Pressure equalizing and foam eliminating cap

Abstract

The present invention is a pressure equalizing and foam eliminating cap for a container. Pressure equalization and foam elimination is accomplished by designing the cap so that it can be rotated between a fully closed position, a gas venting position and a fully open position. This is accomplished in several ways. A first embodiment includes a spring biased, gas separation membrane between the cap and the mouth of the container. A second embodiment includes a finely, transversely perforated, annular plug on the underside of the cap and a seal between the plug and the interior of the neck. Alternatively, in this embodiment, the perforations may be larger and protected by a gas separation membrane. A third embodiment is similar to the second but incorporates two seals, one above and one below the perforations. In this embodiment also, the perforations may be larger and protected by a gas separation membrane. A fourth embodiment has two annular seals, the outer one being larger and having transverse perforations, depending from the underside of the cap. A fifth embodiment is similar to the second except that the plug is not perforated and the seal has fine, outer, axial grooves or scores. A sixth embodiment has two threaded caps which screw onto each other. The inner cap has micro perforations or a section of gas separating membrane in its top. A seventh embodiment is similar to the sixth embodiment except that the outer cap is a flip cap which may be hingedly attached to the inner cap.

Dependencies are inferred from the claim text.