Abstract: Method of determining a surface illuminated by incident light. First the intensity (I1(x,y)) of light reflected from the surface is recorded in a first image of the surface. After this, the intensity (I2(x,y)) of light reflected from the surface is recorded in a second image of the surface, taken at a different angle of illumination. Only the diffusely reflected light is recorded. The difference between the recorded intensities of the first and the second images is determined to obtain a representation that emphasizes variations in gradient of the surface. This representation is further processed by signal-adapted integration to a topographic description, that is, a height function of the surface.

Abstract: An apparatus for drying a fibre web of paper or paperboard is provided. The apparatus includes an adjustable heated press nip including at least one pressure device. The pressure device includes a roll, supporting one side of the web and at least two pressure shoes opposite the device and acting on the other side of the web. Each of the pressure shoes include means for providing an individual pressure respectively on the web. At least one intermediate conduit is arranged in-between the pressure shoes. The intermediate conduit includes means forming an additional individual pressure zone on the web.

Abstract: A method and apparatus for obtaining a basis on which the gloss quality of a sample surface of a sample, such as a paper sheet, can be determined by illuminating the sample surface and registering the intensity of the reflected light.

Abstract: A process and apparatus for manufacturing wood chips as raw material in the production of mechanical pulp in order to reduce energy consumption. The process includes irreversibly deforming a plurality of fibers of at least one piece of wood in a direction perpendicular to the longitudinal axis of the fibers. The wood fibers include summerwood fibers. The irreversible deformation is accomplished through mechanical treatment. The apparatus used includes one or several tools arranged so that the forces created during the process act in a direction substantially perpendicular to the longitudinal axis of the fibers so as to irreversibly deform the fibers across the grain.

Abstract: A method of determining the filler content of paper, wherein the paper stock is examined prior to delivering the stock to the de-watering section of the paper machine, and wherein the volume concentration of particles in the stock that have a size which is greater than the characteristic size of the filler is determined at varying mechanical working of the pulp, and the amount of filler retained in the paper is predicted from the result of at least two such determinations.

Abstract: The invention relates to a method of determining the concentration of sulfide and optionally also of polysulfide in liquors and solutions of smelt deriving from the sulfate process. According to the method, the concentrations are determined by measuring the light absorption of the liquor or the solution in the ultra-violet range. According to one preferred embodiment, the method is applied to determine the degree of reduction in sulfate liquor and smelt derived from burning liquor, wherein the concentrations of sulfate, thiosulfate and optionally sulfite and/or carbonate are determined by measuring the light absorption of the liquor or the solution in the infrared range, whereafter the degree of reduction is calculated from the measuring data obtained.

Abstract: An arrangement for measuring mechanical properties of foil material (10), preferably paper. The arrangement includes a material excitation unit (12) and a material sensing detection unit (14). The two units are connected electrically to a common arithmetical unit (18). This unit is intended to register and convert electrical signals deriving from the two first mentioned units (12, 14) in a manner to produce final signals which represent the material properties to be measured. The excitation unit (12) includes a laser which, through electromagnetic radiation, is intended to generate in the gaseous atmosphere surrounding the material local transient gas-pressure pulses within variable surface zones which are well-defined geometrically, without the excitation unit coming into contact with the material. These gas pressure pulses cause the material (10) to stretch locally in the boundary regions of the zones, such stretching of the material being necessary to the measuring process.

Abstract: A method for measuring the flexibility of fibers, particularly cellulose fibres, in a flowing suspension. The fibre form of a large number of fibres is registered at two different pictures of suspension flow. A predefined fibre form is calculated for each flow picture, and a relationship, for example the quotient between two measurements of mean fibre form is determined and utilized to define fibre flexibility. The invention also relates to an arrangement for carrying out the inventive method, wherein the arrangement includes a flow-through container (20) through which the suspension flows, a transparent window (26) mounted in the container wall, a CCD-type camera (30) which functions to photograph fibres passing the window, a picture analysis unit (34) coupled to the camera (30), and a data processing unit (36) for processing information obtained from the picture analysis unit (34).

Abstract: The present invention relates to a method and to an apparatus for detecting the presence of bark and for determining the barking degree of wood or chips. Accordingly, the apparatus includes a light source (12) which directs a concentrated light beam (14) onto the measurement object (16), for instance a log which is moved continuously in a transport chute (20). The shape and/or size of the light image obtained on the log (16) at the point (18) on which the light beam (14) impinges on the log is detected with the aid of a camera (10), preferably a CCD-camera. The shape and/or size of the light image is mutually different for wood and bark. The detection values obtained by the CCD-camera (10) are evaluated in a processing means.

Abstract: Method of reducing the energy consumption at the refining/beating of cellulose-containing material by the addition of alkali to the material for neutralizing acid groups bonded to the fibre wall. According to the invention, the pH-value in the pulp suspension is measured at the refiner outlet, the alkali is added in an amount depending on the measured pH value for neutralization without excess in the beating zone or immediately before the material enters the same, in an amount of 0.05-9 kg/ton, preferably 0.5-5 kg/ton, suitably 1-4 kg/ton, calculated as NaOH.

Abstract: Variations in the properties of a continuously running web are measured by reciprocating the scanning device across the web. The movement of the scanning device is so time controlled that this movement is out of phase with the variation in the paper properties in the machine direction of the web.

Abstract: The present invention relates to a process for obtaining retention of the manufacture of paper, whereby one adds a cationic, high polymer polysaccharide at the preparation of a stock of paper pulp; that one adds an anionic aluminium compound, or a combination of an aluminium salt and an alkali or an acid to the formation in situ of such an anionic aluminium compound immediately prior to the head box, whereby pH immediately prior to the head box is kept at pH 7 to 8.

Abstract: Method and apparatus for controlling the reactivity of lime produced in a lime cycle process that includes the steps of forming burnt lime in a kiln, washing and filtering of lime sludge, and causticizing of green liquor, which lime cycle process steps are carried out under variable operating conditions. At least one mechanical property of the burnt lime is measured, and at least one operating condition of the time cycle process is adjusted, based on the measured mechanical property of the burnt lime, so as to thereby control the reactivity of lime produced in the lime cycle process.