Abstract: The invention concerns a headbox for a paper/board machine by whose means the basis weight of the web can be regulated. The headbox comprises a stock inlet header (Jl), which becomes narrower towards its end. Tubes (11a1, 11a2 . . . ) in a tube bank (11) open in the stock inlet header (J1) across the machine width, which tubes are connected with thickening elements (12a1, 12a2 . . . ) across the machine width, in which connection a flow (L1) is removed from the thickening element into the duct (D1) and said flow (L1) to be removed is regulated by means of a valve (V1, V2 . . . ). From the thickening element (12a1, 12a2 . . . ) a tube (14a1, 14a2 . . . ) for a flow (L2) of higher consistency is provided, which flow is passed further in the headbox.

Abstract: A means for controlling wires in a twin-wire section in a paper or cardboard machine where the wires run over the other for dewatering stock that is present between the wires, where a dewatering box is provided on one side of the wires and where a number of strips disposed side by side are provided on the other side of the wires, said strips running across the transport direction of the wires and over the total width of the wires, and where the strips have been arranged to be pressed against the wire lying closest to the strips, with the aid of pressure elements, where said pressure elements are disposed to act between the strips and a supporting table or equivalent, said supporting table being fixedly mounting relative to said dewatering box.

Abstract: A single- or a multi-layer headbox of a paper or a board machine intended for consistencies of 0.7-2.2% and provided with a flow ratio adjustment device. The adjustment device operates by removing a part of the stock flow from the slice chamber out of the headbox in a manner that does not change the speed or turbulence of the flow going to the slice at any point of the headbox.

Abstract: The invention relates to a headbox of a paper or board making machine, particularly a hydraulic headbox, which has an inlet header section (1) with a manifold tube section (2) and an equalizing chamber (3) in the stock suspension flow route, a turbulence generator section (4) following the equalizing chamber (3), after which a tapered slice section (8) is located, through which the stock suspension is discharged onto the wire. The headbox also has an attenuation chamber (6) for pressure variations, which defines one or several air spaces (7) under the flow channel of the stock suspension, the spaces being connected with the flow channel by way of a connecting channel (5). The air space or spaces (7) are preferably confined by subjacent frame structures including a bottom wall (16) and vertical walls (18) and walls (19) defining the flow channel from below.

Abstract: The outer walls of the beams of a papermachine headbox are heated by means of heat transferred from the stock to a temperature equal to that of the inner walls in contact with the stock. This is preferably carried out so that the liquid which is circulated in a closed liquid circulation through liquid spaces adjoining the outer walls, is caused to be in indirect heat transfer contact with the stock.