US Patent 8113365 Fully vented nursing bottle with single piece vent tube

A nursing bottle formed of a small volume container, incorporating a venting tube that extends to dissipate pressure at all times. The nursing bottle may have a cylindrical shape or other configuration that prevents formula placed therein from blocking the venting tube when held at any angle. The venting tube extends distally from the insert portion, operatively associated with a collar that holds the vent structures and the nipple to the neck of the container. The vent opens at the volumetric center of the reservoir above the venting tube. Alternatively, the venting tube has a conical shape of decreasing diameter distally toward the center of the bottom to dissipate the pressure that may cause leakage from the bottle.