Abstract: A sensor is provided that measures web caliper using optical and magnetic measuring devices. The optical measuring devices may employ a confocal chromatic aberration method to accurately determine the distance to the moving web and the magnetic devices may be ferrite core coil and target. Means of stabilizing a moving web are included for improving dynamic measurement accuracy.

Abstract: A system for measuring both caliper and tension of a web such as paper wound into a roll. The system may include a standard caliper sensor whose air supply is selectively modified to allow for both the measurement of caliper and tension of the web. In another embodiment two similar or identical measurement devices are installed in tandem where one device measures tension without pinching the sheet and the other device measures caliper. The sensor may include two sheet guides for providing support for tension measurement or one or both sheet guides can be eliminated by support from machinery rolls.

Abstract: A system for measuring both caliper and tension of a web such as paper wound into a roll. The system may include a standard caliper sensor whose air supply is selectively modified to allow for both the measurement of caliper and tension of the web. In another embodiment two similar or identical measurement devices are installed in tandem where one device measures tension without pinching the sheet and the other device measures caliper. The sensor may include two sheet guides for providing support for tension measurement or one or both sheet guides can be eliminated by support from machinery rolls.

Abstract: Pinch valves having a flexible, constrictable sleeve are used to control a dilution headbox for a paper making machine. A variety of pinch valves may be used in the present invention with the pinch valves being actuated by pneumatic or hydraulic pressure or by mechanically pinching the valves' sleeves by means of rams driven by stepper or linear drive motors. For pneumatic control, dynamic differential pressure drops are measured across the valves to determine flow rate through the valves. A pinch valve, referred to herein as a torsional pinch valve, is disclosed for dilution headbox control. In one form, a first end of a sleeve is fixedly mounted in a support frame and the second end of the sleeve is mounted for rotation in the frame. A driver rotates the second end of the sleeve such that a flow path through the sleeve is controlled. The flow path is a maximum when no torsion is placed on the sleeve and is reduced to substantially zero by sufficient rotation.

Abstract: A caliper measuring system is provided for determining the thickness of a moving sheet. The system comprises first and second caliper sensing heads having first and second sensing shoes positioned on opposite sides of the moving sheet for engaging the sheet. A gap sensor is associated with the first and second sensing shoes for generating distance signals representative of the distance between the first and second sensing shoes and for determining the thickness of the moving sheet based upon the distance signals. The gap sensor includes a processor which determines the thickness of the moving sheet from the distance signals, generates a count of lumps sensed in the moving web, and generates a baring profile representative of rapid thickness variations along the moving sheet in the direction of movement of the sheet.

Abstract: An apparatus for optically scanning and measuring the physical parameters of a sheet material by means which are fully enclosed within an air purged cross-machine box-beam structure to protect the radiation source, the radiation detector and the optics from the harsh machine environment. The apparatus may involve a single beam enclosing a combined source/detector module for reflection measurement or dual beams on opposite sides of the sheet for transmission measurement with one enclosing a source module and the other enclosing a detector module. Standardization means are also provided either in the module itself or as an extension of the beam. Means are also disclosed for sealing the opening in the beams through which the radiation passes.

Abstract: Characteristics of moving webs are measured using a radiation source shutter which is rotatably movable between an opened-shutter position and a closed-shutter position and structured to permit access to the radiation source in the closed-shutter position. The source is configured to produce a fan-shaped radiation beam which passes through the web to a detector. The sizing of the fan-shaped beam and the detector together with the spacing the source and the detector are such that the beam width is substantially less than the detector while its length is greater than the detector. This novel beam shaping, detector arrangement provides composition insensitivity, increases solid beam angle and superior streak detection by aligning the beam length dimension with the direction of web movement.

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: A method and apparatus provide for determining properties of a web of traveling sheet material by scanning light including at least selected wavelengths such as IR and/or visible wavelengths across the web of material and also across at least two calibration samples. The signals generated in response to the scanning of the calibration samples is used to calibrate the scanning operation preferably on every scan. By providing at least two calibration samples, better estimates of average calibration parameters can be made and detection of a faulty calibration sample is facilitated. The calibration samples preferably are protected by mounting them within a scanner housing in relatively close proximity to a scanning beam generator. In addition, at least two compensation samples are supported substantially adjacent the moving web of material and preferably at least one compensation sample is positioned on each side of the web.

Abstract: An apparatus and process for measuring physical parameters of sheet material via infrared absorption phenomena is disclosed. The invention employs an integral filter-detector package comprising at least two optical filter-detector combinations. The package is contained within a conventional sensor housing which traverses back and forth across the sheet material. The package may comprise an additional filter-detector combination that is selected to produce a detector response having a significantly higher signal-to-noise ratio than the response of remaining detectors. The former response is used in combination with synchronous detectors to provide a reference of the general shape and phase of the latter responses in the absence of high noise.