Patent EA-002864-B1 (EA)
Title: Apparatus for producing multiple channel duct assembly and method thereof
IPC: B29C48/34
Filed: 2000-05-13
Abstract: 1. An apparatus for producing a multiple channel duct assembly includes: (a) a cross-head die having an outer duct resin passage and a discharge port capable of extruding a melted mass for a outer duct of thermoplastic resin, said cross-head die also having an inner duct insertion passage capable of feeding a plurality of pre-molded inner ducts, centrally through said outer duct resin passage; and (b) a molding means for molding corrugated outer duct, which comprises a mold with corrugated tunnel, drive means for driving said mold, a stationary suction chamber which is connectable to a suction source being positioned to communicate with said corrugated tunnel, and a stationary cooling chamber which is connectable to a source of cooling fluid being positioned to communicate with said mold assemblies; (c) wherein said inner duct insertion passage has a cross sectional shape of a bundle outline, including a plurality of guide grooves and a plurality of guide ridges which are contoured by a outline connecting the outer peripheral surfaces of said inner ducts inserted in abutting contact with each other, in parallel. 2. The apparatus for producing a multiple channel duct assembly of Claim 1, further comprising a rake passage, which is connected to the exit end of said inner duct insertion passage and has the same cross sectional shape as said inner duct insertion passage except having a plurality of rakes protruded from their central portions of said guide grooves toward a central axis. 3. The apparatus for producing a multiple channel duct assembly of Claim 2, further comprising a heating means for preheating the rake passage which is installed on the outside of said rake passage. 4. The apparatus for producing a multiple channel duct assembly of Claim 1, wherein said mold is a pair of complementary mold assemblies with a corrugated tunnel each of which has an endless array of articulately interconnected mold blocks. 5. The apparatus for producing a multiple channel duct assembly of Claim 1, wherein said mold is a round tubular mold which is rotatably supported by a plurality of retainers and provided with an helically corrugated tunnel on its inside surface through its central axis. 6. The apparatus for producing a multiple channel duct assembly of Claim 1, wherein said corrugated tunnel has a substantially round cross sectional shape. 7. The apparatus for producing a multiple channel duct assembly of Claim 1, wherein said corrugated tunnel has a substantially ellipsoid cross sectional shape. 8. The apparatus for producing a multiple channel duct assembly of Claim 1, wherein said corrugated tunnel has a substantially triangular cross sectional shape with round corners. 9. The apparatus for producing a multiple channel duct assembly of Claim 1, wherein said has corrugated tunnel a substantially quadrangular cross sectional shape with round corners. 10. A method of producing a multiple channel duct assembly includes the steps of: (a) assembling a plurality of pre-molded inner ducts to form a tube bundle in abutting contact with each other, in parallel; (b) continuously feeding said bundle of elongate inner ducts through a inner duct insertion passage, while melted mass of polyethylene flowing from a outer duct resin passage is being discharged from a discharge port to extrude the outer duct around said bundle of inner ducts; (c) continuously feeding said pre-molded inner ducts and said melted outer duct together into a vacuum-type mold with a corrugated tunnel; (d) configuring, cooling and solidifying said melted outer duct to have a corrugated tubular section including a plurality of contiguous ridges and troughs extending over the entire length in said mold with a corrugated tunnel. 11. The method of producing a multiple channel duct assembly of Claim 10 further includes the step of preheating said pre-molded inner ducts by their peripheral outer surfaces during passage of said inner duct insertion passage. 12. The method of producing a multiple channel duct assembly of Claim 11 further includes the step of raking said pre-molded inner ducts by their peripheral outer surfaces during passage of said inner duct inserting passage.