摘要 |
A multi-function valve unit for controlling the feed of a combustible gas to a burner apparatus comprises a gas feed passage (2) extending from an inlet aperture (3) to an outlet aperture (4) of the unit, a solenoid valve (5) positioned on the passage (2) with an on-off function, and a pressure regulating device (6) including a valve seat (7) in the passage associated with an obturator (8) controlled by a diaphragm (10) including at least one diaphragm (10) associated for operation with the obturator (8) in such a way that the facing sides (8a, 10a) of the obturator (8) and of the at least one diaphragm (10) respectively are subjected to the same pressure level, the other side of the at least one diaphragm (10) being subjected to a predetermined load. The unit additionally comprises, in association with the obturator (8) of the pressure regulating device (6), a means (14) for returning the obturator (8) to a position in which the corresponding valve seat (7) is shut off and an operating means (15) for moving the obturator (8) with respect to the valve seat (7), in opposition to the return means (14), to regulate the feed pressure by modulation, in such a way that the on-off and modulation functions are both integrated into the pressure regulator (6). The sides (8a, 10a) of the obturator (8) and of the diaphragm (10) respectively also have surface extensions which are substantially equivalent to each other, so that the resultant of the stresses generated in the regulating device (6) by the pressures acting on the facing sides of the obturator and the diaphragm is made ineffective overall, or even reduced to zero.
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