Sizing device for extruded plastic tubing
AssigneeMaillefer S.A.
InventorCharles E. Maillefer
Life of this patent
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Abstract
A vat under vacuum bears in its sidewall a sizing sleeve, the cylindrical downstream portion of which includes annular channels interconnected by distribution channels. Injection ducts leave the bottoms of the annular channels and open out in the inside surface of the sleeve. The interior of the sleeve communicates with the interior of the vat via rows of radial suction ducts. During operation, the injection ducts are supplied with water under pressure which forms a film between the outside of the tubing and the inside surface of the sleeve even when the tubing is pressed against that inside surface owing to the partial vacuum prevailing within the vat.
Claims9
A device for sizing tubing of plastic material produced by extrusion, said device comprising:
- a vat containing a liquid coolant,
- a sleeve having a cooling and sizing portion disposed in said vat within said coolant,
- a passage extending longitudinally through said portion of said sleeve,
- first conduit means within said portion of said sleeve for supplying further liquid coolant to said passage, and
- second conduit means within said portion of said sleeve for sucking said further liquid coolant from said passage,
- said passage being defined by a smooth inside surface of said portion of said sleeve having a constant tubular cross-sectional shape and matching the cross-sectional shape and area of said tubing,
- said first and second conduit means respectively comprising first and second individual radial ducts which open directly into said smooth inside surface, said first radial ducts having predetermined length and diameter, and said first and second radial ducts being alternatingly longitudinally distributed along said portion of said sleeve to maintain a continuous film of said further liquid coolant between said smooth inside surface and said tubing.
Dependencies are inferred from the claim text.