CA2011912A1 - Non-contacting on-line paper strength measuring system - Google Patents
Non-contacting on-line paper strength measuring systemInfo
- Publication number
- CA2011912A1 CA2011912A1 CA002011912A CA2011912A CA2011912A1 CA 2011912 A1 CA2011912 A1 CA 2011912A1 CA 002011912 A CA002011912 A CA 002011912A CA 2011912 A CA2011912 A CA 2011912A CA 2011912 A1 CA2011912 A1 CA 2011912A1
- Authority
- CA
- Canada
- Prior art keywords
- ultrasonic wave
- strength
- web
- laser
- velocity
- 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
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/34—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor
- G01N29/341—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor with time characteristics
- G01N29/343—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor with time characteristics pulse waves, e.g. particular sequence of pulses, bursts
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/07—Analysing solids by measuring propagation velocity or propagation time of acoustic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/24—Probes
- G01N29/2418—Probes using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/34—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor
- G01N29/341—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor with time characteristics
- G01N29/345—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor with time characteristics continuous waves
-
- 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
- G01N33/36—Textiles
- G01N33/367—Fabric or woven textiles
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/023—Solids
- G01N2291/0237—Thin materials, e.g. paper, membranes, thin films
Abstract
ABSTRACT
An on-line system that measures the strength of material within a web without contacting same is disclosed.
Two laser sources having beams which impinge upon the web of material are positioned so that their respective beams are spaced a predetermined distance apart. The first laser source induces a radially propagating ultrasonic wave within the material. The ultrasonic wave causes the beam from the second laser source to be reflected and intercepted by a light sensor permitting the velocity of the wave and the strength of the material to be determined.
An on-line system that measures the strength of material within a web without contacting same is disclosed.
Two laser sources having beams which impinge upon the web of material are positioned so that their respective beams are spaced a predetermined distance apart. The first laser source induces a radially propagating ultrasonic wave within the material. The ultrasonic wave causes the beam from the second laser source to be reflected and intercepted by a light sensor permitting the velocity of the wave and the strength of the material to be determined.
Description
20119~
The present invention relates generally to a system for measuring the strength of material within a web and, more particularly, to an on-line system that measures the strength of paper in a web without contacting same.
A major quality consideration for the production of sheet materials, such as paper, is strength. Until recently, all strength measurements with respect to such sheet materials were made by off-line laboratory measurements.
Recently, on-line measurements have been introduced using contacting gauging techniques that rely on the relationship between Young's Modulus and the speed of sound according to the following equation:
Y = k1 s Where k1 is a function of the density of the material and s is the speed of sound within the material.
The methods of Baum and Habeger, as set forth in U.S.
Patent No. 4,291,577, and others, rely on rotating wheels which contact the moving web of paper or other material whose strength is being measured. The wheels contain piezoelectric or magnetostrictive transducers in their outer peripheries to create a localized contraction and expansion in the moving web of material. This contraction and expansion creates a sonic wave that travels radially from the spot of creation.
Measuring the speed of sound within the material, which is the reciprocal of the transit time between two points of known separation, is used in conjunction with the density of the material to provide a measurement of the strength of the material. This approach has some inherent disadvantages among which are that the required commutation and mechaniral contact produce a signal that contains a significant amount of noise, the rotating wheels are prone to fail, mechanical structures are inevitably more costly and have more parts than electronic devices, the direct contact of the wheels with the material limits the measurement of strength to a single direction (either across the web or along the web), and mechanical methods with slippage and commutation are inherently less accurate than non-mechanical methods.
Photoacoustic interaction has been used to induce ultrasonic waves into a continuous, fast moving web of paper.
U.S. Patent No. 4,674,332 (Pace, et al) discloses the use of a nitrogen laser to illuminate paper with high power ultraviolet pulses. A portion of this optical energy is converted into heat creating an acoustic wave from the resulting thermal expansion. A contacting, ultrasonic sensor or a microphone positioned on the opposite side of the paper receives the acoustic wave and provides an indication of the speed of sound through the paper which can be utilized to determine the strength of the paper in its direction of movement.
Another application of a laser to generate acoustic waves in paper is provided in U.S. Patent No. 4,622,853 (Leugers). The apparatus disclosed in this reference utilizes a Neodymium/Yttrium-Aluminum-Garnet (Nd/YAG) laser with a frequency doubler to illuminate a spot on a moving web of paper. The ultrasonic wave in the paper is detected by an ultrasonic transducer in contact with the paper.
Because of the disadvantages that are inherent in a measuring system that requires contact with the material whose strength is being measured, it has become desirable to develop an on-line, measuring system that does not require such contact.
With a view to overcoming the above-mentioned and other problems and disadvantages associated with the prior art, the invention provides in one aspect a system for measuring the strength of material within a web without 2 ~ Z 2 contacting same comprising a first source of light beams positioned SUCIl that said light beams contact the material and induce an ultrasonic wave therein, means for detecting said ultrasonic wave at a pre-determined distance from the point of inducement of said ultrasonic wave within the material, means for determining the velocity of said ultrasonic wave within the material, means for determining the density of the material, and means for determining the strength of the material based on the veloaity of said ultrasonic wave within the material and the density of the material. A detecting means may advantageously comprise light sensing means which detects the light reflected from the material as said ultrasonic wave traverses therethrough.
According to a second aspect of the invention, there is provided a method of measuring the strength of material within a web, comprising the steps of:
(i) directing a source of light beams toward the material causing an ultrasonic wave to be induced therein;
~ ii) determining the presence of said ultrasonic wave within the material at a location a pre-determined distance - away from the point where said ultrasonic wave was induced;
(iii) determining the velocity of said ultrasonic wave within the material; and (ib) combining the velocity of said ultrasonic wave with the density of the material to determine the strength of the material.
In drawings which illustrate embodiments of the invention, Figure 1 is a schematic diagram of the measuring system of the present invention.
Figure 2 is a schematic diagram of the control circuit utilized by the measuring system shown in Figure 1.
Figure 3 is a schematic diagram of an alternate 20119~ 2 embodiment of the measuring system of the present invention utilizing two light sensors.
Figure 4 is a schematic diagram of the control circuit utilized by the embodiment of the invention shown in Figure 3.
Referring now to the drawings where the illustrations are for the purpose of describing the preferred embodiment of the present invention and are not intended to limit the - invention hereto, Figure 1 is a schematic diagram of the measuring system of the present invention. The measuring system includes a first laser source 10 directed toward a web 12 of material whose strength is to be measured, a second laser source 14 similarly directed toward the web 12 of material and a light sensor 16 located adjacent second laser source 14 and positioned so that its focal point is coincident with the point of impingement of the beam from second laser source 14 on the web 12 of material. The distance "d" between the points of impingement of the beams from laser sources 10 and 14 on web 12 of material is known.
The present invention utilizes an ultrasonic wave pattern induced into the moving web 12 of material by pulses produced by first laser source 10 which generates localized spot heating. Such localized spot heating creates thermal expansion in the material whose strength is being measured.
This expansion pertubation creates a wave which propagates through the web 12 of material in a radial direction giving an elliptical wave front, shown generally by the numeral 18 due to the anisotropy in the wave velocity with the direction of web movement. Measurement of wave velocity in a particular direction can be utilized to determine the strength of the material in that direction.
The light sensor 1~ measures the foregoing wave front 2 ~
by viewing the crests and valleys of the ultrasonic wave as it passes thereunder. Separate viewing laser and light detection systems may be used for the cross-travel direction and the width-travel direction or a single system may be scanned to read both directions. The time of arrival of the sensed pulse is compared with the time of impingement of the beam from first laser source 10 into the web 12 of material, and the difference in time is utilized to calculate the speed of sound within the material. The foregoing speed of sound is then used in conjunction with the density of the material to determine the strength of the material being tested. The foregoing system operates at the speed of light and, as such, any time delays are inconsequential.
First laser source 10 is a C02 laser having an output power of approximately 5.5 watts and is typically pulsed at a rate of 10 pulses per second producing a pulse having a width of approximately 100 ~ sec. or shorter. Second laser source 14 is a HeNe laser having an output power of approximately 2 milliwatts which is operated continuously.
Light sensor 16 can be a silicon photo-detector producing an output in millivolt range.
Referring now to Figure 2, a schematic diagram of the control circuit 30 associated with the present invention is illustrated. This control circuit 30 includes a laser pulser control 32 which regulates the operation of first laser source 10. Each time the first laser source 10 is pulsed, a first timing pulse is transmitted by the laser pulser control 32 to a timing analyzer 34. After the resulting ultrasonic wave caused by the pulse produced by first laser source 10 has propagated through the material whose strength is being measured, the light sensor 16 intercepts the light emanating from second laser source 14 and reflected by the material, and transmits a pulse to a preamp level detector 36 which, in turn, transmits a second timing pulse to timing analyzer 34.
201191~
An output of the preamp level detector 36 is cannected to an input to the laser pulser control 32 and causes the pulser control 32 to increase or decrease the magnitude of the pulses produced by first laser source lO so that the ultrasonic pulses detected by light sensor 16 will be of - sufficient magnitude for detection purposes. The timing analyzer 34 determines the elapsed time, A t, between the transmission of the first timing pulse by the laser pulser control 32 and the receipt of the second timing pulse from the preamp level detector 36. The foregoing elapsed time ~ t and the known distance d between points of impingement on the web 12 of the beams emanating from laser sources 10 and 14 are then combined with a measurement of material density provided by a density measuring device 38 in a strength calculation device 40 to determine the velocity v of the ultrasonic wave within the material whose strength is being measured. An appropriate density measuring device 38 is disclosed in U.S. Patent No. 3,586, 601 entitled "Basis Weight Control System for a Paper Making Machine'~. The strength calculating device 40, which can be a microprocessor, determines the strength of the material since material strength is proportional to K1v2 where v is the speed of sound in the material.
A maximum laser level control 42 and a web speed control 44 are provided as inputs to the laser pulser control 32. The maximum laser level control 42 ensures that first laser source 10 causes no damage to the material whose strenght is being measured and the web speed signal 44 allows the laser level to increase as the web speed increases.
An alternate embodiment of the present invention is shown in Figure 3. In this Figure, two sensing arrangements are employed. Inasmuch as the elements are the same as those shown in Figure 1 and carry the same reference numerals, further discussion of same will not be undertaken. The main 201~
advantage of this embodiment is that the use of two sensing arrangements permits the correlation of the received wave shapes using digital correlation or digital signal processing techniques so as to improve the accuracy of the resulting strength measurement and to allow for less precision and repeatability in the shape of the generated ultrasonic wave shape.
Figure 4 illustrates the control circuit utilized by the embodiment of the invention illustrated in Figure 3.
Here again, those elements which are similar to the elements shown in Figure 2 carry the same reference numerals and will not be discussed. The primary difference between the schematic diagram shown in Figure 4 and that shown in Figure 2 is the use of a digital correlator 46 which, as previously indicated, correlates the wave shapes received by the light sensors 16 and utilizes digital correlation or digital signaling processing techniques to determine the time required for the ultrasonic wave shape to traverse the web of material. Since two light sensors are utilized in the embodiment shown in Figure 3 and Figure 4, it is possible to use less precise and less expensive pulse sources to induce the waves in the moving web of material.
Regardless of the embodiment of the invention utilized, the present invention provides the following advantages:
1) The measuring system is on-line and does not contact the web of material;
2) The system has omnidirectional measurement capability;
The present invention relates generally to a system for measuring the strength of material within a web and, more particularly, to an on-line system that measures the strength of paper in a web without contacting same.
A major quality consideration for the production of sheet materials, such as paper, is strength. Until recently, all strength measurements with respect to such sheet materials were made by off-line laboratory measurements.
Recently, on-line measurements have been introduced using contacting gauging techniques that rely on the relationship between Young's Modulus and the speed of sound according to the following equation:
Y = k1 s Where k1 is a function of the density of the material and s is the speed of sound within the material.
The methods of Baum and Habeger, as set forth in U.S.
Patent No. 4,291,577, and others, rely on rotating wheels which contact the moving web of paper or other material whose strength is being measured. The wheels contain piezoelectric or magnetostrictive transducers in their outer peripheries to create a localized contraction and expansion in the moving web of material. This contraction and expansion creates a sonic wave that travels radially from the spot of creation.
Measuring the speed of sound within the material, which is the reciprocal of the transit time between two points of known separation, is used in conjunction with the density of the material to provide a measurement of the strength of the material. This approach has some inherent disadvantages among which are that the required commutation and mechaniral contact produce a signal that contains a significant amount of noise, the rotating wheels are prone to fail, mechanical structures are inevitably more costly and have more parts than electronic devices, the direct contact of the wheels with the material limits the measurement of strength to a single direction (either across the web or along the web), and mechanical methods with slippage and commutation are inherently less accurate than non-mechanical methods.
Photoacoustic interaction has been used to induce ultrasonic waves into a continuous, fast moving web of paper.
U.S. Patent No. 4,674,332 (Pace, et al) discloses the use of a nitrogen laser to illuminate paper with high power ultraviolet pulses. A portion of this optical energy is converted into heat creating an acoustic wave from the resulting thermal expansion. A contacting, ultrasonic sensor or a microphone positioned on the opposite side of the paper receives the acoustic wave and provides an indication of the speed of sound through the paper which can be utilized to determine the strength of the paper in its direction of movement.
Another application of a laser to generate acoustic waves in paper is provided in U.S. Patent No. 4,622,853 (Leugers). The apparatus disclosed in this reference utilizes a Neodymium/Yttrium-Aluminum-Garnet (Nd/YAG) laser with a frequency doubler to illuminate a spot on a moving web of paper. The ultrasonic wave in the paper is detected by an ultrasonic transducer in contact with the paper.
Because of the disadvantages that are inherent in a measuring system that requires contact with the material whose strength is being measured, it has become desirable to develop an on-line, measuring system that does not require such contact.
With a view to overcoming the above-mentioned and other problems and disadvantages associated with the prior art, the invention provides in one aspect a system for measuring the strength of material within a web without 2 ~ Z 2 contacting same comprising a first source of light beams positioned SUCIl that said light beams contact the material and induce an ultrasonic wave therein, means for detecting said ultrasonic wave at a pre-determined distance from the point of inducement of said ultrasonic wave within the material, means for determining the velocity of said ultrasonic wave within the material, means for determining the density of the material, and means for determining the strength of the material based on the veloaity of said ultrasonic wave within the material and the density of the material. A detecting means may advantageously comprise light sensing means which detects the light reflected from the material as said ultrasonic wave traverses therethrough.
According to a second aspect of the invention, there is provided a method of measuring the strength of material within a web, comprising the steps of:
(i) directing a source of light beams toward the material causing an ultrasonic wave to be induced therein;
~ ii) determining the presence of said ultrasonic wave within the material at a location a pre-determined distance - away from the point where said ultrasonic wave was induced;
(iii) determining the velocity of said ultrasonic wave within the material; and (ib) combining the velocity of said ultrasonic wave with the density of the material to determine the strength of the material.
In drawings which illustrate embodiments of the invention, Figure 1 is a schematic diagram of the measuring system of the present invention.
Figure 2 is a schematic diagram of the control circuit utilized by the measuring system shown in Figure 1.
Figure 3 is a schematic diagram of an alternate 20119~ 2 embodiment of the measuring system of the present invention utilizing two light sensors.
Figure 4 is a schematic diagram of the control circuit utilized by the embodiment of the invention shown in Figure 3.
Referring now to the drawings where the illustrations are for the purpose of describing the preferred embodiment of the present invention and are not intended to limit the - invention hereto, Figure 1 is a schematic diagram of the measuring system of the present invention. The measuring system includes a first laser source 10 directed toward a web 12 of material whose strength is to be measured, a second laser source 14 similarly directed toward the web 12 of material and a light sensor 16 located adjacent second laser source 14 and positioned so that its focal point is coincident with the point of impingement of the beam from second laser source 14 on the web 12 of material. The distance "d" between the points of impingement of the beams from laser sources 10 and 14 on web 12 of material is known.
The present invention utilizes an ultrasonic wave pattern induced into the moving web 12 of material by pulses produced by first laser source 10 which generates localized spot heating. Such localized spot heating creates thermal expansion in the material whose strength is being measured.
This expansion pertubation creates a wave which propagates through the web 12 of material in a radial direction giving an elliptical wave front, shown generally by the numeral 18 due to the anisotropy in the wave velocity with the direction of web movement. Measurement of wave velocity in a particular direction can be utilized to determine the strength of the material in that direction.
The light sensor 1~ measures the foregoing wave front 2 ~
by viewing the crests and valleys of the ultrasonic wave as it passes thereunder. Separate viewing laser and light detection systems may be used for the cross-travel direction and the width-travel direction or a single system may be scanned to read both directions. The time of arrival of the sensed pulse is compared with the time of impingement of the beam from first laser source 10 into the web 12 of material, and the difference in time is utilized to calculate the speed of sound within the material. The foregoing speed of sound is then used in conjunction with the density of the material to determine the strength of the material being tested. The foregoing system operates at the speed of light and, as such, any time delays are inconsequential.
First laser source 10 is a C02 laser having an output power of approximately 5.5 watts and is typically pulsed at a rate of 10 pulses per second producing a pulse having a width of approximately 100 ~ sec. or shorter. Second laser source 14 is a HeNe laser having an output power of approximately 2 milliwatts which is operated continuously.
Light sensor 16 can be a silicon photo-detector producing an output in millivolt range.
Referring now to Figure 2, a schematic diagram of the control circuit 30 associated with the present invention is illustrated. This control circuit 30 includes a laser pulser control 32 which regulates the operation of first laser source 10. Each time the first laser source 10 is pulsed, a first timing pulse is transmitted by the laser pulser control 32 to a timing analyzer 34. After the resulting ultrasonic wave caused by the pulse produced by first laser source 10 has propagated through the material whose strength is being measured, the light sensor 16 intercepts the light emanating from second laser source 14 and reflected by the material, and transmits a pulse to a preamp level detector 36 which, in turn, transmits a second timing pulse to timing analyzer 34.
201191~
An output of the preamp level detector 36 is cannected to an input to the laser pulser control 32 and causes the pulser control 32 to increase or decrease the magnitude of the pulses produced by first laser source lO so that the ultrasonic pulses detected by light sensor 16 will be of - sufficient magnitude for detection purposes. The timing analyzer 34 determines the elapsed time, A t, between the transmission of the first timing pulse by the laser pulser control 32 and the receipt of the second timing pulse from the preamp level detector 36. The foregoing elapsed time ~ t and the known distance d between points of impingement on the web 12 of the beams emanating from laser sources 10 and 14 are then combined with a measurement of material density provided by a density measuring device 38 in a strength calculation device 40 to determine the velocity v of the ultrasonic wave within the material whose strength is being measured. An appropriate density measuring device 38 is disclosed in U.S. Patent No. 3,586, 601 entitled "Basis Weight Control System for a Paper Making Machine'~. The strength calculating device 40, which can be a microprocessor, determines the strength of the material since material strength is proportional to K1v2 where v is the speed of sound in the material.
A maximum laser level control 42 and a web speed control 44 are provided as inputs to the laser pulser control 32. The maximum laser level control 42 ensures that first laser source 10 causes no damage to the material whose strenght is being measured and the web speed signal 44 allows the laser level to increase as the web speed increases.
An alternate embodiment of the present invention is shown in Figure 3. In this Figure, two sensing arrangements are employed. Inasmuch as the elements are the same as those shown in Figure 1 and carry the same reference numerals, further discussion of same will not be undertaken. The main 201~
advantage of this embodiment is that the use of two sensing arrangements permits the correlation of the received wave shapes using digital correlation or digital signal processing techniques so as to improve the accuracy of the resulting strength measurement and to allow for less precision and repeatability in the shape of the generated ultrasonic wave shape.
Figure 4 illustrates the control circuit utilized by the embodiment of the invention illustrated in Figure 3.
Here again, those elements which are similar to the elements shown in Figure 2 carry the same reference numerals and will not be discussed. The primary difference between the schematic diagram shown in Figure 4 and that shown in Figure 2 is the use of a digital correlator 46 which, as previously indicated, correlates the wave shapes received by the light sensors 16 and utilizes digital correlation or digital signaling processing techniques to determine the time required for the ultrasonic wave shape to traverse the web of material. Since two light sensors are utilized in the embodiment shown in Figure 3 and Figure 4, it is possible to use less precise and less expensive pulse sources to induce the waves in the moving web of material.
Regardless of the embodiment of the invention utilized, the present invention provides the following advantages:
1) The measuring system is on-line and does not contact the web of material;
2) The system has omnidirectional measurement capability;
3) Material strength can be determined across the entire web of material;
4) The system is adaptable to rough or hot material surfaces;
.
.
5) The system can utilize digital ~ignal processing techniques; and 6) Power levels are variable in order to optimize operation of the system without causing damage to the web of material.
Certain modifications and improvements will occur to those skilled in the art upon reading the foregoing. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability, but are properly within the scope of the following claims.
Certain modifications and improvements will occur to those skilled in the art upon reading the foregoing. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability, but are properly within the scope of the following claims.
Claims (7)
1. A system for measuring the strength of material within a web without contacting same comprising a first source of light beams positioned such that said light beams contact the material and induce an ultrasonic wave therein, means for detecting said ultrasonic wave at a predetermined distance from the point of inducement of said ultrasonic wave within the material, means for determining the velocity of said ultrasonic wave within the material, means for determining the density of the material, and means for determining the strength of the material based on the velocity of said ultrasonic wave within the material and the density of the material.
2. The system as defined in claim 1 wherein said detecting means comprises light sensing means which detects the light reflected from the material as said ultrasonic wave traverses therethrough.
3. The system as defined in claim 1 further including at least one second source of light beams positioned adjacent said detecting means, said light beams from said at least one second light beam source being directed so as to illuminate said ultrasonic wave as it traverses past said detecting means.
4. The system as defined in claim 1 wherein said first light beam source is a laser having a pulsed output.
5. The system as defined in claim 3 wherein said at least one second light beam source is a laser having a continuous output.
6. The system as defined in claim 1 further including means for varying the output of said first light beam source.
7. A method of measuring the strenght of material within a web comprising the steps of:
directing a source of light beams toward the material causing an ultrasonic wave to be induced therein;
determining the presence of said ultrasonic wave within the material at a location a predetermined distance away from the point where said ultrasonic wave was induced;
determining the velocity of said ultrasonic wave within the material; and combining the velocity of said ultrasonic wave with the density of the material to determine the strength of the material.
directing a source of light beams toward the material causing an ultrasonic wave to be induced therein;
determining the presence of said ultrasonic wave within the material at a location a predetermined distance away from the point where said ultrasonic wave was induced;
determining the velocity of said ultrasonic wave within the material; and combining the velocity of said ultrasonic wave with the density of the material to determine the strength of the material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US359,536 | 1989-06-01 | ||
| US07/359,536 US5025665A (en) | 1989-06-01 | 1989-06-01 | Non-contacting on-line paper strength measuring system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2011912A1 true CA2011912A1 (en) | 1990-12-01 |
Family
ID=23414251
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002011912A Abandoned CA2011912A1 (en) | 1989-06-01 | 1990-03-09 | Non-contacting on-line paper strength measuring system |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5025665A (en) |
| EP (1) | EP0400770B1 (en) |
| JP (1) | JPH0643945B2 (en) |
| AU (1) | AU628574B2 (en) |
| CA (1) | CA2011912A1 (en) |
| DE (1) | DE69013757T2 (en) |
| DK (1) | DK134690A (en) |
| NO (1) | NO900047L (en) |
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| US5361638A (en) * | 1990-03-30 | 1994-11-08 | Stfi | Arrangement for measuring mechanical properties of a foil material through use of an excitation unit that includes a laser |
| SE504576C2 (en) * | 1994-10-06 | 1997-03-10 | Lorentzen & Wettre Ab | Device for measuring ultrasound the elastic properties of a moving web of paper |
| SE504575C2 (en) * | 1994-10-06 | 1997-03-10 | Lorentzen & Wettre Ab | Device for ultrasonic measurement of elastic properties of a moving web of paper |
| US5804727A (en) * | 1995-09-01 | 1998-09-08 | Sandia Corporation | Measurement of physical characteristics of materials by ultrasonic methods |
| US5778724A (en) * | 1995-09-07 | 1998-07-14 | Minnesota Mining & Mfg | Method and device for monitoring web bagginess |
| US5640244A (en) * | 1995-11-02 | 1997-06-17 | Abb Industrial Systems, Inc. | Method and apparatus for on-line determination of fiber orientation and anisotropy in a non-woven web |
| US5801312A (en) * | 1996-04-01 | 1998-09-01 | General Electric Company | Method and system for laser ultrasonic imaging of an object |
| US5678447A (en) * | 1996-04-17 | 1997-10-21 | Eastman Kodak Company | On-line web planarity measurement apparatus and method |
| US5814730A (en) * | 1996-06-10 | 1998-09-29 | Institute Of Paper Science And Technology And Georgia Institute Of Technology | Material characteristic testing method and apparatus using interferometry to detect ultrasonic signals in a web |
| AU3154999A (en) * | 1998-03-26 | 1999-10-18 | British Nuclear Fuels Plc | Improvements in and relating to inspection |
| US6356846B1 (en) * | 1998-10-13 | 2002-03-12 | Institute Of Paper Science And Technology, Inc. | System and method of reducing motion-induced noise in the optical detection of an ultrasound signal in a moving body of material |
| EP1127255A1 (en) * | 1998-11-04 | 2001-08-29 | National Research Council Of Canada | Laser-ultrasonic measurement of elastic properties of a thin sheet and of tension applied thereon |
| US6628408B1 (en) * | 1999-04-15 | 2003-09-30 | Kimberly-Clark Worldwide, Inc. | Amplitude measurement for an ultrasonic horn |
| JP2003057027A (en) * | 2001-08-10 | 2003-02-26 | Ebara Corp | Measuring instrument |
| US6668654B2 (en) | 2001-08-15 | 2003-12-30 | Lockheed Martin Corporation | Method and apparatus for generating specific frequency response for ultrasound testing |
| US6813941B2 (en) * | 2001-12-20 | 2004-11-09 | Kimberly-Clark Worldwide, Inc. | Method to measure tension in a moving web and to control properties of the web |
| US6795191B2 (en) * | 2002-01-04 | 2004-09-21 | Freescale Semiconductor, Inc. | Ultrasonically assisted optical media sensor system |
| DE102007030566A1 (en) * | 2007-03-28 | 2008-10-02 | Man Roland Druckmaschinen Ag | Non-destructive testing of curing or drying of paints and varnishes |
| DE102007015365A1 (en) * | 2007-03-28 | 2008-10-02 | Man Roland Druckmaschinen Ag | Method for determining the degree of cure or degree of dryness of printing ink and varnish layers in printing presses |
| JP5358335B2 (en) | 2009-07-28 | 2013-12-04 | トヨタ自動車株式会社 | Inspection device |
| US8728276B2 (en) * | 2010-05-20 | 2014-05-20 | Honeywell International Inc. | Apparatus and method for controlling curling potential of paper, paperboard, or other product during manufacture |
| DE102011006391A1 (en) | 2011-03-30 | 2012-10-04 | Siemens Aktiengesellschaft | Method and device for detecting parameters of a continuous or circulating material web in a material processing machine |
| CN102564895B (en) * | 2012-01-04 | 2013-07-03 | 燕山大学 | Liquid density on-line monitoring system based on ultrasonic diffraction grating |
| US11105607B2 (en) | 2016-07-28 | 2021-08-31 | Renishaw Plc | Non-contact probe and method of operation |
| US10365252B2 (en) * | 2017-02-13 | 2019-07-30 | Eric M. STROHM | Method and apparatus for sensing a sample |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3952583A (en) * | 1975-01-02 | 1976-04-27 | The United States Of America As Represented By The Secretary Of The Army | Apparatus and method for the remote detection of vibrations of diffuse surfaces |
| US4291577A (en) * | 1979-12-03 | 1981-09-29 | The Institute Of Paper Chemistry | On line ultrasonic velocity gauge |
| US4622853A (en) * | 1985-08-23 | 1986-11-18 | Union Camp Corporation | Laser induced acoustic generation for sonic modulus |
| US4674332A (en) * | 1986-02-20 | 1987-06-23 | Union Camp Corporation | Laser induced acoustic generation for sonic modulus |
| FI79410C (en) * | 1986-06-09 | 1989-12-11 | Stroemberg Oy Ab | FOERFARANDE OCH ANORDNING FOER KONTAKTLOES MAETNING AV SPAENNINGEN HOS EN PLAN FOLIE OCH ISYNNERHET EN PAPPERSBANA. |
-
1989
- 1989-06-01 US US07/359,536 patent/US5025665A/en not_active Expired - Fee Related
-
1990
- 1990-01-05 NO NO90900047A patent/NO900047L/en unknown
- 1990-01-16 EP EP90300436A patent/EP0400770B1/en not_active Expired - Lifetime
- 1990-01-16 DE DE69013757T patent/DE69013757T2/en not_active Expired - Fee Related
- 1990-03-09 CA CA002011912A patent/CA2011912A1/en not_active Abandoned
- 1990-05-29 AU AU56062/90A patent/AU628574B2/en not_active Ceased
- 1990-05-31 JP JP2140141A patent/JPH0643945B2/en not_active Expired - Lifetime
- 1990-05-31 DK DK134690A patent/DK134690A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0400770A2 (en) | 1990-12-05 |
| DE69013757D1 (en) | 1994-12-08 |
| AU628574B2 (en) | 1992-09-17 |
| DK134690A (en) | 1990-12-02 |
| EP0400770B1 (en) | 1994-11-02 |
| NO900047L (en) | 1990-12-03 |
| JPH0643945B2 (en) | 1994-06-08 |
| DE69013757T2 (en) | 1995-03-09 |
| DK134690D0 (en) | 1990-05-31 |
| AU5606290A (en) | 1990-12-06 |
| EP0400770A3 (en) | 1991-04-17 |
| US5025665A (en) | 1991-06-25 |
| NO900047D0 (en) | 1990-01-05 |
| JPH03162645A (en) | 1991-07-12 |
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