A miniature pump has at least one controllable expansion-and-contraction chamber, and associated pair of tiny ducts interconnecting a fluid source and destination. The ducts communicate with the chamber(s); an linking tunnel links the ducts. Valves interact with fluid pressures due to expansion and contraction,...http://www.google.co.uk/patents/US7195465?utm_source=gb-gplus-sharePatent US7195465 - Reciprocating microfluidic pump system for chemical or biological agents
