Acoustic indicator of vacuum level in containers

摘要

This relates to the provision of a vacuum indicator in a container wherein a product is vacuum packaged. Most specifically, an end unit for a conventional container is provided with a vent opening through which air rushes into the container when opened. There is secured to the underside of the end unit a whistle device in communication with the opening so that the inwardly rushing air actuates the whistle device and causes the whistle device to emit a whistling sound in accordance with the vacuum present within the container and thereby gives an audible indication of the freshness of the product.