Fluid dispensing piston

摘要

A fluid dispensing piston for a cylindrical dispensing tube has a recessed transverse end wall formed with at least one aperture. The aperture is normally covered by a fluid seal removably retained on the exterior surface of the end wall. The piston is placed in a cylindrical dispensing tube with the exterior of the end wall pressing against the fluid in the tube and the piston is moved axially down the tube to dispense the fluid. Further fluid may then be added to the tube and a second piston moved axially down the tube to dispense that fluid, the conformable material covering the aperture in the end wall of the first piston being forced away from the end wall to uncover the apertures as the second piston is moved down the tube to create a pathway for the fluid through the first piston.