Patent GB-659062-A (GB)
Title: Improvements in and relating to the moulding of objects from paper pulp
IPC: D21J3/00
Filed: 1947-08-27
Abstract: 659,062. Moulding articles from paper pulp. MARGUERAT, G. Aug. 27, 1947, Nos. 23782 and 23783. Convention dates, May 4, 1942 and June 12, 1942. [Class 87 (ii)] Articles having an open end and a closed end and moulded from a pulp suspension by suction through a perforated mould 1 having a base and side walls are removed from the mould by a blast of compressed air directed predominantly on to the closed end by a tube 3 opening close to the base of the mould, a support such as a table or conveyer belt 6 being provided to limit the movement of the closed end away from the mould until the article is complete detachedly. The mould and support are then separated to clear the article from the mould. The mould may be dipped into the pulp bath or, Fig. 4 (not shown), may be inverted during the moulding and project upwards from the mould carrier 2 which forms the bottom of a receptacle in which a measured quantity of pulp is placed. Holes are provided in the tube 3 adjacent the carrier 2 for the escape of water. In modifications, a receiver is provided which limits movement of the article as a whole away from the mould. Fig. 6 shows a female receiver 8 and Fig. 14 a male receiver 161. In either case the article may be returned to adhere lightly to the mould by applying a slight suction, the receiver then being removed and the article deposited by compressed air, e.g. on the belt of a drying machine. The same tube may be used for compressed air and suction or two concentric tubes, e.g. 4<SP>1</SP> and 71, Fig. 14, provided. Fig. 8 shows a machine for carrying out the invention and comprising four moulds 3 at the ends of two arms 9 curving at right angles. The arms and moulds can reciprocate vertically and also rotate on a central shaft 10. While one mould is immersed in a pulp bath 12 and receiving pulp therefrom by suction through a pipe 4, a previously moulded article is being detached from the mould 90 degrees distant and being received on the belt 6 leading to the drier. After moulding the cross bars 9 are raised and rotated 90 degrees for a repeat operation. Suction is continued for two such movements on each moulded article to remove water therefrom. At 180 degrees from the moulding position the articles are detached in the manner described above and received into a receiver, from which they are returned by slight suction to the mould for removal to the final removal station above the belt 6. Alternatively the receivers may be in two halves which can be separated to release the article, or receivers may belfixed to the belt 6. In these arrangements the articles are not returned to the mould. The articles before being released from the moulds may be dipped into a waterproofing bath. Fig. 11 shows a further modification using separate tubes 71 and 41 for suction and compressed air in which a valve 10<SP>1</SP> with a small opening 11<SP>1</SP> is provided in the suction tube. The valve is closed at the start of a moulding operation, slight suction only being applied to the mould through the aperture 11<SP>1</SP>, When a slight pulp deposit has been formed the valve is opened and full suction applied. This procedure minimizes entanglement of the pulp fibres in the perforations of the mould. To remove the objects from the mould the valve 101 is closed and compressed air admitted, the persisting slight suction together with the compressed air first removing any water remaining in the space 12<SP>1</SP>. When a female receiver is used interruption of the supply of compressed air is sufficient to bring the article back on the mould in view of the constant suction through the aperture 11<SP>1</SP>. The Specification as open to inspection under Sect. 91 states that with the mould of Fig. 14 the male receiver may be dispensed with in the case of small articles. This subject-matter does not appear in the Specification as accepted.