Plastic melt non-return valve

shut-offfor the plastics industryneedle

Hot runner systems gaurantee that the material between machine nozzle and cavity remains plastic. With existing systems which are equipped with a shut-off system, only the Herzog valve element can gaurantee that the mass does not leak out when the machine nozzle is withdrawn. The injection procedure is introduced by the stroke of the plastifying screw. The plastic flows through the machine nozzle into the hot channel and on into the cavity. The needle shut-off in the hot runner system ensures that no mass flows uncontrolled into the cavity. When the machine nozzle is withdrawn, the existing material in the hot channel which is under pressure can cause some leakage. This leakage can be avoided with the implementation of the Herzog valve, which is constructed and works on the principle of a non-return valve. These valves can be built into every mold.