Abstract: A web making machine is monitored to identify at least one cross-machine direction (CD) actuator that is developing local mapping problems. The identified CD actuator and a segment of surrounding actuators are probed to determine a performance curve for the actuator. The center of an insensitivity region of the performance curve is selected as an optimal mapping alignment setting for the identified actuator with the setting for the actuator being updated. Global smoothing may also be accomplished by probing a global smoothness factor to generate a corresponding performance curve that is then similarly used to select an optimal value for the smoothness factor.

Abstract: The invention comprises a method and an arrangement in a paper machine or the like close to a moving web (29) usually supported against a wire (1), and a paper machine including such an arrangement, and a sealing device having several such arrangements (100). According to the invention, a movable sealing (5) is arranged in the drying section of a paper machine, between two regions (3, 4) with different pressures. Certain air amounts (V1, V2) are supplied to and/or discharged from each side of the sealing (5) in order to create certain pressures in said regions. Air can move between said regions only through certain paths. In normal operating situations the seal (5) according to the invention is automatically adjusted to the desired position in relation to the web.

Abstract: A measuring device is provided that includes a camera, and an image-processing unit and a fractionating pipe. The receives a sample from recycled fibre pulp of a recycled fibre process and arranges the particles of the flowing sample in accordance with particle size. The measuring device processes the sample as at least two fractions according to particle size. The camera images at least one fraction. The image-processing unit receives images imaged by the camera and measures at least one parameter of an added substance in at least one imaged fraction.

Abstract: An air stabilization system employing two parallel, opposite-facing Coanda nozzles, with each nozzle exhausting gas at opposite directions, subjects a moving flexible web to opposing forces effective to create local tension within the web. Each nozzle includes an elongated slot that is perpendicular to the path of the moving web. The nozzles serve as separate points along the machine direction for controlling the height of the web. The operative surface with the nozzles can exhibit a flush surface. The nozzles can be formed on elevated structures on the operative surface. The operative surface can be covered with a transparent substrate to minimize shape distortions on the moving web and to prevent debris from collecting around the sensor. By modulating the velocities of gases exiting the nozzles, the shape of the web can be manipulated to present a planar contour. The air stabilization system can be incorporated into a caliper scanner.

Abstract: An apparatus and method for sensing characteristics of a liquid are disclosed. The exemplary embodiment may have an electrode for transmitting electrical signals associated with characteristics of the liquid to and from the liquid. The electrode may have an aperture on the interior of the electrode with the aperture surface in contact with the liquid. The electrode may have a sensor portion in contact with the liquid and a coupling portion with a tapered thread. The electrode may contain an electrical coupling on the isolated outer surface of the electrode for communicating the electrical signal from the electrode.

Abstract: A method and apparatus are presented for determining the quantity of liquid and solid content in a removal stream of a froth created from a suspension that is generated during a froth flotation operation. Specifically, electrodes are immersed in the froth generated from a suspension having a known quantity of fiber particles, and the conductance of the froth is measured to establish a relationship between the measured conductance and the quantity of fiber particles. The electrodes are then submerged in a froth generated from a suspension having an unknown quantity of fiber particles, and the froth conductance is measured. The quantity of fiber particles in the froth can then be determined from the pre-established relationship between conductance and solid particle content.

Abstract: A sheet formation section of a paper machine includes a sensor that measures a first characteristic of a sheet of paper being formed. The sensor may measure a characteristic such as streaking, rises, depressions, or smoothness. The sheet formation section also includes an apparatus that applies a magnetic field to the sheet of paper being formed. The machine also includes a controller that causes the apparatus to apply the magnetic field in response to a signal from the sensor representative of the first characteristic. The magnetic field transforms a second characteristic of the sheet of paper. The apparatus may transform a characteristic such as water content or fiber orientation.

Abstract: A material measurement system (500) includes a THz generator including at least one laser source (111) for emitting optical pulses, the optical pulses coupled to a THz emitter (51) operable for emitting pulsed THz radiation at a sample location on material while being processed (14) by a manufacturing system. A receiver (52) is operable to receive the optical pulses and to detect reflected or transmitted THz radiation from the sample location (14) synchronously with the optical pulses and provide electrical detection signals. Synchronizing optics (112, 113, 114) is operable to receive the optical pulses from said laser and provide the optical pulses to both the receiver (52) and the THz emitter (51).

Abstract: A method includes determining one or more setpoint changes for one or more actuators in a process control system. Determining the one or more setpoint changes includes making larger or more frequent setpoint changes when operating in a first mode and making smaller or less frequent setpoint changes when operating in a second mode. The method also includes outputting the one or more setpoint changes to the one or more actuators. The method could further include entering the first mode after a paper sheet has broken and been rethreaded through a paper machine. The method could also include entering the second mode (i) after a specified amount of time has elapsed since entering the first mode or (ii) after the first mode has been entered and a caliper profile of the paper sheet is within a specified threshold of a desired caliper profile.

Abstract: A method for the determination of a cellulosic-fibre property, namely, residual lignin content or Kappa number of chemical pulp, with the aid of a spectroscopic technique obtained over a range covering the visible and the near-infrared regions of the electromagnetic spectrum, comprising exposing the wet fibres to a light source covering a range in the visible region of 350 nm to 750 nm and a range in the near-infrared of 1100 nm to 2400 nm, reflecting light from the wet fibres, establishing a spectrum, comparing the spectrum with a known spectrum of the property and evaluating the comparison; the method has particular utility in a pulp manufacture line; an apparatus is described for carrying out the method.

Abstract: A method of mixing paper stock, having improved outlet consistency, includes: (a) feeding liquid and feeding paper pulp into a vessel to form a mixture; (b) providing at least one counterflow impeller that is submerged in the mixture, the counterflow impeller being capable of simultaneously inducing both upward flow and downward flow; (c) rotating the counterflow impeller such that downward flow from the impeller is partially recirculated by upward flow from the impeller to form a mixing zone; (d) sensing a parameter of the mixture discharged from the vessel; and (e) controlling the feed rate of the liquid and the feed rate of the paper pulp in the feeding step (a) based on the sensing step (d). An apparatus for mixing of paper stock, having improved outlet consistency, includes a vessel for containing liquid and paper pulp, at least one counterflow impeller, and a feedback system for controlling outlet consistency.

Abstract: In a tissue paper making machine downstream the yankee-cylinder (9) and upstream the tambour roll (14) a spark detector (13) is provided in the vicinity of the paper web running to the winding-up section (4) in order to detect sparks of glowing fibers or fiber conglomerates, which can be enrailed by the high speed run of the paper web and can be transferred to the paper roll (15) where the sparks are trapped between the paper web windings of the paper mill. Knowledge of this fact offers the possibility to avoid fire in the mother-roll storage.

Abstract: Provided is a paper machine contamination preventive agent that has high fixability to rolls and the like of a paper machine, that positively finds a silicone oil capable of imparting releaseability and water-repellent properties to the rolls or the like immediately upon being supplied to the rolls or the like, and that uses the silicone oil as a main component. Further provided is a paper machine contamination preventive agent using a silicone oil that permits transfer of less foreign matters from a wet paper web than that in a case where a contamination preventive agent containing a dimethylpolysiloxane base oil is a main component. The paper machine contamination preventive agent is fed to a paper machine and has a sidechain-type modified silicone oil or a sidechain both-termini modification silicone oil as a main component.

Abstract: The invention relates to a method in the manufacture of a fiber-based web-like product for optimizing the operation of the process being used, in which method quality factors are defined for the product being manufactured control variables, which affect the state of the process, or quality factors of the finished product, are defined for at least part of the process. In addition, an operating model is created, which is used to depict the effect of each control variable on the quality factors, and a user interface is created, through which varying values for the control variables can be input to the operating model and the values of the quality factors can be depicted simultaneously, in such a way that the values of the control variables and the values of the quality factors can be viewed simultaneously.

Abstract: Fast cross direction caliper control recovery time in a sheet making machine during startup of the machine after a sheet break is achieved provided that a preselected time duration measured from the occurrence of the sheet break to the clearing of sheet break has elapsed. One or both of calender stack conditioning and conditioning of a measurement from a sensor for measuring caliper of the sheet, both with feedback CD control suspended, can be selectably performed. These operations can be performed concurrently if the selected time duration for both are identical. A closed loop change in a set of control tuning parameters of a PI controller providing feedback caliper control of actuators associated with the calender stack can be performed after either or both of the other operations are performed.

Abstract: An apparatus and method for correcting an areal weight measurement of a stretchable web using surface topology measurement data is disclosed. Areal weight may comprise a basis weight or a water weight. The apparatus measures a surface of the stretchable web with a basis weight measuring device to obtain a rough basis weight measurement. The apparatus then measures the surface of the stretchable web with a surface topology measuring device to obtain surface topology measurement data. The apparatus comprises a controller that corrects the rough basis weight measurement of the stretchable web using surface topology measurement data. The corrected basis weight measurement may be used as a feedback value in a real time manufacturing process of the stretchable web.

Abstract: A method and system for determining chip pressure in a vessel containing a slurry of lignocellulosic material including: sensing a total static pressure of the slurry in the vessel; sensing a hydrostatic pressure of the liquor in the vessel, and determining the chip pressure based on a difference of the sensed total static pressure of the slurry and the sensed hydrostatic pressure of the liquor.

Abstract: A method and arrangement for controlling short circulation in a paper machine, in which the control of at least one property of the diluted fiber-containing pulp conducted to the headbox is based on consistency measurement or determination in high-consistency fiber-containing pulp, diluted pulp and/or white water. The amount of fiber-based fines in high-consistency fiber-based pulp, diluted fiber-based pulp and/or white water is determined, and the result obtained is used for controlling at least one property of the fiber-containing pulp to be conveyed to the headbox.

Abstract: The arrangement concerns an improved design for at least one of the cooling, dilution and washing at the bottom of a continuous digester for the production of cellulose pulp. By arranging at least one extra strainer section above the lowermost strainer section, with the addition of washing fluid or dilution fluid between the extra strainer section and the lowermost strainer section, more washing fluid can be added at the bottom of the digester without counteracting the flow of the column of chips. This provides space for the increase of production, for improvement of the flow of the column of chips, or for combinations of these effects while retaining good cooling, washing and dilution at the bottom of the digester.

Abstract: An office paper recycling apparatus within a unitary body makes new office paper for use in office equipment from used office machine paper. The apparatus comprises a paper-shredding portion; a pulping portion; a paper-forming portion; a paper-press portion; a paper-drying portion; a paper-finishing portion having a means to trim the paper, a means to adjust the paper forming process by monitoring the stiffness properties and fiber orientation and a means to remove dust debris; and, a paper-collecting portion, where the new sheets are collected and stacked, ready to be used in office equipment.

Abstract: A method of operating a papermaking process containing a press section with at least one press nip is disclosed.

Abstract: The temperature of the ceramic elements of a supporting or wiping strip that is assigned to a wire or a felt in a paper production facility, is controlled by guiding a cooling carrier medium or a heating carrier medium through the supporting or wiping strip. For that purpose, the supporting or wiping strip is formed with at least one channel, through which the carrier medium for heat or for cold is pumped.

Abstract: A method and an apparatus for measuring the depositability of particulate contaminants present in a pulp or paper mill fluid stream and evaluating interactions of such particulate contaminants with other contaminants collects the particulate contaminants on a suitable substrate, such as a plastic film coated with an adhesive or coated with organic contaminate, placed in contact with the pulp or paper mill fluid stream for at least five minutes up to several hours. The amount of contaminants collected on the substrate is quantified and evaluated by taking one or more scanned images of the substrate with a resolution of at least 2,000 dots per inch (DPI) and analyzing the scanned images with image analysis technique.

Abstract: A machine, for at least one of producing and treating a web of fibrous material in which the web is guided along a web guide path by at least one web guide device from one of a web production section and a web input section to pass at least one web treatment device, includes a first apparatus configured for forming a transfer strip of the web and for transferring the transfer strip through the machine, the machine being configured for transferring the web along the web guide path in that the first apparatus is configured for forming the transfer strip which is a leading transfer strip of the web, for guiding the transfer strip through the machine, and for increasing the transfer strip to a full width of the web and thereby performing tail widening; and a second apparatus configured for detecting a break in the web, the second apparatus being configured for responding to a break in one of the transfer strip and the web during a transfer of the web and during an increase in a width of the transfer strip.

Abstract: Machine for producing a web includes a system for predefining a quantity of a grade to be produced utilizing a measuring arrangement for measuring quality data during production of the web. The system defines the quantity of the grade to be produced by using data measured by the measuring arrangement during the production of the web.

Abstract: A method and system for controlling one or more properties of a sheet of material to be manufactured on a sheet-making machine is disclosed. Actuators to control the sheet properties are arrayed in the cross-direction of the machine. Properties data about one or more properties of the sheet of material are measured and both the magnitude of an actuator control action and the cross-direction shape of an actuator control action are controlled to minimize the variation of the measured properties data from a desired target for each of the one or more properties.

Abstract: A method for analyzing in real-time in a paper machine or board machine the surface structure of a web (1) of paper or board which method comprises the direction of an imaging system towards a pre-determined area (3) of the web (1), the arrangement of an illumination system to illuminate the region from a pre-determined direction with obliquely incident light, and the arrangement of an image analysis system in association with the imaging system.

Abstract: An apparatus and method for sensing characteristics of a liquid are disclosed. The exemplary embodiment may have an electrode for transmitting electrical signals associated with characteristics of the liquid to and from the liquid. The electrode may have an aperture on the interior of the electrode with the aperture surface in contact with the liquid. The electrode may have a sensor portion in contact with the liquid and a coupling portion with a tapered thread. The electrode may contain an electrical coupling on the isolated outer surface of the electrode for communicating the electrical signal from the electrode.

Abstract: The invention relates to an apparatus for assessing the condition of at least one circulating band in a papermaking machine including a permeability measuring device, a moisture measuring device, a fiber web moisture measuring device, an evaluator, a reel-up and an other moisture measuring device. The permeability measuring device measures the permeability of the at least one circulating band. The moisture measuring device measures the moisture contained in the at least one circulating band. The fiber web moisture measuring device measures the moisture of the fiber web. The evaluator combines the permeability, the moisture of the at least one circulating band and the moisture of the fiber web to determine the condition of the at least one circulating band. The other moisture measurement device is coupled to the reel-up, and takes a moisture measurement of the fiber web made by the papermaking machine.

Abstract: The arrangement concerns an improved design for at least one of the cooling, dilution and washing at the bottom of a continuous digester for the production of cellulose pulp. By arranging at least one extra strainer section above the lowermost strainer section, with the addition of washing fluid or dilution fluid between the extra strainer section and the lowermost strainer section, more washing fluid can be added at the bottom of the digester without counteracting the flow of the column of chips. This provides space for the increase of production, for improvement of the flow of the column of chips, or for combinations of these effects while retaining good cooling, washing and dilution at the bottom of the digester.

Abstract: The invention relates to a method and an apparatus for order control in a production process for a fiber product. In this case, at least one primary product is provided and processed further to form the fiber product, the processing steps of the further processing being performed by machines, the production process being monitored and controlled. According to the invention, in order to control and monitor a production order constituting the basis of the production process, an actual/target evaluation is performed between a target standard predefined by the production order and an actual status of the production process. The deviation from the target standard determined thereby is displayed.

Abstract: Temperature measurements of sheet material such as paper can be obtained directly from an analysis of the absorption spectrum of water in the infrared region. The technique is based in part on the recognition that the central wavelength position of a selected moisture peak is dependent upon the sheet temperature; the wavelength position also has a known temperature sensitivity. Thus, once the wavelength position of this moisture peak is ascertained, the moisture temperature of the product being monitored can be calculated. The position of the moisture peak is preferably obtained from the derivative of the peak. By measuring the size of the infrared absorption and the wavelength position of the absorption peak, both the moisture content and the moisture temperature of the sheet material can be determined. The data is used for process control. Tunable laser diodes are particularly suited as the source of infrared radiation for the temperature sensors.

Abstract: A method and an apparatus for determining the total peroxide content of a cellulose pulp suspension in the pulp suspension bleaching stage, wherein the bleaching chemical is peroxide. A sample is taken from the pulp suspension, which sample is measured in a measuring device (25, 25?). Before measuring, the pH of the sample is adjusted and after that the total peroxide content or the perhydroxyl content of the sample is measured, of which measurement the total peroxide content of the sample is determined.

Abstract: A reverse bump test, for identifying the alignment of a sheetmaking system while the system remains in closed-loop control, includes the following steps: (a) leaving the control system in closed-loop, (b) artificially inserting a step signal on top of the measurement (or setpoint) profile from the scanner, (c) recording the data as the control system moves the actuators to remove the perceived disturbance (or setpoint change), and (d) refining or developing a model from the artificial measurement disturbance (or setpoint change) to the actuator profile. The technique supplies the probing/perturbation signal to the scanner measurement, which is equivalent to supplying the probing/perturbation signal to the setpoint target) rather than inserting bumps via the actuator set points as has been practiced traditionally.

Abstract: A machine for producing and/or treating a material web, in particular of paper or board, in which the material web can be guided along a material web guide path by means of at least one material web guide device from a material web production section or material web input section, in order to pass at least one material web treatment device, having an apparatus for forming a transfer strip of the material web and transferring the transfer strip through the machine, it being possible for the material web to be transferred along the material web guide path in that, by means of the apparatus for forming and transferring the transfer strip, a leading transfer strip of the material web is formed and guided through the machine, and the width of the transfer strip is increased to the full material web width (what is known as “tail widening”), and having an apparatus for detecting a break in the material web.

Abstract: A torn paper web capture system that is a mechanism for securing a band, tape or strap, preferably composed of paper, across a paper roll as the roll is rotating. A sensor means detects the torn paper web and initiates both the shut down of rotation of the paper roll and the release of the band. The band resides within a guide track, the track being generally C-shaped in cross-section Upon contact with spool journal or similar rotating member the end of the band adheres and is wrapped around the rotating member. This wrapping action takes up the slack in the band and pulls it from the guide track and against the paper web, thereby securing the loose end of the paper web. The contact between the band and the rotating member may be initiated in multiple ways, such as with a nip roller, an actuating shoe member, or the like.

Abstract: A contamination degree determining apparatus for paper determines a final contamination degree of paper on the basis of values of various contamination characteristics indicating the degrees of, for example, creases, wrinkles or stains obtained from the paper. Values of a plurality of contamination characteristics are input to the contamination degree determining apparatus for paper. The apparatus calculates a plurality of evaluation values from the plurality of input contamination characteristics, the contribution degree of each of the plurality of contamination characteristics, reference vectors reflecting the distribution of the plurality of contamination characteristics, and dispersion parameters reflecting the distribution of the plurality of contamination characteristics. The apparatus determines the final contamination degree of the paper on the basis of the calculated evaluation values and the weight of each of the evaluation values.

Abstract: A reverse bump test, for identifying the alignment of a sheetmaking system while the system remains in closed-loop control, includes the following steps: (a) leaving the control system in closed-loop, (b) artificially inserting a step signal on top of the measurement (or setpoint) profile from the scanner, (c) recording the data as the control system moves the actuators to remove the perceived disturbance (or setpoint change), and (d) refining or developing a model from the artificial measurement disturbance (or setpoint change) to the actuator profile. The technique supplies the probing/perturbation signal to the scanner measurement, which is equivalent to supplying the probing/perturbation signal to the setpoint target) rather than inserting bumps via the actuator set points as has been practiced traditionally.

Abstract: A system for the computer-aided measurement of quality and/or process data during the production and/or conversion of a material web, in particular paper or board web, by way of correlation with raw measured data. The raw measured data is present in the form of other quality and process data during the production or conversion process. Measurements of quality parameters in the laboratory may also be incorporated in the raw measured data. The raw measured data is combined to form data sets which in each case are determined simultaneously. Specific laboratory or quality measurements are selected as target data which, by way of at least one soft-sensor algorithm running in a computer-based operation and linking unit, can be calculated from the other data serving as input data, and each data set containing measured data, which relates approximately to the same monitored volume of web and raw material, in particular paper and paper raw material.

Abstract: In a method for the production of a fibrous web, especially a paper or cardboard web, an automatic ash control system and an automatic retention control system for the reduction or suppression of an interactive build-up of the two controls are linked via a model for the dependence between the filler addition and the retention agent consumption. A computer assisted quality control system is also cited.

Abstract: Apparatus for measuring tension or a tension alteration in a paper web. At least one measurement device includes a number of measurement bodies and a number of fluid supply devices, which are intended to apply a fluid pressure to the web. The fluid supply devices are so arranged as to subject the web to an essentially constant fluid pressure in order to provide a fluid cushion between the web and the measurement bodies. The measurement bodies are so arranged as to apply pressure to the web without making contact and are so arranged to be capable of displacement. The position of the measurement bodies in the normal direction of the web is altered depending upon variations in the constitution of the web. A method for measuring web tension and a machine including apparatus for measuring web tension are also disclosed.

Abstract: The present invention relates to a washing apparatus (2) for washing of cellulose pulp, comprising a rotatable drum (4), a stationary support (6), a discharge device (8) that has an outlet orifice (9), a casing that surround the drum and that forms a longitudinal discharge opening (10) and a conveyer worm (12) arranged below the outlet orifice for reception and removal of washed pulp. The conveyer worm (12) is movably arranged relatively the support (6) between a first position (P1), in which the conveyer worm receives washed pulp during operation, and a second position (P2), in which the outlet orifice (9) is exposed and access to the drum (4) via the outlet orifice is possible for carrying out service, maintenance and inspection of the washing apparatus (2).

Abstract: A device and a method for on-line control of the fibre direction of a fire web (8), being manufactured from stock delivered from a headbox (3) through a discharge opening (11) defined by movable lips (9, 10), while using a fibre direction meter (12) located downstream and actuating members (14), which are allonged long the lips for regulation of the discharge opening as a response to individual control signals, each being a function of measured fibre direction values; wherein a control unit (13) receives the measured fibre direction values, calculates the control signals, and transmits these to the actuating members. According to the invention, the control unit identifies an array of fibre direction values, originating from positions in the cross direction of the fibre web which correspond to the positions of the actuating members. The control unit then compares the array of fibre direction values with an array of desired fibre direction values.

Abstract: A method and apparatus are presented for determining the quantity of liquid and solid content in a removal stream of a froth created from a suspension that is generated during a froth flotation operation. Specifically, electrodes are immersed in the froth generated from a suspension having a known quantity of fiber particles, and the conductance of the froth is measured to establish a relationship between the measured conductance and the quantity of fiber particles. The electrodes are then submerged in a froth generated from a suspension having an unknown quantity of fiber particles, and the froth conductance is measured. The quantity of fiber particles in the froth can then be determined from the pre-established relationship between conductance and solid particle content.

Abstract: Methods are provided for determining the surface fatty acid content in a wood pulp or whitewater sample. The methods comprise reacting free fatty acids which are present on the surface of the wood pulp fibers in the sample or in the whitewater with one or more reagents to form a measurable species, and determining the fatty acid content from the quantitative measurement of the measurable species. The method is useful as a quick, portable, accurate and low cost assay for assessing the fatty acid content present at various sample points in pulp and paper mills. The method for determining the free fatty acid content can be conducted in a batch process (e.g., where samples are collected periodically and the test is conducted offline). Alternatively, the method for determining the free fatty acid content can be conducted in a continuous or semi-continuous process (e.g., online sampling/analysis).

Abstract: The moisture profile and/or moisture gradient of a paper web of at least SC quality paper is controlled in a paper machine comprising a calender (1) which has at least two roll stacks (21, 22; 31, 32), one stack has at least three rolls and another has at least five rolls. The web is moisturized to a desired pre-moisture content M1 by a pre-moisturizer (7) before the calender. At least one intermediate moisturizer (3) is arranged between two roll stacks moisturizes the web to a desired intermediate moisture content M2 before the last roll stack (31, 32), in which the web is dried to a desired final moisture value M3. For continuously controlling and optimizing the moisture profile and/or moisture gradient of the web, the pre-moisturizing W1 of the web is controlled by a pre-moisturizer (7) control parameter which corresponds to the final moisture value M3 of the web.

Abstract: In a papermaking system having a headbox to dispense a jet of liquid and paper forming fibers, an improvement comprising at least one sensor arrangement for simultaneously or sequentially measuring in at least one location the jet velocity or jet flow correlation of the jet at plural known angles relative to the machine direction. The measured data is analyzed to generate a velocity vector profile or velocity direction profile of the jet, and hence to determine the profile of fiber orientation angles laid down in the sheet formed of the jet.

Abstract: Method and system for controlling web formation in the forming section of a paper machine includes measuring the amount of white water occurring during drainage in at least one drainage region of the forming section; and carrying out the web formation control on the basis of the white water measurement.

Abstract: The lateral position of a web or fabric edge 11 in a paper machine is determined using an ultrasonic sensor. The ultrasonic sensor has a detector head 42, with an air channel system which opens to the vicinity of the head for forming an air knife which prevents accumulation of dirt on the head. The protective cover 35 has an air guide 43 extending further than the detector head 42, with air flowing thereabove from inside the protective cover 35 through an opening 36. The end component is on top of the protective cover allowing air to flow from the opening between the air guide and the end component to a detent, which turns the direction of the air flow. This provides efficient cleaning without disturbing, however, the operation of the ultrasonic sensor.

Abstract: The present invention is a rapid method of determining the concentration of the major components in a chemical stream. The present invention is also a simple, low cost, device of determining the in-situ concentration of the major components in a chemical stream. In particular, the present invention provides a useful method for simultaneously determining the concentrations of sodium hydroxide, sodium sulfide and sodium carbonate in aqueous kraft pulping liquors through use of an attenuated total reflectance (ATR) tunnel flow cell or optical probe capable of producing a ultraviolet absorbency spectrum over a wavelength of 190 to 300 nm. In addition, the present invention eliminates the need for manual sampling and dilution previously required to generate analyzable samples.