Combined alarm and back-flow prevention arrangement for fire suppression sprinkler system

摘要

An alarm valve and a backflow preventer are provided by a check valve and an alarm valve with a passageway provided between the check valve and the alarm valve preferably having a relief valve which selectively drains the passageway in response to the pressure in the main conduit upstream of the check valve. An alarm is sounded when the alarm valve is open. An impeller flow sensor may be provided in the backflow prevention device.