apparatus for forming plastic melts into strands or filaments wherein molten plastic material is delivered by a pump from a container through a feed line to a distributor means which has a first outlet for the molten plastic material to be processed and a second outlet to a return line leading back to the container , and a control valve is located in the return line to regulate the return of flow of the plastic material to the container , the return flow of the plastic material to the container , the return line and associated control functioning to avoid undesirable plugging of the apparatus or damage to the plastic materials during interruptions in operations , and the like .