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Expired Canadian patentCanada

Drying sand to prevent freezing without the use of salt

CA 2249883 C · Owner: Hadiken, Lawrence · Inventors: Hadiken, Lawrence

CIPO record

Overview

Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A method for supplying dry sand for spreading on road surfaces in freezing temperatures in a condition in which the sand remains fluid in freezing temperatures without the addition of salt includes the steps of drying the sand by providing a naturally occurring bed of the sand having an upper surface of the bed exposed to sunlight; planting on the upper surface a covering crop of a type such as alfalfa having deep roots which extend through the whole bed up to thirty feet deep in search of a water table below the bed and growing the crop for a period of time sufficient to allow the roots to penetrate the bed and to extract moisture from the bed to dry the sand in the bed. The dry sand 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 October 9, 1998 and granted February 13, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 9, 2018.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 9, 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.
FiledOctober 9, 1998
GrantedFebruary 13, 2001
Term endedOctober 9, 2018
Patent numberCA 2249883 C
Classification (IPC)F26B1/00 +2 more

Timeline

Timeline From CIPO dates

1999200120032005200720092011201320152017Application filedOct 9, 1998Patent grantedFeb 13, 2001Term endedOct 9, 2018

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.