US Patent 9517865 Airtight canister lid with flexible seal-breaking bulb

A canister comprises a vessel defining a volume and an opening having a rim and a lid. The lid comprises a flexible bulb and a conformal outer edge configured to create an airtight vacuum seal with the rim to close the opening. The flexible bulb is configured to release pressure from the vessel and break the airtight vacuum seal in response to compression of the bulb. The lid can be configured to be completely contained within the rim.