Sterile bottle closure

Claim 1

A closure for a container adapted to hold sterile fluids said container including a neck formed with inner and outer walls, said neck having a rim at its upper and open end, said closure comprising: a rigid plug adapted to fit down into the upper portion of the neck of the container, said plug having a body sized to fit within the inner wall of the container neck, venting means for communicating with the inside of the container and the ambient air and a central portion for extending above the plane of the container rim outward from said container neck, and an elastic, fluid impervious cap adapted to fit over the open end of the container neck and down on the rim with its peripheral extremity engaging the outer wall of the container neck below the rim, said cap applying to the central portion of the plug an inwardly directed force and sealingly covering the venting means, the cap being provided with ventilating means out of registry with the venting means and adapted to be fluidly connected to the venting means, whereby when the pressure within the container exceeds the ambient pressure, the elastic cap will flex upwardly and allow pressurized fluid in the container to pass through the venting means and out the ventilating means in the cap and whereby, upon reduction of pressure within the container, the cap engages the rigid plug and container neck to seal as aforedescribed.