Air ring having a circular array of a large multiplicity of substantially parallel cell-like passages in the air flow path leading to the outlet

摘要

An air ring of the type mounted concentrically with a moving tube of plastic at a point close to where the plastic emerges from an annular die to receive, guide and discharge air in a desired direction to expose cooling air to the surface of the tube, the air ring having a circular array of a multiplicity of substantially parallel, cell-like passages, each passage having orthogonal lateral dimensions (X and Y directions) transverse to the local direction of flow (Z direction) that are less than one-half of the flow length, and divide the flow path to the outlet into a multiplicity of individual cell-like flow paths, the aggregate flow area presented by the passages being at least 80% of the inlet surface of the array. The array of passages and cooperating surfaces of the air ring are adapted to deliver a general nonhomogeneous flow to the array, to momentarily divide the flow into discrete, parallel, oriented streams which remerge into a second general, radially directed flow toward the surface of the tube, the multiplicity of streams being effective to orient air flow and to remove major turbulences and vortices in both orthogonal directions with relatively little pressure drop occuring across the array.