A welding method in the manufacture of a spirally wound tube and a welding head for performing the method
CA 2134757 C · Owner: Oy Kwh Pipe Ab · Inventors: Blomqvist, Gunnar
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a welding method in the manufacture of a spirally wound tube having a thermoplastic profile (1) of a mainly rectangular cross-section. A hole profile (1) is wound in a screw line form manner on a welding drum (2) simultaneously as profile surfaces (1a, 1b) which are to be welded together are , heated with hot air to a desired temperature wher-, eafter a welding mass (S) is extruded onto the heated profile surfaces (1a 1b) in two streams along each edge of the profile surface (1a, 1b) and the welding mass coated hole profile portions are pressed together by means of a press roller (10). The invention is characterized in that the welding is performed with a …
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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 April 29, 1993 and granted September 4, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 29, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 29, 2015.
- 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
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.