Abstract: A method is described of obtaining cellulase deficient strains which have great ability to degrade lignin at the same time. The method comprises crossing a homokaryotic cellulase deficient mutant of a white-rot fungus having a full sexual cycle with a homokaryotic strain of the same fungus, this strain having great lignin degrading ability. Strains are subsequently selected that have great lignin degrading ability in combination with cellulase deficiency. A suitable white-rot fungis is Phanerochaete chrysosporium. The crossings are suitably performed for a plurality of generations. The strain of white-rot fungus obtained is used for delignifying lignocellulosic material.

Abstract: A method of controlling the properties of a paper web across the feed direction, i.e., cross profile, in a paper machine. The cross profile is adjusted in a plurality of setting positions across the web. Proceeding from a measured cross profile and desired cross profile, an optimum correction in the setting positions is calculated, so that the cross profile is brought into agreement with the desired one. At this calculation the circumstance is utilized, such that a disturbance in the stock in a certain setting position results in a corresponding change in the cross profile of the paper web.

Abstract: The invention relates to a method for producing paper by the addition of a retention - dry strength agent system. The system consists ofcationic starch with a substitution degree of at least 0.005 in an amount of at least 1%,anionic high-polymer with a molecular weight greater than 10.sup.6 and in an amount of 0.003-0.5%, andcationic synthethic polymer in an amount of 0.005-0.5%.

Abstract: The size distribution of wood chips for the manufacture of cellulose pulp is determined by an optoelectric measuring method and device. Light reflected from a conveying surface (2) and lump material distributed thereon, is recorded optically (3) at short time intervals, and recorded signals are processed electronically for obtaining the size distribution of the material over a number of selected size classes.

Abstract: A process of manufacturing cellulose pulp from wood by digesting the wood with sulphite cooking liquor containing additions of sulphide and in the presence of a quinone or hydroquinone compound. According to the invention, the mole ratio between sulphide and sulphite shall amount to 0.01-0.2, preferably 0.05.0.15, suitably 0.08-0.12.

Abstract: The invention relates to an apparatus for producing layers of dry fibres and/or particles on a forming surface pervious to air. According to the invention, the material is distributed in air and passed to a forming unit where a turbulence with high intensity is effected in that air is injected through separate nozzles.

Abstract: A measuring device by which it is possible to measure individually the content of each type of substance in a suspension with at least two types of suspended substances provided the density of the substance in each type is approximately equal and the densities of the substances included in the individual types are known. The measuring device comprises a density meter (10) known per se arranged to measure the density of the suspension and the density of the liquid in which the substances are suspended in order to determine the difference in density. Moreover, the measuring device comprises an apparatus (12) known per se and intended for measurement of particle concentration, which is arranged to measure the ratio of the volume of the suspended substances to the volume of the liquid. Finally, the measuring device also comprises a calculating unit (26) electrically connected to the density meter and the apparatus for measurement of particle concentration.

Abstract: The invention relates to a method of measuring dry substance in the flue gas in liquor recovery units in mills for the manufacture of papermaking pulp in order thereby to render it possible to control the operation of the unit. According to the invention, this is carried out in that the radiation emission caused at the combustion of fuel particles in the hearth of the unit above the fuel supply level is detected optically, and that the signals are used for indication and/or control of the operation of the unit.

Abstract: A method for controlling the combustion and reduction processes in a black liquor (B.L.) boiler of a paper pulp plant by influencing the feeding of black liquor to the B.L. recovery boiler by means of a B.L. gun. Characteristic of the method is that the average thickness of the layer of the B.L. flow, immediately after the black liquor has left the B.L. gun, is controlled to have a desired magnitude. The thickness of the B.L. layer is obtained in the form of an indirect measure which is defined as the droplet index (=DIX) and is constituted by a relationship between the viscosity, the density and the feed rate of the black liquor and by at least the shape and the opening area, of the B.L. gun.

Abstract: Web tension measurement in that the web (5) is caused to oscillate transversely with the resonance frequency for the portion of the web (5) defined by a support (2,2a). The oscillations are measured by detectors (6,7) for determining the web tension. The measuring is carried out free of contact in that a thin air layer is maintained between the support (2,2a) and web (5).

Abstract: The invention relates to a method and an apparatus for producing layers of dry fibres and/or particles on a forming surface pervious to air. According to the invention, the material is distributed in air and passed to a forming unit where a turbulence with high intensity is effected in that air is injected through separate nozzles.

Abstract: Fiber content measuring instruments having radiation detectors are used to indicate the average radius and/or the average length of particles in a flowing medium. In order to determine the average radius, a signal based on the alternating current voltage portion of the signal from a radiation detector having a high resolution is divided by a signal based on the direct current voltage portion and the signal from a radiation detector having the same or another resolution. In order to determine the average length a signal based on the alternating current voltage portion of the signal from the radiation detector having a low resolution is divided by a signal based on the alternating current voltage portion of the signal from the radiation detector having a high resolution.

Abstract: Methods of measuring the crill content of pulp suspensions are disclosed. The methods include passing a first light radiation, preferably ultraviolet light, having a wavelength comparable to the particle diameter of the crill, through the pulp suspension, passing a second light radiation having a wavelength longer than the first wavelength but shorter than the mean pulp diameter through the pulp suspension, collecting both light radiations after they have transilluminated the pulp suspension, and measuring absorbencies for both of these collected light radiations so that the crill content can be determined therefrom.

Abstract: A method of applying liquid in a finely divided form onto a moving surface and an apparatus for carrying out that method. A flow of air containing suspended liquid particles is passed substantially parallel to the moving surface and across its direction of movement within a container which extends across the width of the moving surface. The container has a slit or a series of openings facing the moving surface, through which slit or openings at least a part of the liquid particles entrained in the air flow are deflected and passed substantially normal to the surface to be deposited thereon.

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: Unbleached sulphae fibres are chemically separated from other fibres by the use of high molecular polyalkylene oxides, preferably polyethylene oxide. The polyalkylene oxides are added to aqueous suspensions of fibre mixtures and hereby flocculates unbleached sulphate fibres in a selective manner and the flocks can be separated by known methods such as sedimentation, flotation, filtration etc. Use of polyalkylene oxides for selective flocculation of unbleached sulphate fibres gives the possibility of upgrading for example recovered fibres, broke and secondary fibre raw materials.

Abstract: A centrifugal screening apparatus is provided with screen cleaning means including rotating nozzles which clean the screen of the apparatus by suction.

Abstract: Methods and apparatus for determining the particle size distribution with respect to selected fraction classes in the direction of flow of a medium are provided in accordance with the teachings of the present invention. A plurality of measuring configurations are employed to pass light through the medium to be measured and to detect the light transmitted therethrough. Each measuring configuration exhibits different resolution with respect to one another and particle size distribution for selected fraction classes is determined as a function of measuring signals derived by each of the plurality of measuring configurations from the transmitted light detected during a run of the medium and sensitivity coefficients of the measuring signals. The sensitivity coefficients employed are dependent upon the associated measuring configuration and fraction class. Thus rather than counting particles per se a measure of the concentration in each fraction class is obtained.

Abstract: A method of producing synthetic resins from waste products containing lignin derivatives and sugars, especially waste liquors from cellulose pulp manufacture, is disclosed. The synthetic resins thus produced are especially utilizable as binders in chipboard, plywood, mineral wool slabs and the like. The method comprises treating the waste product in a first step so as to convert a substantial portion of the sugars contained therein into furfural derivatives. In a second step said furfural derivatives are condensed with the lignin to form a synthetic resin.

Abstract: The invention relates to a method of drying with hot air where the drying is divided into at least two partial processes, in parallel or in series with each other, and the circulation flows of the two partial processes are conditioned to substantially different wet temperature levels, and the spent air in the partial process with higher wet temperature is heat exchanged with the circulation air in the partial process with lower wet temperature, in combination with that the spent air flows from the two partial processes thereafter are mixed with each other and caused to pass a heat exchanger common for the processes in order to preheat the supply air to the partial process with low wet temperature and after the passage through the heat exchanger to partially constitute supply air for the partial process with high wet temperature.