Fail-Dry Vents
These patented Fail-Dry vents allow valves with a failed seal to operate until convenient maintenance can be planned. They use a vented chamber to divide two sealed valve portions. The operational chamber commonly houses a spring in a pressure valve, a spring / air chamber in a cutoff valve and a core tube in a solenoid valve. The primary seal (the one in contact with the liquid media) will degrade before the secondary seal as it is under pressure. These Fail-Dry vents help in tracing the amount of liquid leaking out and into the chamber when the primary seal starts to fail. The operative chamber is kept separate by the secondary seal, keeping it dry.