Dielectric elastomer stack actuators for integrated gas valves

Abstract

Dielectric elastomer actuators are suited for the fabrication of gas valves in micro systems. Based on the application of a micro burner unit a complete valve, consisting of the seat, the actuator and a spring structure to produce the closing force, is designed and evaluated. The required flow rate and the allowed pressure drop are derived and used to define the design of the valve seat, actuator and spring structure. This includes dimensions and shape of the valve seat with the outlet and channels for the gas flow. One valve in an array has the size of 15 x 15 mm 2 . The actuator thickness and the shape of its active region are determined to achieve a deflection of up to 50 μm by the use of a finite element simulation. To generate the closing force a spring structure made of nickel with intrinsic layer stresses is fabricated using an electroplating process. For the fabrication a Top-Down process was chosen. The dielectric elastomer actuator is directly fabricated onto a sacrificial substrate containing the spring structure and finally assembled with the valve seat by an plasma bonding process. The fabricated valves are characterized in respect of achieved deflection and flow rates.