Drying apparatus/method
CA 2084649 A1 · Owner: North, Roger Dorrien · Inventors: North, Roger Dorrien
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Apparatus for drying a wet material such as sewage sludge comprises a drum (11) mounted for revolution about a horizontal axis and containing interconnected inner (22) and outer (21) concentric spirals containing a continuously-recirculatable charge of particulate heat exchange/pulverising medium in each coil of the spirals. Sludge is introduced at one end and mixed with the heated charge; the charge and sludge traverse the length of the drum together through the outer spiral while drying takes place; the dried material is removed at the other end and the charge transferred to the inner spiral for transmission to the first end while re-heating tales place by ducted heated air. (Figure 1)
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 June 5, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended June 5, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 5, 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.