Patent GB-670051-A (GB)
Title: Improvements in the production of liners for centrifugal pumps
IPC: B29C35/00
Filed: 1949-08-29
Abstract: 670,051. Moulding liners for centrifugal pumps. LOOI, G. E. Nov. 29, 1950 [Aug. 29, 1949], No. 22365/49. Class 87(ii) Apparatus for producing liners for centrifugal pumps comprises a collapsable core a upon which the liner is to be formed, means upon which the core is mounted, and a vulcanizing mould z<SP>1</SP>, z<SP>2</SP> within which the said means are supported so that the core is held in spaced relation to the inner surface of the mould, whereby pressure due to the weight of the core upon the liner during its vulcanization is avoided. In the embodiment described, the annular core is divided radially and tangentially into seven sections and each section comprises three parts, outer portions c, d which are hollow aluminium castings and an inner wedge portion e which is a solid aluminium casting. A neck portion is similar, comprising outer portions i, j, and an inner wedge portion k. The portions of each section are bolted together by bolts f, and the sections are then bolted together by bolts 8. The core is collapsed by unscrewing the bolts from inside the annulus and drawing the wedges inwards, their thick ends facing inwards to allow this. The rest of the sections, including those of, the neck portions can then be dismantled. The core is supported by being clamped between end-plates o, p mounted on a shaft s, the lower end-plate p resting on the shoulder of a head t on the shaft sand a nut w, with radiating arms w<SP>1</SP>, threaded on the shaft s, being tightened down on the upper end-plate o. End-plate p has a flange q which seats in a co-acting recess formed in the outer portions d of the core sections, whilst end-plate o has a shallow boss r fitting within the circular opening formed at the top of the core by the outer portions c of the core sections. The lower plate p has a boss u which seats in a recess in the vulcanizing mould and the upper plate o has a boss 14 which fits an opening 13 in the mould, in which the core is thus held so that it is spaced from the inner surface of the mould. The two halves z<SP>1</SP> and z<SP>2</SP> of the mould, upper and lower, are clamped together by long bolts 15 pivoted at 16 to the bottom half z<SP>2</SP>. Each half of the mould has a space 23 for the passage of steam. To form the liner, sheet rubber is applied around the core in layers, cemented by rubber gum and, including, optionally, intermediate layers of canvas. The end-plates o, p have shoulders x of depth corresponding to the thickness of liner required, that on the plate o being tapered to provide a conical seating for the door of the liner. A frame of wire or metal strip, to add rigidity, built up of concentric circles with radial spacers, may be covered with rubber and placed outside the liner after it has been built upon the core and before vulcanization. The core, with the unvulcanized liner y on it, is slung by means of the loop s' and lowered into the bottom half z<SP>2</SP> of the mould until the boss u seats in its recess. A flat base portion may be provided upon which the mould may stand in the vertical plane instead of lying flat.