| 摘要 |
Water pressure-controlled valve for heating systems with warm sanitary water production comprising a valve body (1, 2) with inflow (3a) and outflow (3b) channels, mutually connected through a chamber (8) in which a cutoff membrane (7) for the passage between said input and output channels is movable in opposition to preloaded spring means (6), a stem (11) associated with the membrane to actuate microswitches (16, 16a) for switching electric circuits, and a separate duct 9 connected to the outflow channel (3b) and to said chamber (8). The outflow channel (3b) defines a Venturi tube and has means (19, 20) which are adapted to gradually vary the switch on flow-rates of the microswitches and are interposed between the chamber (8) and the Venturi tube (3b) so as to create differential pressures on the cutoff membrane (7) which are proportional to flow-rate values comprised between a preset minimum switch-on flow-rate for the microswitches and the maximum allowed flow-rate. |
