FR2624143A1 - METHOD AND DEVICE FOR REGULATING A COLOR IMPREGNATION BATH FOR PROCESSING A MATERIAL IN CONTINUOUS SCROLL - Google Patents

Abstract

The invention consists in measuring, by photocolorimetry, at determined time intervals, the concentration of bath 2 for each colored constituent contained in the bath, in comparing the values obtained with the reference values corresponding to the initial bath, and in adding a quantity predetermined correction solution when the difference observed for a given component reaches a certain threshold. The correction solution is a concentrated solution if the difference is negative, that is to say in the event of depletion of the bath, and a diluted solution if the difference is positive, that is to say in the event of enrichment of the bath.

Description

METHOD AND DEVICE FOR REGULATING A COLOR IMPREGNATION BATH

  FOR PROCESSING A MATERIAL IN CONTINUOUS SCROLL

  The invention relates to the treatment of a material, in particular textile,

  in continuous scrolling by passing through a colored impregnation bath.

  It relates more particularly to the dyeing of textile fabrics

  off by padding a dye bath and then fixing the colo-

  rants. Materials processing in continuous scrolling, per pass

  said materials in an impregnation bath, are commonly used

  in any kind of industry. Some of these treatments are intended to give the materials some uniform and uniform coloring

  over their entire length. It has been found, particularly in the

  ture off a piece of a textile material, a heterogeneity of the coloring of the material between the beginning and the rest of the piece, and

  this while the colored bath of impregnation is identical and renews

  velvet for the entire duration of the dyeing. This heterogeneity, which can not be easily corrected, eliminates, in certain dyes, the beginning of the pieces thus dyed, which can go as far as

  several hundred meters of fabric.

  This phenomenon can be explained by a difference in

  of certain colored constituents, used in the bath

  impregnation for the material. So at the beginning of the impregna-

  In this way, one of the constituents would rise in greater quantity on the material than on the other constituents, the material would then have a more marked coloration in this constituent while, in the opposite direction, the concentration of the impregnating bath in this constituent.

  decrease; renewed bathing and reduced

  centering of the bath in this constituent would lead, after a certain

  time, to a balance, or at least to differences that result in

  less than the perception of the eye.

  Now we have found and this is the subject of the invention, a

  method of regulating a colored impregnation bath for treating

  ment of a material in continuous scrolling which overcomes the disadvantage noted. According to the invention, the method consists in automatically following the following steps:

  at. the concentration of the bath or a value proportional to the concentration

  bath, for each colored constituent, is measured by

  tocolorimetry at specified time intervals,

  b. the values obtained are compared with the reference values cor-

  responding to the initial bath before impregnation of the material, c. when the difference found for a given colored constituent reaches

  a certain threshold, a predetermined quantity of a solution of cor-

  rection is added to the impregnation bath.

  When the difference observed is negative, that is to say when the concentration of the bath at a given moment is less than that of the initial bath, the correction solution consists in a solution

concentrated color component.

  When the difference found is positive, that is to say when the concentration of the bath at a given instant is greater than that of the

  bath, the solution consists of a diluted solution of the

  colorant or even a solution free of colored component.

  So when the impregnating bath undergoes a variation for

  one of its colored constituents, because of a difference in

  the material's activity passing through the bath, for said constituent, the concentration of the bath in this constituent is immediately corrected by adding to the bath of the correction solution. The correction in question depends on the one hand the threshold corresponding to the value

  minimum of the measured difference and of the predetermined quantity

  born of the correction solution. Each of these parameters is deter-

  that the correction be made so that it is not

  visually no discolouration on the material.

  As we have understood from reading what has just been said, the objective of the process is to make as constant as possible,

  and from the beginning of the impregnation, the concentration of the bath in each

one of the colored constituents.

  Preferably, the measurement of the concentration of the bath or a

  proportional to the concentration of the bath is effected by

  electrical signal version of a luminous flux passing through a circulating bath volume. The electrical signal is obtained in particular by at least one photodetector placed at the output of a filter illuminated by

  the luminous flux passing through the volume of the circulating bath. We have

  completed that the measurement of the bath or a value proportional to the

  concentration of the bath was carried out under good conditions,

  producible, when it was based on the measurement of four electrical signals from photodetectors placed at the output of four

  filters, whose transmission spectra have maximum peaks

  which cover, together, the range of wavelengths

be 400 and 700 nanometers.

  The process of the invention is particularly applicable when the colored bath is a dyeing bath of a textile material, comprising a plurality of dyes, at least one of which has a higher substantivity for said material, at a lower temperature, more great that

lps others.

  It can be advantageous, especially so that the eorrpctinn

  faster, to measure the corresponding color bath.

  excess bath, intended for recycling, after impregnation with

  material. This excess bath is, for example, the bath recovered

  immediately after passing the fabric between the cylinders of

  mage and before return of said bath in the impregnating bachole. This excess bath is that which, having been carried away by the tissue, is extracted from it; so the bath is the most impoverished

  in the colored constituent (s) with the most substantivi-

tee for the fabric.

  It is another object of the invention to protect a device specially designed for the implementation of the aforementioned method. According to the invention, the device comprises: a. a photocolorimetric sensor comprising a measuring chamber in which the colored bath circulates, an optical block consisting of at least one white light source placed on one side of the chamber and processing means capable of measuring, from the luminous flux transmitted by the color bath, the concentration or a value proportional to the concentration of the bath in each of the colored constituents, b. means for comparing the measured value at determined time intervals for a given constituent with respect to the reference value corresponding to the initial bath, c. injection means, actuated when the comparison made

  by the means of comparison shows up for a constituent

  re a difference equal to or greater than a certain threshold, and controlling the in-

  jection in the colored bath of a predetermined quantity of a solution

correction.

  According to a preferred embodiment of the device of the invention, the optical block

  that includes a set of four filters, whose transmission spectra

  mission have maximum peaks that cover, together, the range

  wavelengths between 400 and 700 nanometers.

  The invention will be better understood on reading the description

  which will now be made of an embodiment of the preferred version of the regulating device, illustrated by the appended drawing

  in which the single figure is a schematic view of said device.

  The fabric I, from a diet not shown, plunges

  in the dye bath 2, contained in the bacholle 3; he is suppor-

  three rolls of detour, the first four at the entrance, the second

  x 5 at the bottom of the bacholle 3 and the third 6 at the exit. The fabric

  1, impregnated with the dye bath 2, then passes between the two cy-

  lnders 7.8 squeezers, between which is exerted pressure by

  any known means. The coating of the cylinders 7,8 and the pressure exerted

  are defined so that the fabric 1, after squeezing, comprises a predetermined quantity of the dye bath 2, this quantity being

  uniform in time and homogeneous throughout the width of the fabric 1.

  After this impregnation, the fabric is directed into a heat treatment chamber and / or steaming where the dyes are fixed

  on the constituent material of the fabric.

  The most downstream part of the bacholle 3, in the sense of

  placement of the fabric 1 shown in the figure by the arrow D, is

  terminated by a gutter-shaped elbow 9 extending

  of the lower cylinder 8. This channel 9 is intended to collect

  read the excess bath, after squeezing, carried away by the tissue 1.

  Just at the inlet of the squeeze cylinders, at the lower cylinder 8 and under the plane of the fabric 1, is placed, transversely, a ramp 10 whose bottom is slightly inclined to the duct II connecting said ramp 10 and the bunch 3. Thus the excess weight of the fabric 1 during the expression is collected at least partly in the ramp 10, flows naturally in the conduit II and returns to

the bacholle 3.

  The conduit It passes in a chamber 12 of measurement. This chamber 12 is connected by a double play 13,14 of optical fibers to a block

  15, comprising two parts 16 and 17. In the first part

  tie 16, a source 18 of white light and its associated optics 19

  illuminate the entrance 20 of the first set of fibers 13. In the second part

  17, the output 21 of the second set of fibers 14 is directed to four

  filters, each being associated with photodiodes and converters.

  transform the light flux transmitted through the filter cor-

  responding in an electrical signal.

  The four filters are chosen so that their transmission spectra have maximum peaks that cover, together, the

  range of wavelengths between 400 and 700 nanometers.

  The measurement chamber 12 comprises the duct 11 which passes therethrough, the outlet 22 of the first set of fibers 13 and the inlet 23 of the second set of fibers 14. The outlet 22 and the inlet 23 are positioned facing each other.

  from each other and enter the conduit] 1.

  The converters are connected to a processing unit 24

  electrical signals, the operation of which will be explained later.

  secondly, which controls the implementation of one and / or the other of the three injection nozzles 25,26,27, each of the nozzles is directed towards the inside of the bacholle 3 and is fed using of a concentrated colored solution corresponding to one of the dyes

the composition of the dye.

  In practice, it may be advantageous to provide five nozzles

  corresponding, for a three-color dyeing, to the three solutions

  for the three basic dyes, to a concentrated solution of

  shading dye and a color-free dilution solution

  rant. The implementation of the method of the invention and the operation of the device will be described in the following example of dyeing

  of a piece of cotton fabric using a bath of impregnation 2 com-

  bearing three direct dyes whose yellow diazol light 2JS. This dye has a very important substantivity for the cotton at low temperature, which is translated, when the fabric is immersed in such an impregnation bath, by a rise of yellow diazol light 2JS on the fabric more important than the concentration of this dye in

the bath.

  The piece of fabric I is engaged in the bacholle 3 and immersed in the bath 2, passes between the squeeze cylinders 7 and 8, where it is expressed so as to carry about 40% of its weight in the dyebath. Excess bath carried by the fabric and resulting from the expression by the cylinders 7 and 8 is collected in the ramp 10 and flows into the conduit] 1.

  The light source 18 associated with its optics 19 sends on the

  trea 20 of the first set of optical fibers 13 a luminous flux which is

  directed into the measuring chamber 12. In the chamber 12, this flow, pro-

  from the exit 22 of the fiber set 13 passes through the dye bath.

  ture circulating in the duct II; the incident luminous flux undergoes an absorption which is a function of the dye concentration of the bath, for a given wavelength of light. The flow after passing through the bath, is taken up by the second set of fibers, is

  separated into four separate lanes where it passes through each of the four

  very. The passage on the filters is intended to reveal the specific luminous flux of each dye contained in the bath.

  depending on its wavelength. Photodetectors, converts

  and the treatment unit 24 convert the light intensities

  standard current bending machines (from 4 to 20 mA).

  Beforehand and before any passage of the fabric, we had introduced

  in line 11 the initial dye bath 2. The values of the

  obtained, proportional to the concentration of the bath in each

  any of its dyes, were the reference values.

  When dyeing, the recycling bath comes from the

  Age of the tissue is depleted in yellow diazol light 2JS. This impoverishment

  This is shown by a variation in the value of the corresponding current.

  to this dye. When the difference found between the measured value,

  at a given moment, and the reference value reaches a predetermined threshold

  finished, for example 0.5%, the processing unit 24 controls the in-

  jection by the nozzle 25 of a colored solution containing as colorant

  than the yellow diazol light 2JS and at a higher concentration

  than bath 2. This injection increases the concentration of

  bath 2 in yellow light diazol 2JS and thus corrects

the impoverishment found.

  The exact parameters are to be determined for the skilled person

2 6 2 4 1 4 3

  for an installation according to the volume of bath in the bacholle 3, the rate of carriage after passage between the squeezing rollers 7,8 and for a dyeing pass according to the composition of the dye bath. It is important that the correction of the bath, by injection of a concentrated solution in dye having a greater substance.

  for the fabric, intervene before the difference

  dragged a variation of the color of the fabric. perceptible to the eye.

  The invention is not limited to the embodiment that comes.

  to be described as an example. In particular the measurement of the bath can be made directly on the bath 2 contained in the bacholle 3, and not on the excess bath of recycling. Likewise, what has been

  said for dyeing fabrics is also valid for dyeing

  re son in continuous scrolling using other means

  impregnation and other means of expression.

  Nor is the invention limited to the implementation of a

  colorful impregnation bath with one of the colored constituents

  you have a higher substantivity than the others for the material to be treated. It applies whenever o, for this reason or

  for another, the colored bath of impregnation varies in the concentration

  in one or other of its colored constituents. This may be the case when the means of expression are means using

  compressed air, which is charged with moisture and concentrates the bath of

  cycling; the solution to be injected must then be a solution having

  a concentration lower than that of the initial bath, or even a solution

dye free.

Claims (10)

  1. A method of regulating a colored impregnation bath (2) for the treatment of a material in continuous scrolling characterized by the following steps, performed automatically: a. the concentration of the bath (2) or a value proportional to the concentration of the bath (2) for each colored constituent, is measured by photocolorimetry at determined time intervals,   b. the values obtained are compared with the reference values cor-   corresponding to the initial bath (2) before impregnation of the material, c. when the difference found for a given colored constituent reaches   a certain threshold, a predetermined quantity of a solution of cor-   rection is added to the impregnation bath (2).   2. Method according to claim 1 characterized in that, the deviation cons-   the negative solution, the correction solution is a concentrated solution said colored constituent.   3. Method according to claim I characterized in that, the difference found being positive, the correction solution is a solution.   dilute said colored component or a solution free from said constituent killing.   4. Method according to one of claims I to 3 characterized in that   measuring the concentration of the bath (2) or a proportional value   the concentration of the bath (2) is effected by conversion into   electrical signal of a luminous flux passing through a volume of bath (2) in circulation. 5. Method according to claim 4 characterized in that the signal   is obtained by at least one photodetector placed at the end of the   a filter illuminated by the luminous flux passing through the volume of circulating bath (2).   6. Method according to claim 5 characterized in that the measurement of the concentration of the bath (2) or a value proportional to the concentration of the bath (2) is based on the measurement of four electrical signals from the photodetectors placed at the out of four   filters, whose transmission spectra show maXi-   mum that cover, together, the range of wavelengths between 400 and 700 nanometers.   7. Process according to claim 1, characterized in that the color bath   d is a dyeing bath of a textile material, comprising several   dyes, at least one of which has for said material a   greater activity, at a lower temperature, larger than the others. 8. Method according to claim 1, characterized in that the color bath on which the measurement is carried out at determined time intervals corresponds to the excess bath, intended to be recycled, after impregnation of the material.   9. Control device for implementing the method according to claim 1 characterized in that it comprises: a. a photocolorimetric sensor comprising a measurement chamber   (12) in which the colored bath circulates, an optical block (15) consis-   at least one white light source (18) placed on one side of the chamber (12) and processing means capable of measuring, from the luminous flux transmitted by the color bath, the concentration or a proportional value the concentration of the bath in each of the colored constituents, b. means for comparing the measured value at determined time intervals for a given constituent with respect to the reference value corresponding to the initial bath (2),   c. injection means (25), actuated when the comparison ef-   by the means of comparison shows up for a   killing a difference equal to or greater than a certain threshold, and   the injection into the colored bath of a predetermined quantity a correction solution.   10. Device according to claim 9 characterized in that the optical block (15) comprises a set of four filters, whose transmission spectra have maximum peaks which cover, together, the   range of wavelengths between 400 and 700 nanometers.