CA2251347A1 - Process and device for determining the mechanical properties of paper - Google Patents
Process and device for determining the mechanical properties of paper Download PDFInfo
- Publication number
- CA2251347A1 CA2251347A1 CA002251347A CA2251347A CA2251347A1 CA 2251347 A1 CA2251347 A1 CA 2251347A1 CA 002251347 A CA002251347 A CA 002251347A CA 2251347 A CA2251347 A CA 2251347A CA 2251347 A1 CA2251347 A1 CA 2251347A1
- Authority
- CA
- Canada
- Prior art keywords
- paper
- recited
- measurements
- mechanical properties
- spectrum
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims description 20
- 238000005259 measurement Methods 0.000 claims abstract description 22
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims abstract description 17
- 238000001228 spectrum Methods 0.000 claims abstract description 14
- 238000004566 IR spectroscopy Methods 0.000 claims abstract description 11
- 238000011156 evaluation Methods 0.000 claims abstract description 7
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims abstract description 4
- 239000000835 fiber Substances 0.000 claims description 23
- 238000012937 correction Methods 0.000 claims description 7
- 230000003287 optical effect Effects 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 claims description 3
- 230000009466 transformation Effects 0.000 claims description 3
- 238000007781 pre-processing Methods 0.000 claims description 2
- 238000010183 spectrum analysis Methods 0.000 claims 1
- 239000000123 paper Substances 0.000 description 37
- 229920002678 cellulose Polymers 0.000 description 6
- 239000001913 cellulose Substances 0.000 description 6
- 238000002329 infrared spectrum Methods 0.000 description 6
- 238000004458 analytical method Methods 0.000 description 4
- 239000011111 cardboard Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 229920003043 Cellulose fiber Polymers 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000011087 paperboard Substances 0.000 description 3
- 238000002604 ultrasonography Methods 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000010893 paper waste Substances 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000011545 laboratory measurement Methods 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000275 quality assurance Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/34—Paper
- G01N33/346—Paper paper sheets
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3563—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing solids; Preparation of samples therefor
Abstract
Conclusions about the mechanical properties of paper (10) may in particular be derived from measurements of the connections between the paper fibres.
According to the invention, the connections between the paper fibres are measured by infrared spectroscopy. The presence of mutually linked hydroxyl and/or carboxyl groups at the surface of the fibres is optically sensed and evaluated as a measurement for the mechanical properties of the paper. In the corresponding device, at least one evaluation unit (11-16) is available, in particular for correcting the base lines of the spectra, and then for determining the mechanical properties of the paper based on the bands of the spectrum, in particular the presence of connections between the fibres.
According to the invention, the connections between the paper fibres are measured by infrared spectroscopy. The presence of mutually linked hydroxyl and/or carboxyl groups at the surface of the fibres is optically sensed and evaluated as a measurement for the mechanical properties of the paper. In the corresponding device, at least one evaluation unit (11-16) is available, in particular for correcting the base lines of the spectra, and then for determining the mechanical properties of the paper based on the bands of the spectrum, in particular the presence of connections between the fibres.
Description
CA 022~1347 1998-10-07 ILE, D'~ , T~ r~ AF~?"' Tt'.. r"L.~
[67190/963245]
METHOD FOR DETERMINING THE MECHANICAL PROPERTIES OF PAPER AND
AN ASSOCIATED ARRANGEMENT
The invention relates to a method for determining the mechanical properties of paper, in particular for measuring the fiber bonds in paper. In addition, the invention relates to the associated arrangement for carrying out the method, using a spectrometer having a beam source, an optical system, and a detector.
In the manufacture of paper and/or cardboard, it is necessary to constantly monitor the mechanical properties for quality assurance. These properties are a function of the kind and number of the fiber bonds. For this purpose, the goal is the direct measurement of the fiber bonds in the paper during manufacture, which would permit an online adjustment of the production process.
Thus far, direct measurement of the fiber bonds has not been possible. No sensor is known with which direct measurements can be made as to how well and how solidly the individual cellulose fibers in the paper and/or cardboard are bonded to each other. However, a series of measuring methods has been proposed for monitoring the strength of paper, these methods directly or indirectly relating to the fiber bonds in the cellulose. Nevertheless, the measurements themselves are influenced by the strength of the individual fibers, so that no direct correlation with the desired measuring result exists.
To date, laboratory analyses in the paper factory have been conducted in an ongoing manner, for example, at the paper-making machine, regarding the strength of the paper, in orderto assure a predetermined quality standard. For this purpose, samples are taken from the moving paper web and are analyzed in the laboratory for properties such as strength, resistance to tearing, gas pressure, etc. Such measurements generally are time- consuming and require qualified personnel.
CA 022~1347 1998-10-07 -An online sensor has been already proposed, which, on the moving paper web, measures the rise in the stress-strain curve using the propagation speed of ultrasound in the paper. The sensor is made up of an ultrasound source and two detectors at varying distances. From the difference in propagation times of the ultrasound impulses at the two detectors, the paper strength can be determined. This value is generally determined by the rise in the curve in the stress-strain diagram.
In the journal publications "The Paper" (1991), p. 45-51 and "The Paper" (1993), p. 695-702, the p~ssibilities and limits of the FTIR spectroscopy in characterizing cellulose have already been reported on. In this context, in particular, spectroscopic and electron microscopic analyses of the fine structure of cellulose have been compared with each other. No practical consequences can be drawn from this.
Furthermore, in Tappi Journal (1992), p. 147-149, assertions are made to the effect that measurements can be obtained by means of optical infrared measurements of the lignin content of cellulose pulp, i.e., cellulose having a pulpy consistency.
The object of the invention is thus to indicate a method and to create the associated arrangement which can be used for measuring the fiber bonds in paper.
The object according to the invention is achieved through the use of infrared spectroscopy, the presence of hydroxyl and/or carboxyl groups, joined to each other on the fiber surface, being optically determined and evaluated as a measure for the mechanical properties of the paper. In the associated arrangement, an evaluating unit is present, in which a baseline correction of the spectra is carried out, and, subsequently, on the basis of bands in the spectrum, the mechanical properties are determined, in particular the presence of fiber bonds.
CA 022~1347 1998-10-07 Thus the invention makes available for the first time a sensor which meets the requirements of actual practice, which with the help of infrared spectroscopy (IR) is capable of directly measuring the fiber quality in paper. IR spectroscopy is, on the one hand, a generally known method for producing chemical characterizations of materials, and it has already been proposed, as was mentioned at the beginning, for analyzing cellulose. Now, however, using IR spectroscopy, the fiber quality of paper and/or cardboard can be determined directly.
Within the scope of the invention, the non-trivial reflection has been confirmed that the mechanical properties of paper are determined mainly through the quality of the cellulose fibers.
Fiber quality is a measure for the fibers' property of forming a stable interconnection with other fibers through solid bonds, and thus it assures the mechanical properties of the paper. According to the prevailing theory, the strength of this interfiber bonding is determined by the concentration on the fiber surface of hydroxyl groups and/or carboxyl groups, which are linked to each other by hydrogen bridge bondings.
Fibers may be prevented from bonding by undesirable impurities. In this case, free OH groups are present which are not saturated through bonds. The greater the concentration of saturated OH groups, the greater the strength of the paper.
Further properties and advantages of the invention emerge in the following description of the Figures of exemplary embodiments on the basis of the drawing in connection with further dependent claims. Specifically, Figure 1 shows an infrared spectrum of paper containing waste paper, Figure 2 shows the infrared spectrum of Figure 1 after a baseline correction, Figure 3 shows an infrared spectrum of wood-free paper, and Figure 4 shows a block diagram having associated evaluation units.
CA 022~1347 1998-10-07 Infrared spectroscopy is a standard procedure in tne chemical industry for characterizing materials. For measuring paper, the following specifically should be considered, taking into account the remarks made at the beginning as to the composition of cellulose fibers:
The resonant vibration frequency of free OH groups is in the range of approx. 3700 cm~l. If two OH groups are joined via hydrogen bridge bondings, the OH groups are hindered in their vibration and the resonant frequency is shifted to the range of approx. 3200 cm~1 to 3400 cm1 Therefore, by means of spectroscopic measurement, it can be directly determined whether OH groups are free or bound. By evaluating the spectrum of paper, it can additionally be determined quantitatively how many OH groups are contributing to the fiber bonds and how many OH groups are free. The more OH
groups are bound to each other, the greater the strength of the paper.
For the practical application, an infrared spectrometer should be used, covering the range from 3500 cm1 to 3800 cm~1. A
conventional spectrometer, which is not depicted here in detail, includes an optical system which guides the light from a beam source and a detector. If appropriate, a so-called Fourier-transform spectrometer can also be used, with which the signals are emitted directly in processed form.
At an appropriate place, a paper sample is introduced into the spectrometer and is either irradiated, by the infrared beam (IR), or the diffuse reflection of the IR beam is measured. If the sample is irradiated, which is only possible with papers but not with cardboard, a transmission measurement occurs. A
reflection is also equally possible. In measuring the diffuse reflection, on the other hand, the directly reflected light is screened out and the diffusely reflected light is focussed using concave mirrors and directed to the detector. For normal use, the spectral resolution of the spectrometer must be CA 022~1347 1998-10-07 better than 10 cm-1.
Figure 1 shows an IR spectrum 1 in the range of approx. 3500 cm~ to 3800 cm1, the IR spectrum having been obtained from paper having a high waste paper content. First of all, using a processing unit, a baseline correction is carried out on a raw spectrum of this type, having a structure that can be interpreted as bands, by means of which a corrected spectrum 2 according to Figure 2 is obtained. Latter spectrum 2 is characterized by significant bands. A spectrum of this type can be processed for the purpose of furt'-er evaluation by a Fast Fourier Transformation (FFT).
The latter bands in the spectrum indicate the oscillations of the free OH groups, i.e., of those OH groups which have not undergone binding. These bands arise when not all OH groups participate in the bonds, when the fibers are thus not optimally bonded to each other.
Figure 3 shows a spectrum 3 of high-quality wood-free paper, without a baseline correction already having been carried out.
However, it can still clearly be seen that none of the bands depicted above are to be seen. This means that the fibers are optimally bonded to each other.
In the corresponding block diagram according to Figure 4, a unit 10 contains an IR spectrum which was measured at the paper, for example, spectrum 1. Eleven depicts a unit for Fast Fourier transformation (FFT), which is followed by a unit 12 for mathematical preprocessing. In the latter unit 12, the signals are smoothed out and the already-mentioned baseline correction is carried out. After the signals are deconvoluted, it is possible to determine the line width and the intensities as well as to carry out a component analysis.
In Figure 4, unit 15 contains a mathematical model, "Paper Quality." This model correlates the results of the spectral CA 022~1347 1998-10-07 analysis and the associated evaluation with the criteria of paper quality or the like. Unit 15 controls unit 16, which acts to determine the measures to be undertaken for assuring the paper quality.
In infrared measurement, the sensor can be installed directly at the moving paper web. This makes possible a rapid online control of the paper quality. It is also possible to build the sensor into a measuring frame which moves in a transverse direction over the paper web, just as the measuring frame was advantaseously proposed as transverse to the paper web, for example, for measurements such as surface thickness and/or humidity content. For a transmission measurement, the beam source can be positioned in the upper part of the measuring frame and the detector in the lower part. On the other hand, in the case of measurements of the diffuse reflection, both the beam source as well as the detector are in the upper or in the lower part of the measuring frame.
Apart from the described online measurement, an offline sensor would also provide a significant savings in time as opposed to laboratory measurements. In this case, a sample is taken from the paper web and is measured in the laboratory in an IR
spectrometer. Measurements of this type can be carried out in a few minutes.
[67190/963245]
METHOD FOR DETERMINING THE MECHANICAL PROPERTIES OF PAPER AND
AN ASSOCIATED ARRANGEMENT
The invention relates to a method for determining the mechanical properties of paper, in particular for measuring the fiber bonds in paper. In addition, the invention relates to the associated arrangement for carrying out the method, using a spectrometer having a beam source, an optical system, and a detector.
In the manufacture of paper and/or cardboard, it is necessary to constantly monitor the mechanical properties for quality assurance. These properties are a function of the kind and number of the fiber bonds. For this purpose, the goal is the direct measurement of the fiber bonds in the paper during manufacture, which would permit an online adjustment of the production process.
Thus far, direct measurement of the fiber bonds has not been possible. No sensor is known with which direct measurements can be made as to how well and how solidly the individual cellulose fibers in the paper and/or cardboard are bonded to each other. However, a series of measuring methods has been proposed for monitoring the strength of paper, these methods directly or indirectly relating to the fiber bonds in the cellulose. Nevertheless, the measurements themselves are influenced by the strength of the individual fibers, so that no direct correlation with the desired measuring result exists.
To date, laboratory analyses in the paper factory have been conducted in an ongoing manner, for example, at the paper-making machine, regarding the strength of the paper, in orderto assure a predetermined quality standard. For this purpose, samples are taken from the moving paper web and are analyzed in the laboratory for properties such as strength, resistance to tearing, gas pressure, etc. Such measurements generally are time- consuming and require qualified personnel.
CA 022~1347 1998-10-07 -An online sensor has been already proposed, which, on the moving paper web, measures the rise in the stress-strain curve using the propagation speed of ultrasound in the paper. The sensor is made up of an ultrasound source and two detectors at varying distances. From the difference in propagation times of the ultrasound impulses at the two detectors, the paper strength can be determined. This value is generally determined by the rise in the curve in the stress-strain diagram.
In the journal publications "The Paper" (1991), p. 45-51 and "The Paper" (1993), p. 695-702, the p~ssibilities and limits of the FTIR spectroscopy in characterizing cellulose have already been reported on. In this context, in particular, spectroscopic and electron microscopic analyses of the fine structure of cellulose have been compared with each other. No practical consequences can be drawn from this.
Furthermore, in Tappi Journal (1992), p. 147-149, assertions are made to the effect that measurements can be obtained by means of optical infrared measurements of the lignin content of cellulose pulp, i.e., cellulose having a pulpy consistency.
The object of the invention is thus to indicate a method and to create the associated arrangement which can be used for measuring the fiber bonds in paper.
The object according to the invention is achieved through the use of infrared spectroscopy, the presence of hydroxyl and/or carboxyl groups, joined to each other on the fiber surface, being optically determined and evaluated as a measure for the mechanical properties of the paper. In the associated arrangement, an evaluating unit is present, in which a baseline correction of the spectra is carried out, and, subsequently, on the basis of bands in the spectrum, the mechanical properties are determined, in particular the presence of fiber bonds.
CA 022~1347 1998-10-07 Thus the invention makes available for the first time a sensor which meets the requirements of actual practice, which with the help of infrared spectroscopy (IR) is capable of directly measuring the fiber quality in paper. IR spectroscopy is, on the one hand, a generally known method for producing chemical characterizations of materials, and it has already been proposed, as was mentioned at the beginning, for analyzing cellulose. Now, however, using IR spectroscopy, the fiber quality of paper and/or cardboard can be determined directly.
Within the scope of the invention, the non-trivial reflection has been confirmed that the mechanical properties of paper are determined mainly through the quality of the cellulose fibers.
Fiber quality is a measure for the fibers' property of forming a stable interconnection with other fibers through solid bonds, and thus it assures the mechanical properties of the paper. According to the prevailing theory, the strength of this interfiber bonding is determined by the concentration on the fiber surface of hydroxyl groups and/or carboxyl groups, which are linked to each other by hydrogen bridge bondings.
Fibers may be prevented from bonding by undesirable impurities. In this case, free OH groups are present which are not saturated through bonds. The greater the concentration of saturated OH groups, the greater the strength of the paper.
Further properties and advantages of the invention emerge in the following description of the Figures of exemplary embodiments on the basis of the drawing in connection with further dependent claims. Specifically, Figure 1 shows an infrared spectrum of paper containing waste paper, Figure 2 shows the infrared spectrum of Figure 1 after a baseline correction, Figure 3 shows an infrared spectrum of wood-free paper, and Figure 4 shows a block diagram having associated evaluation units.
CA 022~1347 1998-10-07 Infrared spectroscopy is a standard procedure in tne chemical industry for characterizing materials. For measuring paper, the following specifically should be considered, taking into account the remarks made at the beginning as to the composition of cellulose fibers:
The resonant vibration frequency of free OH groups is in the range of approx. 3700 cm~l. If two OH groups are joined via hydrogen bridge bondings, the OH groups are hindered in their vibration and the resonant frequency is shifted to the range of approx. 3200 cm~1 to 3400 cm1 Therefore, by means of spectroscopic measurement, it can be directly determined whether OH groups are free or bound. By evaluating the spectrum of paper, it can additionally be determined quantitatively how many OH groups are contributing to the fiber bonds and how many OH groups are free. The more OH
groups are bound to each other, the greater the strength of the paper.
For the practical application, an infrared spectrometer should be used, covering the range from 3500 cm1 to 3800 cm~1. A
conventional spectrometer, which is not depicted here in detail, includes an optical system which guides the light from a beam source and a detector. If appropriate, a so-called Fourier-transform spectrometer can also be used, with which the signals are emitted directly in processed form.
At an appropriate place, a paper sample is introduced into the spectrometer and is either irradiated, by the infrared beam (IR), or the diffuse reflection of the IR beam is measured. If the sample is irradiated, which is only possible with papers but not with cardboard, a transmission measurement occurs. A
reflection is also equally possible. In measuring the diffuse reflection, on the other hand, the directly reflected light is screened out and the diffusely reflected light is focussed using concave mirrors and directed to the detector. For normal use, the spectral resolution of the spectrometer must be CA 022~1347 1998-10-07 better than 10 cm-1.
Figure 1 shows an IR spectrum 1 in the range of approx. 3500 cm~ to 3800 cm1, the IR spectrum having been obtained from paper having a high waste paper content. First of all, using a processing unit, a baseline correction is carried out on a raw spectrum of this type, having a structure that can be interpreted as bands, by means of which a corrected spectrum 2 according to Figure 2 is obtained. Latter spectrum 2 is characterized by significant bands. A spectrum of this type can be processed for the purpose of furt'-er evaluation by a Fast Fourier Transformation (FFT).
The latter bands in the spectrum indicate the oscillations of the free OH groups, i.e., of those OH groups which have not undergone binding. These bands arise when not all OH groups participate in the bonds, when the fibers are thus not optimally bonded to each other.
Figure 3 shows a spectrum 3 of high-quality wood-free paper, without a baseline correction already having been carried out.
However, it can still clearly be seen that none of the bands depicted above are to be seen. This means that the fibers are optimally bonded to each other.
In the corresponding block diagram according to Figure 4, a unit 10 contains an IR spectrum which was measured at the paper, for example, spectrum 1. Eleven depicts a unit for Fast Fourier transformation (FFT), which is followed by a unit 12 for mathematical preprocessing. In the latter unit 12, the signals are smoothed out and the already-mentioned baseline correction is carried out. After the signals are deconvoluted, it is possible to determine the line width and the intensities as well as to carry out a component analysis.
In Figure 4, unit 15 contains a mathematical model, "Paper Quality." This model correlates the results of the spectral CA 022~1347 1998-10-07 analysis and the associated evaluation with the criteria of paper quality or the like. Unit 15 controls unit 16, which acts to determine the measures to be undertaken for assuring the paper quality.
In infrared measurement, the sensor can be installed directly at the moving paper web. This makes possible a rapid online control of the paper quality. It is also possible to build the sensor into a measuring frame which moves in a transverse direction over the paper web, just as the measuring frame was advantaseously proposed as transverse to the paper web, for example, for measurements such as surface thickness and/or humidity content. For a transmission measurement, the beam source can be positioned in the upper part of the measuring frame and the detector in the lower part. On the other hand, in the case of measurements of the diffuse reflection, both the beam source as well as the detector are in the upper or in the lower part of the measuring frame.
Apart from the described online measurement, an offline sensor would also provide a significant savings in time as opposed to laboratory measurements. In this case, a sample is taken from the paper web and is measured in the laboratory in an IR
spectrometer. Measurements of this type can be carried out in a few minutes.
Claims (12)
1. A method for determining the mechanical properties of paper, in particular for measuring the fiber bonds in paper, wherein infrared spectroscopy is used, the presence of hydroxyl- and/or carboxyl groups, which are bound to each other at the fiber surface, being detected optically and being evaluated as a measure for the mechanical properties of the paper.
2 The method as recited in Claim 1, wherein the strength of the paper is determined by the fiber bonds and thus is proportional to the concentration of the saturated OH groups.
3. The method as recited in Claim 1, wherein measurements are obtained in transmission.
4. The method as recited in Claim 1, wherein measurements are obtained in reflection, the directly reflected light being screened out and the diffuse reflected light being used for evaluating purposes.
5. The method as recited in one of the preceding claims, wherein measurements are obtained online at a moving paper web.
6. The method as recited in one of Claims 3 and 5, wherein measurements are obtained traversing across the paper web.
7. The method as recited in Claim 6, wherein the evaluation takes place online and the result is taken into account in the process management.
8. The method as recited in one of the preceding claims, wherein measurements are obtained discontinuously after a paper sample is taken.
9. The method as recited in one of the preceding claims, wherein a Fourier transformation of the signals is carried out for evaluation purposes.
10. An arrangement for implementing the method as recited in Claim 1 or in one of Claims 2 through 9, comprising a spectrometer which includes a beam source, an optical system, and a detector, characterized by evaluation units (11-16), with which, in particular, a baseline correction of the spectra is carried out, and the mechanical properties are determined, in particular the presence of fiber bonds, on the basis of the bands in the spectrum.
11. The method as recited in Claim 10, wherein one unit (12) for mathematical preprocessing, in particular for baseline correction, is present.
12. The method as recited in Claim 10, wherein one unit (15) is present which contains a model for the paper quality and correlates the results of the spectral analysis with variables for the paper quality.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19613986.4 | 1996-04-09 | ||
| DE19613986 | 1996-04-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2251347A1 true CA2251347A1 (en) | 1997-10-16 |
Family
ID=7790784
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002251347A Abandoned CA2251347A1 (en) | 1996-04-09 | 1997-04-09 | Process and device for determining the mechanical properties of paper |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0892924B1 (en) |
| AT (1) | ATE262175T1 (en) |
| CA (1) | CA2251347A1 (en) |
| DE (1) | DE59711426D1 (en) |
| WO (1) | WO1997038305A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU727034C (en) * | 1997-12-23 | 2002-03-28 | Sugar Research Australia Limited | On-line measuring system and method |
| AUPP115597A0 (en) * | 1997-12-23 | 1998-01-29 | Bureau Of Sugar Experiment Stations | On-line measuring system and method |
| DE19850825C2 (en) * | 1998-11-04 | 2001-05-23 | Siemens Ag | Method and device for measuring the quality properties of paper and / or cardboard on running material webs |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4602160A (en) * | 1983-09-28 | 1986-07-22 | Sentrol Systems Ltd. | Infrared constituent analyzer and control system |
| US5013403A (en) * | 1987-10-05 | 1991-05-07 | Measurex Corporation | Process for continuous determination of paper strength |
| US4936141A (en) * | 1987-10-06 | 1990-06-26 | Measurex Corporation | On-line paper sheet strength determination method and device |
| SE503101C2 (en) * | 1994-05-18 | 1996-03-25 | Eka Nobel Ab | Ways of determining the wet strength of paper and process control means using the method |
-
1997
- 1997-04-09 EP EP97922829A patent/EP0892924B1/en not_active Expired - Lifetime
- 1997-04-09 AT AT97922829T patent/ATE262175T1/en active
- 1997-04-09 WO PCT/DE1997/000724 patent/WO1997038305A1/en active IP Right Grant
- 1997-04-09 CA CA002251347A patent/CA2251347A1/en not_active Abandoned
- 1997-04-09 DE DE59711426T patent/DE59711426D1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0892924A1 (en) | 1999-01-27 |
| DE59711426D1 (en) | 2004-04-22 |
| ATE262175T1 (en) | 2004-04-15 |
| EP0892924B1 (en) | 2004-03-17 |
| WO1997038305A1 (en) | 1997-10-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |