FLUID DISPENSING APPARATUS AND METHOD

A fluid dispenser (10) for containing and dispensing metered amounts of fluid, the fluid dispenser comprising: a reservoir (15) configured to contain fluid; a chamber (85) positioned in fluid communication with the reservoir for containing a quantity of the fluid; a piston (135) having a first rotational position (P1) defined about an axis extending longitudinally along the length of the piston, a second rotational position (P2) defined about the axis, and a third rotational position defined about the axis, the piston rotatable between the first rotational position, the second rotational position, and the third rotational position, and rotation of the piston between the first rotational position and the second rotational position occurring at the same axial location along the piston, wherein the piston is movable a first distance (L1) along the axis in the first rotational position to draw a first predetermined amount of fluid into the chamber, wherein the piston is movable a second distance (L2) along the axis in the second rotational position to draw a second predetermined amount of fluid into the chamber, wherein the third rotational position is configured to inhibit movement of the piston along the axis, and wherein the second distance is different from the first distance.