GB1084763A - Headbox - Google Patents

Abstract

1,084,763. Paper-making apparatus. BELOIT CORPORATION. Jan. 7, 1964 [Aug. 27, 1964], No. 722/65. Heading D2A. In a floor of a headbox upstream of the slice 81 there is an apron board 85 which has supporting means which apply a controllable force to the board, the force being variable to change the defection of the board. The board may be incapable by itself of supporting the stock, and its curvature is adjusted to correspond to the sag in the breast roll. The board may be supported by a series of rubber bladders arranged along the length of the headbox, the bladders having the same or different fluid pressures therein, or by a fluid pressure chamber 85. The board may be hinged to the rest of the headbox at 86, or at the base of wall 84 with the pressure chamber extending up to wall 84. Fluid seals for the side of board, and adjustable stop means 90 are provided. Instead of being hinged at its rear edge, the board may be supported at its sides at an adjustable height either on columns or by being suspended by turnbuckle means. Air, an hydraulic medium, or paper stock may be used as the pressure medium. The pressure and temperature in the headbox may be measured to control either a valve controlling the flow of fluid in the chamber, or valves controlling the bleeding of fluid therefrom, such that the deflection of the board remains constant. There may be visual indicating means along the length of the headbox showing the deflection of the board. The headbox may be of the pressurised type. Alternatively force couples may be applied to the ends of the board to bend the board, possibly in conjunction with fluid pressure means, or other means such as individual diaphragms, levers, jacks, cams or wedges may be used.