Methods for the non-destructive evaluation of prestressed concrete structures
CA 2192313 C · Owner: Washington Suburban Sanitary Commission · Inventors: Woodcock, Michael W.; Holt, Richard J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method is provided for detecting degraded water main pipes by monitoring sonic and ultrasonic waves (110, 112, 114) and observing the characteristics of those waves. Water main pipes (30) have coiled tensioned steel wire (42) which holds the surrounding concrete (32) in compression. When corroded by water, the steel wire (73) ruptures, relieving compression in the concrete adjacent the rupture. The waves traversing the concrete of pipes have different characteristics for pipes in poor condition as compared to pipes in good condition. The sound waves in pipe in poor condition travel slower with shear waves having less amplitude and reflections occuring at later times. Frequency …
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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 June 1, 1995 and granted September 2, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 1, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 1, 2017.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.