Injection molding apparatus with removable nozzle seal

In an injection molding apparatus having at least one heated nozzle (12) extending forwardly into an opening (148) in a cooled mold (18) extending to a cavity (92) with an insulative air space (62) extending between the at least one heated nozzle (12) and the surrounding cooled mold (18), the at least one heated nozzle (12) having a rear end (42), a front end (76), a front portion (94) adjacent the front end (76) with a generally cylindrical outer surface (96), a melt bore (54) extending forwardly therethrough from the rear end (42), and an embedded heater (52) in the nozzle, the improvement comprising;

• a thermally conductive mounting sleeve (98) mounted around the cylindrical outer surface (96) of the front portion (94) of the at least one heated nozzle (12), the mounting sleeve (98) having a threaded outer surface (104), and
• (b) a removable nozzle seal (132) having a front end (142), a central portion (134), a hollow retaining portion (118), extending rearwardly from the central portion (134), and a sealing and locating portion (136) extending forwardly from the central portion (134), the central portion (134) and the forwardly extending sealing and locating portion (136) having a melt bore (138) extending therethrough in alignment with the melt bore (54) in the heated nozzle (12) and leading to a gate (140) at the front end (142) of the nozzle seal (132), the retaining rear portion (118) having a threaded inner surface (120) removably screwed onto the threaded outer surface (104) of the mounting sleeve (98), and the forwardly extending sealing and locating portion (136) fitting into a cylindrical opening (148) in the mold (18) extending to the cavity (92) to locate the front end (76) of the at least one heated nozzle (12) and prevent leakage of melt into the insulative air space (62) between the at least one heated nozzle (12) and the
• surrounding cooled mold (18).