MULTI-FIBRE OPTICAL PROBE

Abstract

A multi-fibre optical probe for spectroscopically analysing high concentration mediums (i.e. about 40 wt % or higher solid particulates), an extruder comprising a multi-fibre optical probe, use of said multi-fibre optical probe are provided. Methods of generating a predictive model, determining the value of a parameter of a solid particulate dispersion and manufacturing a solid particulate dispersion are also provided.

Claims

1.-20. (canceled)

21. A multi-fibre optical probe for in-line spectroscopic monitoring of high concentration mediums comprising: at least one light detection fibre wherein each light detection fibre is configured to receive light at a light receiving end, and at least two illumination fibres configured to emit light from a light emitting end; wherein the number of illumination fibres is equal to or greater than the number of light detection fibres, and the light emitting ends of each of the illumination fibres are each independently positioned 50 microns or less from the light receiving end of at least one light detection fibre.

22. The multi-fibre optical probe according to claim 21 wherein the, or each, light detecting fibre and the illumination fibres independently comprise a transparent core circumferentially coated by a cladding that is 25 microns or less in thickness.

23. The multi-fibre optical probe according to claim 21 wherein the, or each, light detecting fibre and the illumination fibres are free of additives comprising germanium and/or chlorine.

24. The multi-fibre optical probe according to claim 21 wherein the number of illumination fibres is greater than the number of light detection fibres.

25. The multi-fibre optical probe according to claim 21 wherein the light receiving ends of each light detection fibre are each positioned at the same distance from the light emitting end of at least one illumination fibre.

26. The multi-fibre optical probe according to claim 21 wherein each light detection fibre is connected to a photodetector and each illumination fibre is connected to a light source.

27. The multi-fibre optical probe according to claim 26 wherein the, or each, photodetector is independently configured to detect light at wavelengths of, from UV to mid-IR.

28. The multi-fibre optical probe according to claim 26 wherein the, or each, light source is independently configured to emit light at wavelengths of, from UV to mid-IR.

29. The multi-fibre optical probe according to claim 21 wherein the total number of optical fibres is 50 or more.

30. The multi-fibre optical probe according to claim 21 wherein the ratio of light detection fibres to illumination fibres is 1 to 6 respectively.

31. The multi-fibre optical probe according to claim 21 wherein the ratio of light detection fibres to illumination fibres is 7 to 12 respectively.

32. The multi-fibre optical probe according to claim 21 wherein the light illumination fibres are arranged substantially around the one, or each, light detection fibre.

33. The multi-fibre optical probe according to claim 21 wherein the multi-fibre optical probe does not comprise a window between and/or in front of any of the light emitting ends of the illumination fibres and any of the light receiving ends of the light detection fibres.

34. The multi-fibre optical probe according to claim 21 wherein each illumination fibre has a core diameter of 800 microns or less.

35. The multi-fibre optical probe according to claim 21 wherein each detection fibre has a core diameter of 800 microns or less.

36. The multi-fibre optical probe according to claim 21 wherein the optical fibres are provided substantially parallel to each another in a secured fibre bundle.

37. The multi-fibre optical probe according to claim 21 comprised in, an extruder wherein the optical probe is positioned at one or more of the points of solid particulate input, upstream of the point of extrusion or at the point of extrusion; or a milling system wherein the optical probe is positioned at one or more points of the milling surface; or a heterogeneous flow process at one or more of the points of input, upstream of the point of output or at the point of output.

38. A method, comprising: arranging in relation to a high concentration medium a multi-fibre probe for in-line spectroscopic monitoring of high concentration mediums, wherein the multi-fibre probe comprises at least one light detection fibre wherein each light detection fibre is configured to receive light at a light receiving end, and at least two illumination fibres configured to emit light from a light emitting end, wherein the number of illumination fibres is equal to or greater than the number of light detection fibres, and the light emitting ends of each of the illumination fibres are each independently positioned 50 microns or less from the light receiving end of at least one light detection fibre; and obtaining a spectrum of light scattered or absorbed by the high concentration medium with the multifibre probe.

39. A method of generating a predictive model for determining the value of a parameter of a solid particulate dispersion comprising: (i) spectroscopically analysing a plurality of reference samples of solid particulate dispersions spanning a range of values of the parameter using a multi-fibre optical probe for in-line spectroscopic monitoring of high concentration mediums, wherein the probe comprises at least one light detection fibre wherein each light detection fibre is configured to receive light at a light receiving end, and at least two illumination fibres configured to emit light from a light emitting end, wherein the number of illumination fibres is equal to or greater than the number of light detection fibres, and the light emitting ends of each of the illumination fibres are each independently positioned 50 microns or less from the light receiving end of at least one light detection fibre; (ii) measuring a spectrum of each reference sample, and (iii) processing the spectra gathered in (ii) to generate a predictive model that correlates the parameter to one or more spectroscopic properties.

40. The method according to claim 39, wherein the number of reference samples is 5 or more.

41. The method according to claim 39, wherein the spectra are pre-processed before step (iii) to normalise and/or smooth the spectra.

42. The method according to claim 39, wherein the spectra of the reference samples are processed to derive a feature that correlates with the parameter across at least a portion of said range of the parameter.

43. The method according to claim 42, wherein said feature comprises: at least a first principle component derived from principle components analysis (PCA) of all or part of the spectra or a parameter derived from the spectra, optionally wherein the variance of said first principle component by the parameter is substantially linear across the range of the parameter of said plurality of dispersions; or one or more of a lightness value L*, an a* colour value or a b* colour value of CIELAB colour space derived from the spectra.

44. A method of determining the value of a parameter of a solid particulate dispersion comprising the steps of: (i) subjecting the dispersion to spectroscopy using a multi-fibre optical probe for in-line spectroscopic monitoring of high concentration mediums, wherein the probe comprises at least one light detection fibre wherein each light detection fibre is configured to receive light at a light receiving end, and at least two illumination fibres configured to emit light from a light emitting end, wherein the number of illumination fibres is equal to or greater than the number of light detection fibres, and the light emitting ends of each of the illumination fibres are each independently positioned 50 microns or less from the light receiving end of at least one light detection fibre; (ii) measuring the spectrum of the dispersion, and (iii) determining the value of the parameter by comparing the observed spectrum to a predictive model.

45. A method according to claim 44, wherein the predictive model is for determining the value of a parameter of a solid particulate dispersion and is generated by: (i) spectroscopically analysing a plurality of reference samples of solid particulate dispersions spanning a range of values of the parameter using the multi-fibre optical probe; (ii) measuring a spectrum of each reference sample, and (iii) processing the spectra gathered in (ii) to generate the predictive model that correlates the parameter to one or more spectroscopic properties.

46. The method according to claim 44, wherein comparing the observed spectrum to the predictive model comprises processing the observed spectrum in the same way as the spectra of a plurality of reference samples of solid particulate dispersions spanning a range of values of the parameter, wherein processing the plurality of reference samples comprises: (i) spectroscopically analysing the plurality of reference samples using the multi-fibre optical probe; (ii) measuring a spectrum of each reference sample, and (iii) processing the spectra gathered in (ii) to generate the predictive model that correlates the parameter to one or more spectroscopic properties.

47. The method of claim 44, further comprising manufacturing a solid particulate dispersion by: forming a solid particulate into a dispersion, and where the dispersion has a parameter value within an acceptable range according to the determining of the value of the parameter of the dispersion, processing the dispersion into a finished product.

48. The method according to claim 47 wherein: the forming of the solid particulate into a dispersion is performed by extrusion; and/or the testing of the parameter value one or more times is performed in-line.

49. The method according to claim 48 wherein the forming is performed by extrusion and the testing is performed at one or more of the point of solid particulate input, upstream of the point of extrusion and at the point of extrusion.

50. The method of according to claim 39 wherein the parameter is particle loading amount, particle size distribution, particle distribution, concentration, crystallinity, colour strength and aggregation state.

51. The method according to claim 39 wherein the, or each, spectrum is measured by transmission spectroscopy.

52. The multi-fibre optical probe according to claim 23, wherein the at least one light detecting fibre and illumination fibres are each free of any additives.

53. The multi-fibre optical probe according to claim 33, wherein the multi-fibre optical probe does not comprise any structure covering and/or in front of the ends of the optical fibres at the tip of the multi-fibre optical probe.

54. The multi-fibre optical probe according to claim 34, wherein each illumination fibre has a core diameter of 50 microns or more.

55. The multi-fibre optical probe according to claim 35, wherein each detection fibre has a core diameter of 50 microns or more.

56. The method of claim 38, wherein the high concentration medium comprises a solid particulate dispersion, and further comprising: determining the value of a parameter of the solid particulate dispersion by comparing the obtained spectrum to a predictive model; wherein the parameter is particle loading amount, particle size distribution, particle distribution, concentration, crystallinity, colour strength and aggregation state.

57. The method of claim 38, wherein the spectrum is measured by transmission spectroscopy.

Description

DETAILED DESCRIPTION

[0099] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0100] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the scope of the invention.

[0101] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0102] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0103] Throughout this specification, including the claims which follow, unless the context requires otherwise, the words “have”, “comprise”, and “include”, and variations such as “having”, “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0104] It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means, for example, +/−10%.

[0105] The words “preferred” and “preferably” are used herein refer to embodiments of the invention that may provide certain benefits under some circumstances. It is to be appreciated, however, that other embodiments may also be preferred under the same or different circumstances. The recitation of one or more preferred embodiments therefore does not mean or imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure, or from the scope of the claims.

EXAMPLES

Method 1—Colour Parameter Measurement of Concentrated Red Paint Samples

[0106] A multi-fibre optical probe having 6 illumination fibres and 1 detection fibre was used to measure 3 samples of concentrated red paint. The optical fibres had a fused silica core and polyimide cladding. The concentration of the red paint samples was 1%, 5% and 25% w/w. The light path distance was 125 microns. The 3 paint samples were indistinguishable in colour by eye.

[0107] Analysis was conducted by immersing the tip of the multi-fibre optical probe into each of the 3 concentrated paint samples. The probe was connected to a spectrometer that was able to measure differences in the CIELAB colour parameters of each of the 3 paint samples. In each case, the concentrated paint was measured 3 times, and 3 or more measurements were taken per replicate.

[0108] The CIELAB colour parameters measured are shown in FIG. 5. The measured L*a*b* values for the 1% (circles), 5% (triangles) and 25% (squares) w/w concentration red paint samples are plotted.

[0109] L* is the lightness value component of L*a*b* according to ‘CIELAB colour space’ as defined by the International Commission on Illumination (CIE) where the darkest black is L*=0 and the brightest white is L*=100. The colour channels, a* and b*, represent true neutral grey values at a*=0 and b*=0. The a* value represents the green-red component, with green in the negative direction and red in the positive direction. The b* value represents the blue-yellow component, with blue in the negative direction and yellow in the positive direction.