GB2172102A - Textile structure measurement - Google Patents
Textile structure measurement Download PDFInfo
- Publication number
- GB2172102A GB2172102A GB8601907A GB8601907A GB2172102A GB 2172102 A GB2172102 A GB 2172102A GB 8601907 A GB8601907 A GB 8601907A GB 8601907 A GB8601907 A GB 8601907A GB 2172102 A GB2172102 A GB 2172102A
- Authority
- GB
- United Kingdom
- Prior art keywords
- infra
- measuring
- web
- red
- textile structure
- 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
- 239000004753 textile Substances 0.000 title claims description 18
- 238000005259 measurement Methods 0.000 title claims description 17
- 238000000034 method Methods 0.000 claims description 18
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 8
- 229910052721 tungsten Inorganic materials 0.000 claims description 8
- 239000010937 tungsten Substances 0.000 claims description 8
- 230000005540 biological transmission Effects 0.000 claims description 7
- 239000000835 fiber Substances 0.000 claims description 7
- 239000000853 adhesive Substances 0.000 claims description 2
- 230000001070 adhesive effect Effects 0.000 claims description 2
- 239000011248 coating agent Substances 0.000 claims 1
- 238000000576 coating method Methods 0.000 claims 1
- 238000012544 monitoring process Methods 0.000 claims 1
- 238000005286 illumination Methods 0.000 description 4
- 230000005855 radiation Effects 0.000 description 4
- 239000004744 fabric Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000005282 brightening Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000000411 transmission spectrum Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 210000002268 wool Anatomy 0.000 description 1
Classifications
-
- 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
Description
SPECIFICATION
Textile structure measurement
This invention relates to measuring across textile structures.
It is known to measure properties of textile structures, and particularly fibre webs intended for making yarn or for non-woven textiles, by measuring the obscuring effect of the structure on a light source. A light source is disposed on one side of the web or other structure and a light sensor on the other side. This works quite well and is reasonably linear for light webs where the web fibres obscure up to about 75% of the direct illumination to the light sensor. At higher densities, however, most of the transmitted light is light that has passed through the fibres of the textile structure. The amount of light thus transmitted depends to a considerable extent upon the composition of the fibres, the filament cross-section, the nature and quantity of dye in or on the fibres, whether the fibres have optical brightening agents and like factors.
The present invention provides a method and apparatus for measuring across thick textile structures which is not subject to all the aforesaid disadvantages.
The invention comprises a method for measuring across a thick textile structure comprising measuring transmission through the said structure from an infra-red source.
The infra-red source may comprise a wideband source, which may comprise a tungsten filament lamp, for example, run at a dull glow.
By using a wide-band source, the possibility is avoided or reduced of absorption lines in the transmission spectrum affecting the measurement at certain wavelengths. On the other hand, provided that the infra-red properties of the particular fibre or fibres being measured are known, specific measurement frequencies may be selected by the use of appropriate filters. Of course, when reference is made to a tungsten lamp, which tends generally to be a small, if not exactly a point source, it is intended that where wide webs are concerned, several tungsten lamps will be used spaced apart at intervals to provide a spread of illumination widthwise of the web, or even a wide tungsten source such as a rectilinear filament lamp may be used.Where a wide web is concerned, the average cross measurement may be had or if desired in addition or alternatively a measure of the variation in web cross measurement across the width of the web.
The transmission of infra-red through a thick textile structure is found to be non-linear.
Whereas with a thin fleece with less than about 75% obscuration, the transmission of visible light is approximately linear with web density (say in terms of weight per unit area), with thick fleeces where transmission is predominantly through rather than between fibres, the transmitted energy falls off more rapidly with increasing obscuration and the rate of fall off appears in many instances to be approximately exponential. So as to present a meaningful indication of a cross measurement, the signal from an infra-red sensor in a measuring arrangement according to the invention can be linearised electronically, for example, digitally.
The method can be adapted for measuring the thickness of a thick fibre web, even to such a thickness as may be appropriate for a carpet backing or facing, say from 50 to as much as 1,000 grams per square metre. The thickness can be determined from the transmission measurement assuming a known volume density. On the other hand, if the thickness is known, volume density can be measured. The measurement is, however, found to approximate to area density, which is of most importance in a textile context.
Other variables can also be measured, for example the extent of bonding in an adhesively bonded fibre web or the thickness or regularity of an adhesive or backing layer, or the degree of thermobonding of a thermobonded web, it being merely necessary that sufficient infra-red radiation is transmitted to be detectable.
The invention also comprises apparatus for measuring across a thick textile structure comprising an infra-red source disposed on one side of support means for said structure and detector means disposed on the other side of said support means, and indicating means indicating the measurement.
The indicating means may comprise an analogue or a digital indicator calibrated to a selected variable such as web density in terms of weight per unit area.
One embodiment of apparatus and a method for measuring across a thick textile structure will now be described with reference to the accompanying drawing in which
Figure 1 is a diagrammatic representation,
Figure 2 is a diagrammatic elevation of a wide fleece measuring arrangement,
Figure 3 is a side view of the arrangement of Figure 2, and
Figure 4 is a view of a display screen indicating the results of measurement.
The Figure illustrates a method and apparatus for measuring across a thick textile structure 11, which may comprise a thick fleece having a weight per unit area of from, say, 50 to 1,000 grams per square metre, or a thermobonded fleece or an adhesively bonded fleece or an adhesively bonded laminated structure or a foam backed structure or the like of which it is desired to measure the thickness or the volume density or the area density or other property.
An infra-red source 12 comprises a tungsten lamp run at a dull glow from a mains supply 13 controlled by a control arrangement 14.
The control arrangement 14 comprises a photocell or infra-red detector 1 4a which monitors the output of the lamp 12 and which is connected to a current controller 1 4b in such manner as to maintain the lamp output at a desired constant value.
Infra-red radiation transmitted through the structure 11 is detected at a detector 15 which can be of the type used, for example, in heat-seeking missiles or such other available detector as may be appropriate.
The detector 15 is connected to indicating means 16 suitably calibrated to indicate the desired variable. Since the fall off of transmitted infra-red radiation will often be exponential with increasing web density, it will be desirable to linearise the output of the detector 15 in linearising means 17, which may comprise comparator means comparing the input signal from the detector 15 with a set of standard signals, perhaps as many as fifty in number and assigning an output to the indicating means according to which standard signal the detector 15 input signal compares to. The output may bear a logarithmic relation to the input, so as to compensate for the exponential of the transmission strength to the quantity being measured.
Although the detectors 15 may be expected to be reasonably similar in their characteristics, they may nevertheless display some differences which can, however, be compensated for by calibration. The calibration can involve illuminating the detectors 15 with no fleece present at two different irradiation levels and noting the output voltages of the detectors. The reading from each photodiode can be subsequently adjusted (as in a programmed microprocessor) by a correction factor (assuming the response of each detector
15 to be suitably linear over the illumination range).
The apparatus may be situated at any convenient place in a fleece path, especially just before or just after a point at which web density may be controlled or at which a faulty web needs to be detected.
An alternative method of using the apparatus would be to adjust the lamp current until a predetermined signal is obtained from the detector 15 and note the value of current required as an indication of the web density.
It may be necessary to control the surrounding conditions as by shielding against draughts and strong light from the sun, lighting and machinery in order to avoid spurious readings.
Even in a relatively unsophisticated form, the arrangement has been found capable of readily detecting a change in the area density of a thick cross-folded card web at a cross-folding fault where an over plate is followed by an under plate.
It would be possible to use the apparatus in an inspecting operation for finished fabric, where it might be combined with an optical inspection arrangement using visible light detecting a wider range of fabric faults than either visible light or infra-red used alone.
For wide webs, of course, as indicated above, multiple discrete infra-red sources would be used or a single elongate infra-red filament lamp giving a uniform or substantially uniform illumination over the width of the web, and multiple infra-red detectors would be disposed on the opposite side of the web, which could be averaged or which could be indicated seperately so as to give either an average web density or other cross measurement or a distribution of, for instance, web area density, over the width of the web. Figures 2 and 3 illustrate an arrangement for wide webs including a web-wide elongate filament lamp 21 situated above an inclined web path 22 opposite a battery of infra-red detectors 23.Situating the lamp 21 above the web exposes the web to infra-red radiation, but not to convected heat, and so is less deleterious to sensitive webs (e.g. of wool) than if the source were beneath the web. The inclined web path means that dust and fly has reduced tendency to settle on the detectors 23.
Figure 4 iliustrates indicating means 41 for indicating the lengthwise and transverse distribution of measurements of a travelling web.
The display comprises a video screen or visual display unit (VDU) with a split screen arrangement of which the upper half comprises a bar chart showing the measurement from each of the IR detectors of the embodiment of Figures 2 and 3 for example, while the lower half comprises a bar chart, updated every minute, of the average of the detectors measurements. Between them, these two indications serve as an indication of the uniformity, transverse and lengthwise, of the web.
Instead of a video screen, a liquid cyrstal or other display type can be used.
Claims (16)
1. A method for measuring across a thick textile structure comprising measuring transmission through the said structure from an infra-red source.
2. A method according to claim 1, in which
said infra-red source comprises a wide-band
source.
3. A method according to claim 1 or claim
2, in which said infra-red source comprises a tungsten lamp run at a dull glow.
4. A method according to any one of claims
1 to 3, in which the output of infra-red sensing means is linearised.
5. A method according to claim 4, in which the linearisation is effected digitally.
6. A method according to any one of claims
1 to 5, adapted to and used for measuring the thickness of a fibre web.
7. A method according to any one of claims 1 to 6, adapted to and used for measuring the density of a fibre web.
8. A method according to any one of claims 1 to 7, when used for measuring the extent of bonding in a fibre web.
9. A method according to claim 8, when used to measure the degree of thermobonding of a thermobonded web.
10. A method according to any one of claims 1 to 9, when used to measure the thickness of an adhesive coating on a textile structure.
11. A method for monitoring a moving thick textile structure comprising continuously measuring the moving thick textile structure by a method according to any one of claims 1 to 10.
12. Apparatus for measuring across a thick textile structure comprising an infra-red source disposed on one side of support means for said structure and detector means disposed on the other side of said support means, and indicating means indicating the measurement.
13. Apparatus according to claim 12, said infra-red source comprising a wide-band source.
14. Apparatus according to claim 12 or claim 13, said infra-red source comprising a tungsten lamp and comprising electric supply means therefor adapted to run said tungsten lamp at a dull glow.
15. Apparatus according to any one of claims 12 to 14, comprising linearising means linearising the output of said detector so as to conform linearly to the web cross measurement.
16. Apparatus according to claim 15, said linearising means comprising digital linearising means.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8601907A GB2172102B (en) | 1985-03-09 | 1986-01-27 | Textile structure measurement |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB858506149A GB8506149D0 (en) | 1985-03-09 | 1985-03-09 | Textile structure measurement |
GB8601907A GB2172102B (en) | 1985-03-09 | 1986-01-27 | Textile structure measurement |
Publications (3)
Publication Number | Publication Date |
---|---|
GB8601907D0 GB8601907D0 (en) | 1986-03-05 |
GB2172102A true GB2172102A (en) | 1986-09-10 |
GB2172102B GB2172102B (en) | 1988-10-19 |
Family
ID=26288948
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB8601907A Expired GB2172102B (en) | 1985-03-09 | 1986-01-27 | Textile structure measurement |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2172102B (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2179444B (en) * | 1985-07-31 | 1990-04-11 | Koerber Ag | Method and apparatus for ascertaining the density of a stream of tobacco material |
DE4040490A1 (en) * | 1990-12-18 | 1992-06-25 | Knorr Bremse Ag | CHARGING DEVICE FOR THE BATTERY OF AN ANTI-SLIP SYSTEM OF A RAIL VEHICLE |
GB2259760A (en) * | 1991-09-17 | 1993-03-24 | Richard Edward Davies | Measuring weight per unit length of fibrous material |
US5355561A (en) * | 1990-11-02 | 1994-10-18 | Maschinenfabrik Rieter Ag | Method and apparatus for measuring a characteristic of a fiber structure, such as a fiber composite or a sliver |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1308953A (en) * | 1969-11-12 | 1973-03-07 | Sybron Corp | Radiation detector for apparatus for measuring moisture |
US3806730A (en) * | 1971-10-07 | 1974-04-23 | Nokia Oy Ab | Device for radiation measurements on material webs |
GB1352700A (en) * | 1970-10-29 | 1974-05-08 | Agfa Gevaert | Photoelectric device |
GB1364439A (en) * | 1970-08-25 | 1974-08-21 | Agfa Gevaert | Measurement of optical density |
US4052615A (en) * | 1976-07-30 | 1977-10-04 | Industrial Nucleonics Corporation | Spherical cavity method and apparatus for measuring a sheet material property using infrared radiation |
GB1589152A (en) * | 1978-05-20 | 1981-05-07 | Spencer Wright Ind Inc | Detection of faults in tufted fabrics |
-
1986
- 1986-01-27 GB GB8601907A patent/GB2172102B/en not_active Expired
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1308953A (en) * | 1969-11-12 | 1973-03-07 | Sybron Corp | Radiation detector for apparatus for measuring moisture |
GB1364439A (en) * | 1970-08-25 | 1974-08-21 | Agfa Gevaert | Measurement of optical density |
GB1352700A (en) * | 1970-10-29 | 1974-05-08 | Agfa Gevaert | Photoelectric device |
US3806730A (en) * | 1971-10-07 | 1974-04-23 | Nokia Oy Ab | Device for radiation measurements on material webs |
US4052615A (en) * | 1976-07-30 | 1977-10-04 | Industrial Nucleonics Corporation | Spherical cavity method and apparatus for measuring a sheet material property using infrared radiation |
GB1589152A (en) * | 1978-05-20 | 1981-05-07 | Spencer Wright Ind Inc | Detection of faults in tufted fabrics |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2179444B (en) * | 1985-07-31 | 1990-04-11 | Koerber Ag | Method and apparatus for ascertaining the density of a stream of tobacco material |
US5355561A (en) * | 1990-11-02 | 1994-10-18 | Maschinenfabrik Rieter Ag | Method and apparatus for measuring a characteristic of a fiber structure, such as a fiber composite or a sliver |
DE4040490A1 (en) * | 1990-12-18 | 1992-06-25 | Knorr Bremse Ag | CHARGING DEVICE FOR THE BATTERY OF AN ANTI-SLIP SYSTEM OF A RAIL VEHICLE |
GB2259760A (en) * | 1991-09-17 | 1993-03-24 | Richard Edward Davies | Measuring weight per unit length of fibrous material |
Also Published As
Publication number | Publication date |
---|---|
GB2172102B (en) | 1988-10-19 |
GB8601907D0 (en) | 1986-03-05 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |