Abstract: A caliper gauge for relatively thin moving sheet material is provided by the use of a pair of outer ring air bearings flexibly supported which tend to flatten the sheet. An inner central portion of each ring respectively carries active and passive magnetic circuit means with the passive means being supported by an elongated strap of Kevlar which is elongated in the machine direction of the sheet material. This provides for very low unsprung weight.

Abstract: A system for creating a control signal having a value indicative of the position of the lateral edge of a moving web wherein the system creates a succession of ultrasonic pulses from a transmitter, each of the pulses being created at a known transmit time in response to a transmit signal with the pulses each having a number of oscillations defining a pulse envelope having a pulse start portion. The system directs the ultrasonic pulses toward an ultrasonic receiver along a selected path whereby the position of the lateral edge of the web in the path determines the energy of the pulse as it is received by the receiver and converts the received pulse into an electronic signal having an amplitude determined by the energy of the received pulse. The receiver is spaced from the transmitter a predetermined distance causing the pulses to be received by the receiver at a given time after the transmit signals for a given ambient temperature.

Abstract: A method and apparatus are disclosed for the measurement of tension in a stretched elastic surface. The apparatus includes a rigid housing having at least two diametrically opposed sides and a spring device contained therein with a contact member connected to the spring device which protrudes a predetermined distance outwardly beyond the ends of the housing sides when the spring device is in a resting state. Measuring and display devices are connected to the spring device for measuring the spring deflection when the housing is pressed against an elastsic surface. The housing is placed adjacent the elastic surface to be measured with the contact member in contact with the elastsic surface such that a fixed distance exists between the ends of the housing sides and the surface prior to application of a pressing force. The housing is then pressed against the elastic surface until the ends of the housing sides come into contact with the surface such that the spring device is deflected.

Abstract: A standard control signal for a web forming machine is temporarily interrupted and replaced by a perturbing signal or signgals which are applied to one, a grouping, or all of a series of actuation cells of the web forming machine. One or more actuation cells are driven with an alternating perturbing signal(s) which generate a corresponding action in the actuation cell(s). The perturbing signal(s) alternates from a neutral position of the cell and is selected to minimize means effects over any given period of time. The effects of the alternating signal(s) on the web appear within the area of the web which is affected by the actuation cell(s) such that the mapping and the response of the actuation cell(s) can be determined by monitoring that poriton of the web which is formed while the alternating signal(s) is applied to the actuation cell(s).

Abstract: In a scanning head position sensing method and apparatus, a plurality of distinct electromagnetic signals are transmitted from a corresponding plurality of transmitter sites surrounding a central position on one side of a web of material. The signals are transmitted through the web and are received by an electromagnetic energy sensor on the opposite side of the web of material. The electromagnetic energy sensor is positioned to receive approximately equal signal energies from all the transmitters when the energy sensor is positioned substantially opposite to the central position across the web. The transmitters and the sensor are fixedly positioned relative to the first and second sensor heads such that the relative positioning of the heads is determined by combining the signals with one another.

Abstract: A running blade is adapted to move at the same speed as a continuously running sheet and to generate a burst perforation through the sheet. The force exerted by the blade against the sheet is measured and used to calibrate a non-destructive sheet strength sensor.

Abstract: A sensor for detecting directional variations in a physical characteristic of a moving sheet of material is disclosed. The sensor has a support for supporting the moving sheet. The support defines an open region into which the moving sheet is deflected by a deflector. The support is rotatable to allow detectors coupled to the support to detect and produce signals indicative of the force exerted on the support by the deflected sheet in a number of different directions. Each signal is processed to determine a physical characteristic, such as extensional stiffness, of the sheet of material in each direction. The directional variations of the physical characteristic may be used to determine the fiber orientation angle and the degree of anisotropism of the sheet.

Abstract: A device for measuring the gap between the radiation source and the radiation sensor of a basis weight gauge. A caliper sensor measures the thickness of a sheet of material as it passes through the gap, while the caliper contact shoe rides on the sheet and urges it against a first side of the gap. A linear variable differential transformer measures the distance between a reference point on the contact shoe and the opposed side of the gap. The gap dimension is the sum of the sheet thickness, the distance between the caliper reference point and the second side of the gap, and a readily measurable constant.

Abstract: An apparatus and method for suppressing flutter of a moving web manufacturing operation to include a sensor for sensing the pressure of air in a region proximate the web, which sensor generates a pressure signal representative of the air pressure, a signal processor, connected to receive the pressure signal and to derive therefrom a negative feedback suppression signal phase-shifted to attenuate the air pressure, and an air modulator, positioned to modulate the air in the region proximate the web, which modulator receives the suppression signal and modulates air in response thereto so that flutter is attenuated. The modulator can be a speaker placed in an air supply duct, and in another embodiment it is placed directly in a web pocket.

Abstract: The present invention relates to a novel method and apparatus for determining the periodicity of a changeable characteristic of a textile fabric. The method includes the steps of sensing a property related to the characteristic at pairs of positions which are spaced apart by a distance, S, along a length of the fabric and generating signals representative of the magnitude of the property at the positions. The generated signal values are stored and the products of the signals generated at each pair of positions are summed in accordance with the formula:.SIGMA.X.sub.(y) .multidot.X.sub.(y+s)from y=O to y=Ywhere the parameters are defined in the specification. These steps are repeated for different dimensions, S. The value of S at which the summation of the signals is a maximum is determined and used to generate an output signal representing the value of the periodicity.

Abstract: A magnetic defect detector having a pair of rotatable cylinders made of nonmagnetic material which pinch a running steel strip therebetween, two pairs of bearings being engaged with the end parts of the pair of cylinders. A pair of stationary shafts are respectively housed in the cylinders, the end parts of which are engaged with the bearings. A yoke is housed in one of the cylinders, the free ends of which are placed near to the pinched strip, and a magnetizing coil surrounds the yoke. At least one sensor is housed in the other of the cylinders, and it is placed near to the pinched strip.

Abstract: A contacting thickness gauge comprising a unique surface follower (46). The bottom surface (56) of the surface follower (46) has both contacting areas (64,66) and non-contacting areas (62). The surface follower (46) is in substantially continuous contact with a moving sheet (2) and embodies an electrically conductive target having a target surface that intersects a magnetic field but is substantially free from contact with the sheet during normal operation. The surface follower (46) is designed to minimize damage to the sheet (2) that would otherwise occur from contact between the surface follower and a protruberance of the sheet, and to preserve the characteristics of the target surface.

Abstract: A method and apparatus for rapidly determining the print quality of a porous material which includes contacting a porous surface with a source of ink, providing a known relative acceleration between said ink source and said porous surface, and thereby transferring a predetermined volume of ink from said ink source to a known area of said porous suface. Then, the amount of ink transferred into the porous surface area per unit of time is measured to thereby determine the time between initial ink contact and the initial ink penetration, referred to as wetting delay, and the penetration rate of ink into the porous surface.

Abstract: A method for preparing paper samples for determination of physical characteristics includes immersing the samples in a water-solvent mixture and then allowing the solvent to evaporate. The paper samples are thereby provided with a particular water or dampness content and can then immediately be subjected to testing on a tension testing machine or similar device.

Abstract: A pressure sensitive device, such as a piezoelectric strip or plurality of piezoelectric crystals, is or are arrayed along the surface of a roll, preferably in a spiral pattern, extending for one revolution of the roll which is nipped with another roll. The nip pressure between the rolls, with or without a paper web passing through the nip, produces a signal by the piezoelectric device indicative of irregularities along the nip. These irregularities, which can be indicative of variations in the web caliper, roll surface, hardness and other parameters of roll or web quality, are then passed to a monitor for continuous read-out of the irregularities or non-uniformities along the face of the roll. Other apparatus, such as a signal conditioner and a signal encoder, can be provided for processing the signals determining the exact axial location along the roll surface of the pressure sensitive device passing through the nip at any given time.

Abstract: A sheet tension measuring device is disclosed for measuring the tension of a moving sheet wherein a moving sheet is accurately positioned with pinchers at 2 spaced locations. The sheet is deflected between these pinchers from its nominal straight line path, and the amount of deflection and deflecting force are measured. The pinchers iron out any wrinkles in the sheet as the moving sheet slides through the pinchers. Sheet tension is computed based upon the measured deflection force and deflection distance. The resulting measurements of local sheet tension are used to correct nondestructive sheet strength measurements. A device and method are also disclosed for nondestructively determining the sheet strength and the extensional stiffness of the sheet in the machine direction and in the cross-direction.

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.

Abstract: The warp tension is measured in a weaving loom by measuring the fabric tension downstream of the beat-up point. For this purpose a measuring device is arranged in a suitable position downstream of the beat-up point. Such an arrangement is possible because the fabric tension in the take-up direction is directly proportional to the warp tension. The measuring device includes a measuring beam supported, for example, in the spreader bar or pipe. The measuring beam is in contact with the fabric and cooperates with sensor elements such as foil strain gages, pressure gages, or other suitable sensors or pick-ups such as displacement pick-ups. This type of arrangement has the advantage that the warp thread tension can be measured with high precision due to the mentioned proportionality and independently of temperature influences. Additionally, impairment of, or damage to the warp threads is avoided by measuring downstream of the beat-up point.

Abstract: The ultrasound detector for a thin film includes an ultrasound transmitter and an ultrasound receiver. It is generally known that a plastic film introduced into a sound field attenuates the field to a greater or lesser degree. A sound wave of a frequency of e.g. 40 kHz has a wave length of approximately 9 mm in air. When a plastic film of a thickness of, e.g., 0.50-0.10 mm is introduced, the sound field is typically attenuated with 6-20 dB. The the ultrasound detector is formed as a resonator, and the distance between the transmitter and the receiver corresponds substantially to an integral multiple of one half of a wave length. As a result, the obtained sound field is stronger than previously and the attenuation caused by a plastic film between the transmitter and the receiver is higher than previously. Furthermore, the ultrasound frequency is scanned for taking tolerances, such as changes in temperature and humidity of air into account.

Abstract: A method and apparatus are disclosed wherein a plurality of basis weight sensors are interleaved with one or more processing stations used to conjoin or apply one or more layers to a base substrate to form a multilayer product such that a sensor is located on the input and output sides of each processing station. Each of the sensors can be calibrated with a plurality of product calibrations such that multiple output signals corresponding to multiple products can be generated simultaneously by the sensors. Each of the sensors is calibrated with product calibrations corresponding to the product or intermediate stage of the product which it monitors, the layer applied by the processing station preceding it, if any, and the layer applied by the processing station succeeding it, if any.

Abstract: An apparatus for determining the surface roughness of a material comprised of an acoustic element which is pivotally mounted to a support structure containing a polished end which is maneuvered into contact with the surface of a material to be tested by a spring element. The material is caused to move relative to the acoustic element by a driven roller. A transducer is acoustically coupled to the acoustic element and detects stress waves propagating in the acoustic element as a result of frictional and impact force generated by the rubbing of the acoustic element with the material. The relative stress wave activity is dependent upon the surface roughness of the material. A processor analyzes an electrical signal produced by the transducer to determine the surface roughness of the material which may analyze the electrical signal produced by the transducer to determine the presence of impurities on the surface of the material.

Abstract: A measuring gauge for error compensation of a measured characteristic of a moving sheet measures X, Y lateral displacement of the upper and lower transducer heads of a moving scanner in a cross direction across the paper. This is accomplished by the use of two pairs of eddy current sensors centered on a target on the opposed transducer head. Such eddy current transducers sense the pairs of edges of an aperture in the opposed transducer. Alternatively, slope portions of the lower transducer head are sensed. Other correction inputs are provided by measuring the distance from each transducer head to the moving sheet to provide a "Z" correction. All of the foregoing are then utilized along with caliper measurements, if necessary, to provide a corrected characteristic.

Abstract: A drawframe is disclosed which has a plurality of sets of draw rolls and includes a provision for the early detection of imperfections in rotating elements in the drawframe. The separation of the pairs of rolls is monitored, and a signal representative of that separation is generated. The resulting signal is then processed so that only intolerable errors remain, and the major harmonic elements of the remaining signal are correlated with the rotational frequencies of the rotating elements of the drafting or drawing apparatus. Establishment of synchronism between significant harmonic components in the signal representative of the separation of the cooperating pair of rolls and the rotational frequency of a rotating element in the apparatus makes it possible to identify any unacceptable mechanical cause of error while the machine is still running.

Abstract: Apparatus and method for measuring electric characteristics of sheet-like materials using an instrument which includes a waveguide tube member having one end connected to transmitter for introducing a microwave into the tube member and the other end fully opened, a waveguide terminal member having an opened end facing the opened end of the tube member to form slit of the whole wave guide body constituted from the tube and terminal members and having the other end connected to first microwave detector, and an auxiliary waveguide branching from the wall portion of said tube member adjacent to the slit with the branch-extension end being associated with a second microwave detector.

Abstract: A sensor for sensing a quality of a sheet, such as a paper sheet, related to elastic modulus and bending stiffness as it is being made including a sheet support in the form of a ring and a free running wheel, which depresses the paper into the center of the ring as the paper passes over it. A force transducer mounted to the wheel senses the force of the deflected paper on the wheel and provides a measure of a characteristic of the paper related to its elastic modulus and being stiffness. Alternatively, or in addition, a displacement sensor may be used to sense the distance that the sheet is displaced by the wheel into the ring. These factors, together with basis weight, thickness and paper velocity may be used to determine the strength of the paper on a continuous basis.

Abstract: An apparatus and method for determining the frequency and amplitude of flutter of a moving web in a web manufacturing operation, is shown to include a sensor for sensing the pressure of air in a region proximate the web and for generating a pressure signal reflective of the air pressure and a signal processor, connected to receive the pressure signal, for determining the amplitudes and frequencies of the flutter from the pressure signal and for generating an indication signal representative of the flutter amplitude and frequency.

Abstract: A method and apparatus for measuring the relaxed length of a moving web includes forming a plurality of detectable marks along the length of the web at a repeated length interval. First and second detectors positioned along the web path are separated by a known distance S. A first tensioning force is applied to the moving web, and a first tensioned repeat length of the web is measured by detecting a mark moving past the first detector and then detecting the next mark moving past the second detector. The time separating the detections is determined. A second tensioning force of a known proportional relationship with the first tensioning force is applied to the moving web. A second tensioned repeat length is measured. The speed of the moving web is measured, and a relaxed length is calculated from the first tensioned repeat length, the second tensioned repeat length, and the proportional relationship between the first and second tensioning forces.

Abstract: A direct printing technique for simulating the appearance streaks in fabrics includes the steps of obtaining a data set of yarn physical properties for each yarn in the fabric, programming a digital computer having graphics capability and pixel control of the graphics to average the yarn physical properties and calculating the pixel density from the individual yarn and yarn properties. The pixel density is then displayed as a series of rows of pixels wherein the number of pixels in each row is proportional to the individual yarn property of each yarn in the fabric. A simulation of the actual fabric appearance is obtained by just knowing the constituent yarn properties without having to make the actual fabric. Simulation parameters are confirmed by comparison of simulations with actual fabrics. Simulation parameters are confirmed by comparison of simulations with actual fabrics.

Abstract: To measure the period with which a surface defect recurs in a surface of a web-like material moving in its lengthwise direction, surface defects distributed over the surface are detected in that lengthwise direction. Positional data and distance data as to the detected surface defects relative to one another are collected for a predetermined length of the web-like material. The web-like material is determined to have a periodic surface defect appearing with a period between predetermined maximum and minimum periods when the distance data include a distance equivalent to an elemental period that is a whole-number multiple of a fundamental period.

Abstract: A flatness measuring device for rolled strip (5) according to the invention comprises a measuring roller over which the rolled strip passes. The measuring roller is divided into a number of roller sections (6). The forces on the roller sections are measured and can then be converted, via recalculations, into a measure of the flatness of the strip, whereby a flatness profile across the strip can be obtained. Special to the invention is the method of measuring the force. Between each roller section (6) there is a side member (ABC) which supports the shaft ends (7) of two adjacently positioned roller sections. The side member in principle consists of three beams (A, B, C) connected together in the form of a triangle. The beam A for all the side members is attached to a common plate (1). The first ends of the beams A and B connected together via a flexible diaphragm (2). At the second end of the beam B the shafts are journalled.

Abstract: A sensor is disclosed for sensing a physical property of a sheet material. The sensor includes a mechanism for supporting one side of the sheet along the periphery of a defined region and a mechanism for forcibly deflecting the sheet into the unsupported center of the defined region. A transducer may also be incorporated to sense the force required to deflect the sheet into the unsupported region and/or the distance that the sheet is deflected into the unsupported region. The sensor may be operatively coupled to a computer programmed to determine a physical property of the sheet based upon the sensed force and/or distance, such as the sheet failure strength.

Abstract: An apparatus and method for determining the frequency and amplitude of flutter of a moving web in a web manufacturing operation, is shown to include a sensor for sensing the pressure of air in a region proximate the web and for generating a pressure signal reflective of the air pressure and a signal processor, connected to receive the pressure signal, for determining the amplitudes and frequencies of the flutter from the pressure signal and for generating an indication signal representative of the flutter amplitude and frequency.

Abstract: A sensor and a method for determining the basis weight of coating material on a substrate is described. The determined basis weight is insensitive to changes in the amount of substrate material underlying the coating. Signals from the sensor may be used in the control of a coating mechanism to provide a coating having a uniform basis weight.

Abstract: A method of measuring the yarn density of a woven fabric or the stitch density of a knitted fabric by recording a video image of the woven or knitted fabric to be examined by means of a video camera, converting the video image by an analog-to-digital converter into digital video information, storing the digital video information in a digital image memory and converting said information by a central processing unit into the yarn density or stitch density. The digital video information is converted by a digital band filter (14) with central circle frequency (.omega..sub.o) into a yarn or stitch density, and that the digital band filter (14) is arranged in such a manner that it operates according to the formula:Y.sub.k =A.sub.m .multidot.X.sub.k-m +A.sub.m-1 .multidot.X.sub.k-m+1. . . +A.sub.o X.sub.k -B.sub.1 .multidot.Y.sub.k-1 -B.sub.2 Y.sub.k-2. . . B.sub.n Y.sub.k-nwherein:X.sub.k represents a series of points of the digital information characteristic at interspace T before the digital filtering; Y.sub.

Abstract: An apparatus for use in determining the approximate web tension setting necessary for providing a predetermined web width in a machine, such as a web printer, which is used to process a continuous plastic web of the type which is subject to significant stretching and shrinking in response to relatively small web tension variations, comprising a first web restraining device for holdingly engaging a first end of a length of web material to be tested; a second web restraining device for holdingly engaging a second end of the length of web material to be tested; a force application device for applying a controlled amount of longitudinal stretching force to the length of web material to be tested; and a measuring device for measuring the width of the length of web material to be tested in a mid-region thereof during application of the longitudinal stretching force thereto. The apparatus may also be used for determining web graphics distortion.

Abstract: A method and apparatus for measuring the repeat length (L) of a moving web includes forming a plurality of detectable marks along the length of the web at a repeated length interval. First and second detectors positioned along the web path are separated by a known distance (S). The repeat length of the web is obtained by detecting a mark moving past the first detector and then detecting a mark moving past the second detector, determining the time (t) separating the detections, and measuring the speed of the moving web (V), wherein the repeat length is calculated using the formula L=S+Vt.

Abstract: To determine machine-direction variations in measurements of a travelling sheet during production, the sheet is repeatedly traversed with a scanning sensor and, during each traverse, measurements are taken at a plurality of locations. Then, a series of reference slice locations are selected which extend in the true cross-direction. For the reference locations, measurement values are estimated based upon actual measurements. Then, for each scan, the average of the estimated measurement values is calculated. Next, cross-directional variations in values at each slice location along selected scans are calculated by subtracting the average value from the estimated value at each location along the scan. During the next consecutive scans, machine-directional variations in the sheet property at slice locations are calculated by determining the difference between the measured value and the calculated cross-directional variation value for that slice location along the prior scan.

Abstract: Variations in the properties of a continuously running web are measured by reciprocating the scanning device across the web. The movement of the scanning device is so time controlled that this movement is out of phase with the variation in the paper properties in the machine direction of the web.

Abstract: A device for detecting the degree of deterioration of bank notes has a driving rotary body and a detection rotary body, which are a pair of oppositely disposed rollers each having alternately disposed enlarged diameter portions and annular grooves. These enlarged portions and the grooves of the two rotary bodies are in staggered, opposed relationship so that when a bank note is conveyed between the two rotary bodies, the note is deformed into a wave shape. The rotation of the driving rotary body influences the rotary movement of the detection rotary body depending on the stiffness of the bank note in the wave shape. When the bank note is new and stiff, the influence is strong, while when the bank note is old and deteriorated with a small stiffness, the influence is small. Such influence is detected from variation in rotary movement of the detection rotary body to which a predetermined rotational characteristic is given by a resistance imparting device.

Abstract: A running blade is adapted to move at the same speed as a continuously running sheet and to generate a burst perforation through the sheet. The force exerted by the blade against the sheet is measured and used to calibrate a non-destructive sheet strength sensor.

Abstract: A method and device for determining the strength of a sheet material, such as paper, utilizing floc size and the variability of the local basis weight of the sheet. The force required to deflect the moving sheet out of a nominal position, the distance the sheet is deflected by said force and the average tension applied to the sheet may also be utilized in the above determination of sheet strength.

Abstract: A caliper gauge for relatively thin moving sheet material is provided by the use of an outer ring type air bearing, flexibly supported, which is flexibly connected again to an inner air bearing carrying the magnetic measuring components. The outer air bearing (with its juxtaposed mate) tends to flatten the sheet so that minimum movement is required of the independently actuated inner air bearing. Thus, great accuracy is achieved and tearing or marking of the sheet material, such as super calendered or coated grades of paper, is avoided.

Abstract: Wherein the length of a flexible web or string material, such as a textile material, forming a wound body or roll (10) may be determined by determining a first measure of the weight of the web or string material, determining a second measure of the weight of a predetermined length (1) of the material, and calculating the total length of the flexible web or string material on the basis of said predetermined length (1) and said first and second weight measures. Thus, a roll (10) of a textile material may be placed on a table (12) divided into sections, of which a first section (11) supports the roll while a second section (14) supports the predetermined length (1) of the material. The second section and the web material arranged thereon may be supported by a weighing cell and the whole table (12) and the web material or textile material arranged thereon may be supported be another weighting cell.

Abstract: A method and apparatus for rapidly determining the print quality of a porous material which includes contacting a porous surface with a source of ink, and then providing a known relative acceleration between the ink source and the porous surface. In this manner, a predetermined volume of ink is transferred from the ink source to a known area of the porous surface. Then, the amount of ink transferred into the porous surface area per unit of time is measured to thereby determine the time between initial ink contact and the initial ink penetration, referred to as the wetting delay, the penetration rate of ink into the porous surface, and the volumetric roughness of the porous material. All of these latter parameters are closely correlated to print quality.

Abstract: To determine measurements such as basis weight and caliper of a travelling sheet during production, the sheet is repeatedly traversed with a scanning sensor and, during each traverse, measurements are taken at a plurality of slice locations. Then, a series of reference locations are selected which are spaced apart in the machine direction along the sheet surface. Then, for selected slices, measurement values are estimated based upon actual measurements taken at locations on the selected slices which are not spaced in the machine direction at the same spacing as reference locations.

Abstract: The web in a high speed printing press passes between a transmitter and receiver, the former of which produces ultrasonic sound which the latter receives, after attenuation by the web, and the latter of which converts the sound into an oscillating electrical signal of corresponding frequency. This electrical signal, after being amplified and filtered, is impressed upon a peak detector and a comparator. The peak detector produces a constant potential equal to the amplitude of the peaks in the amplified signal, and this constant potential is reduced a predetermined proportion and is applied to the comparator as a reference potential. The comparator compares the reference potential with the amplified oscillating signal. The reference potential remains undisturbed even though the oscillating signal may momentarily drop due to the further attenuation of the sound caused by a splice moving through it.

Abstract: A method and apparatus for testing the properties of stretch film include collapsing a web of stretch film into a rope, anchoring the rope web at two locations and stretching an intermediate portion of the rope web a first distance in a first direction between the locations where it is anchored. The intermediate portion of the stretched roped web is displaced a second distance along a second direction transverse to the first direction and relative to the locations where it is anchored, and the tension force in the stretched roped web is measured when it is displaced the second distance. Alternatively, peripheral portions of a sheet of stretch film are secured and a central portion of the sheet of stretch film is engaged and deformed a third distance in the second direction.

Abstract: Disclosed is a method of testing the propensity of a paper or board to dust. The method is one which includes pressing a reference surface to the surface to be tested at a predetermined pressure. The dust adhering to the reference surface is then measured such that an indicative reading is obtained.

Abstract: In an apparatus for determining the reduction ratio of a rolled material by measuring the moving speed of a magnetic mark formed on a strip on the inlet and outlet sides of a rolling mill, a rising of a signal of the logical product of a detection signal on the inlet side and a pulse of a gate which is opened by a magnetic mark detection signal on the outlet side and is closed after the lapse of an optimum time is adopted as the timing for detection of the magnetic mark on the inlet side, and the comparison levels of the detectors are automatically changed according to the stored magnitude of the magnetic mark, whereby a worsening of the S/N ratio of the magnetic mark signal on the inlet side or an erroneous detection is reduced.

Abstract: The profile of a measurement roll is stored in a computer during a calibration revolution. On revolution with fiber mats to be measured, the computer reduces the measured values exactly by the measured values of the corresponding calibration profile. The measurement result obtained does not depend on the production quality of the measurement roll.