摘要：

An improved cap, and apparatus and a method for making such cap, including tooling for the first station are provided. The improved cap has a central button feature in its top panel that can move slightly upward or downward with respect to the remainder of the cap. When a container is filled, liquid Nitrogen is added just before the cap is applied. The liquid Nitrogen turns into gas and creates pressure in the container, causing the button to rise. When a consumer opens the cap, the gas is released and the button returns to its normal (down) position, or if pressure is accidentally lost the button returns to its normal (down) position. Thus indicating loss of pressurization and possible resulting spoilage, or will indicate that the container has been open, and may contain only partial product.

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