Abstract: In order to observe the dry line formed on the surface of wood fibre pulp on the moving wire in a Fourdrinier paper machine, its—atrea of appearance is scanned at a low angle with a thin beam cluster (A1, B1) which, being generated by a laser radiation source (20) and representing one or more discrete wavelengths, is distinguishable from the background light. Hereby the surface following the dry line (I) reflects diffusively a major part and specularly a minor part of the arriving radiation than the surface preceding it. A detector (30) located above the level of the wire observes the intensity of the diffusely reflected radiation (A3, B3) hitting it and delivers continuously, as the beam cluster scans the pulp surface, a signal which is proportional to said intensity.

Abstract: In order to observe the dry line formed on the surface of wood fibre pulp on the moving wire in a Fourdrinier paper machine, its—atrea of appearance is scanned at a low angle with a thin beam cluster (A1, B1) which, being generated by a laser radiation source (20) and representing one or more discrete wavelengths, is distinguishable from the background light. Hereby the surface following the dry line (I) reflects diffusively a major part and specularly a minor part of the arriving radiation than the surface preceding it. A detector (30) located above the level of the wire observes the intensity of the diffusely reflected radiation (A3, B3) hitting it and delivers continuously, as the beam cluster scans the pulp surface, a signal which is proportional to said intensity.

Abstract: At the separation of different minerals from the ores by means of flotation, it belongs to known art to monitor a larger part of the uppermost froth layer in the flotation cell by means of a video camera whose signals are analyzed in a digital computer, in order to detect the structure and color of the froth. The new method and apparatus direct and limit the monitoring and analysis to the surface of the floated material within a fixed, narrow strip which is parallel to the overflow edge of the cell and within which the material surface passing it is homogeneous in the stationary state. The said strip thus presents a renewing sample of the surface at the location in question, which sample represents the stationary state in the average sense. The strip is subjected to homogeneous illumination, which may meet the strip at different angles depending on the primary object, i.e. whether the color or structure is being determined.

Abstract: The visually observable information is expressed in quantitive form according to an arrangement wherein there is firstly detected the distribution, size, shape and similar characteristics of objects appearing essentially in one level or plane of the sample and deviating visually from their environment. This detection is carried out by forming an image of the primary physical object on a light sensitive detector using known optic means, such as a microscope, in order to code the random information into a digital form, and thereupon the results of detection, that is the information thus brought into digital form, is transferred for further analysis to a computing and registering unit, such as a special purpose or process computer. Preferably, the detector unit comprises an array or matrix of light sensitive elements, such as photo-transistors.

Abstract: There is disclosed a method and an apparatus for the incorporation of varying flow in the control of process quantities. According to the invention the passing flow is measured and the amount of material flowed through the process is determined by integration of the result of said measurement. Furthermore, values of a variable are determined in direct ratio to the amount of material and the control of the process is performed synchronously with regard to that variable.

Abstract: A new method of effecting flotation of mineral grains on a laboratory scale is provided, wherein a mineral sample of uniform grain size and uniform mineral composition is conditioned to produce a definite degree of adsorption and then subjected to flotation. The floating mineral grains are separated at time intervals to let the flotation rate coefficient to be determined. On the basis of this procedure a method of constructing a continuously operable flotation concentration plant was developed. This method comprises repeating the laboratory scale flotation a plurality of times using a different degree of adsoprtion in each case, which enables the relationship between the degree of adsorption and the flotation rate coefficient to be determined. Thereafter the same procedure is repeated so that all the different grain sizes and mineral compositions present in the material to be handled are covered.