Compound meter assembly

摘要

A compound meter assembly is provided having primary and secondary passageways housing a high flow rate meter and a low flow rate meter, respectively. A flow responsive first valve is disposed within the secondary passageway and moves to a substantially closed position when the liquid flow is increasing through the secondary passageway and exceeds a first predetermined rate. Upon substantial closing of the first valve the liquid flow is diverted from the secondary passageway to the primary passageway. A pressure responsive second valve is disposed within the primary passageway and is held in a closed position with respect to the primary passageway while the pressure drop is below a first predetermined amount across the meter. The second valve is forced to an open position when a substantial pressure impulse is momentarily exerted on the second valve. The pressure impulse is created when the liquid flow is diverted from the secondary passageway by substantial closing of the first valve. The second valve remains open due to the liquid flow through the primary passageway until such time as the flow rate drops below a second predetermined amount. After the pressure impulse has dissipated, the first valve will open again after the second valve has moved to its opened position.