value determined for step 780 (step 790 eliminated). During steps 711 to 717 and 730, the piston is in an intermediate position or the sample is at rest. Thus, the piston is adapted to take at least three positions in which, respectively: - a water passage is open opposite the pressurized clear water circuit, - the water passage is opposite the circulation circuit of the liquid composing the dye bath and - the water passage is closed and facing the sensor. Thus, in the embodiment illustrated in FIGS. 5 to 7, the measurement of the transparency of the dye bath is no longer disturbed by the presence of bubbles or foam in the dye bath, thanks to the use of means for separating said sample from the dye bath and for resting said sample, the sample transparency sensor being adapted to supply a signal representative of the transparency of said sample for at least one spectral range, when this sample is separated of the dye bath. Indeed, once the sample is separated from the dye bath and put to rest, any bubbles present in the sample gradually separate from the liquid and the sensor can measure the real transparency of the liquid. Preferably, the device comprises an anti-foam filter positioned between the position of the sample at the time of sampling and the position of the sample removed from the dye bath. As we have seen, the dye bath monitoring device exposed with reference to FIGS. 5 to 7 comprises: - a chamber for measuring the transparency of liquid coming from the dye bath comprising a light source adapted to emit successively light in a plurality of different spectral bands, - a single optoelectronic sensor adapted to receive the light rays coming from the light source after their passage through the measurement chamber and to emit a signal representative of the quantity of light received by said sensor and - a demodulator synchronized with the light source to successively process the signals from the sensor to provide results corresponding to the different spectral bands successively emitted by the light source. Thanks to these provisions, a single sensor is necessary to process the different spectral bands used for the measurement of bath transparency and for monitoring the exhaustion of the dye bath or the course of rinsing. Any combination of the various embodiments of the present invention set out above constitutes a variant of each of these embodiments. For example, an optical fiber can be replaced by a bundle of optical fibers, the displacement means exposed in FIGS. 1 to 4 can be eliminated or, on the contrary, added in the embodiment exposed in FIGS. 5 and 7.

Claims

1 - Dyeing machine control device (100) into which a dye dye is introduced for a period D, characterized in that it comprises: - a transparency sensor (140) of the liquid contained in said bath suitable for supplying a signal representative of the transparency of said bath for at least one spectral range; - control means (148) adapted to determine a reference point (315) for the evolution of the transparency of the bath corresponding to the transparency that the dye bath would have had if no dye absorption had taken place during the period D. 2 - Device according to claim 1, characterized in that the control means (148) are adapted to determine the end of a duration of rinsing of said bath according to the evolution of the transparency of the bath.

3 - Device according to any one of claims 1 or 2, characterized in that it is adapted to be coupled to a dyeing machine comprising a circulation circuit (120) of the liquid composing the dye bath and in that the the device further comprises means for positioning (133, 134) the transparency sensor (140) in said circuit for circulation of the liquid composing the dye bath.

4 - Device according to any one of claims 1 to 3, characterized in that the control means (148) are adapted to determine said reference point (315) by interpolation of the change in transparency at the start of the introduction, interpolation carried out over the duration D of the introduction of dye into the dye bath.

5 - Device according to any one of claims 1 to 4, characterized in that the control means (148) are adapted to determine a complementary reference point of evolution of transparency of clear water by storing a value representative of the signal emitted by the transparency sensor (140) during a passage of clear water in front of the sensor.

6 - Device according to any one of claims 1 to 5, characterized in that the control means (148) are adapted to control the stopping of dyeing according to the evolution of the transparency of the bath and at least a benchmark for transparency evolution.

7 - Device according to any one of claims 1 to 6, characterized in that the control means (148) are adapted to determine the dye stop when the derivative of the value of transparency is less than a predetermined value.

8 - Device according to any one of claims 1 to 7, characterized in that the control means (148) comprise means for controlling (136) the sensitivity of the sensor (140) as a function of the opacity of the liquid composing the dye bath. 9 - Device according to any one of claims 1 to 8, characterized in that the control means (148) comprise means for controlling (136) the optical path traveled by a light ray generated by the sensor in the component liquid the dye bath depending on the opacity of the liquid making up the dye bath. 10 - Device according to any one of claims 8 or 9, characterized in that it further comprises, an adjustment means (136) of thickness of the dye bath water sample whose transparency is sensed by the transparency sensor (140) and the control means (148) are adapted to control the thickness adjustment means in such a way that the thickness of the sample is an increasing function of the transparency of the bath.

11 - Device according to claim 10, characterized in that the thickness adjustment means is adapted to move, relative to each other, a light source and at least one optical fiber.

12 - Device according to any one of claims 1 to 11, characterized in that the control means (148) comprise means for controlling the capture time of the sensor as a function of the opacity of the liquid making up the bath. dyeing.

13 - Device according to any one of claims 1 to 12, characterized in that the control means (148) comprise means for controlling a means of amplification of the signal / noise ratio of the signal leaving the sensor, in depending on the opacity of the liquid composing the dye bath.

14 - Device according to any one of claims 1 to 13, characterized in that the control means (148) are adapted to implement the Bert-Lambert law to determine the concentration of dye according to the transparency of the bath of dye.

15 - Device according to any one of claims 1 to 14, characterized in that the control means (148) are adapted to control the acidity and / or the salinity of the dye bath depending on the evolution of the transparency of the liquid composing the dye bath.

16 - Device according to any one of claims 1 to 15, characterized in that the control means (148) are adapted to control the bath temperature depending on the revolution of the transparency of the liquid making up the dye bath. 17 - Device according to any one of claims 1 to 16, characterized in that the control means (148) are adapted to control the flow of dye introduced into the dye bath depending on the evolution of the transparency of the liquid composing the dye bath.

18 - Method for controlling a dyeing machine (100) into which a dyeing dye is introduced for a period D, characterized in that it comprises: - a step of capturing transparency (220) of the liquid contained in said bath during which a signal representative of the transparency of said bath is supplied for at least one spectral range; a step of determining (225) a reference point for the evolution of the transparency of the bath corresponding to the transparency that the dye bath would have had if no dye absorption had taken place during the period D.