GB2099994A - Determining coating thickness - Google Patents
Determining coating thickness Download PDFInfo
- Publication number
- GB2099994A GB2099994A GB8215776A GB8215776A GB2099994A GB 2099994 A GB2099994 A GB 2099994A GB 8215776 A GB8215776 A GB 8215776A GB 8215776 A GB8215776 A GB 8215776A GB 2099994 A GB2099994 A GB 2099994A
- Authority
- GB
- United Kingdom
- Prior art keywords
- radiation
- coating
- detector
- base material
- coating layers
- 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.)
- Granted
Links
- 239000011248 coating agent Substances 0.000 title claims abstract description 30
- 238000000576 coating method Methods 0.000 title claims abstract description 30
- 230000005855 radiation Effects 0.000 claims abstract description 65
- 239000000123 paper Substances 0.000 claims abstract description 31
- 239000011247 coating layer Substances 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 16
- 238000005259 measurement Methods 0.000 claims abstract description 13
- 230000005540 biological transmission Effects 0.000 claims abstract description 9
- 239000011111 cardboard Substances 0.000 claims abstract description 5
- 230000005284 excitation Effects 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 14
- 238000010521 absorption reaction Methods 0.000 description 6
- 239000000945 filler Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B15/00—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons
- G01B15/02—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons for measuring thickness
- G01B15/025—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons for measuring thickness by measuring absorption
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
- Length-Measuring Devices Using Wave Or Particle Radiation (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Emergency Protection Circuit Devices (AREA)
- Paper (AREA)
Abstract
The thickness of coating layers 1,3 deposited on both sides of paper, cardboard or equivalent material 2 is measured in the case in which both coating layers 1,3 contain the same component emitting characteristic fluorescent radiation. Typically both coating layers consist of the same material. Two functionally mutually independent radiation source/detector pairs are used, between which the coated paper or equivalent is passed. Excitation of fluorescent radiation is effected in both coating layers under measurement and the total intensity of the excited radiation present at each detector is measured. If the base weight of the paper or equivalent is known, the coating thickness is calculated from the results of the measurements obtained. The said base weight is preferably measured before applying the coating with the aid of a separate source of radiation and a transmission detector. <IMAGE>
Description
SPECIFICATION
Procedure for determining coating rates
The present invention relates to a procedure for determining coating rates in coating layers deposited on both sides of paper, carddboard or equivalent base material and which contain the same component emitting a characteristic fluorescent radiation, in said procedure excitation of fluorescent radiation being effected with a primary radiation obtained from a source of radiation and the radiation intensity being measured with a detector.
In prior art are known methods based on measurement of characteristic fluorescent radiation excited by means of a primary radiation for the measuring of coating rates in one or several superimposed coating layers applied on cardboard or equivalent material. These methods have made use of the absorption in the layer to be measured of the primary radiation and of the fluorescent radiation excited in the layer under the coating layer. When the base material is coated on both sides with coating layers containing the same component emitting characteristic fluorescent radiation, the above-mentioned methods of prior art are no longer usable. A typical example of such cases is a paper web which has been coated on both sides with one and the same coating compound.The present invention preferably provides a method for measuring coating rates which is applicable in these cases, and the invention is characterized in that the coated base material is placed between two radiation source/detector pairs functionally independent of each other and that separately with each radiation source/detector pair is effected excitation of fluorescent radiation in the coating layers on both sides of the base material and measurement of the added intensity of the excited radiation, whereby the coating rates are calculable from the results of measurement obtained and from the base weight of the base material, which is known or has to be separately determined.
The invention is described in detail in the following with the aid of an example with reference being made to the drawing attached, which presents the measuring of the coating layers on a paper web coated on both sides.
As shown in the drawing, the paper web comprises a topside coating layer 1, a paper course 2 and an underside coating layer 3. The coating layers 1 and 3 consist of a coating compound emitting the same isotope- or x-ray tube-excited characteristic fluorescent radiation and they have been applied on the paper 2 with the same coating unit. To the purpose of measuring the coating rates, a source of radiation 5ref emitting a primary radiation 4 has been placed in advance of the coating unit.The fluorescent radiation 5 excited by the primary radiation 4 in the raw paper is measured by means of a detector Df | f and the primary radiation that has passed through the raw paper, 6, is measured with another detector Dlf. Followng after the coating unit, on both sides of the paper web have been disposed radiation source/detector pairs S1, D1 and S2,D2, which have been so collimated that the measurements carried out with them do not interfere with each other.The primary radiation 7 emitted by the radiation source S1 excites in the coating layer 1 the fluorescent radiation 8, which is observed by the detector D1. At the same time the primary raidation 9 emitted by the radiation source S1 acts on the coating layer 3, the fluorescent radiation excited herein, 10, also going to the detector D1. Similary, the primary radiation 11, 13 emitted by the radiation source S2 produces in the coating layer 3 the fluorescent radiation 12 and in the coating layer 1 the fluorescent radiation 14, and the fluorescent radiations produced are observed with the detector D2. The primary radiation 15 passing through the coated paper web is furthermore measured with the transmission detector Dtr.
If we denote m1 = coating rate of the topside coating layer 1 m2 = base weight of the paper course 2 m3 = coating rate of the underside coating layer 3 = Ief = intensity of the fluorescent radiation measured with detector Dref Ii = intensity of the fluorescent radiation measured with detector D1fl 12 = intensity of the fluorescent radiation measured with detector D2 Ci = effective activity of the topside measuring pick-up
C2 = effective activity ofthe underside measuring pick-up Ci = ratio ia/lfl f measured with a given raw paper containing filler C2 = ratio 12/l;;f measured with a given raw paper containing filler = = nself-absorption coefficient" of the coating 4 = combined mass absorption coefficient of the primary and secondary radiations into the coating i - = combined mass absorption coefficient of the primary and secondary radiations into the paper, the intensity of radiation 8 is C1 mi e lis the intensity of radiation 10 is C1 m3 e e m1+'- m2) the intensity of radiation 12 is C2 m3 m3 e e lis m3 ,and the intensity of radiation 14 is
The coating rates may then be determined by the equations (1) and (2), easily calibrated in practice,
When the coating rates are determined in the manner presented, the determination implies information supplied to the computer regarding the base weight (= m2) of the paper that is being coated, and which is obtainable e.g. from a separate, punctiform ss base weight measuring instrument monitoring the raw paper.
It is however more convenient, and conducive to more accurate results, if the continuous monitoring of the raw cardbord is effected with the aid of a transmission detector mounted on the measuring head measuring the raw cardboard and measuring the primary radiation of Sref. It is true that in the latter case no absolutely exact base weights are obtained, but when the calibration of the apparatus as well as subsequent measurements are based on Itrerf, changes in the filler content and composition of the raw paper cannot significantly affect the fluorescence yield measured on the opposite side of the paper (changes of the quantity of coating material present as filler cause a variation in the secondary radiation not nearly as strong as in the primary radiation).It is therefore worthwhile to determine m2 for use in equations (1) and (2) from equation (3) and to determine the true weight of the raw paper separately by another method.
Itref= transmission intensity measured with Dterf Fref = Iref measured with Dtrerf with no paper interposed = = mass absorption coefficient of the paper for the primary radiation in direction Dtref.
The significance of the raw paper's filler content and composition variations in the result of measurement can also be aliminated by mounting on the measuring head monitoring the coated area, another transmission detector Dtr measuring the primary radiation from either S, or S2 and by determining, to begin with, the total coating rate (= m1 + m3) with the aid of two transmission detector readings by the equation (4)
Itr = intensity measured with Dtr
C3 = Itr/ltrref mi = m3 = 0.
= = mass absorption coefficient of the coating for the primary radiation in direction Dtr and the ratio m1/m3 thereafter directly from the simplified equations for Ii and I1 12C, If lef and 12 = C2. m3 + C2' . If lef, whereby mi and m3 are calculable by equations (5) and (6)
If the filler distribution of the paper in the z direction is considerably variable, it may in some instances be indicated, when accurate results are desired, to mount to the reference measuring head a souce/detector pair also on the other side of the paper.
Since the influence of variations in moisture content and base weight on the accuracy of measurement is exceedingly small when for exciting sources of radiation for instance a isotopes are used, the errors caused by the punctiformity of the reference source are usually negligible. However, when coating heavy raw papers or cardboards, it is worthwhile to omit the determination of total coating rate based on transmission and to perform the measurements exclusively based on fluorescences, owing to the fact that the fluorescence yield factor of the coating on the opposite side of the raw paper in equations (1) and (2) diminishes very strongly with increasing base weight of the raw paper, and owing to the fact that the error of measurement incurred through moisture content variations has effect almost exclusively on this factor.
It is obvious to a person skilled in the art that different embodiments of the invention are not confined to the example presented and may instead vary within the scope of the claims following below.
Claims (4)
1. Procedure for determining coating rates in coating layers (1, 3) deposited on both sides of paper, cardboard or another equivalent base material (2), said coating layers containing the same component emitting characteristic fluorescent radiation, in the procedure being effected excitation of fluorescent radiation (8,10,12,14) by means of primary radiation (7,9,11, 13) obtained from asource of radiation (ski, S2) and the radiation intensity being measured with a detector (D1, D2), characterized in that the coated base material (2) is based between two mutually functionally independent radiation source/detector pairs (ski, Di and S2, D2) and that separately with each of these radiation source/detector pairs is effected excitation of fluorescent radiation (8, 10, 12, 14) in the coating layers (1,3) on both sides of the base material and measuring of the added intensity of the radiation excited, whereby the coating rates are calculable from the results of measurement obtained and from the base weight of the base material, which is known or separately determined.
2. Procedure according to claim 1, characterized in that the coating rates are measured in conjunction with the process in which the base material (2) is coated, wherein the base weight of the base material web is measured prior to applying the coating layers (1, 3), with the aid of a source of radiation (Sref) disposed on one side of the web and a transmission detector (Dtrerf) disposed on the other side.
3. Procedure according to claim 1 or 2, characterized in that the intensity of the primary radiation (15) passing through the coated base material (2) is measured with a transmission detector (Dtr) disposed in conjunction with one radiation source/detector pair (S2, D2), whereby from the result of measurement the added coating rate of the coating layers (1, 3) can be calculated.
4. A method as claimed in Claim 1 substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI811652A FI62420C (en) | 1981-05-29 | 1981-05-29 | FOERFARANDE FOER ATT MAETA BELAEGGNINGSMAENGD |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2099994A true GB2099994A (en) | 1982-12-15 |
| GB2099994B GB2099994B (en) | 1985-02-20 |
Family
ID=8514438
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8215776A Expired GB2099994B (en) | 1981-05-29 | 1982-05-28 | Determining coating thickness |
Country Status (7)
| Country | Link |
|---|---|
| CA (1) | CA1189638A (en) |
| DE (1) | DE3219962A1 (en) |
| FI (1) | FI62420C (en) |
| FR (1) | FR2506929B1 (en) |
| GB (1) | GB2099994B (en) |
| NO (1) | NO154570C (en) |
| SE (1) | SE449137B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2254917A (en) * | 1991-02-28 | 1992-10-21 | Heidelberger Druckmasch Ag | Determining the amount of a fluid or the thickness of a fluid film |
| WO1998029709A1 (en) * | 1996-12-17 | 1998-07-09 | Toolex Alpha Ab | Process for optical measurement of the thickness of an adhesive layer, an optical data-storing disc, its manufacturing and also an adhesive and its use |
| US6508956B1 (en) | 2001-07-25 | 2003-01-21 | Lexmark International, Inc | Paper coating test method and composition |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI68320C (en) * | 1982-12-01 | 1985-08-12 | Valtion Teknillinen | FOERFARANDE Før by means of the ATT STRAOLNING FRAON A RADIOISOTOPKAELLA utan att FOERSTOERA sample was MAETA FOERDELNINGEN fyll audio-and / or BELAEGGNINGSMEDEL I TJOCKLEKSRIKTNINGEN audio PAPP ERARTONG or the like OCH Halten from these two MEDEL arranged RGAFOER TILLAEMPANDE audio FOERFARANDET SAMT ANVAENDNINGAR of devices for the AV ERFOARANDET OCH |
| FI68321C (en) * | 1982-12-01 | 1985-08-12 | Valtion Teknillinen | FOERFARANDE Før by means of the ATT STRAOLNING UTSAEND AV ETT ROENTGENROER utan att FOERSTOERA sample was MAETA FOERDELNINGEN FYLL- audio and / or BELAEGGNINGSMEDEL I TJOCKLEKSRIKTNINGEN of paper in Cardboard or the like OCH Halten from these two MEDEL Før TILLAEMPANDE of devices for the AV FOERFARANDET SAMT ANVAENDNINGAR of devices for the AV FOERFARANDET OCH |
| WO1988005909A1 (en) * | 1987-02-06 | 1988-08-11 | Dai Nippon Insatsu Kabushiki Kaisha | Method and apparatus for detecting a material with a fluorescent light-emitting substance to be detected |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE925197C (en) * | 1953-11-11 | 1955-03-14 | Exatest Ges Fuer Messtechnik M | Method for the non-contact thickness measurement of strip-shaped, preferably hot-rolled material by means of hard electromagnetic radiation |
| US3405267A (en) * | 1964-06-17 | 1968-10-08 | Industrial Nucleonics Corp | Inner layer displacement measuring method and apparatus |
| DE1548333A1 (en) * | 1965-09-22 | 1969-08-21 | Atomic Energy Authority Uk | Layer thickness meter |
| FR1495097A (en) * | 1966-09-22 | 1967-09-15 | Atomic Energy Authority Uk | Feeler gauges operating by transmission |
| FI40587B (en) * | 1967-04-01 | 1968-11-30 | Valmet Oy | |
| US4037104A (en) * | 1976-04-29 | 1977-07-19 | Nucleonic Data Systems, Inc. | Dual beam X-ray thickness gauge |
| FI53757C (en) * | 1976-12-13 | 1978-07-10 | Pertti Puumalainen | FOERFARANDE FOER MAETNING AV YTVIKTERNA |
| US4147931A (en) * | 1976-12-13 | 1979-04-03 | Pertti Puumalainen | Procedure for measuring unit area weights |
| US4081676A (en) * | 1976-12-17 | 1978-03-28 | Sentrol Systems Ltd. | On-line system for monitoring sheet material additives |
| FI59489C (en) * | 1978-11-21 | 1981-08-10 | Enso Gutzeit Oy | FOERFARANDE FOER MAETNING AV BELAEGGNINGSMAENGDER |
-
1981
- 1981-05-29 FI FI811652A patent/FI62420C/en not_active IP Right Cessation
-
1982
- 1982-05-27 DE DE19823219962 patent/DE3219962A1/en not_active Withdrawn
- 1982-05-27 CA CA000403859A patent/CA1189638A/en not_active Expired
- 1982-05-28 SE SE8203315A patent/SE449137B/en not_active IP Right Cessation
- 1982-05-28 GB GB8215776A patent/GB2099994B/en not_active Expired
- 1982-05-28 NO NO821806A patent/NO154570C/en unknown
- 1982-06-01 FR FR8209514A patent/FR2506929B1/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2254917A (en) * | 1991-02-28 | 1992-10-21 | Heidelberger Druckmasch Ag | Determining the amount of a fluid or the thickness of a fluid film |
| WO1998029709A1 (en) * | 1996-12-17 | 1998-07-09 | Toolex Alpha Ab | Process for optical measurement of the thickness of an adhesive layer, an optical data-storing disc, its manufacturing and also an adhesive and its use |
| US6508956B1 (en) | 2001-07-25 | 2003-01-21 | Lexmark International, Inc | Paper coating test method and composition |
Also Published As
| Publication number | Publication date |
|---|---|
| NO154570C (en) | 1986-10-22 |
| FR2506929B1 (en) | 1986-09-26 |
| FI62420B (en) | 1982-08-31 |
| GB2099994B (en) | 1985-02-20 |
| CA1189638A (en) | 1985-06-25 |
| NO154570B (en) | 1986-07-14 |
| FR2506929A1 (en) | 1982-12-03 |
| SE8203315L (en) | 1982-11-30 |
| NO821806L (en) | 1982-11-30 |
| SE449137B (en) | 1987-04-06 |
| DE3219962A1 (en) | 1982-12-16 |
| FI62420C (en) | 1982-12-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Effective date: 20020527 |