# US 2014/0154635 A1 · Furnace efficiency tuning device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0154635 A1 - Document ID: US20140154635A1 - Status: Published application - Kind: A1 - Application number: 13/693,106 - Filed: 2012-12-04 - Published: 2014-06-05 - Earliest claimed: 2012-12-04 - Assignees: Utilization Technology Development, Nfp - Applicants: Utilization Technology Development, N - Inventors: Shawn Matthew Scott; Lawrence Brand - Web page: https://patentgrep.com/patent/US20140154635A1 ## CPC - F23L 13/02: pivoted about a single axis but having not other movement (formed as linked slats each pivoted about an axis F23L13/08) - Y02E 20/32: Direct CO2 mitigation - F23L: SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ({air-supply arrangements for fluent fuels F23C;} firebridges with means for feeding air or steam F23M3/04; baffles or shields with air supply passages F23M9/04); VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS {(dampers and throat restrictors for open fire-places F24; air inlet valves for open fire fronts F24)}; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A gaseous fuel fired furnace having a vapor condensing flue gas vent conduit, a flue gas flow restrictor disposed in the vapor condensing flue gas vent conduit having a flue gas upstream side and a flue gas downstream side, and a condensate bypass conduit extending around the flue gas flow restrictor having a condensate inlet in fluid communication with the flue gas downstream side of the flue gas flow restrictor and a condensate outlet in fluid communication with the flue gas upstream side of the flue gas flow restrictor. ## Claims ### Claim 1 In a condensing gaseous fuel fired furnace having a flue gas vent conduit, the improvement comprising: an adjustable flue gas flow restrictor dividing said flue gas vent conduit between a flue gas upstream side and a flue gas downstream side, said flue gas flow restrictor operable for modifying an opening size of a flue gas opening for passage of flue gas in said flue gas vent conduit from said flue gas upstream side to said flue gas downstream side; and a liquid condensate bypass conduit having a condensate inlet in fluid communication with said flue gas vent conduit at said flue gas downstream side and a condensate outlet in fluid communication with said flue gas vent conduit at said flue gas upstream side, and providing a condensate pathway separate from said flue gas vent conduit and said flue gas opening for transmission of condensate from said flue gas downstream side to said flue gas upstream side. ### Claim 2 (depends on 1) The furnace of claim 1, wherein said adjustable flue gas flow restrictor is a valve. ### Claim 3 (depends on 2) The furnace of claim 2, wherein said condensate bypass conduit is formed by a housing of said valve. ### Claim 4 (depends on 3) The furnace of claim 3, wherein said valve comprises a measurement port for sampling said flue gas on said flue gas upstream side. ### Claim 5 (depends on 1) The furnace of claim 1, wherein said adjustable flue gas flow restrictor is a vent damper disposed in said flue gas vent conduit. ### Claim 6 In a condensing gaseous fuel fired furnace having a flue gas vent conduit, the improvement comprising: an adjustable flue gas flow restrictor disposed in said flue gas vent conduit, said flue gas flow restrictor having a flue gas upstream side and a flue gas downstream side; and a liquid condensate bypass conduit separate from said flue gas vent conduit and extending around said flue gas flow restrictor and providing condensate transport from said flue gas vent conduit at said flue gas downstream side to said flue gas vent conduit at said flue gas upstream side. ### Claim 7 (depends on 6) The furnace of claim 6, wherein said flue gas flow restrictor is a vent damper disposed in said flue gas vent conduit. ### Claim 8 (depends on 6) The furnace of claim 6, wherein said flue gas flow restrictor is a valve. ### Claim 9 (depends on 8) The furnace of claim 8, wherein said condensate bypass conduit is formed by a housing of said valve. ### Claim 10 (depends on 6) The furnace of claim 6, wherein said flue gas flow restrictor comprises a measurement port for sampling flue gas in said flue gas vent conduit on said flue gas upstream side. ### Claim 11 A gaseous fuel fired furnace comprising: a vapor condensing flue gas vent conduit; a flue gas flow restrictor disposed in said vapor condensing flue gas vent conduit having a flue gas upstream side and a flue gas downstream side; and a condensate bypass conduit separate from said flue gas vent conduit and extending around said flue gas flow restrictor having a condensate inlet in fluid communication with said flue gas vent conduit at said flue gas downstream side and a condensate outlet in fluid communication with said flue gas vent conduit at said flue gas upstream side. ### Claim 12 (depends on 11) The furnace of claim 11, wherein said flue gas flow restrictor is adjustable based upon one or more operating conditions of the furnace. ### Claim 13 (depends on 12) The furnace of claim 12, wherein said flue gas flow restrictor is a vent damper disposed in said flue gas vent conduit. ### Claim 14 (depends on 12) The furnace of claim 12, wherein said flue gas flow restrictor is a valve. ### Claim 15 (depends on 14) The furnace of claim 14, wherein said condensate bypass conduit is formed by a housing of said valve. ### Claim 16 (depends on 11) The furnace of claim 11, wherein said flue gas flow restrictor comprises a measurement port for sampling flue gas in said flue gas vent conduit on said flue gas upstream side. ### Claim 17 (depends on 1) The furnace of claim 1, wherein said condensate pathway comprises a condensate trap.