Air-gas mixer units for premix burner installations

Abstract

Described here is an air-gas mixer arrangement for a premix burner installation of a boiler, in particular for a condensing boiler, which air-gas mixer arrangement comprises flow guiding means for bringing the air- The gas mixture is directed to the inlet section (2a) of a centrifugal fan (2) with an impeller (4) driven in rotation about a first axis (X), said guiding means comprising a tubular Venturi effect A duct structure (6) having successive converging and diverging sections (6a, 6b) extending axisymmetrically about a second axis (Y) with a section provided between the sections of the duct to which the gas flow is delivered In this section, to mix with the air flow supplied through the duct constriction (6a). The duct (6) communicates downstream of the diffuser portion (6b) with respect to the direction of flow with the inlet section (2a) of the fan whose impeller (4) is housed in a vortex header (5) comprising A housing (5a) for receiving the impeller (4) and a cover plate (5b) for closing the housing (5a), a through hole (7) is formed in the cover plate (5b) so that the Venturi effect conduit (6) It communicates with the inlet section (2a) of the fan. The axis of rotation (X) of the fan (2) does not coincide with the axis (Y) of the longitudinal extension of the Venturi effect duct (6), the offset between the first and second axes (X, Y) being chosen such that the mixer means has a valve unit (3) mounted thereon to supply gas flow into the venturi effect conduit (6) in such a configuration that the venturi effect conduit (6) and the valve unit ( The projection of the overall size of 3) in the direction of the rotation axis (X) is substantially and mainly located within the projection of the fan cover (5b) in the direction of the rotation axis (X).

Description

technical field [0001] The invention relates to an air-gas mixer arrangement for a premix burner installation having the features stated in the preamble of claim 1 , which is the main claim. Background technique [0002] The invention relates in particular to the field of gas burner installations for premix boilers, in which the air-gas mixture is premixed upstream of the combustion head of the burner. [0003] In applications of the type described above, the premixing of air and gas is achieved by means of venturi-effect tubular ducts, where gas is supplied to the constriction of the venturi duct via a valve unit in accordance with the pressure drop signal generated by the air flow. [0004] Premixing is usually also carried out upstream of a fan unit designed to supply a premixed air-gas flow to the burner in delivery mode. [0005] In the applications described above, it is evident that each operating configuration of the entire burner plant assembly requires that the ma...

AI Technical Summary

Problems solved by technology

This leads to the large number of configurations available using conventional components, often of relatively large overall dimensions, so that for each installation the positioning of the individual components relative to each other must be custom designed according to the space available, with the result that each specific boiler Provisioning of layouts generally becomes more expensive and time consuming

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