Multiple melt stream distribution, for coextruders, has two melt streams to each distribution plate and riser channels which feed divided radial streams via vertical channels to the die

摘要

Melt distribution plates (1.1-1.5) lie below the film die and two melt streams are supplied at different levels to the center of each plate. Rising bores guide the melt into several radial bores for each melt stream on the surface of the distribution plate. The latter channels direct flow via Y-shaped channels to vertical bores. The channel arrangement for each melt forms a star shape and arrangements are circumferentially offset from each other. The number of bores originating from the center is always half the number of vertical bores rising to spiral distributors leading to the die. Channels on the surface of each distributor plate are straight and at the point of transition from one to two bores are arranged to give optimum flow. Melt supply bores(3,4) arrive at the center from different directions and the upper is diverted to rise while the lower is diverted to fall before rising again.