Propose and Characteristics Study of a New Actuation Method for Micropumps, Using Membrane Buckling

In this paper, we present a novel idea on actuation system in micropumps. The prominent goal of this paper is to propose and prove a mechanical actuation system which works in high frequency and has good ability in producing flow and pressure in micro actuation system. As like as other common micropumps, the proposed scheme is consisted of two check valves and an actuation space. The actuation space includes a volume of liquid in a chamber and a cylindrical membrane as the actuator. The main aspect of this idea is employment of buckling as a consequence of incensement of its internal pressure caused by temperature rising in the membrane. Rise of temperature is done by passing a controllable current through the membrane and it looses its temperature to its outer space in the chamber. Frequency and amperage of the current are the elements identifying the temperatures membrane vacillates between them. Meanwhile, a nice idea is setting these values in such a way that minimum temperature of the membrane becomes equal to the temperature which membrane starts buckling at. Thermal, elastic and thermoelastic equations of the membrane and fluids dynamic equations is obtained and studied. Using these equations, the validity of the scheme is proved by showing its ability of getting and loosing temperature and also fatigue resistance of the membrane, in high frequencies. The analytical proof is done for a specific design. In the proposed design, Aluminum 1100 is adopted as membrane material and thickness and radius of the membrane are 1 μm and 100 μm, respectively. Maximum flow rate and frequency of the system according to highest temperature of the membrane are depicted in diagrams. According to this design, maximum flow rate in rational frequency and amperage of the current is 8.25 _μL/min. Maximum pressure in that design is 3.5Kpa.