Charging Style Relay Emergency Valve

A charging style relay emergency valve fills the system reservoirs direct from the supply line without the benefit of a pressure protection valve. When the supply line is pressurized air enters the "Emerg/Supply" port, through a one-way check valve (an integral part of the REV) and into the reservoir(s). Because the supply line is not protected a single failure in the system can lower the supply line pressure to critical levels. A 1992 change in US law (49CFR 571.121) dramatically reduced the applications in which a charging valve can be used.
Terminology Index