Reagent addition system and method

摘要

A piston coupling for a micro-liter range liquid dispensing system for connecting a piston to a piston drive shaft generally includes a U-shaped body portion having a U-shaped arm and an annular barrel-shaped bearing seated in the U-shaped body portion and retained by the U-shaped arm. The bearing includes an axial bore for receiving the piston, wherein the annular barrel-shaped bearing is designed for balancing the forces applied to the piston by the piston drive shaft symmetrically about the centerline of the piston.