Patent ID: 7205511

Claim:
A combined heater and heat diffuser for fitting to an injection nozzle ( 10 ) for moulding plastics materials, wherein the nozzle comprises a tubular metal core ( 12 ) with a central, longitudinal injection duct ( 14 ) and an outer lateral surface which is essentially cylindrical ( 13 ), and wherein the heater and heat diffuser includes a heat diffuser element ( 30 ) made of metal and substantially tubular in shape with a central cavity defined by an essentially cylindrical internal surface ( 30 d ) congruent with the cylindrical surface ( 13 ) of the nozzle core and with a concave seat ( 32 ) in the form of a channel in a surface of the diffuser ( 30 ), and a resistor element ( 40 ) accommodated in the said channel-shaped seat ( 32 ); wherein the channel-shaped seat ( 32 ) is formed in the internal cylindrical surface ( 30 d ) and wherein the resistor element ( 40 ) is arranged substantially flush with the said internal surface in order to transmit heat directly to the nozzle core, and wherein the body of the heat diffuser ( 30 ) is cylindrical and bent into a substantially closed ring with a longitudinal discontinuity along a generatrix of the cylinder formed by two facing edges ( 30 e , 30 f ).