| 摘要 |
of the disclosure This invention relates to a method and an apparatus for the production of ribbed pipes. The apparatus comprises a core which together with an extrusion sleeve forms a nozzle through which a plastic material is fed into a moulding space defined between a mandrel and chill moulds moveable with respect to the mandrel. Ribbed pipes produced by means of known apparatuses have, for various reasons, an uneven inner face, incomplete ribs or air closures and weak seams in the pipe walls or ribs. These disadvantages can be eliminated by such a dimensioning of the moulding space of the apparatus and the grooves of the chill moulds that the volume of a space defined between a plane extending adjacent to the end face of the extrusion sleeve, a surface of the mandrel, and a plane comprising the envelope surface of the kernel equals to be combined volume of the grooves positioned within the area of the mandrel at each particular moment. |
