Abstract: The invention relates to a method in the process of manufacturing and/or finishing a fibre web (11), in which method said continuous and moving web (11), and/or a moving means (16, 17) related to the processing of the web (11), is monitored by one or more thermal cameras (10) of the infrared range or a corresponding detector/detectors for the purpose of controlling the quality or condition. According to the invention, a substantially continuous two-dimensional thermal image or continuous thermal chart (20) of an object (11, 16, 17) being monitored and in a propagating and/or rotating movement is formed by said detector/detectors in a time-resolved manner and in synchronization with the movement of the object (11, 16, 17) in the direction of the movement.

Abstract: The invention relates to a method and an apparatus for executing a grade change in a paper machine, in which method a grade change is executed by determining, in advance, target ramps for different process variables, which are ramped according to said ramps during the grade change. Data about the grade changes already executed is collected, whereafter data about successful grade changes is selected and the grade change models to be used are determined on the basis of this data, and the target ramps are determined by means of these grade change models.

Abstract: A method and an arrangement for keeping a measuring device clean, the measuring device being arranged to measure at least one property of a moving web and comprising at least one measuring head with at least one measuring element that is cleaned with cleaning agent during measurement.

Abstract: A method for blowing steam against a paper web, whereby the steam is blown by a steam box having several profiling chambers in the cross direction of a paper machine. The cross-profile of the paper web is controlled by the steam supplied by the profiling chambers. A gas flow is provided between the profiling chambers to prevent the steam blown by a profiling chamber from affecting the effective area of the steam blown by the adjacent profiling chamber. Further, a steam box for implementing the method is disclosed.

Abstract: A device for heating a roll in a paper or paperboard machine or in a finishing machine for paper or paperboard the device including a profiling induction heater (5) which is arranged to heat the roll (3) with a power dependent on the location of the point to be heated in the axial direction of the roll, and a non-profiling induction heater (4) which, to provide basic heating, is arranged to heat the same roll (3) with a heating power which is substantially even over the width of the roll (3). The profiling induction heater (5) and the non-profiling induction heater (4) are placed in the same support structure (1) outside the roll (3). The roll (3) is a calender roll.

Abstract: In controlling the dryer section of a paper machine, the basis weight and moisture of the paper web, the energy fed into the drying cylinders of the dryer section and the machine speed are measured, and then the surface temperature of the drying cylinders is predicted on the basis of the measured values. At the same time, the actual surface temperature of the dryer cylinders is also measured, and if the measured value deviates from the predicted value, any defects in the drying apparatus can be detected quickly. In another aspect, a determination is made of the normal correlation between the power consumption of the drive motors of the cylinders in the drying apparatus and the machine speed. These variables are also measured, and if the correlation of the variables is deviant, it can be concluded that there is a failure in the drying apparatus. In that case it is possible to identify the dryer cylinder where the failure is by measuring the temperature of the cylinders.

Abstract: The invention relates to a method and an apparatus for measuring properties of a moving web. Web properties are measured with a measuring apparatus where at least one sensor element is arranged to a rotating measuring roll. The measuring roll is in contact with the web to be measured, and the circumferential speed of the measuring roll is arranged to substantially equal the web speed, the web being substantially in non-slipping contact with the measuring roll for an arc of the rotation of the measuring roll.

Abstract: The invention relates to a method and a measuring arrangement for determining gloss of paper or paperboard. The paper or paperboard surface is illuminated with collimated light substantially parallel with the normal of the paper or paperboard surface. An image is produced from the paper or paperboard surface by means of reflected optical radiation. The reflected optical radiation is used for producing an image of the paper or paperboard surface onto the pixels of the camera's detector surface, each of the pixels imaging an area in the order of micrometers of the paper or paperboard surface. An aperture provided in front of the camera is used for adjusting the incidence angles of the reflected radiation, which affects the measurement of gloss. Gloss of paper or paperboard is measured on the basis of the intensity of the pixels on the camera's detector surface.

Abstract: The invention relates to a method and a measuring arrangement for determining roughness of paper or paperboard. The paper or paperboard surface is illuminated with collimated light substantially parallel with the normal of the paper or paperboard surface. An image is produced from the paper or paperboard surface by means of reflected optical radiation. The reflected optical radiation is used for producing an image of the paper or paperboard surface onto the pixels of the camera's detector surface, each of the pixels imaging an area in the order of micrometers of the paper or paperboard surface. An aperture provided in front of the camera is used for adjusting the depth of focus of the image, which affects the measurement of roughness. Roughness of paper or paperboard is measured on the basis of the intensity of the pixels on the camera's detector surface.

Abstract: A method of monitoring the condition of apparatuses wherein the condition of the apparatus is measured from one or more rotating objects by means of a fixedly mounted condition monitoring system during the operation of the apparatus when it operates at its normal operating speed. In the method, at least one signal indicating the condition of the apparatus and the steadiness of the operation is measured during the change in the operating speed of the apparatus and desired characteristic values and/or functions are calculated from each signal measured in this manner as a function of measured time and/or rotational speed.

Abstract: An arrangement for measuring properties of a moving paper web. The arrangement comprises measuring means for measuring paper properties, in connection with which a plane-like support surface is arranged. The plane-like support surface supports the paper web and extends substantially over the whole width of the paper web in the cross-direction relative to the direction of travel of the paper web. An opening arrangement formed by at least one opening is arranged on the support surface for measuring properties of the paper web.

Abstract: In the method for heating a roll in a paper or paperboard machine or finishing machine for paper or paperboard, several adjacent induction coils (2) are used which are located at different points in the axial direction of the roll, and said induction coils are made to move back and forth in the axial direction of the roll with respect to the roll (3) to be heated. The movement is utilized to even out such an irregular power distribution and correspondingly uneven heating response in the axial direction of the roll which result from the structure and/or mutual location of individual coils, and it can be used e.g. for profiled induction heating of a calender roll.

Abstract: The present invention is a method and apparatus for calculating the amount and composition of inorganic material in a sheet material. The apparatus of the present invention is capable of calculating the composition of all the additives at once without requiring multiple cycles. The apparatus uses a combination of two techniques, namely an X-ray fluorescence analysis and a preferential X-ray absorption analysis. X-ray fluorescence is measured by a thermoelectrically cooled solid state detector. The apparatus can measure more than three additives. Measurement of argon in the air is used for compensation of electronic drift. An empirical correction is used to compensate for mutual interaction between X-ray fluorescence radiation and clay or talc. The measurement is compensated for dust accumulation by fluorescing the dust.

Abstract: The invention relates to a method and an arrangement for controlling a sheet-making process. In the solution, a sheet matching desired values is manufactured. A measuring unit measures the state of the process to produce one or more measurement value representing the state of the process. A comparator compares each measurement value with a corresponding desired value and, on the basis of the comparison, forms an error representing the difference between at least one measurement value and desired value. A control unit forms at least two control action candidates based on the error using at least two process models, of which at least one is a perturbed process model. A processing unit forms one control action from the control action candidates, with which control action the sheet-making process is controlled to produce a sheet matching the desired values.

Abstract: A method and an apparatus for measuring properties of a paper web, whereby at least one property of the paper web is measured at least at two locations in the cross direction of the paper web simultaneously. Adjacent measuring devices are calibrated by traversing a reference sample in the cross direction such that the reference sample is impinged by the measuring beam from each of the measuring devices.

Abstract: A steam box in a paper machine, the steam box including a main steam zone and at least one side steam zone through which steam is blown to a paper web. The side steam zone is placed in a side section of the steam box and arranged to form a curtain in order to prevent air from entering between the steam box and the paper web from outside the steam box and/or to prevent steam from exiting between the steam box and the paper web. Steam is supplied to the side steam zone from a steam chamber through a side steam zone valve arranged inside the steam box.

Abstract: A steam box includes a elongated steam-distribution chamber, regulator chambers set in a row next to the elongated steam-distribution chamber and covered on one side with a continuous perforated screen. Operating devices distribute the steam from the distribution chamber to each regulator chamber. The steam box is intended to feed steam through the perforated screen to the web, to heat it according to a desired profile. The perforated screen is secured along one long edge to hinge members and along the opposite edge to locking members and is arranged to be able to be opened, to permit access to the regulator chambers.

Abstract: Properties of paper are controlled by modeling the effect of at least one variable (fD) of the paper dryer section on the paper moisture (Moi) and the effect of the stock flow (Fts) and/or stock composition and the flow of retention agent (Fra) on the paper moisture (Moi). By means of the modeling, the paper moisture (Moi) is adjusted by simultaneously controlling at least one variable (fD) of the paper dryer section, the stock flow (Fts) and the flow of retention agent (Fra).

Abstract: The present invention provides a method and apparatus for identifying deformation of a moving sheet. In the present invention, the periodicity of original periodic or nearly periodic markings initially caused on the sheet is determined. Thereafter, a Fourier image of periodic markings of the sheet as it is moved along a path is produced with an imaging device using a Fourier transform optical element. The appropriate peaks of the Fourier image corresponding to the markings of the sheet are located, and the deformation of the sheet is calculated by comparing the measured peaks of the Fourier image to the known initial periodicity of the markings.

Abstract: The invention relates to an apparatus for measuring properties of a moving paper web or cardboard web. The apparatus comprises a sensor and a counterpart. The sensor comprises at least one coil. The sensor is arranged on a first side of the moving web and the counterpart is arranged on a second side of the moving web. The coil comprises a plurality of layers, each layer constituting a part of the coil, the layers being superimposed and coupled in series to constitute the coil.