A rapid exhaust valve is often used in conjunction with emergency stop situations or when compressed air is needed to be released from the circuit as quickly as possible. They allow air to flow through one direction normally with a shuttle valve used to bypass the exhaust, however in the other direction air flow will be allowed to flow straight through the exhaust. Rapid exhaust valves often use a muffler on the exhausted air to both reduce noise and to spread the air as its released preventing a concentrated shot of air releasing which could be hazardous to anyone in close proximity.
