Method of making filter board
CA 1091875 A · Owner: Basf Wyandotte Corporation · Inventors: Gahmig, Herbert M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract of the Disclosure Beads of expandable polystyrene are expanded to a density of 0.4 to 0.6 pounds per cubic foot using a, two-step process in which the beads are expanded to a density of about 1 to 2 pounds per cubic foot in a first step, and then to a density in the above-mentioned range. Thereafter after a suitable length of storage, like 4-30 hours, the beads are used to make filter boards by being, placed into a mold and treated with steam caused to, expand to the desired final dimensions and fused together. If cut, the pieces so molded are divided with the use of a saw, hot wire, or similar mechanical means. This makes it possible to produce filter boards with the use of an …
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 December 23, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 23, 1997.
- 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.