Abstract: Significant improvements in papermaking control can be achieved by employing an array of sensors that are positioned underneath the wire of the machine to measure the conductivity of the aqueous wet stock. The conductivity of the wet stock is directly proportional to the total water weight within the wet stock; consequently, the sensor provides information which can be used to monitor and control the quality of the paper sheet produced. Because CD water weight profile is obtained practically instantaneously, the MD and CD variations are essentially decoupled. Quality improvements to the sheet fabricated will be achieved by providing fast control of the actuators on the machine and by tuning components on the machine to eliminate the sources of variations.

Abstract: A system and method of providing on-line turbulence measurements in a sheetmaking machine and using these measurements to perform on-line adjustments to turbulence-inducing and adjusting elements in the sheetmaking machine to optimize final sheet product quality. Turbulence measurements are obtained using water weight sensors in the wet-end of the sheetmaking machine and specifically under wire water weight measurements. Water weight readings are correlated to turbulence intensity levels by correlating ranges of water weights to intensity level intervals. A turbulence processing sensor sorts accumulated water weight measurement readings into intensity level intervals to obtain turbulence measurements or a turbulence profile. The turbulence measurements or profile is provided to a machine element controller which uses the measured turbulence information and target turbulence information to generate control signals.

Abstract: Paper web formation analyzers can be employed both on operating paper machines at high speed and on cut samples as a desk top unit, so as to unify formation evaluation for both situations.

Abstract: Significant improvements in papermaking control can be achieved by employing an array of sensors that are positioned underneath the wire of the machine to measure the conductivity of the aqueous wet stock. The conductivity of the wet stock is directly proportional to the total water weight within the wet stock; consequently, the sensor provides information which can be used to monitor and control the quality of the paper sheet produced. Because CD water weight profile is obtained practically instantaneously, the MD and CD variations are essentially decoupled. Quality improvements to the sheet fabricated will be achieved by providing fast control of the actuators on the machine and by tuning components on the machine to eliminate the sources of variations.

Abstract: A system and method of providing fast machine direction (MD) and cross direction (CD) basis weight adjustments using a simultaneous multi-point water weight sensor which provides independent MD and CD measurements is described. The water weight sensor is placed under the wire of the sheetmaking machine and provides fast wet end water weight measurements which are converted into predicted dry end basis weight information and used to control operating variables of machine elements in the sheetmaking machine to compensate for high frequency process variations. MD wet end measurements are used to control operating variables of machine elements that influence the MD dry end basis weight and CD wet end measurements are used to control operating variables of machine elements that influence CD dry end basis weight.

Abstract: A device in a measuring station in a paper or cardboard machine for manufacturing a paper or cardboard web, said measuring station being situated between two work stations and comprising a scanner with two measuring heads travelling to and fro across the web and between them defining a space through which the web passes, driven by drive members. According to the invention the device comprises a continuous, flexible support strip extending through said space between the measuring heads, transverse and parallel to the web from one edge to the other, and drive members for winding and unwinding the support strip onto or off rolls arranged at points outside each edge of the web, for displacement of the support strip transversely to the web in the same direction and at the same speed as the measuring heads.

Abstract: A sheet measurement and control system that enables easy installation and/or change of types of sensors to be disposed in or about a sensor head that reciprocally scans a sheet along a cross direction transverse to the sheet flow; wherein a plurality of sensors are disposed in or about the sensor head to measure characteristics of the sheet; a plurality of computation devices corresponding to the plurality of sensors are disposed in or about the sensor head to implement computation of the measuring signals from the sensors; a plurality of communication control devices corresponding to the plurality of computation devices are disposed in or about the sensor head for transmitting the processed measuring signals through a general network communication link attached thereto; and man-machine interface connected to the general network communication link monitors data from said communication control devices related to the measured signal and issues instructions to control the sheet manufacturing process.

Abstract: Apparatus and process for controlling the basis weight of paper produced in a papermaking machine are provided. In the papermaking process, a major portion of the paper stock flows through a first line that is controlled by a thick stock valve and a minor portion of the stock flow from the stuff box to the headbox is diverted through a second line that is regulated by a second valve (e.g., vernier valve). The thick stock valve is controlled by the dry end basis weight and the second valve responsive to measurements of the basis weight of the wet stock at the wire. The second line and control valve along with the wet end basis weight measurements form a fine control loop with fast response time whereas the first line and control valve that is responsive to dry end basis weight measurements form a course control loop. The dual control loops enable fast and actual basis weight control.

Abstract: A regulation system and method in a paper machine for controlling the variation of the basis weight of a paper web in the machine direction in which the basis weight profile of the web is measured by means of a measurement device and a basis weight regulation system receives a signal of the measurement of the basis weight from the measurement device and generates a regulation signal for controlling the flow of thick stock passed into a short circulation circuit in the paper machine by a basis weight valve and/or a regulation pump. The variation of the basis weight in the machine direction in the paper machine is controlled, besides by the short circulation circuit of regulation, also by a substantially faster second circuit of regulation which comprises one or more actuators for controlling the flow rate of the dilution water flow in the dilution profiling system of the headbox and/or the consistency of the dilution water flow across the entire width of the paper web.

Abstract: The present invention is directed to a method for controlling and adjusting the permeability of a cigarette wrapping paper. Permeability is controlled in the paper by adding different sized filler particles in different proportionate amounts. Permeability of the paper is altered without having to change the total amount of filler in the paper. By selectively controlling the permeability of the paper, various characteristics and properties of a cigarette made with the paper can be likewise modified as desired. In one embodiment of the present invention, the permeability of a cigarette wrapper can be automatically maintained or adjusted as the paper is being made.

Abstract: Apparatus for the operation of a plant for producing deinked pulp with state analysers constructed in the form of neural networks for the waste paper suspension.At least one measuring device (ME) records spectral and/or physical characteristic values (IMf, Mp) of a waste paper suspension (PS). Furthermore, there are closed-loop or open-loop control devices (RS1 . . . RS8) for operating means of a waste paper preparation (AAA) in the plant. According to the invention, there is at least one state analyser (ZA), configured in the form of a neural network (NNg) or a plurality of parallel neural networks (NN1 . . . NN4), for the waste paper suspension (PS). This analyser forms from the characteristic values (IMf, Mp) controlled variables (ST: AB, AZ, FL, AA, AS, AT) for process control of the closed-loop or open-loop control devices (RS1 . . . RS8) of operating means at least of the waste paper preparation (AAA).

Abstract: A method for the continuous overall regulation of a single-layer or multi-layer headbox of a paper, board or pulp-draining machine. A physical fluid flow model of a pulp suspension flow discharged from the headbox to be regulated is formed and solved to obtain a simulated flow state based, e.g., on data on the geometry of the headbox and initial and boundary conditions related to the headbox. A target flow state based on the quality requirements of the paper produced from the pulp suspension flow and the costs of operation and runnability of the machine is obtained and a difference between the simulated flow state obtained as the solution of the flow model and the target flow state is determined. This difference constitutes a cost function which is optimized to determine optimal regulation values and set values for instrumentation devices and actuators of the headbox which affect the pulp suspension flow.

Abstract: A system identifier for a paper machine which allows an operator having no special skills to easily implement step responses in a profile control and which comprises a mechanism for storing theoretical positional correspondence determined by paper contraction; calculator device for calculating profiles for slices associated with the operated ends using measured values at the detected end; another calculating device for calculating the conformity of each operated end by multiplying the profile for the slice by an interference coefficient indicating the effect of an operation on an operated end and on the detected end; an output slice selection device to which data of the conformity of each operated end is inputted and which outputs an output slice selection function by performing a neural network calculation wherein self feedback is performed for the operated end and lateral inhibition is performed to inhibit mutual interference between neighboring operated ends within a predetermined range; and a step respons

Abstract: A method for determining the cross-machine shrinkage or expansion profile of a travelling sheet produced in a sheetmaking machine between an upstream location and a downstream location. The method involves marking the sheet at the upstream location with an array of marks at measured, predetermined intervals in the cross-machine direction. The sheet is inspected in the cross-machine direction at the downstream location to measure the spacing of the array of marks. A shrinkage or expansion profile of the travelling sheet is developed based on the changes in the spacing between the array of marks at the downstream location. Apparatus for carrying out the method is also disclosed. The method and apparatus of the present invention permit rapid and precise determination of the sheet shrinkage or expansion profile to allow for better control of property variation across the sheet.

Abstract: A mill for the processing and production of wood pulp is contained substantially entirely within a single, integral structure that defines a unitarily-covered space substantially bounding and enclosing the mill. The mill includes a main control room or station for overall monitoring and control of pulp processing operations in the mill, the main control station being disposed substantially centrally within the covered space, and a plurality of processing stations at which various pulp processing operations take place in a generally sequential manner or order.

Abstract: An apparatus for controlling the degree of fiber variations in paper sheet has a formation meter for receiving an image of transmitted light on one side of an area of paper from a light source located on the other side of the area of paper, an image processing computing element for introducing the image from said formation meter for image processing and a fuzzy control unit for calculating and outputting optimum J/W ratio, optimum foil angle, and optimum deflector pushing degree and angle on the basis of results of image processing from said image processing computing element.

Abstract: This invention relates to the measurement and control of consistency in an aqueous flow stream, as it leaves a stage (i.e. Bleaching Stage) of the papermaking process. More particularly, the present invention relates to the measurement used for control of wood fiber and suspended solids in a papermaking pulp stock flow stream.

Abstract: The system effects an automatic observation of the dry line on wire of the Fourdrinier paper machine and the control actions based on it. In order to produce an image of the dry line range on wire this is illuminated by means of a large, diffusely illuminating surface (20) of even luminosity. The material on moving wire (10) is imaged by an optoelectric camera (40) on a detector whereby the pulp surface preceding the dry line and being specularly reflecting is found homogeneous and bright while the web surface following it and being diffusely reflecting is found homogeneous but matter and darker. The electric image signal delivered by the detector is conducted to a computer (50) in which the dry line is identified as the borderline of said surfaces of different brightness.

Abstract: A control system regulating the transverse profile of properties of a web in a paper or board machine is disclosed. The control system comprises a plurality of actuators and a corresponding plurality of actuator controllers. The actuators are arranged to be effective across the width of the web whose profile is to be regulated. Further included is a process controller and a feedback network connected to the process controller and provided with an arrangement for measuring the web profile to be regulated. The actuators are provided with intelligent actuator controllers. A data bus common to the actuator controllers is provided, along which occur data communications in a control hierarchy between a higher control device and said actuator controllers.

Abstract: A procedure and apparatus for locating faults in the machine elements of a paper machine and in their functioning, wherein variations in the paper characteristics are continuously observed, the periodicity of the variations is recorded and the periodicity of the variations in the paper characteristics is compared with the periodicity in the functioning of the paper machine's machine elements. The apparatus comprises observation members (1-11) for observing the variations occurring in the paper characteristics; synchronizing pick-ups (43-53) disposed on machine elements (13-22) of the paper machine for observing the periodicity of the functioning of said machine elements; a recording means (40) for recording the periodicity of the variations in paper characteristics and the periodicity in the functioning of the machine elements; and a data processing unit (41) for comparing the periodicity of the variations in paper characteristics and that in the functioning of the machine elements.

Abstract: In a paper making machine, a strip of paper is caused to pass around part of the periphery of a rotary device comprising a plurality of cylindrical bodies arranged side-by-side across the width of the strip and each body has means for producing a signal representing the tension in the portion of the strip which controls the body, the thickness of the portions is also measured. From this data, control signals are produced representing the stress per unit of cross-sectional area of the portions of the strip and the paper making machine is controlled to keep the control signals constant across the width of the strip.

Abstract: A web rewet moisture actuator in which a plurality of air atomizing nozzles at spaced locations along a boom extending across the web are supplied with air under pressure by an air manifold on the boom and are supplied with water from a water manifold on the boom through respective proportional valve assemblies which permit flows therethrough in proportion to the magnitudes of control signals applied to the assemblies. A unit located downstream of the boom obtains a moisture profile across the web from which location and control signals are derived and fed to the valve assemblies to control the liquid flow through the valve assemblies in proportion to the magnitudes of the control signals.

Abstract: A control system for a countercurrent pulp washing process in which the pulp is formed as a pulp mat on at least one moving filter surface and the mat is supplied with rinse water to replace water in the pulp mat thereby reducing the soda loss in the mat before it is removed from the filter surface. The process is characterized by at least one predictable process variable including dissolved solids retained in the pulp mat. The system comprises a trainable neural network having a plurality of input neurons having input values applied thereto and output neurons for providing output values and means for training the neural network to provide predicted values for the predictable process variables.

Abstract: A sheet manufacturing system having a steam profiling bar, a moisture profiling bar, a moisture sensor and a computer is disclosed. The computer is programmed to cause the correct amount of steam or water to be applied on a slice-by-slice basis based upon the moisture content profile data generated by the moisture sensor as compared against a preprogrammed, desired moisture content profile. The computer is programmed in such a way as to cause either steam or water, but not both, to be applied as needed to any given portion of each individual slice to achieve the desired moisture content profile. Thus, the combined application of both steam and water to the same portion of the sheet, and the nullifying effects thereof, are avoided, resulting in the use of less steam and less water while still providing full control over the moisture content profile with only one moisture sensor.

Abstract: Apparatus and method for controlling a paper making machine so as to improve the uniformity and quality of the manufactured paper; wherein slicing devices are provided for operating in such direction that a detected profile matches a predetermined profile. The paper making machine comprises a plurality of slices, supply of raw material to make the paper, and sensor for measuring the quality of the paper.

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 sheet manufacturing system having a steam profiling bar, a moisture profiling bar, a moisture sensor and a computer is disclosed. The computer is programmed to cause the correct amount of steam or water to be applied on a slice-by-slice basis based upon the mositure content profile data generated by the moisture sensor as compared against a preprogrammed, desired moisture content profile. The computer is programmed in such a way as to cause either steam or water, but not both, to be applied as needed to any given portion of each individual slice to achieve the desired moisture content profile. Thus, the combined application of both steam and water to the same portion of the sheet, and the nullifying effects thereof, are avoided, resulting in the use of less steam and less water while still providing full control over the moisture content profile with only one moisture sensor.

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 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: The maximum amounts of the retention-influencing variable stock components which can be added are determined as a function of a predetermined degree of flocculation and typical values of the stock suspension with the aid of a mathematical relationship, and control signals for metering retention aids are derived from the amounts so that the greatest possible retention can be achieved without exceeding a set-point for the degree of flocculation.

Abstract: A method of refining fibrous material under predetermined conditions by the help of relatively rotating refining means. The material is during refining passed from the inner circumference of the refining means to their outer circumference and is thereby exposed to bending forces and axial forces. At least two variables of the refining process, such as power and gap width are measured. The measured values of the variables and their relation are used to compare them with the set point values of the predetermined refining conditions for these variables to create control signals for positioning devices for the refining means, thereby returning the refining process to the aforementioned predetermined conditions and keeping these dependent variables constantly at these conditions.

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 and apparatus for producing uniform pulp yields, wherein at least a refiner is controlled in accordance with the UV absorbance of the lignin dissolved in the digester cooking liquor, thereby to produce for a given quantity of wood chips a uniform pulp yield. A backflow control valve is automatically adjusted to maintain uniform flow of a sample of the digester cooking liquor through a UV analyzer, and a flushing arrangement is provided for flushing out contaminates such as sulphur dioxide from the system. Preferably the refiner is of the two-stage type, the first stage being automatically adjusted as a function of the UV absorbance of the digester cooking liquor, and the second stage being automatically adjusted as a function of the freeness of the output fiber slurry. Also, one or more of the cooking parameters is controlled by the UV analyzer to control the fiber yield.

Abstract: A method of controlling the properties of a paper web across the feed direction, i.e., cross profile, in a paper machine. The cross profile is adjusted in a plurality of setting positions across the web. Proceeding from a measured cross profile and desired cross profile, an optimum correction in the setting positions is calculated, so that the cross profile is brought into agreement with the desired one. At this calculation the circumstance is utilized, such that a disturbance in the stock in a certain setting position results in a corresponding change in the cross profile of the paper web.

Abstract: Method and apparatus are provided for effectively controlling cross-machine moisture profile in a paper web undergoing processing, such as water-removal via a press nip. A compartmentalized system is provided in close proximity across a section of a traveling web undergoing dewatering whereby select size cross-machine compartments, for example, about 6" in width, are selectively provided with steam and/or air so as to control wet and/or dry streaks along the traveling web so that web areas opposite each compartment can be selectively heated for accentuated moistre removal or cooled for retarded water removal. In preferred embodiments, control of the profiling system occurs with the air of moisture sensors and a computer.

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 wshing conditions or changed processing conditions.

Abstract: A system for the control of a paper machine headbox having sensors for the measurement of the parameters of the process and actuators of the members of the process, functionally connecting at least most of the sensors to an at least equal number of actuators via a multivariable centralized control member which makes it possible to control each actuator by the taking into account and processing of the measurement information of one or more sensors, and causing the measurement information to act on each of the sensors functionally connected to the actuators on one or more members to obtain a resultant action in which only the parameter measured by this sensor is influenced while the secondary repercussions on the outer parameters are eliminated. Another characteristic, the invention permits rapid intervention taking into account the information on the substance flow rate at the headbox, eliminating the usual disturbing influences due to the hydraulic values of the process.

Abstract: The invention relates to an apparatus for leveling the surface of a strip of paper. The apparatus has at least two rollers forming a roller pair, which can be pressed against the strip of paper guided between them with an adjustable force by means of a load device. At least one roller may have a surface which can be influenced by means of a temperature device.

Abstract: A particular papermachine and type of pulp stock for forming a particular basis weight web are analyzed for deriving a correlation between pulp stock drainage rate and the lowest obtainable critical moisture content of said paper web. From knowledge of the lowest critical moisture content and main steam pressure, differential pressure values between the several dryer pressure sections of the papermachine are determined for drying said web along the most energy-efficient drying rate trajectory. Also disclosed is a dryer steam pressure differential control program for maintenance of a pre-determined magnitude of condensate inventory within the drying cylinders under normal running conditions and under conditions of interrupted web continuity.

Abstract: Apparatus for attenuating low frequency pressure variations in a stock suspension being fed to a paper machine. The apparatus includes a pressurized overflow chamber having an inlet which delivers a stock suspension therein and an outlet for discharging stock from the chamber. A first control means controls the pressure applied to the suspension in the overflow chamber. The chamber communicates with a sump which receives the overflow from the overflow chamber. A sensing means senses the stock pressure in the inlet conduit and a second sensing means senses the level of stock in the sump. A high pass filter receives a signal from the first sensing means and a low pass filter receives a signal from the second sensing means. A summing amplifier receives the output of the high and low pass filters. A control means receives the output of the summing amplifier and is connected to the overflow means to control operation of an overflow valve in response to the output of the summing amplifier.

Abstract: Waste water effluent from online production machinery and/or clean-off water from shut-down machinery is deposited in a settling tank in which the solids settle out. Water, relatively clear of the solids, is returned to the production plant. A slurry containing a high concentration of these solids is, depending on the percentage of solids, either returned to the production machinery via a slurry tank or returned to the settling tank for further concentration. The degree of concentration of solids in the slurry tank is carefully controlled in order to permit the addition of these otherwise wasted solids to the virgin asbestos-cement slurry in the various production machineries. This addition of the otherwise wasted solids is carefully monitored at each of the production machinery installations in order to provide proper quality control of the product produced thereby.

Abstract: A processing system including a pressurized blow tank for receiving the high pressure discharge from a wood pulp digester and utilizing the digester steam in evaporators or other heat recovery units. The blow tank which receives the treated cellulose, cooking liquor and high pressure steam from the digester also provides some additional fiber conditioning since the cellulose remains under significant pressure and temperature during the interval before it is discharged from the blow tank. A valve is provided in the blow tank for withdrawing high pressure steam separately from the cooking liquid and treated cellulose, and the valve is operated by a controller responding to pressure sensed in the blow tank. Cold cooking liquor is pumped into the blow tank in response to temperatures measured in the blow tank and the temperature of the cold liquor itself. Alternately the flow of additional cooking liquor can be controlled in response to levels sensed in the blow tank.

Abstract: A method and apparatus for forming a multi-ply web of paper wherein a first layer is carried on the underside of a traveling felt to a bonding station located over the top of a forming cylinder on which a second layer is formed with a water bead in the nip between the layers and a laser or other device for generating a beam of energy at one end of the nip directing the energy along the water bead parallel to the nip and a receiver at the other end to detect the laser beam with means operated by the receiver for controlling the size of the water bead.

Abstract: The characteristic profile of a paper web is adjusted on the fourdrinier by means of a number of fluid spray stations positioned across the papermachine. Each spray station is provided with two or more fan spray nozzles of different flow capacity oriented to impact the pond with fluid along a common line. Flow to each nozzle is binary controlled with respective binary command, full flow valves. By discrete manipulation of valve selection, total flow rate to the web may be adjusted without flow throttling and consequent impact velocity variations.

Abstract: A papermaking machine having pulp supplied in a regulated excess amount through a feed channel onto a movable water-pervious element and having a sump positioned at the end of the feed channel to receive the overflow. The amount of pulp in the sump relative to the desired overflow rate is used to produce a control signal for regulating the machine. Should there be an excess amount of pulp in the sump over the desired amount, the negative pressure in the vacuum box is increased to withdraw more water. Also, the degree of grinding of the pulp can be varied in dependence on the control signal.

Abstract: A method of on-line control of opacity of moving sheet material being produced by a paper making machine includes an opacity control loop where an opacity additive is controlled and a basis weight control loop where the stock input to a headbox is controlled. These two control loops are decoupled by means of an opacity to stock feed forward and a basis weight to titanium dioxide feed forward. In addition, the effect of moisture change is decoupled from opacity.

Abstract: A technique for controlling the amount of dissolved material in a slurry liquid stream containing dispersed particulate solids which is being continuously processed in a zone of countercurrent particulate solids separation and washing. Flow rates and conductivity measurements are made on streams entering such zone which are then used to estimate the amount of dissolved material in a starting slurry liquid. Preferably, conductivity measurements are made with electrodeless conductivity measuring probes. The technique is well adapted for use in a brown stock washing system employing a plurality of counterflow washers. The technique can be used for measurement of the quantity of gas in an agitated process stream in such a zone.

Abstract: At least one channel in a multi-channel paper machine distributor is maintained in flow velocity slave relation to another of the channels by monitoring the velocity with a pressure transducer of stock flow through the latter channel and by such monitoring controlling the stock velocity in the slave channel.

Abstract: A method for the control of basis weight of a sheet material made from liquid stock controls the consistency of liquid stock flowing to a flow box by a consistency feedback loop, and varies the level of liquid stock in the flow box to effect a change in the flow of dry fiber to the sheet former. Level is maintained in a midrange and any level called for outside of midrange is handled by adjusting consistency.

Abstract: In a paper machine headbox system including a stock pump and a headbox receiving stock from the stock pump, the stock pump is shunted by a by-pass line. The stock flow to the headbox is primarily controlled by controlling the by-pass flow in the by-pass line by use of a by-pass flow control valve. When the by-pass flow control valve approaches one of its operating limits, i.e. either full open or full closed, the flow to the by-pass line is manipulated so as to reposition and maintain the by-pass flow control valve within its operating limits. A logic inhibit means, logically responsive to by-pass flow control signals, inhibits the stock flow rate in the main stock line.