| 20090235916 | NON-RETURN VALVE FOR AN EXHAUST DUCT OF FLUE GASSES - The invention regards a non-return valve for a exhaust duct of flue gases of a boiler, comprising a valve body in which a passage opening of flue gases is defined, to said valve body a obturator being associated which, in a determined operating condition, closes said opening, said obturator comprising a first swing element, hinged on said valve body at said passage opening of flue gases. Advantageously, said obturator comprises a second swing element, hinged on said valve body at said passage opening of flue gases, said first and second swing elements being hinged at or in proximity to a middle plane of said opening. | 09-24-2009 |
