Plastic-canister screw closure

Claim 1

In a screw closure for a plastic canister, the plastic canister having a pouring nozzle that bears an external screw thread and one air venting through hole in a wall of the pouring nozzle, which opens into an end face of the pouring nozzle and leads to inside the canister, the screw closure comprising a screw closure shroud with an internal thread complementary to the external screw thread on the plastic canister and coaxial to a geometrical longitudinal axis of the screw closure, a screw closure bottom substantially perpendicular to the geometrical longitudinal axis, a coaxial annular wall having an outer wall region, emerging from the bottom and extending a distance shorter than the shroud, a coaxial sealing ring with an inner region held in defined contact by the outer wall region of the annular wall, and defining a sealing plane for the pouring nozzle, the improvement wherein (a) the annular wall resists radial forces from deforming the pouring nozzle, (b) on the far side of the sealing ring relative to the sealing plane, the screw closure bottom has an annular channel that is arranged coaxially, is open away from the screw closure bottom and extends widthwise between the annular wall and the shroud, (c) at least one through air hole is provided in the screw closure bottom and is positioned within the annular channel, (d) a liquid outflow hole is provided in the screw closure bottom within the annular wall, (e) downstream of the liquid outflow hole, a flexible pouring spout is connected in liquid-tight manner to the screw closure, (f) in a screwed-on position the sealing ring engages with an inner surface of the pouring nozzle, and (g) the annular channel is defined between an inner surface of the shroud and the outer wall region of the annular wall and communicates with the air venting through hole.