Patent ID: 6991137

Claim:
A pump for administering doses of fluid, said pump comprising: a reservoir formed to accommodate at least one of the doses of fluid; a fluid-collecting chamber in fluid communication with said reservoir, said fluid-collecting chamber including a dose-control portion which encompasses a volume defined by two dimensions; a first piston disposed to urge fluid from said reservoir and at least into said dose-control portion so that fluid may collect in said dose-control portion, said first piston being continuously spaced from said entire dose-control portion; a second piston disposed to reversibly slide within at least said dose-control portion so as to selectively displace at least a portion of the fluid collected in said dose-control portion wherein, with the pump being in a quiescent state, said second piston is spaced from said dose-control portion; and, a nozzle, wherein said nozzle is located such that fluid displaced by said second piston from said dose-control portion is generally urged towards said nozzle.