US Patent 9815592 Leak-free airless container having piston device

An airless container includes: an elongated shaft having an open top and an open bottom and having a constant internal cross-section, and having attachment means for securing a fastening collar thereto; a fastening collar; a liquid outlet piece; a piston to sealably and moveably fit within the elongated shaft, the piston having external sides with a peripheral upper blade and a peripheral lower blade, each of said peripheral upper blade peripheral lower blade having a plurality of peripheral ridges running perpendicular to the elongated shaft elongation direction.