Svenska Traforskningsinstitutet

Inge J Lundqvist

Hakan I Karlsson

Jan G Pettersson

Gerdt H Fladda

Thomas L Stman

Bengt Y Hardin

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.

Method of controlling cross profile of properties of paper web

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.

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Spanga, Sweden

Inge J Lundqvist