GB444490A - A process and apparatus for the manufacture of sheets or slabs from vegetable fibre pulp - Google Patents

Abstract

444,490. Moulding pulp sheets &c. BASLER, H., 7, Am Zirkus, Berlin. Sept. 20, 1934, No. 27085. [Class 87 (ii)] In moulding sheets or slabs from pulp wherein the pulp is given a preliminary pressing and then subjected to a final pressing with the simultaneous application of pressure, vacuum and heat, the pulp is introduced into a pre-shaping mould having a closable perforated base 4, 5 while the base is closed, the base is rapidly opened, and pressure is simultaneously applied to remove the greater portion of the liquid. The pre-shaping press comprises a mould frame 3 and the base is formed by a fixed perforated plate 4 and a horizontally-movable perforated plate 5 which can be displaced into a groove 7 by a pinion 7a so as to place the perforations out of register and close the base. A loose perforated plate 10 is placed on the plate 4. The plates are supported by a carrier frame 9 mounted on a ram 8. In use, pulp is supplied from a container 2 by a rotatable feed pipe 2a and a cover 11 is lowered and fixed on the frame 3. The plate 5 is displaced to open the base, the interior of the frame 9 is connected to vacuum by a pipe 9<a> and the ram 8 is raised. The sudden opening of the base creates a vortex effect to cause some of the fibres to assume a sloping or vertical position After pressing, the cover is raised and a trolley carrier is wheeled over the mould. The carrier comprises a U-iron frame carrying displaceable knife-edged sheets adapted to engage under the moulded slab. The slab and plate 10 are ejected by the ram and are passed through the carrier, secured thereon and removed to a final pressing apparatus, Fig. 6. The final pressing plates 21, 26 are secured on a ram table 19 and a press cover 25 respectively. The plates 21, 26 are provided with grooves or slots 21a and with heating coils 22 and are covered by perforated plates 27. The grooves 21<a> are connected to a vacuum pipe 24 and the coils 22 to heating conduits 23. The table 19 is carried by a ram 18 and the plates are pressed together within a frame box 16 slidable on rods 17. The plate 21 is adjustable on the table 19 by screws 20. The perforations on the plates 22, 27 are greater in number per unit surface and the heating coils are closer towards the centre of the plates. This enables drying to be uniform across the slab Soft porous slabs, heat and sound insulating slabs or hard slabs are produced according as the pressure is increased. Before the final pressing the slab may be re-impregnated with 25 to 30 per cent of water and then pressed at temperatures above 160‹ C.