Fan one way air valve

A method for controlling gas flow through a vent comprising the steps of:

• moving an inner leaf and an outer leaf in alignment with the inner leaf on the vent from a closed state which covers the vent and blocks gas flow through the vent in a first direction to an open state which opens the vent and allows gas flow through the vent in a second direction with gas flow moving in the second direction through the vent, the inner leaf and the outer leaf defining a plane when they are in the closed state;
• and
• stopping the gas flow in the second direction allowing the inner leaf and the outer leaf to each move to the closed state.

A valve for a vent comprising:

• an inner leaf having a closed state which covers the vent and blocks gas flow through the vent in a first direction, and an open state which opens the vent and allows gas flow through the vent in a second direction, the inner leaf includes inner lobes that align with the gas flow in the second direction when the inner leaf is in the open state;
• and
• an outer leaf having a closed state and an open state, the outer leaf opposing the inner leaf, the outer leaf includes outer lobes that align with the gas flow in the second direction when the outer leaf is in the open state, the inner lobes oppose associated outer lobes and move away from each other when the inner leaf and the outer leaf go from the closed state to the open state.

A method for controlling gas flow through a vent comprising the steps of:

• moving inner lobes of an inner leaf and outer lobes of an outer leaf opposing the inner leaf on the vent from a closed state which covers the vent and blocks gas flow through the vent in a first direction to an open state which opens the vent and allows gas flow through the vent in a second direction with gas flow moving in the second direction through the vent by moving the inner lobes and outer lobes associated with the inner lobes away from each other when the inner leaf and the outer leaf go from the closed state to the open state;
• and
• stopping the gas flow in the second direction allowing the inner leaf and the outer leaf to each move to the closed state.