Our Green Off-Patent Report provides selected highlights of green patents which have completed their 20-year terms and recently expired or will complete their terms and expire within the next week or so (assuming the patentee paid all requisite maintenance fees; U.S. patents require payment of fees 3 1/2, 7 1/2, and 11 1/2 years after issuance to stay in force).
Many of the green technologies in use today are off-patent, i.e., the patents covering the technologies have run their 20-year term and expired.
Knowing which technologies are off-patent is important because those technologies are in the public domain and can be exploited by anyone. It’s also interesting because it provides a window into what was cutting edge technology twenty years ago.
The green off-patent searching is performed by Cleantech PatentEdge™.
U.S. Patent No. 5,344,722, entitled “Phosphoric acid fuel cell” and directed to phosphoric acid electrolytes which improve fuel cell performance due to enhanced oxygen reduction kinetics. Filed June 25, 1992; issued September 6, 1994; will expire June 25, 1992.
U.S. Patent No. 5,208,115, entitled “Solid-electrolyte fuel cell system” and directed to a solid-electrolyte fuel cell system comprising a plurality of solid-electrolyte fuel cells, a plurality of oxygen gas passage devices, and a plurality of fuel gas passage devices. Filed June 17, 1992; issued May 4, 1993; expired June 17, 2012.
U.S. Patent No. 5,215,156, entitled “Electric vehicle with downhill electro-generating system” and directed to a vehicle having an electro-generating system in which a dynamoelectric generator is linked to a rotating axle of the road wheels and can be used to generate electricity and recharge a storage battery. Filed June 25, 1992; issued June 1, 1993; will expire June 25, 2012.
U.S. Patent No. 5,226,926, entitled “Plastic and oil waste processing method” and directed to a method of processing plastic and and spent vegetable oil and shaping the resultant mixture into a solid fuel product. Filed June 15, 1992; issued July 13, 1993; expired June 15, 2012.
U.S. Patent No. 5,232,467, entitled “Process for producing dry, CH4-enriched sulfur-free enriched synthesis or fuel gas” and directed to a process for producing syngas using cryogenic liquefied natural gas as a source of refrigeration and methane. Filed June 18, 1992; issued August 3, 1993; expired June 18, 2012.
U.S. Patent No. 5,232,487, entitled “Method of simultaneous disposal of solid and liquid wastes” and directed to methods of disposing of solid and liquid wastes by introducing the wastes into a gasification reactor having a cooled reactor inner wall and liquid slag discharge and gasifying the solid and liquid wastes at certain high temperatures. Filed June 19, 1992; issued August 3, 1993; expired June 19, 2012.
U.S. Patent No. 5,215,557, entitled “Dry scrubber with integral particulate collection device” and directed to a scrubber and particular collection device for sulfur dioxide and other contaminants and particulates from combustion flue gas. Filed June 24, 1992; issued June 1, 1993; will expire June 24, 2012.
U.S. Patent No. 5,225,175, entitled “Self-scrubbing removal of submicron particles from gaseous effluents” and directed to methods and systems for separating very fine particulates from gaseous effluents resulting from the burning of coal and other fossil fuels using SO2 to enlarge the particles. Filed June 22, 1992; issued July 6, 1993; expired June 22, 2012.
Eric Lane is a patent attorney at McKenna Long & Aldridge LLP in San Diego and the author of Green Patent Blog. Mr. Lane can be reached at email@example.com