A fluid system for an article of footwear or other products is disclosed. In one aspect of the invention, the fluid system includes a pump chamber and a pressure chamber. The pump chamber is formed to exhibit a four layer structure to imparts an expandable configuration. The four layers are bonded to...http://www.google.com.au/patents/US7409779?utm_source=gb-gplus-sharePatent US7409779 - Fluid system having multiple pump chambers
