Patent GB-404530-A (GB)
Title: Improvements in vacuum boxes for the manufacture of paper and similar products
IPC: D21F1/50
Filed: 1933-05-20
Abstract: 404,530. Suction - boxes for papermaking and like machines. LAMCRT FILS, E. ET M., Vitry-le-Francois, Marne, France. May 20, 1933, No. 14653. Convention date, May 20, 1932. [Class 96.] A suction-box for paper-making and like machines comprises rollers arranged beneath the wire cloth and end stoppers filling the ends of the box, a vacuum being created in the spaces around the end stoppers between them and the rollers and cloth. The sides of the box are formed by two parallel copper covered rollers, beneath the wire cloth 1 and resting on a third rubber coated roller 5. The roller 5 is rotated and causes the rollers constituting the sides of the box to rotate. The end stoppers are shaped to fit the spaces between the rollers and the cloth, and each comprise a head 7 carried on a hollow rod 8 to which is secured a shell 9 leaving a space 10 between its edges 11 and those 12 of the head. Compressed air forced along the pipe 8 escapes at 10 thus creating sufficient suction to suck the air and water from the box and to counteract leakage of air into the box. Water is drawn on to a plate 14 on the upper part of the head 7 and ensures air tightness. The width of the joint between the end stoppers and the rollers may decrease from a maximum at the bottom. In a modification the end stopper comprises a plate through which passes a pipe connecting the inside of the box with a vacuum pump. Along the space between the periphery of the plate and the moving parts is provided a channel connected by conduits with the vacuum pipe. In a further modification an end stopper similar to that shown in Fig. 2 has a chamber provided adjacent the nozzle but on the side thereof remote from the box, and the air and water from the box flow through this chamber. An overflow pipe causes the water to accumulate in the box and only to be sucked away after reaching a certain level. In a further modification each end stopper is formed by two plates through both of which a suction pipe passes and through the outer of which a pipe passes to supply compressed air to the nozzle formed between the edges of the two plates. In this case the suction at the peripheries of the end stoppers serves merely to prevent leakage of air into the box, and this is facilitated by grooves provided on the periphery of the inner plate. The air extracted from the suction box is returned under pressure to the narrow aperture between the plates. If desired the lower roller 5 may be replaced by a fixed table, the joint between the table and the side rollers being made air tight by a suction caused by air expelled through a nozzle provided in the table at the base of the rollers. A sealing tongue slides on the surface of the table to close the space between the table and the end stoppers. The bottom of the suction box may also be constituted by an endless band passing over two rollers, and this band may form the bottom of a number of suction boxes, and if desired a single roller only may act as partition between adjacent boxes. The end stoppers are adjustable laterally to vary the width of the paper.