Performance comparison of piezo actuated valveless micropump with central excitation and annular excitation for biomedical applications

In recent years, microfluidic devices, particularly micropumps, are extensively utilized in biomedical applications. The micropump used in biomedical applications needs to possess precise delivery of fluids at requires rate and pressure. The present work proposes a valveless mechanical micropump with a disposable chamber integrated with a novel concept of annular excitation of the diaphragm to fulfil the need for precise delivery of fluids in biomedical applications. The proposed design of the micropump involves a reusable configuration of the amplified piezoelectric actuator (APA) for micropump actuation and a disposable pump chamber. The pumping of the fluids occurs through the oscillation of the silicone rubber bossed diaphragm. The performance of a mechanical micropump depends on the oscillation amplitude of the diaphragm. Thus, the conventional approach of central excitation of the bossed diaphragm is replaced by a novel approach of annular excitation intended to enhance the deflection range, thus the volumetric performance of the micropump. An experimental comparative study is carried out to assess the deflection characteristics of central excitation and annular excitation of the bossed diaphragm. The maximum deflection measured with the annularly excited configuration of the bossed diaphragm is about 1953.4 +/- 8.00 mu m at 150 V, 43.5 Hz, which is superior to the maximum deflection of centrally excited configuration delivering 717.99 +/- 4.00 mu m at 150 V, 9.5 Hz. Further, the experimental studies aimed to fabricate and characterize the micropump with central and annular excitation approaches. The proposed micropump with central excitation delivered the maximum water flow rate of about 7.192 +/- 0.147 ml min(-1) and backpressure of 0.294 kPa at 150 V, 5 Hz. However, the enhancement of the deflection characteristics of the bossed diaphragm under annular excitation leads to performance enhancement of the micropump with the flow rate of 95.10 +/- 0.444 ml min(-1) and backpressure of 1.472 kPa at 150, 30 Hz