Patent ID: 8016142

Claim:
A vent valve assembly for connection to the bottom open end of a liquid dispensing container, which comprises: a bottom cap having a bottom wall with a central portion, a peripheral portion surrounding the central portion, and a side wall extending upwardly from the peripheral portion, the central portion including a raised inner wall and a rigid vent disc having at least one hole therethrough, the vent disc extending substantially horizontally across the inner wall and having a radially outer portion that merges with the inner wall, the side wall having an interior surface with structure for connecting the bottom cap to the bottom open end of the container, a sealing member positioned for sealing the bottom cap with the bottom end of the dispensing container when they are connected together, and a vent valve that is flexible, the vent valve having a raised top portion and an upstanding member that extends upward to and merges with the top portion, the top portion having a thin flexible radially inwardly extending flap that covers the at least one hole in the vent disc, so that the weight of the liquid in the container above the flap presses the flap down over and closes the at least one vent hole to prevent direct contact of the overlying liquid with and leakage through the hole when the liquid dispensing container is in an upright position, and negative pressure during feeding or dispensing will cause the flexible flap to flex away from the at least one hole and provide a pathway for vent air to flow into the container and alleviate the vacuum created in the container during feeding or dispensing when the container is in a tipped feeding or dispensing position.