FLUID DISPENSER.

摘要

A fluid dispenser (10) comprises a dosing chamber (20), a piston member (14), a fluid outlet (52) through which fluid will be dispensed, a fluid conduit (34, 46) for conveying fluid from the dosing chamber towards the fluid outlet, and a seal (50, 54) for sealing the fluid outlet; wherein: the piston member has a first end (22) that acts as a piston within the dosing chamber for: a) pumping fluid from the dosing chamber through the fluid conduit towards the fluid outlet when moved in a first manner relative to the dosing chamber, and b) filling the dosing chamber with fluid from a supply of fluid when moved in a second manner relative to the dosing chamber; the piston member has a second end (42) positioned outside the dosing chamber and forming at least a part of the seal; the seal is movable from a normal closed state, in which the seal prevents fluid communication between the fluid conduit and the fluid outlet, to an open state, in which the seal provides for fluid communication between the fluid conduit and the fluid outlet; and the dispenser is adapted such that movement of the first end of the piston member in the first manner causes fluid in the fluid conduit to be pressurised to an extent sufficient to move the seal from its normal closed state to its open state thereby enabling fluid to be pumped through the fluid outlet. A one-way valve (31) may be carried by the first end of the piston member for controlling the flow of fluid into and out of the dosing chamber. The fluid conduit may comprise a section (34) which extends through the piston member, e.g. a lumen thereof.