Patent ID: 6843467

Claim:
A flap valve for controlling a gas flow, comprising: a valve tube ( 13 ) that conveys the gas flow a controllable tube cross section ( 135 ), a valve flap ( 14 ), disposed in the valve tube ( 13 ), the valve flap ( 14 ) being non-rotatably supported on an adjustable flap shaft ( 15 ) and supported to be pivoted between an open position that maximally unblocks the tube cross section ( 135 ) of the valve tube ( 13 ) and a closed position that blocks the tube cross section ( 135 ), and a tube end of the valve tube ( 13 ) is inclined so that a tube edge ( 131 ) of the tube end is essentially disposed in a plane extending at an acute tube inclination angle (β) in relation to the tube axis ( 132 ) of the valve tube ( 13 ), the valve flap ( 14 ) having an at least approximately elliptical outer contour and being disposed in the valve tube ( 13 ) in the region of the inclined tube end so that a tube normal ( 20 ) of the valve flap ( 14 ) encloses an acute flap inclination angle (α) with the tube axis ( 132 ).