A device for feeding a fluid to a vessel to be filled, comprising: - a fluid inflow or inlet opening intended to be placed in fluid communication with a fluid source; - a distribution valve placed between said inlet opening and said vessel to be filled; - a fluid supply line between said distribution valve and said vessel to be filled; - at least one valve member intercepting said supply line and movable between at least one first position in which it allows the passage of fluid between said inlet opening and said vessel to be filled and a second position in which it obstructs such passage; - at least one compartment or cylinder (7a, 7b) operatively connected to said at least one valve member; - at least one branch line (8a, 8b) extending between said supply line and said at least one compartment or cylinder (7a, 7b), said at least one branch line (8a, 8b) being intended to feed fluid to said at least one compartment or cylinder (7a, 7b), so as to cause the movement of said valve member into said at least one first or into said second position; - at least one shut-off valve placed on said at least one branch line; - means for actuating said at least one shut-off valve intended to move said at least one shut-off valve into respective operative positions; characterized in that it comprises: - at least one safety line extending from said supply line (5, 5a); - valve means (13a, 13b, 13e) for opening-closing said at least one safety line; and - adjusting means (14, 22) for adjusting the position of said valve member, said adjusting means being in fluid communication with said at least one safety line and actuatable due to the fluid fed thereto. - a fluid inflow or inlet opening intended to be placed in fluid communication with a fluid source; - a distribution valve placed between said inlet opening and said vessel to be filled; - a fluid supply line between said distribution valve and said vessel to be filled; - at least one valve member intercepting said supply line and movable between at least one first position in which it allows the passage of fluid between said inlet opening and said vessel to be filled and a second position in which it obstructs such passage; - at least one compartment or cylinder (7a, 7b) operatively connected to said at least one valve member; - at least one branch line (8a, 8b) extending between said supply line and said at least one compartment or cylinder (7a, 7b), said at least one branch line (8a, 8b) being intended to feed fluid to said at least one compartment or cylinder (7a, 7b), so as to cause the movement of said valve member into said at least one first or into said second position; - at least one shut-off valve placed on said at least one branch line; - means for actuating said at least one shut-off valve intended to move said at least one shut-off valve into respective operative positions; - at least one safety line extending from said supply line (5, 5a); - valve means (13a, 13b, 13e) for opening-closing said at least one safety line; and - adjusting means (14, 22) for adjusting the position of said valve member, said adjusting means being in fluid communication with said at least one safety line and actuatable due to the fluid fed thereto.