Piezoelectric Microvalve and Micropump for Controlled Fluid Delivery

MEMS based micropropulsion devices are becoming highly demanding for the repositioning of micro/nano satellites. Microthruster is the solution for the re-orbiting of small satellites whereas the microvalve controls the propellant flow and micropump keeps the propellant pressure constant. The microvalve consists of a silicon membrane, two holes made in silicon wafer and a commercially available piezoelectric stack. The silicon membrane has a boss tip at the center of top side and is structured using conventional KOH bulk micromachining. The membrane is directly attached to the piezoelectric stack actuator which moves in an out-of-plane motion against the bottom structure. The microvalve developed here is a normally closed, low cost, capable of controlling the flow of gases as well as liquids, leak tight and can be used for high pressure application. The micropump developed and presented in this dissertation is silicon based valveless diffuser /nozzle elements to rectify the fluid flow. Piezoelectric actuation is used in this case for diaphragm vibration. This book presents the detail design and development procedures of those devices with satisfactory test results.