Plasma arc cutting process and apparatus using an oxygen-rich gas shield
CA 2108121 C · Owner: Sobr, John · Inventors: Luo, Lifeng; Sobr, John; Couch, Richard W. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A plasma arc torch (10) has a secondary gas flow (46) that is extremely large during piercing of a workpiece (36). The secondary flow (46) exits the torch immediately adjacent the transferred plasma arc (34) and is an extremely uniform, swirling flow. A swirl ring (60) is located in the secondary gas flow path (50) at the exit point. A prechamber (58) feeds gas to the swirl ring (60), which is in turn fed through a flow restricting orifice (56). For certain applications the secondary gas (46) is a mixture of an oxidizing gas and a non-oxidizing gas in a flow ratio of oxydizing to non-oxidizing in the range of 2:3 to 9:1. A network (44) of conduits and solenoid valves (SV1-SV17) operated …
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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 March 9, 1992 and granted November 11, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 9, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 9, 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.