Recordall® Turbo Series Meter (Reduced Pressure Backflow Preventer)Source: Badger Meter
Badger Meter’s Model 450 fire hydrant reduced pressure backflowpreventer meter is designed to protect the potable water system by preventing backflow through fire hydrants.
For use in measuring potable cold water from a fire hydrant or other non-permanent installation where flow is in one direction.
Water flows into the meter’s measuring element where flow readings are obtained by rotor revolutions transmitted by magnetic drive coupling through the meter’s cover plate to the sealed register. Magnetic drive is achieved by a right angle worm drive, coupling the rotor to the vertical transmission spindle. A ceramic magnet on the spindle rotates around the vertical axis. Through the magnetic coupling, rotor rotation is transmitted to a follower magnet which transmits rotation to the register gearing.
After being measured the water flows through the pretested double cam-check assembly. Both check valves open to allow full water flow. Any backflow or downstream pressure condition is prevented by the double check valves closing. Any pressure between these valves is vented to atmosphere through a third valve located between the main double check valves.