Non-return valve for a plastication screw

摘要

In the case of a non-return valve for the plastication screw of a plastics injection moulding machine, there is the problem that the spacers provided for maintaining a predetermined clearance between a locking ring (9) guided in the barrel (1) and the screw head (3) are subject to wear and therefore have to be frequently exchanged. To be able to avoid the exchange of the spacers, in particular balls (14), as far as possible, the spacers consist of ceramic, preferably surface-polished material, which is largely wear-resistant. <IMAGE>