GB1143514A - Moulds for the manufacture of asbestos-cement products - Google Patents

Abstract

1,143,514. Injection moulding asbestos cement. URALITA S.A. 2 June, 1967 [2 June, 1966], No. 25631/67. Heading B5A. [Also in Division E1] An asbestos cement article, e.g. a squaresection pipe, is formed in a mould cavity 24 containing a distensible, e.g. rubber, pressure applying member 14 and wherein the cavity is fed from a chamber 17 at one side by pressure flow in a laminar manner through an elongated slot 19, corresponding to the shape of the article, whereby excess asbestos cement material from the cavity 24 discharges through a similar elongated slot 18 at the other side of the mould, to a similar chamber 17. In the production of a square-section pipe, the distensible member 14 is supported on a core 13 and supplied with pressure air, through a hollow core spindle 15, after the mould has been filled, via a supply pipe 22 from an injector, and with excess material returned to an agitator via a similar discharge pipe 21. Mould walls 1 and 2 are hinged to open and close about end members 10, 11 wherein are defined the chambers 16, 17. The cavity defining portions of the mould walls are perforated at 4, for drainage of excess water, and lined with a filter 5 of perforated sheet, wire mesh or synthetic fibre woven fabric. The distensible member 14 seals at each end of the cavity against rubber rings 8, 9 and may be successively distended to compress successive charges of material against charges previously compressed against the cavity walls. Cylindrical and straight or curved tubes or tube forks or triple forks may similarly be moulded. In an alternative mould for production of a tip or ridge tile (Figs. 3 and 5, not shown) the mould cavity is defined between mould halves (28, 25), Fig. 3, not shown, which may be pivotally connected, or between mould halves (46, 43), Fig. 5, not shown, the lower whereof may be slidably raised within the upper to compress the material prior to a further compression by distensible members; the tile is formed with longitudinally extending corrugations and a channel at one end extending transversely thereto. The corrugations and channel are defined by respective upper mould members (30) which clamp the distensible pressure applying members (31). The inlet and outlet elongated slots to this construction of mould are respectively closed by a weakened zone (33) of one distensible member (31) abutting with the lower mould half and the other distensible member (31) contacting a rubber member (34) on the lower mould half. The moulding may be removed by suction grippers.