Exhaust air and water: The pressure or gravity of the conveying line causes the valve to open, quickly exhaust air and water, and shorten the heating time. Steam blocking: The steam entering the valve cavity causes the bimetallic element to bend to generate thermal tension, and close the valve ball against the pipeline pressure. The thermal pull varies with the corresponding saturated steam curve. Therefore, it can work effectively within its pressure range. Draining condensed water: The condensed water gradually reduces the thermal tension of the bimetal element, so that the discharge hole is gradually opened, and the condensed water is discharged unobstructed. It acts as a check valve: the valve ball can immediately close the discharge hole when the pipeline generates backflow, without additional devices.