
The hood (1) has a tubular duct (2) in axial correspondence with the hole provided in the base thereof and in whose inside the overflow tube (3) is guided. Between the duct (2) and the side wall of the hood (1) the pneumatic chamber (11) in which the float (4) moves is formed. The cock (19) filling the tank with water has in its radial connecting nozzle of the flexible tube (21) some outer axial direction grooves (22) that remain partially covered by said flexible tube (21), thus admitting air t...











