Patent ID: 8763865

Claim:
A metering device for dispensing a dose of a pressurized fluid from a pressurized container, said metering device comprising: a valve body mountable in a fluid-tight connection to a lid of a pressurized container and having upper and lower openings; a gasket captured between the lid and the upper opening of the valve body; a delivery tube penetrating through the gasket; a valve element supported by the delivery tube within the valve body, said valve element contacting the gasket to close the delivery tube and movable by the delivery tube away from the gasket to open the delivery tube; a cylindrical chamber having a cup-like form that is defined by an inner tube that houses at least a lower portion of the valve body, an upper roof extending radially outward from said inner tube, and an outer wall extending downward from said upper roof to a rim that defines a lower opening of the cylindrical chamber, wherein the outer wall is larger than the inner tube, such that said cylindrical chamber includes an annular volume between said inner tube and said outer wall, and a cylindrical volume below said inner tube, the lower opening of the valve body being in fluid communication with said cylindrical chamber via said inner tube; a piston reciprocable within the cylindrical volume between an upper position and a lower position, which upper and lower positions define the dose of pressurized fluid to be dispensed, wherein at its upper position the piston seals the lower opening of the valve body from the cylindrical chamber and at any of its positions the piston partitions the cylindrical volume from the lower opening of the cylindrical chamber; and a fluid passage from the container to the cylindrical chamber, such that, independent from the position of the piston within the cylindrical chamber, pressurized fluid can flow into the cylindrical chamber based on a pressure difference between the container and the cylindrical chamber.