Compact cartridge hot runner nozzle having two heaters

摘要

The present invention provides an electrically heated nozzle (22) for injection molding which is insulated to prevent conduction of electricity and loss of thermal transmission to the casing, wherein a first heater (80) and a second heater (90) are in thermal contact with said nozzle. At least a part of the electrical insulation comprises a layer of dielectric insulator material (84) with an electrical resistance wire heater (80) wound spirally thereabout and another dielectric insulator layer (86) thereover. The first and second insulating layers (84, 86) may be provided by spraying or through telescoping, self-supporting sleeves.