Apparatus for applying a back pressure to a pump drive shaft seal
CA 2040575 C · Owner: Thompson, Peter · Inventors: Thompson, Peter
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An arrangement for applying a back pressure to a shaft seal of a mechanism such as a pump comprises a piston slidable in a cylinder one end of which communicates with the fluid being pumped and the other end of which contains oil communicating with a sealed chamber on that side of the seal remote from the fluid. Hitherto, the piston has created a preponderance of the back pressure over the pressure of the fluid by virtue of its weight. This preponderance has been very small and the rolling diaphragm seal, needed on the piston has been easily ruptured if the oil has been lost thereby, allowing possibly hazardous fluids to escape. A greater preponderance of the back pressure, allowing the use …
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
- Filed April 16, 1991 and granted November 26, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 16, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 16, 2013.
- 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.