GB952158A - Method and apparatus for evening the flow of paper to a paper machine headbox - Google Patents

Abstract

952,158. Paper-making. WEST VIRGINIA PULP & PAPER CO. Dec. 14, 1962 [Dec. 14,1961], No. 47244/62. Heading D2A. To provide uniform flow across the width of a paper machine headbox 10 dilute paper stock is supplied through a tapered pipe 18 to a plurality of rows of identical parallel pipes 19 which discharge into a headbox inlet chamber 20 in which a perforated flow mixing roll 21 is mounted in spaced relation from the outlet ends of the pipes 19. The pipes are designed to provide relatively high velocity streams under fully turbulent flow conditions at relatively high pressure drop through the pipes. The high pressure drop serves to equalise the velocities in the pipes and to prevent pressure surges upstream of the pipes from adversely affecting the flow in the headbox. The turbulent flow conditions provide a deflocculating action on the paper stock. Relatively high velocity jets of paper stock emerge from the outlets of the pipes 19 and impinge upon the roll 21 being blended thereby into a single uniform stream of paper stock that flows into the headbox. The inlet chamber 20 is attached to the headbox in angled relationship with the upstream end wall 16 and with the bottom wall and is of uniform rectangular section of width equal to the width of the headbox. The pipes 19 are attached to the end wall 24 of the inlet chamber in a uniformly spaced pattern (Fig. 3 not shown). The bearings for the roll 21 are mounted so as to provide adjustment of the distance between the roll and the outlet ends of the pipes 19 (Fig. 4 not shown) this adjustment being desirable to accommodate varying paper stock flows.