Sunds Defibrator Industries Ab

Valmet Fibertech Aktiebolag

Sunds Defibrator Ab

Kmw Aktiebolag

Sven-Ingvar Thorbjornsson

Kurt Schedin

Goran Lundgren

Lars-Otto Sislegard

Lars-Otto Sislegangrd

Method of manufacturing lignocellulosic board

Method of pre-pressing fibrous material during the manufacture of board

Method and apparatus for pre-pressing fibrous materials during the

A method and apparatus for forming a web having a predetermined grammage profile in its transverse direction is provided. The method includes the steps of introducing a flow of particulate material into the distribution chamber of a forming head through an oscillating nozzle and depositing the material on an air permeable belt to form a web while changes in the upper surface of the web are detected downstream of the distribution chamber, signals are generated in response to any change which are compared with predetermined set points, and an output control signal is generated as a result of the comparison. The pattern of movement of the nozzle is controlled in response to the output control signal to provide the predetermined grammage profile for the web. In addition, the speed of the web may be measured and used to control the frequency of the nozzle so that a web having uniform grammage in the longitudinal direction is also provided. An apparatus for accomplishing each of the steps of the method is additionally provided.

Method and apparatus for forming a web

A method and apparatus for forming a web having a predetermined grammage profile in its transverse direction is provided. The method includes the steps of introducing a composite flow of particulate material suspended in air into the distribution chamber of a forming head and depositing the material on the upper surface of an air permeable belt while applying suction to form a web and while the grammage profile is controlled by measuring the profile of the web downstream of the distribution chamber, comparing the measurement with predetermined set points, generating a control signal representative of any detected difference and controlling the amount of suction applied in predetermined suction sections in response to the control signal so as to provide a web having a predetermined grammage profile. An apparatus for accomplishing each of the steps of the method is also provided.

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Karlstad, Sweden

Sven-Ingvar Thorbjornsson