Watertight manhole insert
CA 1237314 A · Owner: Frw Industries, Inc. · Inventors: Runnels, Franklin D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A watertight manhole insert is provided for preventing rainwater from entering a sanitary sewer system through manhole covers. The insert includes a shallow dish-shaped body and a mounting flange designed to rest upon the supporting flange of a manhole frame. A recess is formed in the bottom of the body portion and includes a valve for releasing pressure which builds up beneath said insert. The valve is shielded such that it will not be struck by a manhole cover sliding across said insert. Additionally the valve can be used as a handle to remove the insert from a manhole.
Read the whole patent
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
- Granted May 31, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 31, 2005.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
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.