A procedure for measuring the relative quantities of pulp components in wood or paper pulp, wherein for the pulp components (a,b) present in the pulp, for each one separately, is measured the distribution, or probability density, function (b.sub.a, b.sub.b) of a given fibre-specific characteristic thereof, from the distribution functions are by calculation formed distribution functions (b.sub.a/b) corresponding to the pulp mixture, the distribution function (b.sub.x/y) of the corresponding characteristic of the pulp is measured, and by calculation are determined the correlations of the distribution function (b.sub.x/y) of the pulp under examination with the distribution functions (b.sub.a/b) found by calculation, for determining the proportions of the different pulp components.
The invention relates to a procedure for determining a quantity dependent on the rate of diffusion in the fibre wall for diffusion occurring through it, in which procedure a diffusible tracer is introduced into the fibres under measurement, the fibres are suspended in an aqueous phase and the tracer concentration is determined after a certain time has elapsed since the time of suspension of the fibres, and the quantity dependent on the rate of diffusion is calculated on the basis of the concentration and time. In addition, the invention relates to a procedure for determining the proportion of secondary fibre in a fibre suspension containing primary fibre and secondary fibre, in which procedure virtual diffusion coefficients are determined in the fibre wall for diffusion taking place through it in at least two fibre suspensions for which the proportions of primary and secondary fibre are known and in a fibre suspension under measurement, and that the proportion of secondary fibre in the suspension under measurement is estimated by assuming that the diffusion coefficient depends mainly linearly on the proportion of primary and secondary fibre in the fibre suspension.
The invention relates to a method and arrangement for measuring the quality of wood. The wood comprises not only a pure body but also components of bark and knots, having optical properties different from those of the pure body. Barked trees (308) are turned into wood powder (322). The wood powder (322) is illuminated with optical radiation and the radiation is received by means of a camera (330). The camera (330) transmits a signal consistent with the radiation reflected from or passed through the wood powder (322) to a computer (332) which, by means of the optical properties of the wood powder (322), determines the amount of bark, knots, and/or defective wood present in the wood.
The invention relates to a filler for use in paper manufacture, said filler containing pigment and noil produced from cellulose fibre and/or mechanical pulp fibre by refining. According to the invention, the pigment has been mixed with noil fibrils, to be used as filler in paper manufacture. The invention also relates to a method for producing a filler for use in paper manufacture, said filler containing pigment and noil produced from cellulose fibre and/or mechanical pulp fibre by refining. According to the invention, the pigment is mixed with noil fibrils, to be used as filler in paper manufacture.
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.
The invention relates to a filled used in paper manufacture and mainly consisting of calcium carbonate, and to a procedure for producing the filler. The filler consists of porous aggregates formed by precipitated calcium carbonate particles. In the procedure, calcium carbonate is precipitated.
