Abstract: Methods for forming particle mat from lignocellulose-containing particles in the production of sheet material are disclosed including providing a flow of lignocellulose-containing particles from a supply source at an elevated height, depositing the flow of lignocellulose-containing particles from that height by means of gravity onto a forming belt at a lower height, and retarding the flow of lignocellulose-containing particles as it passes from the upper height to the lower height. Apparatus for carrying out the method is also disclosed.

Abstract: A method for continuously forming a fiber mat for use in manufacturing fiberboard is disclosed including metering fibrous material, depositing the fibrous material onto a moving surface, forming a fiber mat from the fibrous material by applying adjustable rotary rolls to the surface of the fiber mat with the rolls being disposed along a predetermined direction and including a final adjustable rotary roll, in which a bulb of the fibrous material is formed prior to the final adjustable rotary roll which, in turn, defines the upper surface of the fiber mat, detecting the size of the bulb of fibrous material, and controlling the vertical position of the final adjustable rotary roll based on the size of the bulb of fibrous material.

Abstract: Continuous methods for manufacturing finished board are disclosed which include disintegrating lignocellulose material prior to drying, gluing, and forming into mats, and in which the pressing of the mat into a board includes a first step in which the mat is pressed in the presence of steam in a heating medium to produce a partially pressed board having a substantially uniform density, and a second compressing step in which the outer layers of the partially pressed board are increased in density as compared to the center of the board.

Abstract: Methods for the continuous manufacture of board from lignocellulose-containing material are disclosed including disintegrating the lignocellulose material into particles or fibers, drying, coating with glue, forming the glued board into a mat, heating the mat with steam, compressing the heated mat to a predetermined thickness approximately equal to the final desired thickness of the board, and pressing the compressed mat into the board.

Abstract: Methods for prepressing lignocellulose-containing fibrous material are disclosed including forming a lignocellulose-containing fibrous material into a web, initially compressing the web and permitting expansion of the web, recompressing the web in an entry section of a prepress to a density proximating that of the density of the initially pressed web, permitting the recompressed web to undergo controlled expansion in an expansion section of the prepress, injecting steam into the web within either the entry or expansion sections of the prepress, and transferring the expanded web into a finishing press.

Abstract: A method for pre-pressing webs of lignocellulose-containing fibrous material is disclosed including forming the predetermined density, further compressing the mat without the addition of heat to a density approximating that of the predetermined density, and feeding the compressed mat to the finishing press while permiting the controlled expansion of the mat. Apparatus for pre-pressing the web of lignocellulose-containing fibrous material prior to the finishing press is also disclosed.

Abstract: 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.

Abstract: 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.