US Patent 10895252 Fluid pumping device

A fluid pumping device includes a barrel body and a piston mechanism. The barrel body has a cavity. The piston mechanism includes a piston member, a first annular plug, and a second annular plug. The piston member movably extends into the cavity. The piston member has two annular grooves where the first and the second annular plugs are disposed respectively. Each of the first the second annular plugs has an annular base section and an annular protrusion section. The annular protrusion section has a first outer annular abutting face. The annular base section has an outer annular base face. The first outer annular abutting face abuts against the inner wall of the cavity.