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US 6,805,824 B2Granted
Process for manufacturing a porous drainage medium
OwnerLarry Yawinventor
Life of this patent
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Abstract
In a process for making a porous drainage medium composed of entangled strands of thermoplastic resin, subsequent to forming a tubular preform, the preform is formed with necked-down sections at intervals along the length thereof before proceeding to a cooling tank. As such, the drainage medium can be flexed in the cooling tank and can be discharged continuously and conveniently out of the cooling tank without being cut.
Claims3
A process for manufacturing a porous drainage medium, comprising the steps of:
- a) extruding a molten thermoplastic resin material to form a plurality of strands;
- b) blowing said strands in plasticised condition using a high-velocity fluid to entangle said strands while passing said strands through a forming device, so as to result in a preform consisting of entangled strands;
- c) pinching said preform to form necked-down sections at intervals along the length of said preform, thus providing a plurality of links interconnected by said necked-down sections;
- and
- d) cooling said preform having said necked-down sections.
2 more elements
Dependencies are inferred from the claim text.