Patent ID: 8689994

Claim:
A storage tank safety system, comprising: a storage tank configured to store a fluid having a first port used to fill the tank with the fluid and a second port used as an air vent; and a safety device connected at the second port configured to permit air to vent and configured to prevent the fluid from flowing through the second port, wherein said safety device comprises: a stop positioned centrally between a first open end and a second open end of the safety device and extending inward from an outer edge of said body and along a circumference of said body, said stop defining a hole located centrally therethrough; and a stem positionable between a first position within said hole to allow airflow in two directions through said hole and a second position to prevent fluid flow in a direction out of said tank through said hole, wherein a weight of the stem is determined to permit the air to flow through the safety device and prevent the fluid from flowing through the safety device.