| 摘要 |
What is described is an air-gas mixer device for premix burner equipment of boilers, particularly of condensing boilers, comprising flow guide means for guiding an air-gas mixture to the intake section (2a) of a centrifugal fan (2) with an impeller (4) driven in rotation about a first axis (X), the guide means including a tubular Venturi effect conduit structure (6) with contiguous converging and diverging portions (6a, 6b) developed in an axially symmetric manner about a second axis (Y), a section being provided between the portions of conduit into which section the gas flow is delivered for mixing with the air flow supplied through the converging portion (6a) of the conduit. The conduit (6) is in communication with the intake section (2a) of the fan, downstream of the diverging portion (6b) with respect to the direction of the flow, and the impeller (4) of the fan is housed in a scroll manifold (5) including a housing (5a) for receiving the impeller (4) and a cover plate (5b) to close the housing (5a), a through aperture (7) being formed in the cover plate (5b) to put the Venturi effect conduit (6) into communication with the intake section (2a) of the fan. The axis of rotation (X) of the fan (2) does not coincide with the axis (Y) of longitudinal development of the Venturi effect conduit (6), the offset between the first and second axes (X, Y) being chosen so as to allow the mixer device to have a valve unit (3) mounted on it for supplying the gas flow into the Venturi effect conduit (6) with a configuration in which the projection of the overall dimensions of the Venturi effect conduit (6) and of the valve unit (3), in the direction of the axis of rotation (X), lies substantially and predominantly within the projection of the cover plate (5b) of the fan in the direction of the axis of rotation (X). |
