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US3812348A - Device for electro-optically ascertaining holes in moving webs - Google Patents

Device for electro-optically ascertaining holes in moving webs Download PDF

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Publication number
US3812348A
US3812348A US00308013A US30801372A US3812348A US 3812348 A US3812348 A US 3812348A US 00308013 A US00308013 A US 00308013A US 30801372 A US30801372 A US 30801372A US 3812348 A US3812348 A US 3812348A
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US
United States
Prior art keywords
light
light sensitive
sensitive means
web
pairs
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Expired - Lifetime
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US00308013A
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English (en)
Inventor
R Hiemke
P Lippke
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Individual
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Individual
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    • 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
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • G01N21/8901—Optical details; Scanning details
    • 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
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • G01N21/892—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
    • G01N21/894—Pinholes

Definitions

  • the present invention relates to a device for electrooptically ascertaining holes in moving webs of paper and the like, in which at one side of the web there is provided an illuminating device whereas on the other side there are provided light sensitive elements the emanated signals of which are conveyed to amplifiers.
  • An important disadvantage of the heretofore known device consists in that the light source as well as the photoelectric cells have to be arranged closely below or above the web if a hole in the web is to initiate a signal for indicating a flaw in the web. If the photoelectric cells are spaced from the web at a greater distance, they will no longer be able to emanate a sufficiently strong signal to indicate a flaw because the light of luminous substance lamps with relatively large illuminating surfaces emanates with a correspondingly low illu- 'minating density so that the illuminating strength in the plane of the light sensitive elements will change only immaterially or to an insufficient degree. This is true if the diameter of a hole-is approximately 1 mm as is frequently the case with holes in paper webs.
  • the illuminating system together with the necessary special current supply causes high costs.
  • the employed extremely sensitive photo multipliers together with the necessary filters which correspond to the ultraviolet radiation and which are intended to eliminate the influence of outside light are expensive.
  • operators remaining for a longer period of time within the range of the checking device may suffer eye damage.
  • an object of the present invention to provide a device of the type involved which will have relatively simple elements only and which will be safe in operation while the distance between the illuminating device and the light sensitive elements can be made relatively great.
  • FIG. 1 is a side view and partially a section of a device according to the invention.
  • FIG. 2 shows the arrangement of the light sensitiv elements on a support
  • FIG. 3 illustrates a front view of preferred incandescent lamps for the illuminating device.
  • FIG. 4 illustrates an electric circuit for compensating for the influence of the light which continuously passes from the surrounding area onto the light sensitive elements.
  • the device for electro-optically ascertaining holes in moving webs of paperand the like is characterized primarily in that an illuminating device is provided with a thread-Iike light source arranged transverse to the direction of movement of the web, and is furthermore characterized in that the light sensitive elements are arranged in pairs while the elements forming the pairsare located in one or the other of two rows which are located one behind the other in the direction of movement of the web and are parallel to the longitudinal extensionof the light source while being located in a plane parallel to the plane of the web.
  • the device according to the invention is also characterized in that the elements of each pair are electrically arranged in series-opposed manner so that light which simultaneously hits two elements of one or more pairs will not initiate asignal.
  • the thread-shaped light source is in conformity with the function of a pinhole camera portrayed in the plane of the light sensitive elements.
  • the light sensitive elements By taking advantage of this effect, it is possible to arrange the light sensitive elements at a greater distance from the web and nevertheless to obtain a signal which is sufficient for indicating a flaw.
  • a device according to the present invention has yielded satisfactoryv checking results if the light source or the light source and the light sensitive elements respectively were arranged at a distance of approximately 30 cm from the web.
  • the imageof the thread-shaped light source in the plane of the light sensitive elements is for holes nonnally occurring in paper webs so sharp and bright combined with a corresponding increase in the illuminating strength at this point that the signal emanated when a hole is present is sufficient to indicate a flaw.
  • This effect which is taken advantage of in connection with the invention, would not occur if instead of a thread-like light source, for instance, incandescent lamps with frosted glass bulbs were employed or corresponding luminous substance lamps were used. .
  • iamps on the one hand, have too large a light emanating surface so that they cannot furnish a sufi'tciently'effective signal when taking advantage of the just described effect. On the other hand, they have too low an illuminating density.
  • incandescent lamps with frosted glass bulbs have an illuminating density of 50 cdlcm whereas the thread-shaped light sources employed with 'the device according to the invention have a light densityof 2,000 cdlcm Tubes with luminous substance have a still lower light density than incandescent lamps with frosted glass'bulbs.
  • the illuminating device can be produced in a simple manner.
  • light sensitive elements according to the invention are arranged in pairs and with regard to each pair are electrically arranged in a series-opposed manner. In this way only such light influences can initiate'a signal which hit the two elements of one or more pairs in a non-uniform manner. This is the case when portraying the threadshaped light source in the plane of the elements in case there is a hole in the web. In such an instance first one and subsequently the other light sensitive element of each pair receives a higher illuminating strength.
  • the reference numeral 1 designates a web which, for instance, is
  • an illuminating device 4 which comprises primarily a housing 5 with incandescent lamps 6.
  • light sensitive elements 10, 11 arranged on a support 13.
  • the incandescent lamps 6 have a preferably non-coiled thin filament 7 which forms the light source.
  • the filaments 7 of the incandescent lamps 6 arranged adjacent to each other in the housing 5 portray a nearly uninterrupted thread-shaped light source which extends transverse to the direction of movement of the web and is located parallel or nearly parallel to the rows 8 and 9 of the light sensitive elements 10, 11.
  • the thickness of the filaments 7 is of a magnitude of 1/ l0 mm so that when a hole occurs in the web 1, a relatively sharp image of the filament or filaments 7 is obtained in the plane of the light sensitive elements 10 and 11 without any optical auxiliary means.
  • Such image of a filament is illustrated in FIG. 2 and designated with the reference numeral 12.
  • the image 12 extends with sufficient .illuminating strength in the plane of the elements over a plurality of elements 10, ll of a row so that the suggested device according to the invention furnishes the further advantage that only relatively few light sensitive elements are needed for checking the entire width of a web because the elements of each row may be arranged at a relatively great distance from each other on a support 13.
  • incandescent lamps by a corresponding plurality of incandescent lamps with point-shaped light sources, if such incandescent lamps are arranged closely adjacentto each other. Aside from the difficulty of producing for this purpose sufficiently point-shaped light sources, and aside from the employment of a greater number of elements, it would additionally be necessary to arrange the light sensitive elements of a row closer adjacent to each other so that also more of these elements would be needed.
  • the incandescent lamps 6 are provided with glass bulbs 14 which, for all practical purposes, do not affect the optical function
  • the filament 7 of' an incandescent lamp 6 is connected with the two contacts 15 and 16 for the supply of current.
  • the filament 7 is held in its predetermined position by a supporting coil 17.
  • an image 12 will first pass over the light sensitive elements 11 of row 9 and subsequently will pass over or scan the elements 10 of row 8.
  • the outlets of the light sensitive elements 10 and 11, which elements are arranged in pairs 22 on the support 13, are connected to one or the other inlet of differential amplifiers 18.
  • Additional devices 19 for indicating flaws are connected to the outlets of the amplifiers 18. in order to improve the effect of the images 12 and to compensate for changes of the light impacting from the surrounding area upon the light sensitive elements 10 and 11, a suitable bias is conveyed to the inlet of the differential amplifiers 18. This is done by a voltage divider 20, 21.
  • the elements in such a way within the framework of a paper making machine or the like that the surrounding daylight or the light of the light; source in the vicinity will not or will not directly pass onto the elements.
  • a particular advantage of the device according to the invention consists in that it operates without any auxiliary optical means.
  • a device for electro-optically ascertaining holes in a moving web, especially web of paper which includes: a source of illumination comprising a thread-shaped light source, light sensitive means adapted to initiate a signal, said light sensitive means being arranged in pairs one behind the other so that the two light sensitive means of all of said pairs are respectively arranged in two common seperate rows substantially parallel to each other and to the longitudinal extension of said thread-shaped light source, said light sensitive means also having outlets for releasing signals, said source of illumination and said light sensitive means being arranged one above the other in spaced relationship to each other, and conveying meansfor conveying a web between and in spaced relationship to said source of illumination and said light sensitive means, said threadshaped light source having its direction of length arranged transverse to the conveying direction of said conveying means, and the light sensitive means of each of said pairs of light sensitive means electrically oppos- 6 ing each other so that light simultaneously hitting both light sensitive means of one and more of said pairs will not initiate a signal.
  • the light source comprises at least one tubular incandescent lamp with a thin filament in aclear glass bulb.
  • a device which includes a voltage divider, and differential amplifier means having inlets respectively electrically connected to the outlets of the pairs of said light sensitive means through said voltage divider for compensating for the influence of undesired light hitting said light sensitive means.
  • a device in'which said light sensitive means are protected against the influence of undesired surrounding light from surrounding foreign light sources by shields.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
  • Treatment Of Fiber Materials (AREA)
  • Length Measuring Devices By Optical Means (AREA)
US00308013A 1971-11-18 1972-11-20 Device for electro-optically ascertaining holes in moving webs Expired - Lifetime US3812348A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2157247A DE2157247A1 (de) 1971-11-18 1971-11-18 Einrichtung zum elektro-optischen feststellen von loechern in bewegten bahnen aus papier und dgl

Publications (1)

Publication Number Publication Date
US3812348A true US3812348A (en) 1974-05-21

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Application Number Title Priority Date Filing Date
US00308013A Expired - Lifetime US3812348A (en) 1971-11-18 1972-11-20 Device for electro-optically ascertaining holes in moving webs

Country Status (4)

Country Link
US (1) US3812348A (de)
JP (1) JPS4863779A (de)
DE (1) DE2157247A1 (de)
GB (1) GB1362320A (de)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3906238A (en) * 1973-05-30 1975-09-16 Eigo Yagi Size control device for continuously produced elongate object
US4227091A (en) * 1978-02-27 1980-10-07 Erwin Sick Gmbh, Optik-Elektronik Optical monitoring apparatus
US4343998A (en) * 1979-02-23 1982-08-10 Sukeo Mori Method and apparatus for detecting sewing defects on a stocking toe closer
US4501953A (en) * 1981-01-09 1985-02-26 Tann-Papier Gesellschaft M.B.H. Method of and apparatus for controlling apparatus for perforating strips of paper or the like by disruptive spark discharges
US4572666A (en) * 1981-03-13 1986-02-25 Satake Engineering Co., Ltd. Apparatus for detecting cracked rice grain
US4766325A (en) * 1986-07-18 1988-08-23 Siemens Aktiengesellschaft Method for testing for faulty plated-through bores circuit boards
US5220178A (en) * 1991-12-19 1993-06-15 Phillips Petroleum Company Apparatus and process for detecting the presence of defects on a moving sheet of material
US5323015A (en) * 1992-02-27 1994-06-21 Rydborn Sten Angstrom O Directional movement sensor using three light sensing elements and differential amplifiers
US5352887A (en) * 1992-08-28 1994-10-04 Motorola, Inc. Circuit for detecting a droplet in motion and method therefor
US5666199A (en) * 1994-07-11 1997-09-09 Phillips Petroleum Company Apparatus and process for detecting the presence of gel defects in oriented sheets or films based on polarization detection
US5760414A (en) * 1995-12-19 1998-06-02 Monarch Marking Systems, Inc. Web of record members and method of and apparatus for making same and system for detecting indicia
EP2799378A4 (de) * 2011-12-27 2017-05-10 Toray Industries, Inc. Herstellungsvorrichtung und herstellungsverfahren für mikroporöse folienrolle

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8432099D0 (en) * 1984-12-19 1985-01-30 Fenner Co Ltd J H Conveyor belt monitoring system

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3906238A (en) * 1973-05-30 1975-09-16 Eigo Yagi Size control device for continuously produced elongate object
US4227091A (en) * 1978-02-27 1980-10-07 Erwin Sick Gmbh, Optik-Elektronik Optical monitoring apparatus
US4343998A (en) * 1979-02-23 1982-08-10 Sukeo Mori Method and apparatus for detecting sewing defects on a stocking toe closer
US4501953A (en) * 1981-01-09 1985-02-26 Tann-Papier Gesellschaft M.B.H. Method of and apparatus for controlling apparatus for perforating strips of paper or the like by disruptive spark discharges
US4572666A (en) * 1981-03-13 1986-02-25 Satake Engineering Co., Ltd. Apparatus for detecting cracked rice grain
US4766325A (en) * 1986-07-18 1988-08-23 Siemens Aktiengesellschaft Method for testing for faulty plated-through bores circuit boards
US5220178A (en) * 1991-12-19 1993-06-15 Phillips Petroleum Company Apparatus and process for detecting the presence of defects on a moving sheet of material
US5323015A (en) * 1992-02-27 1994-06-21 Rydborn Sten Angstrom O Directional movement sensor using three light sensing elements and differential amplifiers
US5352887A (en) * 1992-08-28 1994-10-04 Motorola, Inc. Circuit for detecting a droplet in motion and method therefor
US5666199A (en) * 1994-07-11 1997-09-09 Phillips Petroleum Company Apparatus and process for detecting the presence of gel defects in oriented sheets or films based on polarization detection
US5760414A (en) * 1995-12-19 1998-06-02 Monarch Marking Systems, Inc. Web of record members and method of and apparatus for making same and system for detecting indicia
EP2799378A4 (de) * 2011-12-27 2017-05-10 Toray Industries, Inc. Herstellungsvorrichtung und herstellungsverfahren für mikroporöse folienrolle

Also Published As

Publication number Publication date
JPS4863779A (de) 1973-09-04
GB1362320A (en) 1974-08-07
DE2157247A1 (de) 1973-05-24

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