Patent GB-1025649-A (GB)
Title: Improvements in or relating to pulp moulding
IPC: D21J5/00
Filed: 1963-01-22
Abstract: 1,025,649. Moulding pulp. BELOIT CORPORATION. Jan. 22, 1963 [Jan. 22, 1962], No. 2746/63. Heading B5A. In a method of forming a hollow shell on the forming surface of a porous mould, fluid stock containing particles in suspension is forced through the mould to deposit a shell on the forming surface, the shell is then impregnated with a binder and dried. The apparatus used comprises a plurality of stations at which the various actions are performed. At the forming station, Fig. 1, a controlled quantity of stock from a tank 31 is supplied at a predetermined constant pressure for a predetermined time to a conduit loop 18, 19, 29 by a pump 34, the loop also receiving water from a pipe 37. In the loop is a porous mould 10 located in a housing 11 which during moulding is connected to vacuum via a conduit 21 so that stock is forced through the porous mould to form a shell surface 25. At the end of the forming period the rotary agitator 27 is withdrawn from the mould with the discharge conduit 19. In a modification the stock from the tank is supplied to a second tank, the top of which is supplied with air at constant temperature and pressure and the bottom of which is connected via a conduit to the mould which is closed, during forming, by an air dome. From the forming station the container 11 and mould 10 move to a pressing station where an inflatable bladder is located in the mould to exert pressure on the surface 25 to flatten the fibrous material and squeeze moisture therefrom. At the succeeding station the mould and housing are located in communication with a tank containing a resinous impregnation liquid. When the inside of the shell has been filled with impregnant the housing 11 is connected to vacuum as at the forming station to cause the impregnant to penetrate the shell. The housing and mould are then fed to a drying station in which a perforated drying member is located within the shell in the mould and is supplied with warm air for a predetermined period of time. At the succeeding station the housing 11 is lowered to position the mould over a perforated mandrel which is connected to a suction line while the housing chamber 12 is pressurized so that the shell is transferred to the mandrel. The housing and mould are removed and the mandrel with the shell passes to an oven. In a modification, a cleaning station in which fluid is flushed through the mould precedes the forming station. The drying station may comprise an endless belt conveyer to which articles are fed and from which articles are delivered, the belt being located under a hood to which heating air is supplied. In a modification the forming, pressing and drying are as before and the shell and its housing are then moved on a rotatable turret, to a transfer station wherein the shell is transferred on to a mandrel, an impregnating station at which the external surface of the mould is impregnated and a pressing station and finally the article is passed under a drying hood. At the impregnating station, a hood carrying impregnating spray jet is located over a mandrel, the inside of which is connected to vacuum.