Patent GB-1149348-A (GB)
Title: Process and apparatus for the manufacture of fibrous-cement slabs, particularly of asbestos-cement slabs
IPC: B28B1/52
Filed: 1966-10-10
Abstract: 1,149,348. Moulding asbestos cement slabs. ISPRA S.p.A. 10 Oct., 1966 [14 Oct., 19651, No. 45115/66. Heading B5A. Fibrous cement slabs, e.g. asbestos cement, and which may be flat or of configured, e.g corrugated, section, are produced by deposition of a slurry, e.g. of 100 parts cement, 14 asbestos and 500 water, on to a suction die 38, of the desired configuration, which is vertically reciprocable, on power cylinders 37, into and out of a slurry tank 5 and is also laterally reciprocable on a carriage 29, by a power cylinder 30, whereby the configured slabs are deposited on to the lower half 4 of a drying mould which is reciprocable on rollers 4 into a press 1 wherein excess water is removed by compression and from whence the dried slabs are transferred e.g. by a suction device, for stacking in contact with each other within sealed containers to which, at the completion of the setting process, water is fed at 40‹ C. The thickness of the asbestos-cement layer deposited on the suction die 38 is regulated by a configured deformable scraper 22 which is mounted on a carriage 19 for traversing movement, on guides 17, 18, under the raised die 38 whereby excess material is collected in a carriage space 25 for subsequent deposition into a lower section 7 of the tank 5 as the carriage 19 moves down a sloping terminal section of the carriage guides 17, 18; upon the return of the empty die 38 to above the tank 5, the underside thereof is cleaned by a water spray 23 from the carriage 19 as this returns to its initial position. The slurry tank 5 is provided with a gate 8 which defines an outlet slot 9 therefrom and the lower tank section 7 is provided with a lower partition wall 10 for collecting lumps of fibre or cement and, coplanar therewith, an upper gate 11; fresh slurry is delivered via pipe 12 to lower section 7 and is circulated therefrom, by pump 14, to the deposition tank 5; upon completion of slurry deposition, the residual slurry is dumped through gate 8 and the feed to tank 5 is renewed and maintained during the deposition process.  The suction die (38), (Fig. 2, not shown) is provided on the interior thereof with suction distribution pipes and the moulding surface thereof comprises a configured foraminous metal sheet (45) to the exterior of which is fixed a gauze (46) lined on its outer face with a fabric (47). In a further embodiment (Fig. 7, not shown) a multi-ply slab is formed by the successive deposition on to the drying mould (4) of layers from each of a pair of dies (38, 38a) carried in fixed spaced apart relationship on the carriage (29) and reciprocated respectively between the drying mould (4) and a respective slurry tank (5, 5a) on either side of the mould station. In a further embodiment (Fig. 8, not shown) a similar pair of slurry tanks and associated pair of dies are sited at either end of a drying press (1) employing two drying moulds (4, 4a) whereby one mould (4a) is being pressed whilst another (4) is beneath either suction cup of a carriage (29) and, after pressing, the mould (4a) is shifted out of one side of the press (1) for removal of the moulded slab at stacking station (62, 62a) whilst the other mould (4) enters the press (1) at the other side. Multi-ply slabs may be formed with layers dyed a different colour. The machine is automatically sequenced utilizing microswitches.