Pressure diferential control valve for compressed air system

摘要

A compressed air system includes an air dryer which dries compressed air before the compressed air is communicated to a reservoir. The air dryer includes a desiccant which is purged by using air stored in the reservoir. A pressure reference purge control valve is installed between the air dryer and the reservoir and includes a housing which defines a pressure reference volume. A pressure which is a function of the highest pressure level communicated to the reservoir is trapped in the reference volume. The valve permits purging only until a pressure is reached which is a predetermined pressure drop below the reference pressure level, whereupon purging is terminated.