Plastic pipe with bell

摘要

A multi-layer bell is formed from the outer shell of a multi-layer pipe in a secondary process, thereby allowing the extrusion process to be conducted at normal speeds. The bell may include a strain limiting membrane fused or mechanically secured between the outer shell extrusion layer and the inner liner extrusion layer, increased hoop or circumferential stiffness. This invention allows the extrusion process to be in its simplest form, with no adjustments to the corrugator or extruder speeds.

主权项

1. A method of forming a bell on the end of a plastic pipe, the method comprising the steps of:
forming a heated segment of plastic pipe having an inner liner and outer layer attached to the inner liner, a portion of the outer layer having a bell shape adjacent an end of the pipe; allowing the heated segment of plastic pipe to cool to a temperature wherein the bell shaped outer layer portion holds its bell shape; and heating the cooled inner liner and forming the inner liner to the bell shaped outer layer portion such that the inner liner substantially covers an inner surface of the bell shaped outer layer portion, inner liner thereby reinforcing the bell shaped outer layer portion.