CAP WITH VALVE SYSTEM PROVIDED WITH FLOW REDUCER

A fluid vent valve () for a fuel tank, comprising: a valve body () having an inlet opening connected or connectable to a tank, an outlet opening and a main chamber () interposed between said inlet opening and said outlet opening (); a piston () inserted or insertable in the main chamber () and movable therein so as to define a closed configuration and an open configuration; a pendulum () hinged to the valve body () and coupled to the piston () so as to promote a movement of the piston () between the two configurations; a flow reducer () operatively interposed between the outlet opening () and the piston ().