摘要 |
Apparatus for producing thermoplastic injection-molded parts reinforced with long fibers, includes a compounder having two meshing screws rotating in a same direction for continuously generating a stream of melt of thermoplastic material reinforced with long fibers. Melt is alternatingly conducted to at least two piston and cylinder units for injection into at least one cavity of an injection mold at a suitable pressure. Each of the piston and cylinder units includes a cylinder and a differential piston movably received in the cylinder and dividing the cylinder into a feed chamber and an injection chamber, wherein the piston has a relatively greater piston surface, adjacent the injection chamber, and a relatively smaller piston surface, adjacent the feed chamber. The differential piston has a passageway for interconnecting the greater piston surface and the smaller piston surface to permit a flow of melt from the feed chamber into the injection chamber, whereby a flow of melt from the injection chamber back to the feed chamber is inhibited by a non-return valve disposed in the passageway of the differential piston.
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