Process and device for applying a layer of lubricant on the inner surface of a plastic duct.

摘要

This invention concerns a process and a device for applying a layer of lubricant on the inside surface of extruded plastic ducts. The layer is applied under constant pressure via an annular slit (1,1 min ) in the mandrel (9, 10) of the extrusion equipment. Thus the layer of lubricant has a uniform thickness and can be uniformly distributed on the entire circumference of said inner surface.