Accuray Inc.

Process Automation Business Inc.

Abb Industrial Systems, Inc.

Industrial Nucleonics Corporation

Paul Williams

Gary N Burk

Thomas O McCanney

Thomas Michael Domin

Dan R Landis

Bradley M Pankonin

Roger A Holmes

Steven M Wilson

Jon Francis Pugh

Eugene S Green

Tom Domin

A detector of a measuring system sensitive to light energy receives light from a process being measured and also from a separate light source which is modulated such that it can be detected in signals generated by the detector. The separate light source is turned on and off to modulate its output such that output signals from the detector can be separated into on-times and off-times of the separate light source. The difference in on and off signal levels generated by the detector, or elements of the detector if the detector has a plurality of elements, are used to calibrate the detector. The light energy is conveyed to the detector by an energy conduit which may be a 'leaky' optical fiber which receives light at one end and leaks the light out one sidewall along a portion of the fiber which is positioned adjacent to and preferably secured to the detector. The leaky optical fiber can be made by removing cladding from at least a portion of the sidewall along the portion of the fiber which is to leak light to the detector. Alternately, a bundle of fiber optics can be utilized with one end of the bundle receiving light and the other end being broken out to direct one or more of the fibers toward elements of the detector.

Method and apparatus for monitoring/calibrating a process measuring

A paper web is monitored for measurement and manufacturing control by a stationary web sensor extending across the entire web which is raster scanned by the motion of the web. Massive amounts of data are processed by a look up table memory addressed by digitized sensor data and the output from a reference memory containing element specific information. The lookup table is loaded with data to define a characteristic or property of the web corresponding to digitized sensor data interpreted in view of element specific data from the reference memory. Rapidly processed data is stored in a memory in a form facilitating its display and interpretation by an operator of the web manufacturing machine and also control of the machine. By controlling operation of the machine, uniformity of the web is substantially improved and, by taking the measurements closely adjacent the initial processing end of the web, corrections of nonuniformity in the web are quickly effected. To measure and control absolute characteristics and properties of the web, a second, preferably stationary, sensor adjacent the finished end of the web monitors the web adjacent a takeup reel. Alternately, for basis weight measurement and control, the weight of the takeup reel is monitored and combined with the web width and machine operating speed to determine an absolute web basis weight. Thus, uniformity of the web and absolute values of characteristics and properties of the web can be measured and controlled.

Measurement/control of sheet material using at least one sensor array

Improved ultrasonic energy transducers each include a material contacting member secured to a piezoelectric element at an interface region between oppositely operated first and second regions of the piezoelectric element. The material contacting member intensifies and amplifies movement of the interface region as the first and second regions of the piezoelectric element operate in a push-pull mode relative to the interface region. The first and second regions of the piezoelectric element can be electrically driven to move the material contacting member for transmission of ultrasonic energy or mechanically driven by the material contacting member for receipt of ultrasonic energy. A variety of piezoelectric elements can be used in the improved transducers including, for example, generally rectangular bars and discs segmented into two or more portions. A variety of material contacting members can also be used including, for example, a cylindrical stud and a more narrow dowel.

Transducers for transmitting and/or receiving ultrasonic energy

The velocity or speed of ultrasonic energy in moving webs of material is measured on-line as the webs are manufactured by engaging and preferably scanning a measuring head over the web of material. Improved ultrasonic energy transducers are employed wherein a material contacting member is secured to an interface region between oppositely operated first and second regions which intensify and amplify the movement of the interface region and hence the material contacting member by operating in a push-pull mode relative to the interface region. The transducers are calibrated by means of reference paths having known ultrasonic transmission characteristics which reference paths are separate and apart from the web of material which is being measured. The transducers can be selectively contacted with the web of material or not under the influence of vacuum which is applied to a measuring head into which the transducers are installed. A large plurality of ultrasonic energy signals are received by one or more receiving transducers and digitally integrated or summed and averaged to eliminate substantial noise which is present on the received ultrasonic energy signals due to the relative motion of the transducers and the web of material being measured. The travel time between the transmitting transducer and the receiving transducer or transducers is then combined with the distance or distances therebetween to arrive at the velocity or speed of the ultrasonic energy in a web being measured.

On-line measurement of ultrasonic velocities in web manufacturing

An air bearing gauge 10 is characterized by a flat land 30, instead of the prior art's 'knife-edge' 30', so as to provide an area 32 over web 12 through which pressurized gas flows in escaping from the gas supply means 16 and the gas bearing region 24. The land 30 provides an upward scaling of the readings obtained on-line, which can correlate the reading to standard TAPPI caliper gauge measurements of sheets as are obtained off-line, in the laboratory.

On-line caliper gauge

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.

Sheet-contacting thickness gauges

A light source module for use with a multi-camera array in a video surface inspection system includes a first light emitter which extends lengthwise across the entire width of a sheet to be inspected. Light from the first light emitter, which preferably comprises one or more fluorescent lamps, is received by a light guide and carried by the guide to uniformly illuminate a band extending entirely across the width of the moving sheet. The light guide comprises a transparent thermoplastic such that the light receiving end of the guide can be bent to define a plurality of sections which can be axially aligned with a corresponding plurality of fluorescent lamps. The fluorescent lamps may be powered by individual inverter ballasts which may be driven inturn by one or more variable dc power supplied to control the intensity of light emitted by the lamps. The light source module can also assist the inspection system in overcoming redundant data processing problems by providing second light emitters which illuminate the sheet in overlapping portions of the field of view of adjacent cameras of the multi-camera array to define data dividing points. Accordingly, duplicated data generated by the video cameras can be divided among the cameras at the defined data dividing points such that duplicated data is only processed once by the video surface inspection system.

Light guided illuminating/sectioning device for sheet inspection system

Apparatus for inspecting sheet material having known characteristics is disclosed. The apparatus comprises means for providing a plurality of pixel signals each having a magnitude representing the intensity of electromagnetic radiation received from a corresponding point on the sheet material. The apparatus also comprises signal processing means for comparing the magnitude of each one of the pixel signals to a corresponding reference range defined by the known characteristics of the sheet material and generating a characteristic signal. The characteristic signal includes an event signal for each of the magnitudes falling outside of the corresponding reference range and a data signal for each of the magnitudes falling within the range, wherein the data signal represents the magnitude of the pixel signal. The signal processing means also generates an address signal representing the point on the sheet material at which the characteristic signal is generated. The apparatus also comprises system processing means for storing the event signals and the corresponding address signals to provide an indication of deviation from the known characteristics of the sheet material.

Apparatus and method for inspecting sheet material

Disclosed are sheet inspection apparatus and methods for rapid, repetitive measurement of a quality attribute in each of a plurality of measurement zones of a continuously-manufactured sheet of material, wherein measurement is based on the interaction of one or more radiation wavelength bands with one or more constituents of the sheet. Simultaneous resolution of measurement zones is provided in both scanning and non-scanning applications.

Sheet inspection apparatus and methods providing simultaneous resolution

For measuring a property such as caliper of a traveling sheet, a sensor body and a target body are located on opposite sides of the sheet and constrained (e.g., by gas bearings) along a sensor path intersecting the path of the sheet. Gas bearings maintain these bodies at, substantially constant distances from the opposite surfaces of the sheet while permitting them to move in response to the position and thickness of the sheet. An active sensor element aboard the sensor body and a passive sensor element aboard the target body interact through the sheet to produce aboard the sensor body a response dependent on the sheet property. Manifestations of this response, such as light beam modulations, are produced, without solid bodily connections, at a location spaced from the sensor body where the manifestations are detected to produce a sheet property-indicative signal.

Sheet measuring apparatus with two structurally isolated non-contacting

A gauging apparatus for sheet materials and the like comprises a surface follower body (14,20,30) adapted to be constrained without substantial solid bodily contact and guided (e.g., by gas bearings between 32 and 36 and 38) for movement along a surface follower path that intersects the path of a traveling sheet (10) to be gauged. The body has a passage (46) adapted to carry a flow of pressurized gas to be discharged against one surface of the sheet. The discharge of the gas is effective when the body is at a predetermined distance from the surface to generate a levitating force (on 20) urging the body away from the sheet surface. Means (70,64,62) responsive to the pressure of the gas in the passage exerts on the body (at 64) a counteracting force that tends to move the body closer to the surface. The counteracting force increases when the pressure increases and decreases when the pressure decreases, and coacts with the levitating force in such a manner that the predetermined distance of the body from the surface is normally maintained substantially constant and is relatively unaffected by minor variations in the pressure of the gas in the passage.

Pneumatic surface follower with negative feedback of a variable force

Apparatus is provided for sensing a property of a sheet (18). A sensor element (32) is adapted to be placed alongside the sheet path, and a base member (34) is adapted to be positioned on one side of the sheet and in sliding contact with one surface thereof. The sensor element is enabled to produce a sheet property sensing interaction with the sheet in a limited region of the sheet path, the interaction region being movable to any one of a plurality of sensing locations spaced across the width of the sheet. The base member has a pair of groove portions (44, 46) forming gas conducting channels with open sides exposed to the sheet surface in contact with the base member. Each of the groove portions has a part (40, 40A) extending upstream of the interaction region. The groove portions diverge from each other as they extend in a downstream (20) direction. A source of subambient gas pressure communicates with the groove portions for reducing the gas pressure therein so that the contacting surface of the sheet is at least nominally depressed into the groove portions to such an extent that the divergence of the grooves and the longitudinal movement of the sheet exert thereon a transverse tension. This tension is sufficient to substantially smooth out longitudinally extending sheet wrinkles. Typically a plurality of gas removal devices are provided for minimizing the introduction of gas between the base member and the sheet.

Sheet property sensor with sheet wrinkle remover

An apparatus such as a caliper gauge can be utilized in performing a measurement, such as a thickness measurement, of a traveling sheet or the like. The apparatus comprises a surface follower body (18, 72, 74) adapted to be constrained during the measurement for movement along a surface follower path intersecting the path of the sheet (10, 80) and urged by a force toward one surface of the sheet. The body has a gas confining wall (32a, 90, 104) bounded by a uniformly distributed pressurized gas supply aperture or apertures (46, 92, 106) for pressurizing a gas bearing region (48, 108, 110) contiguous to the sheet surface with sufficient pressure against the sheet and the wall to levitate the body against the urging force. The pressurization is effected without producing substantial amounts of high velocity gas flow over the surface of the sheet within the gas bearing region. The body is maintained at a distance from the sheet surface that is substantially constant and relatively unaffected by variations in the roughness of the surface.

Gauge having a surface follower with peripheral vent

Methods and apparatus are provided for gauging the thickness or other property of a plastic film such as blown film or other material having a front side, a back side, and characteristics including a substantial transparency to radiation at a reference wavelength and a degree of transparency depending on the value of the property at an absorption wavelength. These methods and apparatus provide a useful measurement of the material property in the presence or absence of detrimental effects such as those caused by a broadband absorbing substance (e.g. carbon black) or scattering substance (e.g. TiO.sub.2) in the material, or variations in the apparent reflectivity of one or both of the surfaces on the front and back sides, as a result, for example, of the minute surface irregularities in high-density polyethylene. Radiations, typically infrared radiations at the reference and absorption wavelengths, are directed into the front side of the material, and reflected radiations including the reference and absorption wavelengths are detected from the front side at the specular reflection angle. From the detected radiations there is produced an instrument response wherein the effects of the reference and absorption wavelengths reflected from the front side have been selectively subdued, whereby the response is indicative of the value of the property primarily as a function of the reference and absorption wavelengths reflected from the back side of the material. Typically the method is performed by additionally directing into the front side of the material a third wavelength, (e.g. 3.43 microns) to which the material exhibits a substantial opacity, additionally detecting from the front side at the specular reflection angle reflected third wavelength radiation, and producing the response so that the principal effects therein of the reference and absorption wavelengths reflected from the front side are cancelled by the effect of the third wavelength. Typically the method includes directing into the front side of the material a second reference wavelength of radiation, detecting the reflected second wavelength from the front side at the specular reflection angle, and producing from the detected first and second reference wavelengths a composite reference component of the instrument response, derived in accordance with a function which relates the relative intensities of the reflected first and second reference wavelengths to the differences in wavelength among the absorption and first and second reference wavelengths.

Radiation reflection method and apparatus particularly for gauging

A property of a thin, infrared radiation-transmissive film of plastic or the like with specular surfaces is measured with substantial freedom from errors caused by wave interference effects, utilizing first and second infrared radiations having wavelengths selected so that one of the radiations is subject to greater absorption in the film material than the other radiation. Beams of each of the radiations are directed from a multiplicity of points as on the diffusively reflective inner surface of a sphere to a surface of the film at a broad spectrum of incidence angles so that the beams traverse a multiplicity of paths through the film constituting a broad spectrum of path lengths. Radiations leaving the film are intercepted and redirected from a multiplicity of points to a surface of the film at a broad spectrum of incidence angles so that the redirected radiations also traverse a multiplicity of paths through the film constituting a broad spectrum of path lengths. Each of the first and second radiations are detected with detecting means so arranged with respect to the directing and redirecting points that detected components of each radiation are added at substantially all possible phase angles and so that the components of each of the respective radiations at each of the possible phase angles approach equality of intensity as detected by the detecting means. A response produced is indicative of the film property as a function of the ratio of the detected intensities of the first and second infrared radiations.

Growing community of inventors

Columbus, OH, United States of America

Paul Williams