Gas boiler incorporating a noise reduction arrangement

摘要

A combustion apparatus such as a boiler comprises a standing wave arm (15, 15') for establishing a standing wave connected to a flue gas outlet (14) of a burner (10) of the device. A gas flue outlet system (17) is connected to the standing wave arm at the zero pressure point or mid-point (16) of the standing wave. The standing wave arm (15, 15') is configured to generate a standing wave in proportion to one half of the wavelength of a resonant frequency to be attenuated.