Plasma arc torch ignition method
CA 2136202 C · Owner: Bailey, William V. · Inventors: Peterson, Jeffrey L.; Bailey, William V.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A high frequency, high voltage starting circuit (10) for a plasma arc cutting torch (16) is operated in pulses to restart the torch if an initial arc extinguishes before the arc transfers to the workpiece (24). The starting circuit (1) includes a D.C. power supply (28) with its negative output (28A) connected to an electrode (18) of the torch (16). A positive output (29b) is connected to a nozzle (22), and at a higher positive voltage to a workpiece (24). A surge injector circuit (38) of a resistor (R2) and surge capacitor (C4) is connected in parallel with the power supply to supply current to the arc as soon as breakdown occurs. The duration of the interval between restart pulses is …
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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 30, 1993 and granted May 20, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 30, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 30, 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
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.