Patent ID: 8070011

Claim:
A cover to be attached to a container having a mouth defined at an open end thereof, the cover comprising: a body having a plane surface defined at an upper end thereof and which is connected to a flap defined at a lower end of the body for sealingly engaging the mouth of the container; a continuously semi-spherical shaped expansion chamber disposed between and directly connecting the plane surface to the flap, wherein an upper edge of the expansion chamber abuts an outer edge of the plane surface and a lower edge of the expansion chamber abuts the flap; an inner trunk-conic wall abutting the plane surface and extending away from the plane surface and toward the mouth of the container, the inner trunk-conic wall terminating at a bottom wall, wherein the bottom wall extends transverse relative to a longitudinal axis of the cover and is located closer to the flap than the plane surface defined at the upper end of the body; and an exhaust hole defined in the bottom wall, wherein an area of the exhaust hole is less than an area of the bottom wall to exhaust gases therefrom at a relatively low speed to provide an insufficient drag force that would lift drops of a beverage within the container toward the exhaust hole.