abstract:In scuba diving, a freeflow occurs when the diving regulator continues to supply air instead of cutting off the supply when the diver stops inhaling, or starts to flow when out of the diver's mouth due to a pressure difference over the diaphragm or a bump to the purge button, and continues to flow due to the "venturi effect" of reduced internal pressure caused by high flow velocity of the escaping air. If the freeflow is caused by a "venturi effect", simply closing the mouthpiece over will stop it immediately.