A disposable plastic pump for dispensing liquids is disclosed which comprises two basic unitary, preferably all plastic, elements: a chamber forming body having an open outer end and an inner end in fluid communication with a liquid reservoir, and a piston formed to slidably fit into the chamber. The...http://www.google.com.hk/patents/US5975360?utm_source=gb-gplus-share專利 US5975360 - Capped piston pump
