Abstract: A headbox includes a nozzle type stock channel with an outlet gap. The nozzle type stock channel is defined by two flow guide walls. Arranged on the discharge end of the upper flow guide wall is a movable aperture to which attach numerous adjustment spindles which are arranged distributed across the machine width. Each adjustment spindle has on its end away from the aperture a spindle drive. Provided on the upper end of each spindle is a measuring device serving the determination of the local position of the aperture. The measuring device has a measuring housing and a measuring element movable in it. The measuring element is connected positively with the aperture, independently of the spindle, by way of a measuring rod. The measuring housing is positively connected with the area of the flow guide wall on the near side of the aperture, by way of an oblong tubular measuring reference.

Abstract: A method and system are provided for controlling the feed of comminuted cellulosic fibrous material (e.g. wood chips) to a continuous digester utilizing a chips meter of variable speed. A quality of the chips related to mass flow--preferably density--is continuously determined, preferably while the material is in free fall, not immersed in liquid. The speed of the material meter is controlled in response to the quality determined to provide a target mass flow of material from the meter to the digester. A nuclear type density gauge may be utilized having a source and a detector mounted on opposite sides of a chip chute, and above the level of liquid in a chip chute so that density is determined during free fall of the chips, not immersed in liquid. A level sensor may also be associated with the chip chute with a shield between the nuclear source and the level sensor. The chip meter speed is controlled in the range of about 0-16 rpm.

Abstract: A method and apparatus in the press section of a paper machine for regulating the axial linear-load profiles in its nip or nips (N.sub.1,N.sub.2,N.sub.3). The axial temperature profile(s) of the outer mantle(s) of a press roll or rolls (11, 13, 16, 17) is/are regulated. Thereby, the distribution of the diameter of the press roll in the axial direction is controlled on the basis of thermal expansion. Also thereby, the distribution in the transverse direction of the machine of the linear load in the press nip or nips (N.sub.1,N.sub.2,N.sub.3) formed by the press roll or rolls (11, 13, 16, 17) is affected. The temperature profile of the outer mantle(s) (11', 13',17') of the press roll or rolls (11, 13, 17) is regulated by a press felt or felts (10, 14, 18) running through the press nip or nips (N.sub.

Abstract: In a method and apparatus for making a dry sheet-like sample of solid particles from a suspension, a part of the suspension is sampled by a sampling unit as it flows through a pipe or while it is retained in a storage tank, then the sampled suspension is stirred by supplying a compressed air and then dewatered by filtration with vacuum, thereby forming a wet sheet-like intermediate sample of solid particles deposited on a filter, subsequently, the filter and the intermediate sample deposited thereon are conveyed by an overturning conveyor unit to a drying station while being turned upside down, thereafter intermediate sample is removed from the filter by a sample removing unit, and finally, the wet sheet-like intermediate sample is dried with heat and pressure whereby a dry sheet-like final sample is obtained.

Abstract: A method for determining bending stiffness of a moving sheet using an on-line sheet bending stiffness sensor. The sensor continuously bends the sheet as it is being manufactured and, based upon the force required to bend the sheet, the amount of bending and the tension applied to the sheet, the sensor determines a parameter indicative of sheet bending stiffness. The resulting parameter can be correlated with conventional destructive laboratory tests of sheet bending stiffness.

Abstract: A sensor for the detection of wood chip level in a digester, for example, a Kamyr digester, which consists of: (a) a probe, several meters long, vertically mounted inside the top part of the digester; (b) a series of bare metal electrodes in the side of the probe, spaced typically a few centimeters apart, and electrically insulated from the probe wall; (c) electronic circuit processing to allow any pair of electrodes to be selected, and (c) a means to allow the electrical properties of a liquor or wood chip and liquor mixture between the electrodes of a pair to be measured, and the level deduced from the measurement.

Abstract: Apparatus utilized in the continuous manufacture of sheet material, such as paper, includes a frame having at least one hollow beam for carrying means such as sheet-gauging heads operatively associated with the sheet material being fabricated. Thermal stability of the at least one hollow beam is enhanced by circulating fluid within the beam. Fluid displacement means which may be in the form of a series of inserts disposed end-to-end within the hollow beam define with the interior wall of the beam a fluid conduction channel. The fluid displacement means may also include generally helically oriented guides projecting into the fluid conduction channel for inducing turbulence in the circulating fluid.

Abstract: The invention concerns a method for regulation of the moisture profile of a paper or board web in a size press in which the paper or board web (W) is made to run through a nip (N) formed by the rolls (1,2) in the size press. Films (F.sub.1, F.sub.2) of size are applied to the faces (3,4) of the rolls in the size press by means of coating devices (10,20) so that these films (F.sub.1 F.sub.2) of size are transferred onto the paper or board web (W) in the roll nip (N). A size (F.sub.1) of substantially invariable profile is spread onto the face (3) of the first roll in the size press (5), and the profile of the size film (F.sub.2) to be spread onto the face (4) of the second roll is regulated so that the moisture profile of the web (W) at the reel-up can be made substantially invariable. The invention also concerns a film size press for implementing the method.

Abstract: The jet velocity along a slice opening of a papermaking machine is monitored at plural locations to provide a jet velocity profile. This jet velocity profile may be adjusted to more closely match a reference velocity profile for the jet. Preferably, microwave doppler-effect velocity sensors are utilized for sensing a jet velocity. In one specific embodiment of the invention, preamplifier and automatic gain control circuitry is used to minimize variations in the sensed signal due to changing conditions of the jet.

Abstract: Device for measuring the condition of a felt (4) in a paper machine and for reconditioning it, comprising a measuring head (7) provided with a suction chamber (7b) and a measuring surface (7a) to be positioned against the surface of the felt (4) and provided with suction holes (15) leading into the suction chamber (7b); a suction conduit (17) leading out of the suction chamber (7b) and communicating with a vacuum source (9) for sucking air and water through the suction holes (15) from the felt (4) into the suction chamber (7b) and for discharging water and air from the suction chamber (7b); and measuring means (18) for measuring the vacuum pressure in the suction chamber (7b). In the reconditioning and measuring device according to the invention, the measuring head (7) comprises two suction conduits (16, 17) for sucking water and air, respectively.

Abstract: The invention provides multiple steam applicators which are used to distribute steam against a web during calendering. The invention includes a primary steam applicator located adjacent a side of the web to which steam is applied. The primary steam applicator has a manifold, a primary inlet valve, and a plurality of steam valves spaced along the primary manifold. Each steam valve regulates a steam flow distributed to a cross-directional section of the web. A secondary steam applicator is located adjacent the side of the web to which steam is applied. The secondary steam applicator has a manifold, a secondary inlet valve, and a plurality of steam valves spaced along the secondary manifold, each steam valve regulating a steam flow distributed to a cross-directional section of the web. A gloss sensor measures the gloss finish of the web.

Abstract: A system and process for continuously determining the strength of paper sheet material during manufacture includes a plurality of sensors for detecting proxies related to properties such as the strength of individual fibers, length distribution of fibers, quantity of fibers, distribution of fibers, orientation of fibers, number of bonds between fibers, and bond strength of fibers. For a given papermaking machine and paper type, multiple regression analysis is used to determine correlations between the measured proxies and laboratory tests of paper strength. Then, during operation of a papermaking machine, changes in the proxy measures are used to indicate paper strength and to adjust operation of the papermaking machine based upon changes in the strength of sheet material being produced.

Abstract: A slice lip control mechanism for the slice lip of a head box of a paper making machine. The control mechanism has a linear actuator, a spindle extending from the actuator and a link on the lip to attach to the spindle. Movement of the actuator is thus transmitted to the lip, through the spindle, to deform the lip locally to control a head box outlet orifice whose upper edge is defined by the slice lip. The spindle includes a pressure transducer whereby the load applied to the lip by the actuator that communications with the pressure transducer through the spindle can be assessed and the lip's position calculated.

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: A device for determining the characteristics of particles in suspension in a liquid, comprising a sampling device (2) for injecting samples of particles; a fractionator (3) for sorting those particles as a function of their length; an optical measurement cell (4) which receives the output of the fractionator, and a programmable controller (6) for calculating the values of the intensities and combinations of those values in the various directions of the optical radiation. The optical measurement cell includes a laser for transmitting polarized, coherent light through the particles in suspension and for collecting the light diffracted in various directions.

Abstract: The present invention relates to a method of qualitative and quantified monitoring of the instant local physical state of a substantially incompressible fluid material such as a liquid or pasty substance (for instance slurry or pulp) and a device for carrying out this method and the various applications and uses resulting from the working of the method and/or device for the automatic control of said physical state. The invention is also directed to the various equipment and systems provided with at least one such device.

Abstract: A paper weight sensor system is intended for use on a paper-making machine having a headbox with a slice-lip mounted thereon for forming a moving web of material. Plural slice-lip actuators are provided for setting the slice-lip gap to control the amount of material in the web and are mounted on the headbox. Plural stationary optical sensors are located at a first station and extend across the width of the web in a continuous array for detecting the transmissivity of the web in a one-to-one relationship with the slice-lip actuators at an aligned location downstream of each actuator. Each sensor includes plural light detectors therein which are operable to generate a first transmissivity signal representing the transmissivity of the web for discrete regions thereof adjacent each light detector corresponding to a given actuator.

Abstract: In a method and apparatus for making a dry sheet-like sample of solid particles from a suspension, a part of the suspension is sampled by a sampling unit as it flows through a pipe or while it is retained in a storage tank, then the sampled suspension is stirred by supplying a compressed air and then dewatered by filtration with vacuum, thereby forming a wet sheet-like intermediate sample of solid particles deposited on a filter. Subsequently, the filter and the intermediate sample deposited thereon are conveyed by an overturning conveyor unit to a drying station while being turned upside down, thereafter intermediate sample is removed from the filter by a sample removing unit, and finally, the wet sheet-like intermediate sample is dried with heat and pressure whereby a dry sheet-like final sample is obtained.

Abstract: A method and control system are provided for controlling apex flow in an array of parallel hydrocyclones, used for cleaning aqueous cellulose fiber suspensions, and arranged in a housing with a common inject chamber, base chamber and apex fraction chamber common to all hydrocyclones in the array, featuring the control of apex flow of cellulose fiber suspension by monitoring and maintaining apex flow at a selected value, increasing apex flow through the array whenever apex flow diminishes due to plugging of a hydrocyclone in the array, to aid in avoiding plugging of other hydrocyclones in the array.

Abstract: A method and an apparatus for the automatic determination of the dry pulp content, the infiltration capacity and the wire retention of a pulp suspension. In the method the automatically or manually taken pulp suspension sample is brought to the sample container (2) of the determination equipment (1) located in the immediate neighborhood of the production or the operation process. According to the invention the quantity of the sample in the sample container is measured by weighing, the sample is in case of need attenuated into the processing consistency range, a part of the sample is led to the filter (4), is filtrated in the filter with and/or without a filtering paper, the sample cake obtained is transferred to the desiccator (8) and dried with the desiccator, the dried sample cake is weighed and the test results are written out with the output equipment (11).

Abstract: A method for controlling high-speed sheetmaking machine after abrupt process changes and during start-up periods and the like, includes operating a scanning sensor to periodically traverse back and forth across a sheet in the cross direction to detect values of selected sheet property along each scan while the cross-directional width of each scan is controlled to be substantially less than the width of the sheet being scanned.

Abstract: In a drum washer for washing the pulp for making paper to remove pulping liquors, the method and apparatus for providing the filtrate liquid being drained from the drum and pulp mat during a portion of the rotation cut-off which liquid can be continuously sampled and analyzed to give a more positive indication of washing efficiency.

Abstract: A system and process for continuously determining the strength of paper sheet material during manufacture includes a plurality of sensors for detecting proxies related to properties such as the strength of individual fibers, length distribution of fibers, quantity of fibers, distribution of fibers, orientation of fibers, number of bonds between fibers, and bond strength of fibers. For a given papermaking machine and paper type, multiple regression analysis is used to determine correlations between the measured proxies and laboratory tests of paper strength. Then, during operation of a papermaking machine, changes in the proxy measures are used to indicate paper strength and to adjust operation of the papermaking machine based upon changes in the strength of sheet material being produced.

Abstract: The method and apparatus automate the observation of the dry line on the wire of the Fourdrinier paper machine on whose visual observation by eye the conventional control of the paper machine is based. In the invention, the position of the dry line and its such values which deviate from normal, and the quantities which express its form, are reproduced to the operator repeatedly. In order to carry out this, it is formed as one essential feature of the invention, the image of the plane of the wire with an opto-electric camera and the electric, discrete image information is transmitted into a computer. While the conventional observation of the dry line is based on reflections from the pulp surface which are brighter than the other surface, these, however, disturb an instrumental observation and check an interpretation of the result of observation.

Abstract: A system and process for controlling the displacement of a thickness regulating member which regulates the basis weight of a sheet being formed from fluid material. The displacement of the thickness regulating member is determined by measuring the forces which slice rods exert on the thickness regulating member.

Abstract: An apparatus for measuring air permeability and boundary air flow for a papermaking fabric, such as a dryer felt. The apparatus includes a housing having an open front end bordered by a lower straight edge. An air flow measuring device, such as an anemometer is mounted in the rear surface of the housing a funnel-shaped deflector directs air entering the open front end of the housing to the anemometer. Air flowing through the anemometer generates an electrical signal in proportion to air flow. The electrical signal actuates a visual display mounted on the housing which provides a visual indication of air flow. A thin blade is mounted at the open front edge of the housing and is adapted to ride along the moving fabric when the apparatus is used. A handle is secured to the upper surface of the housing and extends forwardly of the front end and is adapted to be grasped by an operator.

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 system and method for controlling sheetproducing machines includes measurement devices for measuring properties of a sheet at cross-directional locations to provide cross-directional profiles, and spatial-frequency splitting means for separating low spatial-frequency components from high spatial-frequency components for each profile. The separated high and low spatial-frequency components provide operating signals to controllably adjust properties of the sheet.

Abstract: A system and method to continuously determine the pulp consistency in the discharge blowline (112) of a continuous pulp digester (100) having a gamma gauge (116) disposed adjacent to the blowline (112) for continuous measurement of the intensity of gamma radiation attenuated by the pulp slurry passing through the blowline (112), a density gauge (118) disposed adjacent to a cold blow liquor line (102) for continuous measurement of the density of the cold blow liquor in the cold blow line (102) independent of variations in the gamma radiation mass-attenuation coefficient of the cold blow liquor in the cold blow liquor line (102), a gamma gauge (120) disposed adjacent to the cold blow liquor line (102) for measuring the intensity of gamma radiation attenuated by the cold blow liquor passing through the cold blow liquor line (102) and a computer (122) for receiving signals output from the first gamma gauge (116), the density gauge (118) and the second gamma gauge (120) indicative of intensity of gamma radiation a

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: The present invention discloses a method and apparatus for the on-line measurement of fiber orientation in a translucent sheet. To measure the fiber orientation, coherent light is directed onto one surface of the sheet in a pattern of sufficient intensity to produce a second pattern on the other surface of the sheet. The shape of the second pattern is determined, at least in part, by the orientation of the fibers in the sheet. A sensing apparatus including a video camera and frame grabber, views the second pattern and produces a freeze frame image signal. Even though the second pattern may be moving, the sensing apparatus freezes this motion and produces the freeze frame image signal to represent a stationary image of the second pattern. The freeze frame image signal is analyzed to determine the shape of the second pattern and from this shape the orientation of the fibers in the sheet is determined. Also disclosed is an apparatus for using the method and an improved system for making paper using the method.

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: A method for controlling high-speed sheetmaking machine after abrupt process changes and during start-up periods, includes operating a scanning sensor to periodically traverse back and forth across a sheet in the cross direction to detect values of selected sheet property along each scan while the cross-directional width of each scan is controlled to be substantially less than the width of the sheet being scanned, the progressively increasing the width of the scan until each scan encompasses the full width of the moving sheet.

Abstract: Apparatus and method for automatically detecting and removing contaminant particles from a moving pulp mat are provided, detection of the particles being accomplished using a light source for transmitting light to the pulp mat, a light detecting means for detecting decreases in the intensity of light across the pulp mat corresponding to positions or locations of contaminant particles in the mat, and a control package for generating signals corresponding to the detected positions to be used in the contaminant removal proceses, removal of the particles being accomplished by cutting a rectangular section containing the particle from the mat using a bank of fluid jet nozzles which produce longitudinal slits and transverse cuts in the pulp mat as the mat travels past the nozzle bank.

Abstract: The present invention concerns a method in a paper machine for the measurement of air penetrability or permeability of fabrics penetrable by air, in particular of a wire or felt. In the method, the fabric penetrable by air such as a wire is passed over at least one roll, where a positive pressure is formed at an inlet side of the fabric with respect to the roll when the fabric runs and in an inlet nip formed between the moving fabric and a face of the roll, and a negative pressure is formed at an outlet side of the moving fabric with respect to the roll in an outlet nip formed between the moving fabric and the roll face. The positive pressure and negative pressure depend up on the permeability of the fabric penetrable by air. According to the method, at least one device is mounted below the fabric penetrable by air such as a wire, this device being sealed relative to the moving roll face so that an at least partially closed pressure space is formed between the device, the roll face, and the fabric.

Abstract: This invention is directed to a filtration simulator. More specifically, this invention is directed to a Dynamic Filtration Simulator (DFS) and method of determining the interaction and effect on liquid flow of additives to paper stock in a papermaking machine, which comprises:(a) admixing one or more additives to be tested with paper stock in a slurry tank to form an aqueous paper stock slurry;(b) pumping said slurry from step (a) to a filtration means comprising permeable filter material, the interior of said filtration means being in fluid communication with an exit pipe which is in fluid communication with said slurry tank, whereby aqueous slurry permeates said filter material to form a permeate and said permeate flows through said exit pipe back to said slurry tank;(c) measuring the pressure and volume flow of the aqueous paper stock slurry into the filtration means; and(d) measuring the pressure and volume flow of the aqueous permeate.

Abstract: A method and apparatus for monitoring and controlling the operation of a counter-current pulp washing system. The dilution factor, soda loss, wash liquor ratio and displacement ratio of the washing system are determined on-line. The value of either the soda loss or of dilution factor is continuously maintained within a preselected range and changes in the value of the other variable are monitored to provide an indication of whether the washing system is operating optimally. Based on the on-line determination of displacement ratio and wash liquor ratio, the efficiency of the washers is monitored, the cause of any decrease in efficiency is identified and the appropriate control action is applied to adjust the operating parameters of the washers to compensate for changed washing conditions or changed processing conditions.

Abstract: A method for measuring the permeability of pervious sheet material is disclosed; the measurement is based on the flow rate of water ejected at a given pressure between 2 and 1000 kPa through a nozzle pressed against one surface of the sheet material whose permeability is to be measured.

Abstract: A sheet inspection station including pneumatic means for guiding the sheet past one or more measurement sensors in non-contacting fashion, thus eliminating measurement error resulting from fiber/dust buildup associated with friction between the sheet and conventional guide rails. Air is directed from components, that extend from a sensor surface, onto the sheet surface.

Abstract: A sensor for sensing a quality of paper related to elastic modulus and bending stiffness as it is being made including a paper support in the form of a ring and a free running wheel, which depresses the paper in 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 characteristics of the paper related to its elastic modulus and bending stiffness. This factor, together with basis weight, thickness and paper velocity are used to determine the strength of the paper on a continuous basis.

Abstract: Complete definition of a papermachine headbox slice opening requires the measurement of three interdependent dimensions including (1) the projection distance of the slice lip edge below the slice beam, (2) the projection distance of the slice apron edge beyond the plane of the slice lip edge and (3) the slice opening distance between the slice lip edge and the upper face plane of the slice apron. A single gauging tool is provided for measuring all three headbox slice dimensions.

Abstract: A modified infra-red scanning gauge used in measuring the moisture content of a paper-web during manufacture or when subject to a coating practice, has a measurement channel and a reference channel. The measurement channel is based on the infra-red absorption spectrum of water which has an absorption band centered on 1.94 microns. The reference channel is conventionally at a wavelength of 1.83 microns where water has previously been considered to be transparent to infra-red or at a wavelength of 1.68 microns. The gauge is intended for measurement of high water content, where at 1.94 microns absorption effectively becomes total thereby preventing measurement being made, and uses a narrow-band filter of 0.03 micron wavelength offset from the peak of the 1.94 micron absorption band in the range 1.76 to 1.87 microns, previously considered stable as regards water content but now disclosed as showing a water-dependent variation at high water contents. In a specific example a 1.

Abstract: Method and apparatus for compensating bending of a lip beam in a paper machine when papermaking pulp flowing through the slice formed with the lip beam causes loading upon a bottom surface of the top lip beam. The bending of the beam caused by the loading is compensated by bending the lip beam in the opposite direction, by creating a temperature difference in the lip beam between a top part and a bottom part of the same.

Abstract: Apparatus is disclosed for continuously measuring the conductivity of the liquor in a pulp mat on a pulp washer. The apparatus comprises a probe which rests on and squeezes washing liquor from the pulp mat. Two modifications of the probe are disclosed, one fixed and one rotatable. In each case, the probe comprises a pair of electrodes separated from one another by non-conducting material. The electrodes are arranged on the probes to be submerged within the washing liquor squeezed from the mat. The electrodes are connected to an energy source, and when current is applied to one electrode, the current flows through the liquor to the other electrode to complete an electrical circuit. The measurement of the current flow or the resistance to current flow is directly related to the conductivity of the liquor and can be correlated with the soda loss in the pulp washing step.

Abstract: Apparatus for sensing the thickness of a pulp suspension, having zones or slices, on the forming wire of a paper making machine includes an array of ultrasonic transducers located in the apertures of a structural member mounted in a cross-direction under the forming wire near the headbox of the machine. Each ultrasonic transducer is mounted on a flexible sheet which is mounted to an aperture and the transducer moved into close proximity to the bottom of the forming wire by means of air pressure in the structural member. A second array of transducers downstream of the first can be utilized for diagnostics.

Abstract: A method and suitable apparatus for periodically analyzing pulp stock, including wood pulp and water, in a pulp digester, to determine the amount of cooking to which the pulp has been subjected. The method includes taking a sample of the pulp stock from the digester, diluting the sample to a predetermined range of consistency, and determining the exact consistency of the sample. Next, the sample is transferred to a reaction chamber. A reagent is then added to the sample and allowed to react with the sample at a predetermined temperature. The light absorbance of the reagent during the reaction is continuously monitored during the reaction. After the light absorbance has clearly passed a peak, the value of the peak is combined with the consistency of the sample, previously determined, to arrive at the amount of cooking to which the sample had been subjected prior to the test, from a known relationship thereof to the light absorbance of the reagent and the consistency of the sample.

Abstract: A device for measuring the moisture content and basic weight of paper in a gravimetric and more accurate manner than before. The device includes a cutting device for cutting the sample from a specimen sheet, a balance for weighing the sample, a computer for computing the moisture content and the basic weight of the sample, an output device for printing out the results of the moisture content and basic weight as well as a controller for controlling the device automatically and advantageously a drying device for drying the sample.

Abstract: In a contaminant detector for processing paper pulp including sticky contaminants, a pulp sample is diluted to less than 0.5% consistency and passed through a concentrator from a plurality of classified samples having heavy and light particles. The inclined classified samples are again diluted to less than 0.5% consistency and passed as thin sample flow through an open channel having a light transmitting base. The flow is back lighted and a photodetector includes a linear array of sensitive elements aligned to receive the transmitted light. The sensitive elements aligned with particle creates a signal proportional to the width. By rapid sequential activation of the elements, a digital data stream is created which is processed by a microprocessor to determine the particle size and produce a plurality of contaminant relative signals related to different classified size ranges, such as heavy, medium and small contaminant particles.

Abstract: A surge control system for dewatering press felts on a papermaking machine which includes a suction pipe, a variable speed drive motor, a centrifugal exhauster driven by the variable speed drive motor and connected to the suction pipe to provide vacuum to a felt passing over a slot for dewatering thereof. A surge valve is provided and is opened to admit air to the centrifugal exhauster so as to prevent surge when the centrifugal exhauster is operating at a predetermined level at which the centrifugal exhauster will surge.

Abstract: A method and suitable apparatus for periodically analyzing pulp stock, including wood pulp and water, in a pulp digester, which may or may not be part of a paper machine, to determine the amount of cooking to which the pulp has been subjected. The method includes diluting a sample of the pulp stock from the digester, diluting the sample to a predetermined range of consistency, and determining the exact consistency of the sample. Consistency can be determined by any suitable commercially available apparatus. Next, substantially all the water is removed from the sample. A reagent, preferably a 14 percent solution of nitric acid in water, is then added to the sample and allowed to react with the sample for a predetermined time interval at a predetermined temperature. The light absorbance of the reagent during and after the reaction is determined by the amount of cooking to which the pulp has been subjected and the consistency of the sample.