| 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 cond uit (34, 46) for conveying fluid from the dosing chamber towards the fluid o utlet, 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 tow ards the fluid outlet when moved in a first manner relative to the dosing ch amber, and b) filling the dosing chamber with fluid from a supply of fluid w hen moved in a second manner relative to the dosing chamber; the piston memb er has a second end (42) positioned outside the dosing chamber and forming a t 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 co mmunication between the fluid conduit and the fluid outlet; and the dispense r 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 exte nt sufficient to move the seal from its normal closed state to its open stat e thereby enabling fluid to be pumped through the fluid outlet. A one-way va lve (31) may be carried by the first end of the piston member for controllin g the flow of fluid into and out of the dosing chamber. The fluid conduit ma y comprise a section (34) which extends through the piston member, e.g. a lu men thereof. |
