Float Type Auto Drains
Low Maintenance Drain Option
How our float drain's work. Water and contamination accumulates in the bottom of the bowl, and causes the lifting of the float. The air pressure in the bowl will then vent to atmosphere through the opening, blowing the water and debris from the bowl as it does. When the accumulated water is gone, there's nothing left to "float" the valve, and it drops back into the orifice, sealing off the exit from the bowl.
The air pressure in the bowl will keep that drain hole sealed until such time as the water overcomes the air pressure by lifting the float, and the cycle repeats.
These are a great option as they are maintenance free and provide an outlet to remove the water from your compressed air system.