In the present paper, we propose a microvibrating flow pump (micro-VFP), which is a novel micropump. The micro-VFP is constructed using an actively vibrating valve that has a cantilever-like structure fixed on a wall of a microchannel and a slit orifice downstream. The slit orifice is designed to make the flow asymmetric around the vibrating valve and to effectively generate a net flow in one direction. At the same time, the valve works as an actuator to induce liquid flow in the microchannel. Since the valve is made of a flexible material including magnetic particles, it is manipulated by changing the magnetic field from outside the micro-VFP. This design allows external operation of the micro-VFP without any electrical or mechanical connections. In addition, the micro-VFP, which realizes pumping with a chamber free design, is advantageous for implementation in a small space. In order to demonstrate its basic pumping performance, a prototype micro-VFP was fabricated in a microchannel with a cross section of 240 lm 9 500 lm using microelectromechanical systems technologies. The vibration characteristics of the valve were investigated using a high-speed camera. The pump performance at various actuation frequencies in the range of 5 to 25 Hz was evaluated by measuring the hydrostatic head and the flow rate. The proposed micro-VFP design exhibited an increase in performance with the driving frequency and had a maximum shut-off pressure of 3.8 ± 0.4 Pa and a maximum flow rate of 0.38 ± 0.02 ll/min at 25 Hz. Furthermore, in order to clarify the detailed pumping process, the flow characteristics around the vibrating valve were investigated by analyzing the velocity field based on micron-resolution particle image velocimetry (micro-PIV). The validity of the hydrostatic measurement was confirmed by comparing the volume flow rate with that estimated from micro-PIV data. The present study revealed the basic performance of the developed micro-VFP.

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In this paper, we propose a novel micropump, so-called micro vibrating flow pump (micro-VFP). Micro-VFP consists of a microchannel and an actively vibrating valve which has a cantilever like structure fixed on a wall of a microchannel. This valve works as an actuator for liquid flow in the microchannel. Since the valve is made of a flexible material including magnetic particles, it can be deformed by externally applying the magnetic field. After removing the magnetic field, the valve returns back to its original position by its own elasticity. By periodically changing the magnetic field, the valve vibrates and gives kinetic energy to the liquid. Furthermore, we designed sleeves on the side walls of the microchannel in the downstream of the valve. By adding the sleeves, the valve vibrates asymmetrically to generate net flow in one direction. To investigate the basic performance of micro-VFP, a prototype one is fabricated using soft lithography processes. The flow dynamics around the actuating valve is investigated in detail using particle image velocimetry.