| 摘要 |
<p>The four-way valve (10) enables a liquid to be distributed and controlled to the user appliance, and comprises a delivery branch (RM) for the liquid originating from the plant delivery column, and a return branch (RR) for conveying the liquid originating from the user appliance to the return column. The delivery branch (RM) comprises: an inlet port (17) and an outlet port (18); a by-pass chamber (19) open to the outside to enable the housing of a by-pass actuator (23) arranged to cooperate with a relative seat (24) which bounds a by-pass port to connect the delivery branch (RM) to the return branch (RR). This latter comprises: an inlet port (29) and an outlet port (30); an interception chamber (38) and a shutoff valving element (40) maintained abutting against a relative seat (39) by a spring (46), the shutoff valving element (40) being operable by an external actuator (47) to bring it into its open position; means (33, 35) for regulating the flow rate of the liquid in the return branch (RR).
The by-pass chamber (19) communicates directly with the inlet port (17) of the delivery branch (RM). The by-pass valving element (23) is prevented from abutting against the relative seat (24) to allow a predetermined minimum flow rate of liquid to pass. The shutoff valving element (40) also presents an additional valving element (45) intended to cooperate with the by-pass port (27) to prevent the passage of liquid through this port (27). Said means for regulating the flow rate through the return branch (RR) comprise: a pre-regulation chamber (58), which also acts as the interception chamber (38), communicating with the inlet port (29) of the return branch (RR) and with the relative outlet port (30) through a port (49) bounded by the shutoff seat (39); and means (35, 36) for positioning a pre-regulation ring nut (33) more or less close to the shutoff port (49).</p> |
