Blow head for the manufacture of tubular film from thermoplastic synthetic resin
CA 2085184 C · Owner: Windmoller & Holscher · Inventors: Achelpohl, Fritz
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A blowing head is provided for the manufacture of tubular film from thermoplastic synthetic resin. The blowing head includes a supply of molten synthetic resin through an annular extrusion orifice for producing a tube of resin film; ducts for the supply and exhaust of cooling air applied to the interior of the extruded tube; and an external cooling ring surrounding the extruded film provided with air which can be varied in temperature at different points around the periphery of the film. Greater control over the final thickness of the film is achieved through the provision of an external cooling ring in which sections around the periphery of the tubular film can be differentially heated or …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed December 11, 1992 and granted October 21, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 11, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 11, 2014.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.