The float ball type AIR RELEASE & VACUUM BREAKER, model WB17, was designed, manufactured & tested for allowing atmospheric air through the valve to rapidly displace draining liquid in the pipeline and prevent internal negative pressure damaging the arrangements potentially.
To prevent damage, vapor must be allowed into or out of the pipeline & at specified vacuum condition. The volume rate of venting depends upon the pipe size, the pumping rates and the temperature. Refer to AWWA standard C512 for the procedures to determine venting requirements.
The range of size is 1/2" ~ 12", Carbon Steel/Duplex/Bronze/C.R Lining materials are available.