Method and apparatus for joining helically wound pipes
CA 2227805 A1 · Owner: Doolan, Gordon Thomas · Inventors: Pelkinen, Roy Lauri Uolevi; Doolan, Gordon Thomas; Ross, Paul Turner
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of joining a pair of first and second pipes and a joint construction comprising a first and second pipe a, coil spring wire, and a sealant. The pipes are formed by helically winding a hollow tube on a mandrel and then welding together adjacent windings of the tube. The tube has a space between an inner wall and an outer wall. The method comprises of inserting an end of a coil spring wire into the open tube of the first pipe and threading it a predetermined distance through the space of the first pipe followed by, inserting the opposite end of the spring wire into the open tube of the second pipe. The second pipe is then rotated so that the spring wire is threaded through the space …
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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 January 23, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 23, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 23, 2020.
- 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.