GB2361229A — Metering valve

USPTO Abstract

A valve assembly for a metered dose container comprises a metering chamber 10 having a wall which forms a common boundary with the pressurised storage reservoir 40. The limits of the metering chamber 10 are defined by an insert 52 which lies between the first and second seals 22, 24. This means that the seals themselves do not come into contact with product in the metering chamber, and so do not suffer from deteriorating chemical effects. A valve stem 20 may be moved between a first position in which the metering chamber 10 is filled with product from the storage reservoir 40, and a second position in which the metering chamber 10 is sealed from the storage reservoir 40 and the product from the metering chamber 10 is dispensed via the valve stem 20. In another embodiment the spring 62, which normally biases the valve stem to the first position, in which the metering chamber 10 is in communication with the storage reservoir 40, is arranged to act between the outside of the metering chamber 10 and the outside of the valve stem 20, so that it does not come into contact with the product. This avoids corrosion of the spring material due to contact with the product. In a third embodiment, the valve stem 20 is coated with a friction-reducing coating, at least at the regions where it contacts the first and second seals 22, 24.