Experimental study of the behavior of a valveless impedance pump
When a fluid-filled flexible tube is connected to tubing of different impedance, a net flow in either direction can be induced by periodically pinching the flexible section asymmetrically from the ends. We have experimentally demonstrated a variety of conditions under which pumping occurs; including changes in actuator position, size and pinching frequency, transmural pressure, systemic resistance and materials. Data collected includes dynamic pressure and flow-rate measurements at the inlet and outlet of the pump and ultrasound imaging of the tube walls. The net flow rate is highly sensitive to pinching frequency. The pump does not require a closed loop and can sustain a pressure head. We have also shown that a flexible, yet inelastic material is a sufficient condition for impedance-driven flow. A micro-scaled version of the pump was simultaneously tested demonstrating the feasibility of a miniature design.
© 2005 Springer-Verlag. Received: 17 August 2004; Revised: 31 January 2005; Accepted: 31 January 2005; Published online: 11 March 2005. We would like to give thanks to the Fehrer Fellowship, Benjamin J. Rosen Fellowship, Moore and Hufstedler Fellowship and Grubstake Fund for providing support for this project. We would also like to thank Apex Microtechnology for their contribution of hardware components.