Abstract: A method and a device for measuring concentrations especially in a pulp suspension, from which a sample has been taken. The sample is collected in a measuring vessel, in which a piston is guided upwards and downwards in order to press the sample from each direction through a measuring sensor collected at the side of the measuring vessel via communicating tubes connected in an upper and a lower position to the measurement vessel, whereby the sample is stirred totally to eliminate flocculation in the same. Measurement of the concentration of the sample is made either during the upwards and downwards movement of the piston in the measuring vessel and first occurs when the speed of the sample through the measuring sensor is constant and the sample has been homogenized after at least some movement upwards and downwards of the piston.

Abstract: The concentration or amount of living micro-organisms in a liquid sample can be determined in a reliable manner by determining the concentration of a substance, secreted by the micro-organisms, in the sample, which sample then is subjected to a treatment killing the micro-organisms; whereupon the concentration of the substance is measured anew. The relation between the first and second concentration is used as a measure of the concentration of micro-organisms in the sample.

Abstract: The invention relates to a method and a device for measuring concentrations especially in a pulp suspension, from which a sample (3) has been taken. The sample (3) is collected in a measuring vessel (2), in which a piston (6) is guided upwards and downwards in order to press the sample (3) from each direction through a measuring sensor (5) connected at the side of the measuring vessel via communicating tubes (4,4′) connected in an upper and an lower position to the measurement vessel (2), whereby the sample (3) is stirred totally for eliminating of a flocculation in the same, whereupon a measurement of the concentration of the sample (3) is made either during the movement upwards or downwards of the piston (6) in the measuring vessel (2) and first when the speed of the sample (3) through the measuring sensor (5) is constant and the sample has been homogenized at least after some movement upwards and downwards of the piston.

Abstract: A method and a device for measuring the content of chemicals used in connection with bleaching of preferably cellulose fibers in a pulp, suspension for the purpose of providing a better and more uniform product quality and preventing overdosage of the bleaching chemical used. According to the invention a measurement sample is derived from a predetermined volume of the pulp suspension after or during the bleaching. Further, a catalyst in the shape of the enzyme catalase is added to the sample, which is agitated so that the bleaching chemical is decomposed and oxygen gas is generated, which oxygen gas pushes out a certain sample volume for the measurement sample, which sample volume is directly or indirectly converted, e.g. via a simple algorithm, to a value representing the content of the bleaching chemical used.

Abstract: The invention relates to a method and a device for measuring the amount/activity of the enzyme catalase before or in connection with bleaching of cellulose fibers preferably in a pulp suspension for the purpose of providing a better and more uniform product quality and a correct dosing of the actual bleaching substance during the bleaching. According to the invention a measurement sample is derived from a predetermined volume of the pulp suspension after or during the bleaching. Further, a determined amount of bleaching substance is added to the sample, which is agitated so that the bleaching substance is decomposed and oxygen gas is generated, which oxygen gas pushes out a certain sample volume from the measurement sample, which sample volume is measured after a determined time and is directly or indirectly converted, e.g. via a simple algorithm, to a value representing the actual amount of catalase.

Abstract: A method for measuring substantially spherical particles, such as dust. Two signals are formed, one of which is an approximately linear function of the particle concentration independently of the particle diameter and the second one is an approximately linear function of the particle diameter independently of the particle concentration. In order to obtain these signals the particles are illuminated with light in a direction different from their direction of flow. At least two detectors are arranged in such a way that the light in the beam path from the light source (3) to the first detector (6) is substantially only influenced by scattering and by light absorption of the particles and that the light in the beam path from the light source to the second detector (7) passes substantially only via reflections against the particles. The two signals are formed by definite relations between the d.c. voltage components of the output signals of the detectors and the average value of the squared R.M.S. value of the a.

Abstract: The percentage of suspended substances in a flowing medium is indicated by illuminating said medium with light perpendicularly to the direction of flow. The light intensity is held mainly constant at a predetermined value. Detection is made by a first light detector of light radiated from the medium in a predetermined direction and the electrical signal obtained is led to a device squaring the effective value of the portion of said signal lying within a predetermined frequency range. The percentage of the suspended substance is obtained from said square of the effective value.

Abstract: This invention relates to improvements in measuring the concentration of suspended substances in a liquid, the substances consisting of components of different geometrical size. The liquid is flowing in a pipe and is illuminated transverse to its flow direction by one or more light sources. A detecting means is arranged to detect light spread by the suspended substances in the liquid in another direction than that of the illuminating incident radiation. This detecting means delivers two electrical signals, the first of which represents a D.C. level measured during a predetermined time and corresponding to a detected level of luminous intensity. The second signal represents the number of times during the same said predetermined time that the detected level of luminous intensity has exceeded a definite discriminator level.

Abstract: A device for determining by means of light the average thickness of a layer, permeable to said light, arranged on a surface having properties different from those of the layer with respect to the light used, and also adapted to be used to provide a measure of the topography of a surface substantially opaque to the light used, includes an opaque shield that bears substantially perpendicularly with one edge against the layer when thickness is being determined or against the surface when surface topography is being measured. At least one light indicator shielded from direct incident light is arranged on the side of the shield opposite to the side on which the light source is located.