US Patent 8235044 Inhaler valve

Rotary metering valve (200) with a valve inlet (260), a valve outlet (270) and a rotary valve member (280) for transferring a metered dose of aerosol formulation from the inlet to the outlet, wherein the rotary valve member is provided with an inlet port (290) and an outlet port (300), both in communication with a metering conduit (310) in the rotary valve member, the rotary valve member in sequence being rotatable between at least three positions:inlet position where the inlet port is in communication with the valve inlet and aerosol formulation enters the metering conduit,metering position where both ports are closed preserving a metered volume of aerosol formulation in the metering conduit,outlet position where the outlet port is in communication with the valve outlet and the metered dose of aerosol formulation is dispensed from the valve.