GB804543A - Improved flow control apparatus - Google Patents

Abstract

804,543. Flow-spreaders for paper-pulp etc.; air-felting machines. KIMBERLY-CLARK CORPORATION Aug. 12, 1955, No. 23345/55 Class 96. Apparatus for controlling the flow of fluids in paper-making machines comprises a flowspreader 33, Fig. 1, into which a stream of fluid, e.g. aqueous paper pulp, is fed through a conduit 31. The flow-spreader has two diverging walls in one or both of which are one or more slots 37 through which a controlled amount of fluid can pass to increase the average kinetic energy of one or both boundary layers of the spreading stream and thus prevent separation of the boundary layer or layers from the main stream and formation of vortices. A conduit 35 conveys the fluid from the flow-spreader to the paper-making machine. Fluid may be removed through the slots by a suction pump 39 acting through a conduit 45, manifolds 43 and valves 47. When the pressure of fluid in the flow-spreader is sufficiently high, fluid can be discharged through the slots without applying suction. Alternatively, fluid may be fed into the flow-spreader through the slots. The upstream edge of each slot may be rounded and the downstream edge may be dulled. The width of each slot may be one-quarter to four times the width of the adjacent boundary layer. Each slot may extend for at least three-quarters of the height of the wall in which it is located and outwardly from it for a distance at least twice the width of the slot. A plurality of flowcontrol members separated by equi-angular spaces may be disposed within the flow-spreader to give substantially uniform flow of fluid across the stream issuing from the flow-spreader. These members may be vanes as described in Specification 733,851 or rotatable circular rods. In an air-felting machine, Fig. 16, a bat 145 of natural or synthetic fibres is fed by a roller 149 to a picking roller 147 rotating in a chamber 151. Fibres 153 removed from the bat are directed on to an endless travelling forming wire 155 by air, which enters the chamber through openings 159 and 161. Air is blown into the machine through a duct 171 and passes, through conduits 173, flow-spreaders 177 and conduits 189, into the chamber 151. Each flow-spreader is rectangular in cross-section and increases uniformly in width until it achieves the width of the chamber. Each flow-spreader is provided with slots 179 connected, through valves 187 and conduits 181 to a main conduit 183 leading to a suction fan 185. Flow-control vanes may be provided in the flow-spreader. The fibres form a loose web 167 which is compressed and rendered selfsupporting by rubber-covered rollers 169. Air is drawn off into a suction-box 163.