Abstract: A method and apparatus for recirculating flue gas in either a vertical or a horizontal pulse combustor which is dedicated to deliberate one-stage pulse combustion. At least one combustion chamber wall defines a mixing region and a combustion chamber which is adjacent the mixing region. A fuel inlet conduit or a fuel/air inlet conduit is used to supply fuel into the mixing region. An air inlet conduit or a fuel/air inlet conduit is used to supply air into the mixing region. Air valves are in communication with the fuel inlet conduit, the air inlet conduit and/or the fuel/air inlet conduit. An ignition source is positioned within with mixing region for igniting the air/fuel mixture and beginning the pulse combustion process. An exhaust system removes flue gas containing products of pulse combustion. A portion of the flue gas produced during pulse combustion is then recirculated to the mixing region.

Abstract: A method and apparatus for recirculating flue gas in either a vertical or a horizontal pulse combustor which is dedicated to deliberate one-stage pulse combustion. At least one combustion chamber wall defines a mixing region and a combustion chamber which is adjacent the mixing region. A fuel inlet conduit is used to supply fuel into the mixing region and an air inlet conduit is used to supply air into the mixing region and thereby form an air/fuel mixture within the mixing region. Air valves are in communication with the fuel inlet conduit and the air inlet conduit. An ignition source is positioned within with mixing region for igniting the air/fuel mixture and beginning the pulse combustion process. An exhaust system removes flue gas containing products of pulse combustion. A portion of the flue gas produced during pulse combustion is then recirculated into the mixing region, air inlet, and/or an air decoupler.

Abstract: This invention relates to a flapper check valve having a valve housing which has at least one outlet opening. A valve backer plate having a plurality of arcuate backer through holes is positioned generally parallel to a valve port plate having a plurality of arcuate port through holes. The valve port plate and valve backer plate are sealably secured with respect to the valve housing. In an open position of the flapper check valve, the backer through holes are in communication with the port through holes. At least one peripheral spacer/hermetic seal is positioned at a generally peripheral location relative to the valve port plate. Upon combustion within the combustion chamber, the flapper check valve prevents fluid/gas backflow in a direction from the valve backer plate to the valve port plate. At least one flat central spacer is positioned at a generally central location relative to the valve port plate and the valve backer plate.