| 摘要 |
The invention relates to a system of production of a joint of the bell type for corrugated pipes in plastic material, preferably in polyolefins, comprising in a first working phase an appropriate processing of an axial end of normal pipe; in a second phase the injection by means of plastic material, at said end, of the external joint part shaped with a sleeve, mainly of cylindrical shape on its inner surface, of appropriate diameter but in any case greater than the outside one of the coupled pipe; moreover, it being possible to weld said sleeve at the time of injection, on the circumference of the processed end of the pipe, as above, and being coaxial thereto; an annular seat, designed to contain the sealing gasket of the joint, being moreover formed, in the operation of injection, in an appropriate position of the inner surface of the sleeve, as above; said system then comprising in a third phase the injection of the same sealing gasket, made in a suitable elastic material and in an appropriate shape, directly in the aforesaid seat of the sleeve, and placed already in a work position.
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